View Full Version : Slowly obtaining a spare set of valves for my Croft preamp and TD Copper amp
As I treasure the unique sonic qualities of NOS valves, I've started to source a full replacement set of tubes for my power amp, which uses:
4 x GEC KT88s (late 50s vintage)
4 X Brimar CV1988s
2 x Mullard GZ34s
I will seek to obtain mint unused NOS examples where possible, so the project has been kicked off by winning this little chap on Ebay:
http://img852.imageshack.us/img852/6277/kgrhqqokoce0g2pwowlbnys.jpg (http://img852.imageshack.us/i/kgrhqqokoce0g2pwowlbnys.jpg/)
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=230589032039
Some bloody price mint NOS GZ34s go for now!! :eek: But, hey-ho, it's worth it if they'll last as long as my current ones have (approx 14 years - and they're still going strong!)
NOS valves in general don't just sound better, but last MUCH longer, too, so one has to factor in their high cost and rarity now against how many cheaper current production valves one would go through in the same time span. Therefore if it costs me £180-odd for 14 years service with GZ34s, then I reckon at around £6 per year, for the amount of use I give the amp, it's a bargain.
I'll continue to update this thread as and when I secure more of the valves I need. It goes without saying of course that if anyone sees any mint NOS examples of the above listed valves for sale to please let me know - chuz, dudes! :cool:
Marco.
P.S The GECs must be matched Quads.
chris@panteg
08-03-2011, 12:51
Hi Marco
I think is worth it as when i had my BP psu's ,which used GZ37's ,they came with modern chinese version's one of which lasted just 14 months and it went pop .
Hi Chris,
Other than Shuguang Treasures, Chinese valves are just shit. I wouldn't touch them with a bargepole.
I've just won two of the CV1988s on Ebay which I need for my amp:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&_trksid=p4340.l2557&rt=nc&nma=true&item=160555236513&si=CQ30cZ8JFdoDjR4ssS1SuELGwoQ%253D&viewitem=&sspagename=ADME%3AB%3AONA%3AGB%3A1157&autorefresh=true
http://img849.imageshack.us/img849/9858/kgrhqjiqe1nfm81wbbncrdo.jpg (http://img849.imageshack.us/i/kgrhqjiqe1nfm81wbbncrdo.jpg/)
These are nice because they're a matched pair and have been properly tested (totally NOS apart from that), and so I'm pretty happy with the price I paid (£159.23).
I know where another pair are too, so now I just need to win those! :cool:
Marco.
i see you've gone for the cheapies, try metal base GZ34's :eek:
Lol - yeah, and also Osram B65s (metal-based 6SN7s) are too stupidly priced even for me! :eyebrows:
Besides, I tried some (had a pair a couple of years back) and they're not massively better than the Brimars - certainly not worth the price difference.
It's amazing what (unused) NOS valves do for an already superb amp; they really bring it to life in quite a significant and musically satisfying way! :cool:
The new GZ34 has made quite an improvement (I just need another one now). I also fitted an (unused) NOS Mullard CV4004 in the Croft today, bought from Chelmer, and that was also quite a revelation :)
http://img848.imageshack.us/img848/6072/mullardcv40042.jpg (http://img848.imageshack.us/i/mullardcv40042.jpg/)
Marco.
selfaddict
13-03-2011, 10:05
I also fitted an (unused) NOS Mullard CV4004 in the Croft today, bought from Chelmer, and that was also quite a revelation :)
http://img848.imageshack.us/img848/6072/mullardcv40042.jpg (http://img848.imageshack.us/i/mullardcv40042.jpg/)
Marco.
Hi Marco.
Did you replace the Tesla EC83CC's with Mullard CV4004's? If you did please tell me more, I have been thinking this replacement option as well :).
chris@panteg
13-03-2011, 11:57
Lol - yeah, and also Osram B65s (metal-based 6SN7s) are too stupidly priced even for me! :eyebrows:
Besides, I tried some (had a pair a couple of years back) and they're not massively better than the Brimars - certainly not worth the price difference.
It's amazing what (unused) NOS valves do for an already superb amp; they really bring it to life in quite a significant and musically satisfying way! :cool:
The new GZ34 has made quite an improvement (I just need another one now). I also fitted an (unused) NOS Mullard CV4004 in the Croft today, bought from Chelmer, and that was also quite a revelation :)
http://img848.imageshack.us/img848/6072/mullardcv40042.jpg (http://img848.imageshack.us/i/mullardcv40042.jpg/)
Marco.
I still have some of these CV4004's and some ECC83/82's (Mullard)
Will have to dig out my box of valves and see what i have .
chris@panteg
13-03-2011, 12:01
Hi Chris,
Other than Shuguang Treasures, Chinese valves are just shit. I wouldn't touch them with a bargepole.
I've just won two of the CV1988s on Ebay which I need for my amp:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&_trksid=p4340.l2557&rt=nc&nma=true&item=160555236513&si=CQ30cZ8JFdoDjR4ssS1SuELGwoQ%253D&viewitem=&sspagename=ADME%3AB%3AONA%3AGB%3A1157&autorefresh=true
http://img849.imageshack.us/img849/9858/kgrhqjiqe1nfm81wbbncrdo.jpg (http://img849.imageshack.us/i/kgrhqjiqe1nfm81wbbncrdo.jpg/)
These are nice because they're a matched pair and have been properly tested (totally NOS apart from that), and so I'm pretty happy with the price I paid (£159.23).
I know where another pair are too, so now I just need to win those! :cool:
Marco.
Very nice , i shudder to think how much a full set of NOS 2A3's would cost for the 2nd audio's that i used to have and indeed my M8 John still uses , he's currently running some from Chelmer , but i think they are chinese and sound a bit harsh .
Hi Juha,
Did you replace the Tesla EC83CC's with Mullard CV4004's? If you did please tell me more, I have been thinking this replacement option as well.
Yes, that's what I've done - for the moment. I'm currently assessing which is better overall in my system, as both have their respective merits, sonically.
I'll post my thoughts later in the week once I've got a proper handle on what both valves are doing :)
Marco.
selfaddict
13-03-2011, 16:24
Hi Juha,
Yes, that's what I've done - for the moment. I'm currently assessing which is better overall in my system, as both have their respective merits, sonically.
I'll post my thoughts later in the week once I've got a proper handle on what both valves are doing :)
Marco.
Thats great, many thanks Marco :cool:
The Grand Wazoo
14-03-2011, 00:52
The ECC83 type preamp valve combination the works best for me is 5751's in the line stage & CV4004/M8137's for the phono stage
Hi Chris,
Sounds like a nice combo. My Croft only uses one ECC83 in the power supply - the output valves for the line and phono stage are 6SL7s :)
5751s I like, but they have less gain than ECC83s, and in the Croft I prefer the effect of the latter's extra gain.
Anyway, I've been comparing the CV4004 to the Tesla, and results have been interesting...
The difference between these valves isn't night and day, and definitely quite subtle, so more than ever in this instance, results will be very system dependent. Therefore, folks, please bear that in mind.
What I've found is that in comparison with the CV4004, the Tesla has a more pronounced top-end, although it's sweet sounding and not in any way aggressive, which although adding some clarity and sparkle that can initially be impressive, it is in my opinion, evidence of coloration.
The midrange of the Tesla also lacks a little warmth, and when combined with its more 'obvious' top end, can lend the presentation of music a slightly forward, cool, and 'emotionally dispassionate' characteristic. In contrast, the CV4004 to my ears has a warmer and more neutral balance, and also ultimately a more musically rewarding one, but is in no way 'phat' or dull sounding - quite the opposite, in fact!
Quite simply, it does something magical in the midrange (which IME is a common trait with Mullards, as I get a similar effect with the ECC35 used in the joint line/phono stage of the Croft) and so voices and instruments are 'fleshed out', and thus are rendered with greater clarity and intelligibility.
In summary, the CV4004 sucks you into the music and stimulates longer listening sessions in a way that the Tesla doesn't quite manage.
I'd say that the Tesla is the ideal ECC83-type to inject some sparkle and vitality into a perhaps a system that's a little lacklustre, but my system didn't need that. However, I'd never have known it had those traits, and that my preamp could be improved further, until I experienced the unique and desirable musical qualities of the superb Mullard CV4004.
Thoroughly recommended! :cool:
Marco.
I'd say that the Tesla is the ideal ECC83-type to inject some sparkle and vitality into a perhaps a system that's a little lacklustre, but my system didn't need that. However, I'd never have known it had those traits, and that my preamp could be improved further, until I experienced the musical qualities of the superb Mullard CV4004.
Thoroughly recommended! :cool:
Marco.
Interesting... when I sent you a CV4004 couple of years ago you preferred the Telefunken you had. I guess your system's changed quite a bit since then!
Hi Mike,
Nice to see you again. Hope all is well :)
Indeed (and as an aside, the Tesla was better than the Telefunken) - either that or the respective CV4004s just sounded different. We both know from experience how supposedly identical valves can still have slightly different sonic signatures.
Marco.
The Grand Wazoo
15-03-2011, 00:22
I originally tried the 5751's in order to attempt to match the differences in gain between phono & line inputs my preamp & didn't notice the slightest bit of difference in the output I was getting when comparing them with the old arrangement of ECC83's all round. However, I did find that the combination worked especially well in the sound quality department & I've stuck with it for years.
At the moment, though the internal phono stage is having a rest as there's a problem with it. In the meantime, it's my LFD MC1 that's doing the job into a spare line input.
My impression of the Telefunkens was that they were a bit too crisp, almost perfunctory for my liking.
I'd agree about the Telefunkens - it appears to be a bit of a German thing, as the type of signature you describe is also often present in their turntables and speakers...
However, much depends on the balance of your system, and so the Telefunkens could be just the ticket in some set-ups.
The Tesla was my favourite ECC83-type before I tried the CV4004 from Chelmer, and it is a very good valve, but ultimately for me the CV4004 sounds more musical, less coloured, and thus more sonically 'correct'.
Marco.
Doing some further research on premium ECC83-type valves, I came across one I hadn't heard of before, and that's the "legendary Genalex B759":
http://img228.imageshack.us/img228/391/showitemimage.jpg (http://img228.imageshack.us/i/showitemimage.jpg/)
Has anyone heard of or used this particular valve before? From the description below, it sounds intriguing...
British vacuum tube manufactory GEC made the best ECC83 tube among England. Tha legenary Genalex B759 was all made and selected by GEC short plate O type getter ECC83. GEC ECC83 has all advantages of British made ECC83: sweet midrange, rich bass, best for vocal. And what's more, it has impresive extension, dynamic sounding, low noise and ect. which other British brand dont have...
So who's tried a B759 or knows anything about them? :cool:
I'd love to try one!
Marco.
Good luck with that...
http://cgi.ebay.co.uk/1-NOS-12AX7-GENALEX-B759-GOLD-LION-ECC803S-ECC83-/300537168883?pt=Vintage_Electronics_R2&hash=item45f96943f3
There's always the re-issue. Won't be the same though.
http://cgi.ebay.co.uk/Genalex-Gold-Lion-12AX7-ECC83-B759-tubes-Brand-New-/160559592848?pt=LH_DefaultDomain_0&hash=item256218f590
Oh FFS!! :mental: :mental: :lol:
Not even I'd go there! However, it looks rather different to the ones in the pic I posted above....
Thanks for that, though, dude - most interesting :cool:
Might try the reissue for a giggle - we'll see!
Marco.
I can't even remember why now, but the ECC83 family was (is?) a bit of a "hobby horse" of mine. :scratch:
If you have a good luck at your CV4004 you should find an acid etched code on it somewhere. Tell me what it is and I can probably tell you where and when it was made. How fucking sad is that! :doh:
Yes, they look very different to the pic you posted but if you search further all the stuff out there refers to "Genalex Gold Lion" as being the daddy.
I should get a life....
S'ok, Mikey, I knew you were a bit of an expert on this :eyebrows:
Next time I've got the lid off of the Croft, I'll have a look at the CV4004 and let you know.
I probably need to get a life too, as I find all this stuff fascinating! :mental:
Marco.
Next time I've got the lid off of the Croft, I'll have a look at the CV4004 and let you know.
You mean the lid is actually ON the thing for a change!?! :stalks:
Only since this morning! :lol:
Marco.
If anyone fancies a nice M8137, this looks like a good bet:
http://cgi.ebay.co.uk/M8137-ECC83-Mullard-made-Great-Britain-64l-R613-/370492017238?pt=UK_Consumer_VintageAudio_RL&hash=item56430b8a56
Marco.
BTH K10A
17-03-2011, 00:16
Marco
The ECC808 is probably the best ECC83 variant I've ever come across.
Uses a different pin out configuration but if the sockets are hard wired the mod is simple and reversible.
Even if you can't use them currently, it's a good one to remember for the future. :)
http://cgi.ebay.co.uk/1-X-ECC808-VALVO-USED-V-G-TUBE-CRYOTREATED-/310303635079?pt=Vintage_Electronics_R2&hash=item483f89b687#ht_3864wt_1207
Hi Andy,
Noted, dude :)
I'd forgotten about the 85A2 voltage regulator valve that's used in my Croft, which currently is an Amperex one that's been fitted inside the preamp since I got it over 5 years ago, so I've just bought this NOS one to replace it:
http://img101.imageshack.us/img101/2316/kgrhqvhee1gwck9spbndqf6.jpg (http://img101.imageshack.us/i/kgrhqvhee1gwck9spbndqf6.jpg/)
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=120694756402&ssPageName=ADME:B:EOIBSA:GB:1123
May as well, eh? Can't do any harm! :)
Marco.
selfaddict
17-03-2011, 21:41
Hi Marco and many thanks for interesting review :cool:.
I contacted Steve some time ago and he is sending me a pair of Mullard CV4004's, so will be interesting to see what happens them inside the preamp or phono stage. I also received a pair of black plate, triple mica RCA 5751's today, so plenty of tube rolling this weekend scheduled :).
Gentlemen,
I sense a possible bit of misunderstanding here. A lot of alternative valve designations and type numbers are bandied about as if they were synonymous. They are not.
This is best exemplified by the CV system of notation (Component & Valves; an UK government system introduced during WW II to catalogue the hundreds of valve types). Even if two valves had an identical electrode structure and geometry and hence identical electrical performance, some might be made to tighter tolerances, others might have be tested to more stringent levels, and yet others might be hand picked samples for use in critical areas (such as electronic telephone exchanges). All would have different CV numbers, and yet ostensibly be the same valve.
Then there are the valve designs that whilst not being identical are sufficiently similar that for most, less demanding, applications can be regarded as interchangeable.
I compiled an article on this for the Library: http://theartofsound.net/forum/showthread.php?t=3285 .
To give an example, consider the ECC83 discussed on this thread. The following is taken from charliehall.proboards.com
The 12AX7 was introduced by RCA in late 1946 or early 1947, along with the 12AU7. The original construction was the "long plate" style, identical to the 12AU7 plates. As was common at the time, popular designs were cross-licensed between manufacturers, and since the design was specified to the mechanical level, all American 12AX7s through the 1950s had the identical long-plate construction.
In the early 1950s, various European manufacturers started making their own versions of the 12AX7 (some under license from RCA), and called it the ECC83. The early versions had the RCA-style long plates, but I've seen some some exceptions, such as the Mullard "box-plate" version. Some European tubes started to be imported to America, most notably tubes from Mullard, Telefunken, and Philips (labeled Amperex for the American tube company that Philips bought around 1945). These European tubes were generally made to better standards than the American tubes and typically had lower noise and microphonics. As a result, high-fi vendors started using these tubes. To fight back, RCA and GE came out in 1961 with a re-designed 12AX7 called the 12AX7A that had lower noise and microphonics. They did this by using a shorter plate structure (with the grid pitch and distances adjusted to keep the same electrical specs) which allowed stiffer cathodes and grids. This became the American "short-plate" structure. It seems to be based on the design of the 12AY7 by GE around 1949, which started with a box-plate but by the early 1950s had moved to a short-plate structure. It may also be related to the ruggedized 5751 which came out around the same time and had the short-plate structure.
Interestingly, Sylvania, the other first-tier American Tube manufacturer, made only a long-plate 12AX7A that had more ribbing and reinforcement than the old long-plate. Based on curve-tracer measurements, the Sylvania 12AX7As have somewhat higher bias currents than the standard 12AX7, i.e. at a given negative bias, it draws more current.
As far as one can tell, the 7025 is identical to the RCA 12AX7A, but was made to cater to those who wanted an "industrial" type number. This was kind of a fad with hifi designers in the late 1950s. Maybe it was tested to tighter specs, but most 7025s are marked 7025/12AX7/12AX7A.
Philips (and hence Amperex and the other Philips companies such as Mullard and Valvo) adopted a short-plate design for the ECC83 around the same time as the American 12AX7A came out. With the exception of the box-plate Mullards, all the western European ECC83s were either long-plate or short-plate designs.
On the other side of the iron curtain, the USSR came up with a completely different design for the ECC83/12AX7 that one thinks originated with the 6N2P. There was a shield between the two sections, the plates were even shorter than the American/European short-plates, and the plates were spaced rather far from the grids. Again, the grid and cathode were adjusted to give the standard ECC83 characteristics. This design also showed up in China, and the bulk of newer tubes from Russia or China are of this design.
So, with the exception of the later Sylvania 12AX7As, all these tubes have essentially the same characteristics - the I vs V curves. What, then makes them sound different? One doesn't really know for sure. It can be suspected the cathode material and processing makes the biggest difference. There may be secondary emission effects that depend on the plate material. As far as we know, the getter shape doesn't affect the sound, but if the getter flash got into the wrong places, it could cause leakage and noise. The type of glass used might even be a factor, since different glasses have different resistivities which affects how long electrons "stick" to the inside of the bulb.
One thinks the best we can do is note which tubes sound like what in which system, note it, and then use the knowledge to chose your next tubes. In this sense it is more of a taxonomy than a predictive science.
Read more: http://charliehall.proboards.com/index.cgi?board=general&action=display&thread=7194#ixzz1GtpAPkS0
Going further afield we have for the ECC83:
Identical or near identical: 12AX7 12AXR
Different rating or performance but similar: 12AX7A 12AX7S 12AX7WA
5751 5751WA
6057 6681
6L13
7025 7382 7494 7729
3339 CK5751
CV 10319 CV4004 CV4017 CV492
CV8155 CV8222 CV8312
E2164 E83CC ECC803 ECC803S
ECC863
M8137 QB339
and the recently, short lived E813CC.
But were not finished - two different manufacturers can make valves having identical electrode geometry using identical materials, yet connoisseurs will often prefer one over another. Rather like two vineyards making wine from the same grape from the same harvest.
It's a bit of a minefield. Great fun for the aficionado, but I'll stick to 'sand'.
Thanks for the info, Barry - it's all good fun! :)
Marco.
P.S However, you may wish to spell Aficionado properly ;)
Thanks for the info, Barry - it's all good fun! :)
Marco.
P.S However, you may wish to spell Aficionado properly ;)
Done! I'm sure I checked with Google. :scratch: But then you know speelying is not neccessarily my strong suit. Anyway, I'm half a bottle of red down at the moment. Well that's my excuse!
Have you noticed how much better Hamish's and André's spelling has become?
We should all strive for the highest standards here on AoS.
Regards
Hi Barry,
I sense a possible bit of misunderstanding here. A lot of alternative valve designations and type numbers are bandied about as if they were synonymous. They are not.
This is best exemplified by the CV system of notation (Component & Valves; an UK government system introduced during WW II to catalogue the hundreds of valve types). Even if two valves had an identical electrode structure and geometry and hence identical electrical performance, some might be made to tighter tolerances, others might have be tested to more stringent levels, and yet others might be hand picked samples for use in critical areas (such as electronic telephone exchanges). All would have different CV numbers, and yet ostensibly be the same valve.
I said more or less the same thing several years ago. But no-one took any notice and still went on and on about "military spec" valves. I gave up! :scratch::rolleyes:
I think at the end of the day all that matters is what a valve sounds like in a given application. If it's a 'military spec' one which does the business best, so be it. I don't get bogged down with that type of thing.
I've no idea if CV4004s are sonically superior to M8137s (I believe their 'domestic' equivalent), but I do know that in my current set-up, the CV4004 I obtained from Chelmer is so far the best ECC83-type valve I've heard - and by quite a margin :)
Marco.
If it's a 'military spec' one which does the business best, so be it.
The point is; there's no such thing!!! :brickwall:
CV stands for "Common Valve" by the way, not "components and valves". Or so I'm lead to belive!
http://www.tubecollector.org/cv-valves.htm
You can find the info on decoding the acid etched code on there too.
Yep, and that's why we're putting the description inside inverted commas, simply because it is somewhat ambiguous....
However, valves were obviously used in military applications during the war, and I do believe that those which were used in such applications were tested to have greater reliability and durability than standard offerings, which *can* sometimes reap rewards when the same valves are used for audio purposes.
What you choose to refer to them as however, 'military spec', or whatever, is up to you :)
Marco.
However, valves were obviously used in military applications during the war, and I do believe that those which were used in such applications were tested to have greater reliability and durability than standard offerings
I would imagine that "during the war" they would have slapped in anything that worked! And bloody quickly too!
Lol - indeed. I'm thinking in specialised areas such as telecommunications, etc, where reliability was crucial, and not by the soldiers in the front line! :eyebrows:
Anyway, that's my view :)
Marco.
BTH K10A
18-03-2011, 19:44
"The CV or common valve designation being applied to valve types selected for use by the UK government for both civil and military applications"
http://www.r-type.org/exhib/aai0007.htm
STC Footscray and ITT for that matter was only a few miles away from where I grew up. A few schoolfriends did their apprentiships at STC like their fathers before them so, when I first got into valves I consulted them to understand the various codes and designations.
I was told the CV designated valves had to meet certain specifications. These varied dependant on the proposed application. A lot of these specs were met by the standard production items and only had to be demonstrated by batch testing and quality control. Specs for increased ruggedness, longevity and tight tolerences sometimes required a different (more expensive?) internal structure i.e. an extra mica spacer.
Andy
Specs for increased ruggedness, longevity and tight tolerences sometimes required a different (more expensive?) internal structure i.e. an extra mica spacer.
Known as "reliable" valves.
For example, the M8137 (CV4004) being the reliable version of the ECC83 (CV492).
There is no real difference between a CV4004 and a M8137 (from the same manufacturer) other than the labels. They all came off the same production lines.
The "CV" designation just simplified valve selection for technicians who were not necessarily conversant with the intricacies of of different designations and the numerous equivalents that were available at the time. It is not true that CV valves were built to a special specification just for the military.
Yep I think, in a round about way, we're in agreement.
The bottom line for me though is that any valve ('reliable' or 'military spec'; the label for me is irrelevant) which has been subjected to more rigorous standards of quality control (in terms of the key aspects of its construction Andy referred to) when used in audio applications is, due to the nature of audio reproduction, liable to offer superior performance - and I can hear the results myself whenever I do the comparison :)
Marco.
selfaddict
18-03-2011, 21:12
Known as "reliable" valves.
There is no real difference between a CV4004 and a M8137 (from the same manufacturer) other than the labels. They all came off the same production lines.
This is correct. I have in front of me one pair of Mullard M8137 valves, which have been marked, with same silk screening CV4004 on the back of the valve. On the front there are Mullard M8137 markings. These valves are boxed anode type compared to 'normal' ECC83 types. My understanding boxed anode type valves are meant to tolerate vibration etc. bashing better compared to the 'civil' version.
This is the same case with Russian ****-EV valves which have been used for example inside MIG fighter jet radars etc. So when you use these valves on your preamp or phono stage they can take a lot of G-force :lol: Another example is Tesla E802CC, which is absolutely same valve for the civil market and for the military. Military valves just has crossed swords silk screened on the valve compared to the civil valves. I assume these crossed sword marked valves are just selected and matched to better accuracy to be used on the military applications.
BTH K10A
18-03-2011, 21:13
Known as "reliable" valves.
For example, the M8137 (CV4004) being the reliable version of the ECC83 (CV492).
There is no real difference between a CV4004 and a M8137 (from the same manufacturer) other than the labels. They all came off the same production lines.
Yes, thats what I understand happened.
"CV" designation just simplified valve selection for technicians who were not necessarily conversant with the intricacies of of different designations and the numerous equivalents that were available at the time. It is not true that CV valves were built to a special specification just for the military.
My understanding is slightly different. I was told that "CV" was a Government manufacturing specification that ensured conformity between different manufacturers products. It covered the whole range from common to specialised versions of a standard set of valves.
Supposedly the various specifications were derived from the requirements of key users that would have not only included the military but also the GPO, manufacturers, scientific research etc.
I must stress that the above can only be treated as anecdotal as I never saw any of the specification sheets, but it did come from a reliable source within the industry.
We are generally in agreement here, however a quote form a document I have:
There is a belief that CV valves are “better” than the commercial equivalent.. For general usage this is not true and indeed many CV specifications show electrical relaxations from that best achievable.
Unfortunately, there are some people in the Internet community who seem determined to perpetuate the myth of 'military spec' valves. I have a number of CV valves right here which are clearly marked "GPO", obviously they were never intended for use in Lancaster bombers or the like! :lol:
This will quite likely continue to artificially inflate the prices of CV type valves. I wonder if this has anything to do with "ego"?... "Look at me, I have some military spec valves"! :rolleyes:
The Grand Wazoo
19-03-2011, 00:29
I thought the CV designation was an attempt by Govt. to give a uniformity of coding system to all the various (non standardised) codes that all of the various manufacturers that they procured from.
I thought the CV designation was an attempt by Govt. to give a uniformity of coding system to all the various (non standardised) codes from all of the various manufacturers that they procured from.
Agreed! :)
The Grand Wazoo
19-03-2011, 00:33
Ah good, I remembered something then!
(Hi Mike - you OK?)
(Hi Mike - you OK?)
Not really! :ner:
The Grand Wazoo
19-03-2011, 00:39
Oh.......OK.
Nothing serious, I hope?
Nah... just a divorce! :lolsign:
The Grand Wazoo
19-03-2011, 00:43
Ah, right, not something I can offer help with then, eh?!!
Hope you get it all sorted as smoothly as possible, Mikey.
Marco.
BTH K10A
19-03-2011, 01:11
Unfortunately, there are some people in the Internet community who seem determined to perpetuate the myth of 'military spec' valves. I have a number of CV valves right here which are clearly marked "GPO", obviously they were never intended for use in Lancaster bombers or the like! :lol:
I've quite a few marked GPO as well. The only valves I've seen with military markings were suffixed VR and were RAF so might well have been in a Lancaster. :lolsign:
The US JAN valves seem no better than the standard offerings with possibly the exception of some Bendix valves. The 6900 spprings to mind.
The German Wehrmacht valves again are nothing special but often the inclusion of an eagle produces premium prices. The Laboratory (Spezialvestarkerrohren) and Post valves are in a different league though.
On the subject of military valves I have this 1918 Telefunken output triode as used in the radion transmitter of a U-Boat.
http://i46.photobucket.com/albums/f120/emttsd15/104-0415_IMG-1.jpg
Ooooh - that's a sexy valve! :)
Marco.
Just won the other NOS (brand new) GZ34 I needed:
http://img291.imageshack.us/img291/3782/kgrhquokkue1gkh7sdbne5s.jpg (http://img291.imageshack.us/i/kgrhquokkue1gkh7sdbne5s.jpg/)
http://img22.imageshack.us/img22/1673/kgrhqioknme1umq3yk5bne5.jpg (http://img22.imageshack.us/i/kgrhqioknme1umq3yk5bne5.jpg/)
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=290544344393
£15 cheaper than the last one, too... Result! :cool:
Marco.
As I'm currently clearing out some surplus valves, I decided to treat myself to a couple of rare-ish ECC83 types, and have just won these now on Ebay:
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=310302737649
http://img860.imageshack.us/img860/2087/kgrhquokm4e1uppspbpbndb.jpg (http://img860.imageshack.us/i/kgrhquokm4e1uppspbpbndb.jpg/)
The Marconi is something I've wanted to try for a while, as the company has quite a respected heritage (I also don't have any chrome plate-type 12AX7s). They'll be tried in the Croft.
http://img855.imageshack.us/img855/6922/movbooklarge.jpg (http://img855.imageshack.us/i/movbooklarge.jpg/)
I bet that'd be an interesting book to read: http://www.torresamps.com/movbody.htm
Watch this space to find out if the Marconi or Mini-Watt are better than the Mullard CV4004, or if they're pish! :doh:
:eyebrows:
Marco.
P.S Does anyone know anything/have any experience of Marconi valves?
BTH K10A
19-03-2011, 23:05
Marco
I might be wrong but....
That looks like a Canadian Marconi company (CMC) valve as opposd to a Marconi Wireless & Telegraph (MWT) one. The companies started to diverge from about 1948 when English Electric bought MWT but only took just over a 50% stake in CMC. After GEC purchased EE in the fifties the valve products were certainly not the same.
Canadian Marconi's were often re-badged Philips valves, which seems to be confirmed by the matching Miniwatt valve in your pic. I would assume it was probably made in Haarlem. It probably has more in common with Mullard which from 1927 was owned by philips.
Andy
Thanks for that, Andy. I suspect you're right. Still, they're different ECC83-types from the norm, and ones I haven't tried before. It'll be interesting hearing how good (or not) they are in use! :)
Marco.
BTH K10A
19-03-2011, 23:35
Marco
I've looked more closely at the auction pics. They look more like Mazda chrome plates. If they are you might have struck lucky. :cool:
Andy
Lol - why, are they any good? I just thought that for two decent NOS valves, tested with good emission, they were a good price :)
Marco.
BTH K10A
19-03-2011, 23:41
Are they the same as these
http://www.upscaleaudio.com/tubes/12ax7/mazda-12ax7.html
They are supposed to be quite good. Gets us back to the military thing though. :lolsign:
Lol - indeed! They do look rather similar (certainly both have chrome plates):
http://img651.imageshack.us/img651/6936/kgrhqqokjoe1uctlytnbndb.jpg (http://img651.imageshack.us/i/kgrhqqokjoe1uctlytnbndb.jpg/) http://img696.imageshack.us/img696/9277/mazda12ax7c2.jpg (http://img696.imageshack.us/i/mazda12ax7c2.jpg/)
Might have landed a bargain, then :)
Marco.
Marco
I might be wrong but....
That looks like a Canadian Marconi company (CMC) valve as opposd to a Marconi Wireless & Telegraph (MWT) one. The companies started to diverge from about 1948 when English Electric bought MWT but only took just over a 50% stake in CMC. After GEC purchased EE in the fifties the valve products were certainly not the same.
Canadian Marconi's were often re-badged Philips valves, which seems to be confirmed by the matching Miniwatt valve in your pic. I would assume it was probably made in Haarlem. It probably has more in common with Mullard which from 1927 was owned by Philips.
Andy
Think you could well be right Andy. The logo for the Marconi valve is not the same as that used on the UK products.
I think he's almost certainly right, Barry. However, I also suspect Andy's right about the Mazda/Miniwatt chrome-plate connection :)
Not bad if I've landed $160 worth of NOS valves for $46! :eyebrows:
Marco.
Well clearly they’re not Phillips Miniwatt
https://www.tubeworld.com/12ax7mull2.jpg
(£170 each)
nor are they Canadian Marconi
https://www.tubeworld.com/12ax7can-thumb.jpg
(no price as yet)
yet they might be a Phillips item from the 1960 ($125 each) Still looking for an image.
If they are Philips Mazda products they would have been made in France. This is taken from http://www.guitaramplifierblueprinting.com/12ax7.html
ECC83/12AX7 MAZDA GREY PLATE
A French military valve that is noted for its Mullard tone. In audio application these valves were detailed, lively and very balanced. Plenty of bass slam in these babies. The valves are very high gain, yes more gain than the famous Mullard ECC83. The distorted tone was rich and fat . Treble response was clear even when really distorted. The valves were supremely quiet, however due to the immense gain special selected version would be needed if your amp has a cascading gain pre amp section.
ECC83/12AX7 MAZDA SILVER ANODE
A French military valve with special silver plates made for special application military use.
In audio amps the valve displayed a slight treble forwardness. This gave the impression of less bottom end thump when compared to the Mazda grey plates. A fantastic detailed performer the sound stage was big. The valve was again very quiet which shows how well made they are. The gain of these valves are somewhat less than the grey plates but still in the medium to high gain bracket.
And this taken from http://www.audiotubes.com/12ax7.htm might be of interest:
ECC83: This is the European version of the 12AX7, and is identical to it. Most tubes with ECC83 listed on the label are European, and the ones in demand are Telefunken, Amperex, Mullard, and Siemens. More difficult to find but worth seeking are German made Valvo and the early Holland made Philips Miniwatt and Philips "SQ". Telefunken tubes have a diamond shape molded into the glass on the bottom center of the tube. The most desirable of the Telefunken ECC83 tubes is the "smoothplate" or "flatplate" versions. Like the name implies, the dull grey plates are perfectly smooth. It does not matter if some of these on the market are labeled for Fisher or Dynaco, as Telefunken made these tubes for many OEM applications. They are the EXACT same tube regardless of the label. Watch for the rare Telefunken smoothplates with a cloth label on the glass marked "selected tube". Often these have red painted tips, and watch for blue painted tips, and laboratory grade smoothplates made for Leeds & Northrup as well. These were all screened for critical use in medical equipment, with the "selected tube" or L&N versions being the best. Both red and blue tips are incredibly quiet and very three dimensional in sound. Amperex and Mullard tubes have a pair of alphanumeric date codes printed in dark grey near the bottom of the tube. The rarest of these are the Bugleboy cartoon tube label for Amperex (especially if it also has the treble clef music symbol next to the Bugleboy image), and the older Mullard logo that looks like a shield, especially with the letters "BVA" below it. Watch for the Mullard "10M" series of ECC83 tubes in the distinctive royal purple and gold boxes. These sweet tubes were factory screened for a 10,000 hour heater life, matching internal triodes, and low noise, rather like the Telefunken ECC803S tubes. The 10M Master Series has gold plated pins, and the 10M Concert Series has standard pins. Demand and scarcity has driven the price of these babies to record heights lately. The 1950s versions of Mullard and Amperex (and some rare Siemens) tubes often had long narrow plates, with D or square getters, and are the scarcest and finest sounding of these two brands. The 6L13 is the rarest of the longplates, made for ultra low noise. They are nearly impossible to find today. BEWARE: the Amperex Bugleboy and Telefunken smoothplates are being faked! The fake Amperex may have the words "Bugleboy" and the cartoon tube on the box, and the label will not wash or wipe off. The fake Telefunken may have gold pins (real Telefunken ECC83 tubes had only standard pins) and a perfect, baked enamel label that won't wipe off. Our tubes are carefully screened for fakes when we obtain them, and are guaranteed genuine.
and
AMPEREX, PHILIPS, MAZDA and other Holland/France/Belgium made NOS: These tubes are a great balance of a clean, airy top end, nice midrange warmth, and accurate bass. They are very pleasant, clean, and musical to listen to in hi-fi applications. Unlike other clean European tubes, these break-up impressively when overdriven in a guitar amp. Check out the Mazda 12AX7S silver plates for critical phono preamp or microphone preamp duties. These tubes are dead quiet, with a great sense of air and dynamics, with incredible speed and impact. The Philips Miniwatt series, usually made in the same Heerlen, Holland factory that produced the Amperex Bugleboy tubes, are a great alternative to the increasingly rare Bugleboy. They are identical internally, carry the same factory code markings, and sound the same. These Holland tubes can often be found, sometimes made for other brands or OEM labelled for amplifiers, when the Bugleboys cannot. The rare longplate versions are the same sonically, but with even more soundstage space and detail. The rare French Mazda has the air and sparkle of the Telefunken, the touch of warmth of the Amperex, and adds a nice bit of dynamic punch to the sound.
MULLARD, GENALEX, BRIMAR, and other British made NOS: Like a warm British jacket of the finest tweed, these glorious tubes have an attractive sweet warmth in their midrange and lower regions. The top end is silky and pleasant, without being rolled-off. The best of these tubes retain a fine sense of "air" at the top, and the upper midrange is smooth and liquid. These tubes reproduce the human voice, especially female voices, with haunting realism. The rare longplates and Genalex versions have an eye-popping huge soundstage, razor sharp focus and detail, and an uncolored top end while retaining the warmth of the lower priced versions.
Trust this is of some interest
Regards
Most informative, Barry, so thanks for that :)
The Marconi/Miniwatts I've landed appear to be most like the Mazdas Andy linked to earlier, so I have the feeling I'm onto something interesting....
Any further info you can find would of course be appreciated :cool:
Marco.
BTH K10A
20-03-2011, 08:55
I think this answers the speculation. :) It's a Mazda
http://vacuumntubes.com/nos-mazda-silver-plate-marconi-12ax7-ecc83-audio-tube
I seems that there were at least two changes to the centre part of the box but its certainly the same valve.
Marco, it seems that you have a pair of valves made by Mazda France for both Miniwatt (French Philips) and Canadian Marconi Co.
One further twist to this is that Thorn AEI purchased Brimar from ITT in the 60's to supplement the BTH, Ediswan, Mazda businesses they already had. I Know for a certainty that Brimar made valves for Mazda France as I've seen documented evidence in the form of a shipping order. So there is an outside chance they are of British manufacture.
http://frank.pocnet.net/other/Philips/PhilipsCodeListAB-v8.pdf
From the above link you should be able to solve this from the factory codes
Andy
Wow - thanks for that info, Andy, and your efforts in researching it. I think you're spot on! :)
The idea was to obtain a couple of 'interesting' ECC83/12AX7s to play with and compare with the CV4004, so I think I've achieved that, don't you? ;)
When the valves arrive, I'll check the date codes against the list you've linked to and find out if the Marconi and Miniwatt were of British manufacture or not.
Interesting stuff!
Marco.
Looks like Andy has 'nailed it'. Now all we need is for you to use the Philips factory code list to tell us the valve's provenance.
Won't be able to sleep until I know!
Me neither! :eyebrows:
Nice find though, eh? :)
Marco.
i picked up 3 Mini watt valves in a French flea market for 1 euro last year, i will dig them out tommorow and have a look,
BTH K10A
20-03-2011, 21:13
Won't be able to sleep until I know!
Me neither! :eyebrows:
Marco.
I though you were both insomniacs. :lol: better not post the good bit then, you need your :zzz:
WHAT good bit? Spill! :)
Marco
WHAT good bit? Spill! :)
Marco
Not until you've told us where your Mazda valve was made! :eyebrows:
I won't know until I can see the date codes, so I'll have to wait for the valves to arrive :)
Marco.
BTH K10A
20-03-2011, 22:22
Are you two still awake :eek:
Nothing special, had a saved link a while back that coincidentally has exactly the same valve in it. ;)
Also realised I've saved so many hifi links now, it's difficult to find anything quickly, its quicker to google. :doh:
BTH K10A
20-03-2011, 22:27
Forgot link
http://www.youtube.com/watch?v=_6d-cZB7DgA
Excellent video, Andy. You're making me feel happier that I bought the Marconi/Miniwatts by the minute! :eyebrows:
Meanwhile, in terms of 'interesting' valves for the Croft, I've just bought these on Ebay:
http://img846.imageshack.us/img846/8936/bewinwb2kkgrhquhckerghy.jpg (http://img846.imageshack.us/i/bewinwb2kkgrhquhckerghy.jpg/)
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=230398265110&ssPageName=ADME:B:EOIBSA:GB:1123
http://img851.imageshack.us/img851/5286/464a12.jpg (http://img851.imageshack.us/i/464a12.jpg/)
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=350153170775&ssPageName=STRK:MEWNX:IT
The Croft uses 5 x 6SL7s as output valves, two of which are for the line-level output and two for the phono stage. The other one in the middle feeds both the line output AND phono stage, therefore I use this valve to 'flavour' the line and phono stage with a sonic signature I consider as being neutral and musical, which matches that of the existing valves (NOS GE 5691s and NOS Brimar CV1985s), thus voicing my preamp 'by ear', as it were.
It's this role that I've got lined up for the Westinghouse and Raytheon, which is currently occupied by a 1950s Mullard ECC35.
The nice thing is that they were cheap and NIB (new in box), so I doubt I can go wrong - proper vintage stuff, too! :)
Are any of you chaps familiar with Westinghouse or Raytheon, or know something of their pedigree? I know that they're American, but that's about it!
Marco.
This is an interesting site, showing the history of some renowned names in vintage valves (check out the info on Marconi, both Canadian and British, about halfway down):
http://tone-lizard.com/Vintage_Tube_Boxes.htm
:)
Marco.
BTH K10A
21-03-2011, 06:56
Good site. Typical American view on history though, just like the capture of the enigma machine.;)
The Marconi history is a litle more complicated than portrayed.
On a serious note though, it wouldn't surprise me if CMC had set up a deal to market RCA valves in Canada under the CMC brand and later rebranded many other makes.
Andy
Such is the shady world of commerce, Andy ;)
Know anything about Westinghouse or Raytheon? Both seem to have a nice heritage with quality vacuum tube production :)
http://img710.imageshack.us/img710/1250/212pxraytheon1934tubebo.png (http://img710.imageshack.us/i/212pxraytheon1934tubebo.png/)
Marco.
BTH K10A
21-03-2011, 07:52
All I know is that I've fouund Westinghouse 5U4G's to be very good and Westinghouse as a company has a very good reputation.
The Rayethons seem to be Sylvanias.
https://www.tubeworld.com/6sl7.htm
Andy
Yep, looks like it, although the box its in is an early Raytheon type (see details on the tone-lizard vintage tube site I linked to earlier).
Nothing wrong with NOS Sylvanias, though. They, along with RCA, were the first companies to introduce the 6SL7GT. In my experience, whenever I've used them, they're quality.
Ok, since you're a man of culture, I'd like a little advice.... I would like to buy one more NOS (NIB) 6SL7, and I have the choice of either this (a NIB 1952 Sylvania JAN-CHS-6SL7WGT 6SL7-WGT):
http://img52.imageshack.us/img52/6484/b3ctegkkgrhqjhyew5bfpqc.jpg (http://img52.imageshack.us/i/b3ctegkkgrhqjhyew5bfpqc.jpg/)
Tested on a Hickok TV-7B/U @ 80/78 Min 32/32 Triode #1/Triode #2.
Or this (a NIB JAN CHS 6SL7WGT from 1954):
http://img534.imageshack.us/img534/5742/cwwvwegkkgrhqrhiezeph3d.jpg (http://img534.imageshack.us/i/cwwvwegkkgrhqrhiezeph3d.jpg/)
Tested on a Hickok 6000A: Min = 1000/1000. 2100/2050.
Or this Sylvania Gold Brand 6SL7GT (described as, I quote: "a cool, super-rare vintage 6SL7 made in the U.S. by Sylvania"):
http://img854.imageshack.us/img854/442/sylvaniagb6sl7.jpg (http://img854.imageshack.us/i/sylvaniagb6sl7.jpg/)
I can get that from the supplier as a, quote: "Platinum grade - The best of the best. Lowest noise and microphony with the tightest triode balance we have available".
Or lastly this RCA 6SL7GT/VT-229 (described as, I quote: "1942 vintage military stock. Like the 1944 vintage Sylvanias, these were left there by the U.S. Army after World War II, completely undisturbed in warehouses. The boxes say "Western Electric," but the octagon etched on the glass tells us they are RCA. Well... so does the RCA logo on the base of the tube... Great sounding tube that's quiet with nice detail and clarity").
http://img40.imageshack.us/img40/9449/rca6sl73.jpg (http://img40.imageshack.us/i/rca6sl73.jpg/)
I can get that from the supplier as a quote: "Platinum grade - The best of the best. Lowest noise and microphony with the tightest triode balance we have available".
I would also like to buy one last top-notch 'Premium' ECC83, for my forthcoming tube-rolling sesh, and have the choice of this (a 1957 Amperex foil strip 12AX7 D-Getter 'Bugle Boy'):
http://img846.imageshack.us/img846/6342/kgrhqfg8e1fmgqv5zbndgo6.jpg (http://img846.imageshack.us/i/kgrhqfg8e1fmgqv5zbndgo6.jpg/)
Tested on a Hickok 6000A : Min = 1250/1250. 2200/2050.
Or this, described as, I quote: "A very rare 1958 Amperex 12AX7 / ECC83 tube has long gray plates with copper grid posts and a D getter with foil strip. The white print on the glass has the early Amperex logo and says "Made in Holland." The Heerlen factory code is etched in the glass":
http://img703.imageshack.us/img703/9532/217ampecc83800.jpg (http://img703.imageshack.us/i/217ampecc83800.jpg/)
Which ones would you go for, and why? :cool: Oh, and other folks can obviously answer this, too!
I'm tempted by the first 6SL7 (Sylvania), as it looks quite early, and I generally prefer the sound of the earlier valves, and also Sylvanias (more often than not) to RCAs. And the last Amperex, for similar reasons, as it's a nice early one.
Any input from our resident valve aficionados would be greatfully received!
Marco.
Ali Tait
21-03-2011, 11:29
I'd agree that the older a valve is, the better it seems to sound. I still remember how good Steve Sheils '30's 300a's sounded at a previpus Owston meet.
Yup - defo. What would you go for, Ali?
{Edit: I've just bought the Amperex 'Bugle Boy'} :)
Details here: http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=180636317666&ssPageName=ADME:B:EOIBSA:GB:1123
Now which 6SL7 shall I nab - whaddyathink...? :hmm:
Marco.
Ali Tait
21-03-2011, 12:33
The RCA one mate, it's the oldest!
Ali Tait
21-03-2011, 12:40
Marco, on the sale of that Amperex, there is no mention made of.whether the valve is NOS or not. Did you check with the seller?
This is an interesting site, showing the history of some renowned names in vintage valves (check out the info on Marconi, both Canadian and British, about halfway down):
http://tone-lizard.com/Vintage_Tube_Boxes.htm
:)
Marco.
I've added this site to the list in The Library's valve data base (and acknowledged you).
Regards
BTH K10A
21-03-2011, 13:08
Marco
I'd go for the NIB 1952 Sylvania JAN-CHS-6SL7WGT 6SL7-WGT, because I've always found the JAN valves to be very reliable.
One other recommendation is the 6188. Give it a try and you might be surprised. :)
Andy
Hi Ali,
The RCA one mate, it's the oldest!
Lol... Coincidentally, that's probably what I'll be going for. I may also go for the NIB 1952 Sylvania JAN-CHS-6SL7WGT, as it's reasonably priced.
Marco, on the sale of that Amperex, there is no mention made of.whether the valve is NOS or not. Did you check with the seller?
Yup - only used for testing, so therefore NOS used, rather than NOS unused :)
I've seen NOS 'Bugle Boys' go for lots more money (good like this ones are as rare as hen's), so I consider that I got a bit of a bargain.
Marco.
I've added this site to the list in The Library's valve data base (and acknowledged you).
Interesting site, isn't it? Cheers for that, Barry! :)
Marco.
Hi Andy,
Marco
I'd go for the NIB 1952 Sylvania JAN-CHS-6SL7WGT 6SL7-WGT, because I've always found the JAN valves to be very reliable.
One other recommendation is the 6188. Give it a try and you might be surprised. :)
I'll likely also snaffle the Sylvania...... :eyebrows:
6188? Not heard of that one. I'll do some research!
Btw, I'm splurging out on valves for my amps because I've decided that I'll not be getting rid of them any time soon (I'm really happy with the Croft and Copper amp), so thought that I might as well max-out on tubes to last me a lifetime - and whilst the NOS ones I want are still available! :cool:
Marco.
"NOS" and "used" !
Silly boy! :lol:
It can't be both...
I've seen NOS 'Bugle Boys' go for lots more money (good like this ones are as rare as hen's), so I consider that I got a bit of a bargain.
See if it's got this logo on it!
http://members.cox.net/radiostuff9/6bl8amperexbbx22.jpg
"NOS" and "used" !
Silly boy! :lol:
It can't be both...
Lol, what I mean by "NOS but used" is that it's a vintage valve, but it's been used, either just for testing, or perhaps also in equipment. The 'NOS' Bugle Boy I've just bought comes under the former category :)
I understand that "NOS" means 'new old stock', but it's also a term frequently used to denote vintage, as opposed to current production valves, whether they're actually new or not.... ;)
Marco.
Ali Tait
21-03-2011, 14:46
Naah, he means it was used in the testing machine, so yes, it is NOS.
Indeed. Mikey does like to wear his pedant's hat sometimes (along with his floral dress and strappy sandals)! :eyebrows:
;)
Marco.
See if it's got this logo on it!
http://members.cox.net/radiostuff9/6bl8amperexbbx22.jpg
Those look like nice early ones! :)
So do these:
http://img190.imageshack.us/img190/3972/1300762871.jpg (http://img190.imageshack.us/i/1300762871.jpg/)
Marco.
Naah, he means it was used in the testing machine, so yes, it is NOS.
Hmmm.... from elswhere!
NOS (used) GE 5751 (ECC83 equivalent with slightly less gain)
NOS (used) Yugoslavian Ei ECC83
NOS (used) 1940s RCA 6SN7
NOS (used) 1940s Tung Sol 6SU7GTY (premium version 6SL7)
3 x NOS (used) Russian 8H9C (6SL7 equivalent)
1 X NOS (used) thin black base 1950s Mullard ECC35
2 x NOS (used) thin brown base 1950s Mullard ECC35
2 x NOS (used) fat brown base 1960s Mullard ECC35
:D
Don't worry... just having a giggle, I bought one of 'em anyway.
Even though it's probably one I gave him in the first place, the price was too good to turn down... ;)
Indeed. Mikey does like to wear his pedant's hat sometimes
S'true! :ner:
Hmmm.... from elswhere!
:D
Don't worry... just having a giggle, I bought one of 'em anyway.
LOL. I think Ali was talking about the 'Bugle Boy' I bought, which is NOS, despite having been tested ;)
Even though it's probably one I gave him in the first place, the price was too good to turn down...
F*ck, is that where that came from! :doh:
I was wondering why I'd bought a 5751...... Soz, I owe you a few beers then! :cool:
Marco.
BTH K10A
21-03-2011, 18:46
Hi Andy,
I'll likely also snaffle the Sylvania...... :eyebrows:
6188? Not heard of that one. I'll do some research!
Btw, I'm splurging out on valves for my amps because I've decided that I'll not be getting rid of them any time soon (I'm really happy with the Croft and Copper amp), so thought that I might as well max-out on tubes to last me a lifetime - and whilst the NOS ones I want are still available! :cool:
Marco.
Marco, this link has some interesting comments on 6SL7's
http://www.stereophile.com/interviews/196rankin
Confirms your thoughts on Sylvania's and gives a little bit of info on the 6188
Andy
Very interesting, Andy. I'll defo look more into the 6188. I'll probably also nab that early NOS Sylvania :)
Btw, that chap Gordon Rankin certainly knows what he's talking about:
You know, distortion is a part of life. The reproduction of sound will always include distortion products—both even- and odd-order. Any type of reproducing device will exhibit distortion in its output. And canceling even some of it can have a detrimental effect to the sound itself as a whole.
Hear, hear - I've been saying that for years... It's high time the pig-headed measurement freaks, in their fruitless quest for 'zero distortion' with everything, embraced and accepted that fact!!!
It also explains why valve amps often sound better than their solid-state counterparts, despite measuring more distortion. The fact is, not all distortion is bad!
Marco.
Well, after much consideration, I've decided to go for the 1940s RCA VT-229 (6SL7) and have ordered two of these babies for the phono stage in my Croft:
http://img143.imageshack.us/img143/4682/s6sl7rca2kleintad.jpg (http://img143.imageshack.us/i/s6sl7rca2kleintad.jpg/)
I came to this decision as, by sheer chance when looking through some valves that I wasn't using, I found a NOS (and yes it was NOS - LOL) Tung-Sol VT229, with black glass (I forgot that I had the bugger! :doh:) and popped it in the Croft in the position of 'middle valve' between the line-level and phono stage, and BLOODY HELL, WHAT A SOUND!! It totally blew me away!!! :eek:
So I'm sorted now in terms of the 'middle valve' position in my preamp, and of course I've got the Raytheon and Westinghouse valves still to play with, so happy days! :cool:
Marco.
anthonyTD
22-03-2011, 09:47
Well, after much consideration, I've decided to go for the 1940s RCA VT-229 (6SL7) and have ordered two of these babies for the phono stage in my Croft:
http://img143.imageshack.us/img143/4682/s6sl7rca2kleintad.jpg (http://img143.imageshack.us/i/s6sl7rca2kleintad.jpg/)
I came to this decision as, by sheer chance when looking through some valves that I wasn't using, I found a NOS (and yes it was NOS - LOL) Tung-Sol VT229, with black glass (I forgot that I had the bugger! :doh:) and popped it in the Croft in the position of 'middle valve' between the line-level and phono stage, and BLOODY HELL, WHAT A SOUND!! It totally blew me away!!! :eek:
So I'm sorted now in terms of the 'middle valve' position in my preamp, and of course I've got the Raytheon and Westinghouse valves still to play with, so happy days! :cool:
Marco.
:)
Yesh, your advice, oh great one, did play a part in me deciding to go for the VT-229s ;) I just love how 'truthful', wide-open, scarily dynamic and uncoloured these valves sound!! :eek:
They're not, however, for 'tubey' freaks, seeking to create euphonic coloration - but then that's not why I love valves (or valve amps).......
Marco.
anthonyTD
22-03-2011, 17:12
your welcome !;)
:lolsign:
Fank u :)
I've also decided to buy that rather nice 1952 NIB Sylvania:
http://img832.imageshack.us/img832/6484/b3ctegkkgrhqjhyew5bfpqc.jpg (http://img832.imageshack.us/i/b3ctegkkgrhqjhyew5bfpqc.jpg/)
Couldn't resist it - and at that price it would be rude not to.... Hey, you can't have this much fun with transistors!! :eyebrows:
Marco.
I've also just spied these for sale:
http://img827.imageshack.us/img827/1153/1300321268.jpg (http://img827.imageshack.us/i/1300321268.jpg/)
Should, I - or do I have enough now? Mmmmm.... :hmm:
Marco.
I've also just spied these for sale:
http://img827.imageshack.us/img827/1153/1300321268.jpg (http://img827.imageshack.us/i/1300321268.jpg/)
Should, I - or do I have enough now? Mmmmm.... :hmm:
Marco.
Valves are affectionately known as 'bottles', so why not treat them as you would a fine wine: lay them down to enjoy in a few years time? ;)
Regards
Yes, and they're also called 'tubes', which suggests, erm, that only 'tubes' are daft enough to buy them.................! :eyebrows:
Marco.
The latest addition to my collection of NOS 6SL7s (these are NIB)....
http://img508.imageshack.us/img508/8241/kgrhqzhye1fq8epqqbn7zzt.jpg (http://img508.imageshack.us/i/kgrhqzhye1fq8epqqbn7zzt.jpg/)
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=330535854537
I liked the description of a guy who'd carried out some extensive listening tests on a variety NOS 6SL7s. These were his findings:
First, 6SL7's (and equivalents).
- Best: Sylvania 6SL7WGT Gold (JAN-CHS-6SL7WGT). Brown base, gold print
on tube, chrome top. As one review says, it puts you front and centre -
like the main instruments are just a couple of feet ahead of you -
forward of the speakers. Excellent depth and detail and solo
instruments and classical music just come alive. A real eye opener when
you listen to these.
- 2nd best: Sylvania 6SL7WGT. Brown Base, green text. Just about
idential to the ones above in sound.
- Equal Second best: Sylvania JAN CHS 6SL7GT/VT-229 (actually says both
on base). Tall bottle, chrome at the bottom, black base, white writing.
3rd best: Raytheon JAN VT-229.
The 2nd and 3rd best ones are similar to the best one: front and
centre, very clear and pronounced. The best one only edges them out by
a tiny amount.
Fourth:
- Mullard ECC35. These are GREAT for really clear voice and have good
detail (a little better than the tubes above), smooth and flowing (good
jazz style tubes) but the clarity, the focus just isnt like the first
three. I can live with these but for certain kinds of music the ones
above just win hands down.
5th: RCA 6SL7 smoked glass. Sounds pretty good all around, but just
doesnt stand out like some of the others.
Ones Im not so impressed with:
- Tungsol Round Plate 6SL7GT. Black base, black glass: too quiet and
innaccurate compared to the ones above.
- Red Base RCA 5691: I have a perrrrrrrfect NOS NIB pair of these and
am not very impressed. They just dont have the depth or detail. I think
its best summed up by one site that says "they lack bandwidth".
I'm going to use these in the line-level output of the Croft, where I think that they'll be an interesting contrast to the V229s in the phono stage, or I can swap them around and see where best results are obtained :)
I'm done now on the 6SL7 front, unless I see something exceptionally interesting! Can't wait for them all to arrive, so I can begin tube-rolling :cool:
Marco.
I've just bought this :doh:........
http://img405.imageshack.us/img405/5680/ce1klybgkkgrhqfk8e1fubq.jpg (http://img405.imageshack.us/i/ce1klybgkkgrhqfk8e1fubq.jpg/)
Only because I have a 'thing' about Amperex valves..... The ones I've used are top-notch quality.
http://img811.imageshack.us/img811/9568/amprexcover.jpg (http://img811.imageshack.us/i/amprexcover.jpg/)
http://img827.imageshack.us/img827/8865/amperex2020pink20cover.jpg (http://img827.imageshack.us/i/amperex2020pink20cover.jpg/)
Right, that's the lot - no more!! :mental: :lol: :mental:
Marco.
Have you signed the pledge? :rolleyes:
BTH K10A
25-03-2011, 21:19
The latest addition to my collection of NOS 6SL7s (these are NIB)....
http://img508.imageshack.us/img508/8241/kgrhqzhye1fq8epqqbn7zzt.jpg (http://img508.imageshack.us/i/kgrhqzhye1fq8epqqbn7zzt.jpg/)
Marco.
;)
For a phase inverter though, I still think the 6188 is the best.
I hear ya, dude, but I can't seem to find any 'sexy' NOS ones that tickle my fancy. There appears to be a much bigger selection of interesting and unusual NOS 6SL7s.... Unless you can recommend a sexy 6188?
I like rare and unusual :)
Marco.
BTH K10A
26-03-2011, 19:06
I hear ya, dude, but I can't seem to find any 'sexy' NOS ones that tickle my fancy. There appears to be a much bigger selection of interesting and unusual NOS 6SL7s.... Unless you can recommend a sexy 6188?
I like rare and unusual :)
Marco.
I found the best to be the later Philips ones, common now since the US military released loads into the public domain. These have black bottoms.
Your quest for the rare and exotic takes you into sexy brown bottom territory. :bum:
Great - oi lurves a nice plump tanned arse! :lol:
Marco.
BTH K10A
26-03-2011, 20:59
Great - oi lurves a nice plump tanned arse! :lol:
Marco.
The Aussies better watch out then. :lol:
http://i46.photobucket.com/albums/f120/emttsd15/326084588_795e79aecb.jpg
BTH K10A
26-03-2011, 22:26
Good site for pics of UK valve boxes amongst other things.
http://www.vintage-technology.info/pages/ephemera/ephemhome.htm
That's excellent. I'd love to make some of them into posters and frame them for my music room :)
Marco.
BTH K10A
26-03-2011, 22:59
That's excellent. I'd love to make some of them into posters and frame them for my music room :)
Marco.
Good idea, a bit like the vintage car boys do in their garages. :)
http://i46.photobucket.com/albums/f120/emttsd15/brimcat61.jpg
Very Terrance Conran
Did you mean Terence Conran? ;)
Indeed - and with shades of Mondrian :)
Marco.
BTH K10A
27-03-2011, 11:33
Did you mean Terence Conran? ;)
Indeed - and with shades of Mondrian :)
Marco.
Yep
I should have just said "that Conran Bloke" :)
Aye!
Valves are starting to arrive now.... Today I put the NOS Ken-Rad V229s, and Amperex 85A2 voltage reg valve, in the Croft.
Whoa - VERY nice!! :eek:
Quality NOS valves like these really do give your amp a shot in the arm. You don't really realise how performance slowly tails off, as valves lose emission, until you do a back-to-back comparison with brand new ones :)
Now all I'm waiting to arrive is the Amperex Bugle Boy, Marconi and Mini Watt (Mazda) 12AX7s, Westinghouse, Raytheon, Sylvania, and Amperex single NOS 6L7s, and a matched pair of NIB NOS Sylvanias 6SL7s.
All should be here by the end of the week. Can't wait! :cool:
Marco.
All valves have arrived now, apart from the NOS Amperex 6SL7, which was the last one I bought, and that should arrive any day.
I've had a chance now to thoroughly evaluate most of them (apart from the Raytheon, which only arrived today), and aside from the Ken-Rad/RCA VT229s, which really are superb, the real standouts have been......
The 1957 NOS Amperex 12AX7 'Bugle Boy':
http://img141.imageshack.us/img141/6342/kgrhqfg8e1fmgqv5zbndgo6.jpg (http://img141.imageshack.us/i/kgrhqfg8e1fmgqv5zbndgo6.jpg/)
This is a truly phenomenal sounding 12AX7/ECC83 and genuinely lives up to the hype. I thought the Mullard CV4004 was brilliant, until I heard this! :eek:
The CV4004 is still a fantastic sounding valve, with a very 'musical' signature, but the Amperex has an openness and extension in all areas of the frequency range which escapes the CV4004, and any other ECC83-type valve I've heard so far, and its way with music is simply breathtaking.
It has shimmering, sparkly highs which illuminate all genres of music with addictive insight, but that never strays into forwardness or fatigue. The midrange is both 'creamy', yet incisive, showing incredible clarity, and bass has the uncanny knack of exhibiting superb extension, yet with it, massive grip and gravitas.
The Bugle Boy really opens up and throws a spotlight on all recordings, dissecting them for forensic inspection, yet does so without the listening experience becoming in any way fatiguing - magical stuff! Expensive, yes, but if you truly want the best........
Another stand-out has been the 1952 Sylvania CHS 6SL7WGT:
http://img9.imageshack.us/img9/6484/b3ctegkkgrhqjhyew5bfpqc.jpg (http://img9.imageshack.us/i/b3ctegkkgrhqjhyew5bfpqc.jpg/)
This provides a nice contrast to the VT-229s, and performs the role of 'middle valve' between the line-level and phono stage exceptionally well, adding a slight touch of warmth and richness to compliment the wide-open and explicit, hugely detailed, nature of the Ken-Rad/RCAs, creating a heady cocktail of sonic fireworks and musical addictiveness.
VT-229:
http://img145.imageshack.us/img145/4682/s6sl7rca2kleintad.jpg (http://img145.imageshack.us/i/s6sl7rca2kleintad.jpg/)
I've still to hear the NOS Raytheon and Amperex 6SL7s, in the role of 'middle valve', but unless they are truly exceptional, I believe that I've hit upon the ideal mixture of insight and musicality with the combination of the 1940s VT-229s and 1952 vintage Sylvania CHS 6SL7WGT.
The addition of the VT229s to the line-level stage has now allowed me to move the superb GE 5691s to the phono stage:
http://img717.imageshack.us/img717/8404/6895691ge800.jpg (http://img717.imageshack.us/i/6895691ge800.jpg/)
...which have ousted the Brimar CV1985s. I'll be keeping those now as spares.
The result is that the phono stage of the Croft now sounds better than ever, as the sonic qualities of the Bugle Boy have also had a significant influence.
Lastly (for the moment) one other little valve which has had a surprising influence on performance, is a NOS 1967 Mullard 85A2/OG3 regulator valve, which I actually prefer to the NOS Amperex one I bought:
http://img204.imageshack.us/img204/7430/cdguqcgkkgrhqzie0eeuhcg.jpg (http://img204.imageshack.us/i/cdguqcgkkgrhqzie0eeuhcg.jpg/)
I wouldn't necessarily say that in isolation it's better than the Amperex, but it marries beautifully with the sonic signature of the Bugle Boy (both are in line with the power supply), creating a lovely rich, enveloping sound, full of airiness and detail. The NOS Amperex 85A2 was just a touch clinical sounding in comparison.
So have I achieved a significant upgrade by completely re-valving my Croft preamp with all these 'exotic' NOS tubes? YOU BETCHA!!
Quite frankly, it's a no-brainer, and the Croft has never sounded so good. It was bloody good before, but I've now achieved an ideal balance of it being both highly revealing and insightful, yet wonderfully relaxing and musically rewarding, where one at low or high volumes, can revel in the beauty of musical performances, relaxing into them and feel satisfied like never before.
All-in-all, on the valves I've selected for the Croft, I've spent just over £300 (this doesn't include the valves I haven't used), which for the results I've achieved, I think is pretty good value.
I doubt that I could've obtained the unique sonic qualities I've achieved any other way, and in the past I've spent three times that amount on one pair of interconnect cables, and not gotten anything like as significant an improvement in sound quality.
So, Croft-wise, it's job done - or rather it will be once I've assessed the Raytheon and Amperex 6SL7s.
Once done, my focus will then be on finishing re-valving the copper amp, so watch this space for further, and rather novel, developments on that front, in terms of the KT88s. I shall say no more for the moment! ;)
Marco.
So, Croft-wise, it's job done - or rather it will be once I've assessed the Raytheon and Amperex 6SL7s.
The Amperex has now arrived, and I've had time to analyse its sonic effect and also that of the Raytheon ... The Raytheon was excellent, but in the final analysis, just ousted by the 1952 Sylvania, in terms of its marginally more expressive midrange and overall 'musicality'. It'll certainly be a nice spare to have!
However, it all changed when I put the Amperex in.... Jeez, that turned out to be the 6SL7 equivalent of the 'Bugle Boy', and exhibited exactly the same wonderful and highly addictive sonic characteristics as its ECC83 'little brother'! :eek:
Ultimately, the Amperex was just a smidgen less coloured sounding than the Sylvania and, in my opinion, more faithful to what was actually on recordings, which as I seek accuracy (as far as possible, subjectively) is a trait I will always favour in the final analysis.
Therefore, if you use 6SL7s in any of your amps, and spy one of these chaps:
http://img845.imageshack.us/img845/5680/ce1klybgkkgrhqfk8e1fubq.jpg (http://img845.imageshack.us/i/ce1klybgkkgrhqfk8e1fubq.jpg/)
...snap it up, as IMO, it's one of the best sounding 6SL7s there is, along with the VT229 (RCA, Ken-Rad or Tung Sol), and the GE 5691. So, in terms of 're-valving' the Croft, it's job done! :)
Now to finish off the Copper amp... And I have a cunning plan up my sleeve when it comes to finding some nice KT88s - or rather, they may not actually be KT88s, at all..... Watch this space! ;)
Marco.
Hi
Is this bugle boy 12ax7 (ecc83) made in holland?
If so the philips ecc83 are the same.
Marco can you see some dato code on the valve?
Check this link:
http://www.tube-classics.de/TC/Tubes/Valvo%20ECC83/ECC83.htm
best Jan
Hi Jan,
Yes it is. Internally, the 'Bugle Boy' looks identical to the Phillips Mini Watt long-plates from the 1950s, shown on the site you linked to. However, I've heard Phillips Mini Watts (albeit 'chrome plate' types), and they sound great, but not quite as good as the 'Bugle Boy'. Perhaps the 'long grey plate' ones do?
In any case, I suspect you'd pay just as much, or perhaps more, for the (rare) 'long grey plate' 1950s Mini Watts, shown on the website, as you would for a 'Bugle Boy'....
As an aside, could you do me a favour please and add your basic location to your profile? This info is now required from all members - cheers! :cool:
Marco.
Ok, just a quick update on the ECC83/12AX7 situation in the Croft....
There was one tube I noticed when someone earlier in the thread posted a link to Upscale Audio in the States (a NOS Mazda 12AX7), which I fancied trying before putting the whole ECC83/12AX7 thing to bed, and so I duly ordered one of the 'Platinum Grade' versions (see here):
http://www.upscaleaudio.com/tubes/12ax7/mazda-12ax7.html
I think, all in, with shipping, it cost £85.00. Incidentally, just a word about Upscale Audio - the service they give is absolutely FIRST CLASS, and are undoubtedly the best company I've ever dealt with abroad. Therefore I'd recommend them highly to anyone here.
Anyway, so after some further tube-rolling and much critical listening, I've settled on this NIB NOS 1963 Mazda 12AX7, as my favourite for the Croft (btw, these sound different from the Marconi and Phillips Mini-Watts I've got, even though they look very similar):
http://img41.imageshack.us/img41/9277/mazda12ax7c2.jpg (http://img41.imageshack.us/i/mazda12ax7c2.jpg/)
The Mazda has all the desirable sonic qualities of the Amperex 'Bugle Boy' (filigree detailing, impact and drive, and sparkly highs) and the CV4004 (beautiful midrange tone and texture), but adds its own magic, in the form of extremely low coloration (you can hear why these tubes were once used in the recording industry) resulting in a 'hear through' effect, which gives microscopic insight into recordings, and a gorgeous 'creamy' quality imparted to vocals and all instrumental detail - just my thing! :)
After now having tried numerous 'premium quality' ECC83-types, IMO, the Mazda has it all. One thing I would say is that it's not a 'warm' sounding tube, but rather one which is ruthlessly revealing, but not in a cold and clinical sense. It manages to shine a bright light onto recordings, revealing every small detail and nuance in all its glory, but without causing listening fatigue. Therefore those of you who enjoy a more euphonic presentation, or have a system with a somewhat explicit top-end, should perhaps look elsewhere.
So that's it - job done! As an aside, John (Camtwister) is now the happy owner of the CV4004 and 'Bugle Boy', so all's well that ends well :cool:
Marco.
"1 tube électronique"? No doubt your Croft now enjoys a certain "je ne sais quoi" or a bit of Gallic "savoir faire" :eyebrows:
Well done! Are you able to identify the acoustic terroir? ;)
Hi Barry,
Lol... With the sound I'm getting at the moment, it's more like a healthy dose of joie de vivre!! :)
Marco.
Busybee330
29-06-2011, 08:28
Hello Marco
As I am the new owner of a Croft Micro 25 pre :) , I could well get these Mazda tubes you are fond of .
Did you choose to have them cryogenically treated ?
Also , planning on getting the Series 7 Amp , I suppose that this tube would also be ideal in the amp . Or would you go for the CV4004 or the Amperex ?
Thank you.
Bernard
Hi Bernard,
No, the Mazda was non-cryo'd, as I don't believe that this option was mentioned as being available. However, I suspect that if you mentioned it to Upscale, they'd cryo it for you, at your own risk. Remember that not all tubes survive the process, especially NOS ones! ;)
The Mazda is superb if you like a very revealing and detailed sound, which marries well with the signature of the other tubes used in my Croft preamp, but if you prefer a slightly warmer sound, then others I'd look at are the Mullard CV4035s, currently for sale on Tubemonger:
http://www.tubemonger.com/Mullard_CV4035_NOS_NIB_1961_Prem_CV4004_Whyteleafe _p/2050m.htm
Those I suspect will also be real quality. I've ordered one to test against the Mazda, so I'll let you know how that goes! :cool:
Marco.
Busybee330
29-06-2011, 08:42
Ok , I will wait for your review :)
Hi Bernard,
No, the Mazda was non-cryo'd, as I don't believe that this option was mentioned as being available. However, I suspect that if you mentioned it to Upscale, they'd cryo it for you, at your own risk. Remember that not all tubes survive the process, especially NOS ones! ;)
The Mazda is superb if you like a very revealing and detailed sound, which marries well with the signature of the other tubes used in my Croft preamp, but if you prefer a slightly warmer sound, then others I'd look at are the Mullard CV4035s, currently for sale on Tubemonger:
http://www.tubemonger.com/Mullard_CV4035_NOS_NIB_1961_Prem_CV4004_Whyteleafe _p/2050m.htm
Those I suspect will also be real quality. I've ordered one to test against the Mazda, so I'll let you know how that goes! :cool:
Marco.
Hi Marco - Just thought I'd gate crash the thread as it's a subject close to my heart (ears?) ;)
I took delivery of these recently (http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=230552938357&ssPageName=STRK:MEWNX:IT#ht_10577wt_936) together with another very similar pair and have had them in the Croft 25R for a while - they truly are stunning :)
In the past I've had TFK's, Brimar's, TESLA (NOS not JJ) and latterly Philips Miniwatts (these were very nice - same as Amperex BB's) - anyway, in my setup the RCA 12AX7A's "better" the lot - they combine the fast pace and pure highs of the best TFK's but have the rich mellow tuneful mid range of the Philips (not as warm as the Brimar/Mullards). Also they are uber quiet. Coupled with the Brimar 6060 Yellow T the 25R really is world class IMHO.
Inteerstingly, the RCA's did not sound so good in the Croft S4s whereas the Miniwatts just sound fabulous. Strokes for folks of course but I can heartily recommend the RCA's. I have 2 spare pairs (not as good as the ones I am using but mighy fine nonetheless if you would care to try them for yourself :)
Steve
Busybee330
07-07-2011, 08:46
Hi Marco
Did you receive these Mullard CV4035 ? :)
Not yet, dude. There's been a bit of a delay... Should be soon, though :)
Marco.
Hi Marco - just installed a GEC A2900 (12AT7) in the Croft 25R gain stage - it is truly stunning! I thought the Brimar Yellow T 6060 was impressive (better by miles than the TFK ECC801S I was using before) but this is in a class of it's own! OK so not cheap (but then neither are those Mazda's).
Steve
Hi Steve
I also play with a Croft 25RS.
I use a 12bh7a Sylvania black plate. nice tube also.
Can i use ecc81 and ecc82 tube in the anode follower(gain stage)?
I want a more dry sound, because i also play with a series 7R and old Tannoy monitor gold 15". And the sound is a littel dark.
best jan
Can i use ecc81 and ecc82 tube in the anode follower(gain stage)?
I want a more dry sound, because i also play with a series 7R and old Tannoy monitor gold 15". And the sound is a littel dark.
best jan
Hi Jan, yes you ca use an ecc81 in the gain stage. I think a Brimar 6060 Yellow T might give you the dry sound you are looking for.
Regards
Steve
My recently acquired power amplifier has two RCA Radiotron 5687 tubes. Are these good stuff?
Hi
Just tried a Mullard e80cc insted of the 12bh7a in my Croft Series 7.
Wow this e80cc sound good.More later.
jan
Hi,
I see that worrasf sourced a set of GEC A2900 valves and I have recently discovered that at least one in my Croft OTL is in the process of dying. I have tried others but I find them rather poor in comparison.
So, I wonder, could anyone point me in the direction of a supplier?
Many thanks
Withani
Mr Kipling
19-09-2012, 20:32
Did you know there's three different types? Looking on the 'net I found there's a double mica, a later triple mica and an early triple mica. The later triple is marked ar CV6091 and the early triple has a batch no of 100. This is reckoned to be the best of the three. Here's quite an old link:
http://hktubeaudio.homestead.com/files/12AT7.html
Thanks Mr Kipling.
My 2900' s seem to be the type number 3) - they are Lot 27 with a UF Z code on the glass.
Anyone know where I might source any?
Cheers
Withani
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