View Full Version : Calling Valve experts...
After a bit of a brown trouser moment with my valve amp I think there's new valves in my (hopefully not immediate) future.
Currently running matched Quad of Gold Lion KT88's.
Looking ahead, thinking to pick up the best KT88's I can get.
The Svetlana Winged 'C' was Marco's reccy, but they are really hard to get.
Only found them as a matched pair, and I need 4 in all.
Could I get away with 2 separate matched pairs?
I know its not ideal, but is it really such a problem?
Alternatively looking to Shuguang Treasure KT88-Z or PSVane TII, though they are a bit more expensive.
What's yer thoughts on these and are there any alternatives worth looking into?
thanks.
Anthony your man to talk too
Stick with the Golden Lions...possibly the best current production KT88s. I had some NOS Winged Cs in my last amp but preferred the Golden Lions. It largely depends on the circuit they're in so take with a massive pinch of salt any hard and fast recommendations people might make on power valves. Just because they sound good in one amp is no recommendation they'll sound good in another. Some NOS are worth the money but most aren't imho. Current production valves are getting better all the time although there's still quite a high failure rate on the cheaper (read "non premium") brands. Many of the brands from Eastern Europe come out of the same factory anyway and are simply (quality) matched and re-branded. Pre/driver valves often make a larger difference than swapping out power valves.
Magna Audio
14-09-2013, 17:22
Best are GEC nos. Arm and leg and each time you turn on you burning your cash up. I preferred Electro Harmonix to Svets and Tesla's. The Svets quite aggressive, the Tesla's dry.
Of course other amp components etc affect / have to find synergy
Ali Tait
14-09-2013, 17:25
After a bit of a brown trouser moment with my valve amp I think there's new valves in my (hopefully not immediate) future.
Currently running matched Quad of Gold Lion KT88's.
Looking ahead, thinking to pick up the best KT88's I can get.
The Svetlana Winged 'C' was Marco's reccy, but they are really hard to get.
Only found them as a matched pair, and I need 4 in all.
Could I get away with 2 separate matched pairs?
I know its not ideal, but is it really such a problem?
Alternatively looking to Shuguang Treasure KT88-Z or PSVane TII, though they are a bit more expensive.
What's yer thoughts on these and are there any alternatives worth looking into?
thanks.
Two matched pairs is fine mate. What matters is that they are reasonably well matched in each channel.
I would get Ali to measure the voltages in the amp before you start burning money.
Ali Tait
14-09-2013, 17:35
Aye, doing that tomorrow Nick.
Taking the big lump over to Ali's tomorrow Nick, so worth checking as you say.
Anything else you'd say was worth looking at?
One thing that interested me was possibly fitting KT120 valves later on if it's do-able.
I believe though you need to make sure the transformers can handle them.
How would you do that Nick, could be useful to know for the future.
The lump weigh's 5 stone, wont be shunting it about that often!
Thanks.
I really like the Golden Lions.. probably the best I have used. the EH KT88s are also of good consistent quality, last well and sound good, and are good VFM.
I think that new sensor have made a big investment in QC and test gear as a factory matched quad bias very closely and hold their bias very well once burned in and adjusted.
For me, I wont go NOS as it is a crap shoot albeit that they are probably still the best if you can be sure that you are really getting what you are paying for. far too many fakes and shagged tubes being sold as NOS for me to put my money there. a geniine set of Gec KT88s will last much longer than any equivilent modern Kt88s but are virtually all gone and cost the earth, so modern kt88s are a better option in the real world.
Chinese valves are also a bit hit and miss as I've had too many Shuguangs going gassy or crackley, but they can be very good if you get tested and selected valves. unfortunately there are too many grey importers selling rejects to be a safe purchase imho. The shuguang treasures and psvane kt88s have a good rep but are overhyped and overpriced so I havent tried them.
The tung sol Kt120 is my favourite power tube of all, and I have eight in my lp125sa. they sound just fabulous if.your amp can use them safely and make the most of what they can do.
Good luck and experiment a little!.
A vote from me for Electro Harmonix. We don't know the design of your amp but some KT88 amps can use 6550 valves as drop in replacements and well worth trying IMO if you are able. I had a WAD KaT88 and preferred it with the 6550's.
There is also the consideration of KT90 as alternatives as well.
I believe though you need to make sure the transformers can handle them.
How would you do that Nick, could be useful to know for the future.
Not sure if you can know that. If they are biased to pass the same current then you need to know if your heater winding can supply a extra 1A or so of current. Without know the transformer spec you cant say.
Knew it was complicated!
Some info on the amp, not all technical unfortunately.
But an internal pic, not sure if it will help.
Its a heavy lump (about 5 stone) so lots of iron in there I think.
http://forum.audiogon.com/cgi-bin/frr.pl?ramps&1220733371&&&/Image-Audio-65i-Tube-amp-
*edit*
some more info, see how good your chinese is... :)
http://www.imageaudio.cn/product_view.asp?id=104
thanks.
Sovereign
14-09-2013, 19:22
Hi Mate, I have a matched quad if you want to buy them.
After a bit of a brown trouser moment with my valve amp I think there's new valves in my (hopefully not immediate) future.
Currently running matched Quad of Gold Lion KT88's.
Looking ahead, thinking to pick up the best KT88's I can get.
The Svetlana Winged 'C' was Marco's reccy, but they are really hard to get.
Only found them as a matched pair, and I need 4 in all.
Could I get away with 2 separate matched pairs?
I know its not ideal, but is it really such a problem?
Alternatively looking to Shuguang Treasure KT88-Z or PSVane TII, though they are a bit more expensive.
What's yer thoughts on these and are there any alternatives worth looking into?
thanks.
Hi Gaz,
Seems like Langrex have run out (hopefully just temporarily) of Svetlana 'Winged C' KT88s. Perhaps give them a ring and find out the stock position? However, if your amp can safely take KT120s, I'd go with those instead, as in my opinion and experience with my own amp, they considerably outperform their smaller brothers in any sonic parameter you care to mention, save perhaps the glorious midrange characteristics of the best GECs KT88s.
Incidentally, does anyone know where Icon Audio got their KT150s from? I've searched to find somewhere that sells them, but have drawn a blank. However, they must exist somewhere for Icon to have obtained them!
I'm wondering whether those could be safely used in my Copper amp? I've not had a chance to discuss this yet with Anthony.
Nick, perhaps you would know? :)
Marco.
Parts Connexion seem to have them.
http://www.partsconnexion.com/product25822.html
Looks like you should allow a extra 400ma per valve for the heater.
http://www.pyndt.dk/Tung-Sol%20KT150%20Curves.pdf
However, if your amp can safely take KT120s, go with those instead, as IMO, they considerably outperform their smaller brothers in any sonic parameter you care to mention...........
Marco.
Have you heard KT120's? When and where and in what amp? Do KT120's sound the same in every amp? What did you hear that caused you to conclude that KT120's produce a sound that elevates them above all the alternatives?
To say they 'outperform their smaller brothers in any sonic parameter' is a thoroughly unqualified sweeping statement, not backed up with evidence. That statement has the potential to suggestively encourage the ignorant to dismiss KT66, KT88 and KT90, not to mention several plug in alternatives.
Constantly you advocate the 'trust your ears' approach. However, your recommendation here seems to suggest, ' trust MY ears', yet you fail to provide any evidence as to why we all should trust your 'golden ears' :scratch:
I don't buy it. I seriously hope most other readers don't accept your statement on this topic either.
Parts Connexion seem to have them.
http://www.partsconnexion.com/product25822.html
Looks like you should allow a extra 400ma per valve for the heater.
http://www.pyndt.dk/Tung-Sol%20KT150%20Curves.pdf
Cheers, Nick! I'll speak with Anthony about it :)
Marco.
Not sure if you can know that. If they are biased to pass the same current then you need to know if your heater winding can supply a extra 1A or so of current. Without know the transformer spec you cant say.
Is there a way to measure that or would you need the original spec from the manufacturer?
Have you heard KT120's? When and where and in what amp? Do KT120's sound the same in every amp? What did you hear that caused you to conclude that KT120's produce a sound that elevates them above all the alternatives?
To say they 'outperform their smaller brothers in any sonic parameter' is a thoroughly unqualified sweeping statement, not backed up with evidence. That statement has the potential to suggestively encourage the ignorant to dismiss KT66, KT88 and KT90, not to mention several plug in alternatives.
Constantly you advocate the 'trust your ears' approach. However, your recommendation here seems to suggest, ' trust MY ears', yet you fail to provide any evidence as to why we all should trust your 'golden ears' :scratch:
I don't buy it. I seriously hope most other readers don't accept your statement on this topic either.
Er, Greg, calm down and stop being so aggressive! I'm only offering my opinion - I shouldn't have to prefix every sentence I write with with 'IMO, IMHO', for that to be understood.
I currently use KT120s in my Copper amp (and have been doing so for a year and a half), which replaced GEC KT88s. I've also tried every example (I know of) of current production KT88s, and to my ears, KT120s are significantly sonically superior. For me, there are no downsides, in comparison with most KT88s. That is simply my opinion, yours may differ.
Three people I know of have done the same with their valve amps and moved from using KT88s, to KT120s, and all of them have arrived at the same conclusion.
Marco.
Is there a way to measure that or would you need the original spec from the manufacturer?
Well, you would only know for certain if you had the winding details. You might make a guess based on the core size, the windings and the size of wire used, then check by keeping a eye on the TX core temperature while running.
Er, Greg, calm down and stop being so aggressive!
Please do not attempt to patronise me. You may be able to apply parental/teacher style control over other members here, but it doesn't work with me.
I currently use KT120s in my Copper amp (and have been doing so for a year and a half), which replaced GEC KT88s. I've also tried every example (I know of) of current production KT88s, and to my ears, KT120s are significantly sonically superior. For me, there are no downsides, in comparison with most KT88s. That is simply my opinion, yours may differ.
That rather confirms what I have said. You've tried them in your amp and like them over other options, but you probably have no knowledge of how they perform in other designs. I know you think you amp design is the best ever, but that opinion is not necessarily shared by others, probably because others have different ears ;)
Three people I know of have done the same with their valve amps and moved from using KT88s, to KT120s, and all of them have arrived at the same conclusion. Marco.
Ah, so that is conclusive evidence that 120's better 88's per se....is it? That is a very low percentage of conclusion especially if those concluding possibly come from a trio of your AOS groupies. Your statement is nonsense. It all depends on the overall design of the amp. As ever, your sweeping statements are not helpful although it is completely valid that you share your limited experience. It would be good if in future, you emphasise that your experience is just that, limited.
Greg,
You've obviously been at the pop again... Go and have lie down, old chap, and return when you're sober! :eyebrows:
Marco.
walpurgis
14-09-2013, 21:46
http://i39.tinypic.com/1zd8ayr.jpg
southall-1998
14-09-2013, 21:49
Greg,
You've obviously been at the pop again... Go and have lie down, old chap, and return when you're sober! :eyebrows:
Marco.
Or, you go and rub his feet :)
Lol... I think I'll pass on that one!
Marco.
You've obviously been at the pop again... Go and have lie down, old chap, and return when you're sober! :eyebrows:Marco.
Sadly as with most of your comments and posts on this, your forum, that is a completely unqualified and actually an insulting presumption. Other members here will not be impressed with your response unless of course, they are your groupies. As the proprietor here, you should be ashamed of your ridiculous presumptive suggestion. You are wrong, but no matter. It is completely unacceptable for you to reply to me in such a condescending and (trying to apply) controlling manner. As said, you are not my parent or teacher. You have no authority over me. (Or anyone else actually).
Your approach to me is actually doing you and AOS a disservice. You are showing what your mindset really is. Keep going on this way and you will continue to loose any respect or kudos you currently hold here.......hmm, some members here just post in response to you in a certain way just to wind you up and witness how you come back because they enjoy egging on your totally inflated ego. Certainly, I've done it :lol:
Wake up and maybe reflect!
Have to say, having met Greg a couple of times he's a laid back considered kinda character.
To me, he's one of the good guys, he's been very generous with his (not inconsiderable) knowledge of valve amps and DIY with me.
You too Marco, enjoyed our chat on the ham bone that last time.
Sitting across a table sharing a beer is usually how you get the measure of someone, not on a forum imo.
Its all good and at the end of the day its only hifi.
Sure that's right? :)
Greg,
Lol - I'll "wake up", sweetheart, when you've sobered up! :wave:
Marco.
walpurgis
14-09-2013, 22:43
Why so serious Greg? I'm sure you're a decent fella, but you come across as very formal and 'proper'. Can you relax a bit?
(just being friendly, not criticising). Geoff. :)
southall-1998
14-09-2013, 22:46
Why so serious Greg? I'm sure you're a decent fella, but you come across as very formal and 'proper'. Can you relax a bit?
(just being friendly, not criticising). Geoff. :)
Greg, you are getting a smile from Geoff.....VERY, VERY RARE!!
Sorry Geoff, can't resist!! :lol:
Have to say, having met Greg a couple of times he's a laid back considered kinda character.
To me, he's one of the good guys, he's been very generous with his (not inconsiderable) knowledge of valve amps and DIY with me.
You too Marco, enjoyed our chat on the ham bone that last time.
Sitting across a table sharing a beer is usually how you get the measure of someone, not on a forum imo.
Its all good and at the end of the day its only hifi.
Sure that's right? :)
Indeed, Gaz. I've met Greg loads of times, and we get on fine in real life, and on here (most) of the time, too. However, sometimes he blows more hot and cold than a menopausal woman!! :lol:
Therefore, if he thinks I'm rising to this pish, he's got another thing coming! ;)
Why so serious Greg? I'm sure you're a decent fella, but you come across as very formal and 'proper'. Can you relax a bit?
(just being friendly, not criticising). Geoff. :)
He's a policeman, Geoff - and tonight a (seemingly) rather pished one!! :drunk:
Marco.
walpurgis
14-09-2013, 22:56
He's a policeman, Geoff
Ah, that would explain the rather 'statement' like posts. ;)
Indeed. He does get rather carried away sometimes! ;)
The bottom line is that I've experimented quite considerably with both KT88 and KT120 valves - all in the same amp, of course: my own amp, the one I use every day and whose sound I know inside out, and therefore the one most able to produce meaningful results (for me). Therefore, my comments are based solely in that context (I never said otherwise), and of course results may vary in other amps and systems.
All that should be pretty obvious, and so not require qualifying in every comment I make on the matter. Furthermore, the results obtained were the same in Ian Walker's and Steve Toy's system (both using TD Copper amps), where the KT120s significantly outperformed the KT88s that were in it before.
Gaz, I can go into more detail, if you wish, about the sonic differences we all perceived, and of course then make up your own mind on the matter. I'm not asking you to agree with me or consider my opinion as fact (heaven forbid), but then you knew that anyway!! :)
Marco.
Just as an aside to some of the recommendations being made here, can I please stress that if tempted to drop in a set of KT120s as a replacement for KT88's then DON'T. At least do not until you have checked with your amp manufacturer that your circuit is designed to cater for the extra filament current that KT120's draw (up to 0.3A per valve which is SIGNIFICANT). I've seen good customers of mine burn out power supplies by over biasing amps to run KT120s because "someone on a forum said they sounded better". I don't know if Greg was meaning to allude to this, but if he was, then objectively, Greg has actually made a perfectly valid point.
KT = Kinkless Tetrode so the distortion characteristics of a KT88, KT90 and KT120 are pretty much the same, and by and large, the "sound" that they deliver is similar. What sets them apart is power output. KT120's have a lot more welly and this naturally makes them sound different, more powerful. It does not mean that their phase accuracy or any other aspect of how something sounds is drastically different if level matched. Again, it is largely dependant upon the circuit they are in as the sound of a valve amp is not made or broken by a single component in its chain, rather by the way the circuit is designed, the amount of distortion produced, the frequency response, feedback, and output impedance etc etc and this is a function of the overall circuit, the quality of the power supplies and the quality of the output transformers. Sorry to bang on about this, but it's a reaction to the inaccurate general statements made as if fact that just swapping output valves can transform every amp...that simply is not the case. Be careful when messing with output valves. Your amp was designed around a particular valve for a reason. Before deciding to swap that out for one which draws different current, its a prudent move to check what the consequences might be. Sorry if it' a bit late for some down to earth sentiments :lol:
walpurgis
14-09-2013, 23:16
I'm not sure personal experience and personal opinion should require 'qualification' at all. Each to their own views obviously and we can all make our minds up as to what we consider useful info.
Granted. I'm just trying to be objective and helpful. Each to their own about what sounds right for them and rightly so, but please re-read what I wrote as it was pointing out some of the pitfalls of ignoring whether their valve amps are up to rolling more powerful valves, that's all. The advice is meant in good faith, but is there to be taken or left as you see fit. However, when I see something that could be misconstrued as fact that could need further explanation, if not challenge due to the potential consequences as explained, then its equally as valid to express that viewpoint.
Hi Paul,
Just as an aside to some of the recommendations being made here, can I please stress that if tempted to drop in a set of KT120s as a replacement for KT88's then DON'T. At least do not until you have checked with your amp manufacturer that your circuit is designed to cater for the extra filament current that KT120's draw (up to 0.3A per valve which is SIGNIFICANT). I've seen good customers of mine burn out power supplies by over biasing amps to run KT120s because "someone on a forum said they sounded better".
Absolutely, and thanks for pointing that out, although Nick had partly dealt with it earlier. The same would also apply with me before I attempt to try some KT150s. I wouldn't dream of doing so without checking first with Anthony.
KT = Kinkless Tetrode so the distortion characteristics of a KT88, KT90 and KT120 are pretty much the same, and by and large, the "sound" that they deliver is similar. What sets them apart is power output. KT120's have a lot more welly and this naturally makes them sound different, more powerful.
Indeed, and that extra "welly" can have a profound effect on the musical presentation and sonic performance of the partnering system, especially when the amp has been designed to take full advantage of that extra power. That is precisely what prompted my recommendation for them over KT88s, which to my ears sound 'small', somewhat tonally imprecise, and dynamically limited in comparison.
The only criticism I'd levy at the 120s, is that in comparison with my GEC KT88s, they lack the latter's rather beguilingly open and lucid sounding midrange, and sound slightly constrained there in comparison - but that's only because the GECs are quite exceptional in that respect. However, in normal circumstances, KT120s are not lacking in any area of their sonic presentation. In my opinion, in comparison with 'normal' KT88s, particularly in terms of authority and bass grip, they leave them standing, especially the modern production variety - that is of course if your amp and system suits them!
Again, it is largely dependant upon the circuit they are in as the sound of an amp is not made or broken by a single component in its chain, rather by the way the circuit is designed, the amount of distortion produced, the frequency response etc etc and this is a function of the overall circuit, the quality of the power supplies and the quality of the output transformers. Sorry to bang on about this, but it's a reaction to the inaccurate general statements made as if fact that just swapping output valves can transform every amp...that simply is not the case. Be careful when messing with output valves. Your amp was designed around a particular valve for a reason. Before deciding to swap that out for one which draws different current, its a prudent move to check what the consequences might be. Sorry if it' a bit late for some down to earth sentiments :lol:
Not at all. Your warning is entirely appropriate and understandable, so thanks for giving it.
Marco.
I'm not sure personal experience and personal opinion should require 'qualification' at all. Each to their own views obviously and we can all make our minds up as to what we consider useful info.
Precisely!! However, we'll let Greg off with it since it's obviously his 'time of the month' :eyebrows:
Incidentally, Paul is blameless, in terms of the valuable technical information he offered, and caution based on that for anyone who might read this and wrongly think that KT120s are 'drop in' replacements for KT88s. Quite simply, as he rightly said, they are not!
Marco.
walpurgis
14-09-2013, 23:52
I think Paul thought I was responding to his post. I wasn't, he managed to post just before I did and I hadn't seen what he'd said! :eyebrows:
Exactly. That's why I was clearing that up :)
Okies, it's time for me scratcher! :goodnight:
Marco.
I think Paul thought I was responding to his post. I wasn't, he managed to post just before I did and I hadn't seen what he'd said! :eyebrows:
My apologies Geoff...crossed wires on my part due to a quick succession of responses tripping one another up!
anthonyTD
15-09-2013, 09:49
Hi All,
I have been looking into the new KT150 and have contacted one of my suppliers who will hopefully be getting some stock soon, as for the parameter differences, they should work in some amps designed to use KT88, however, as Nick [Lurcher] has pointed out, the biggest issue is the extra heater current, considering a standard KT88 draws around 1.5amp at a steady state, KT120 around 1.6 amp, and it would seem the new KT150 around 1.7 amp, now it doesn't seem much of a difference comparing single tube figures, however' when you start looking at the amp as a whole, then, remember, for most common stereo push-pull KT88 based amps, thats an extra 800 ma of heater current the mains transformer has to supply, now as i said earlier, there are a lot of well designed amps out there that would cope fine [mine included] but it would be down to the individual to inquire with their amp manufacturers to find out if it is indeed the case with their products, there are a lot of amps out there that i fear' are already on the limit as far as mains transformer supplies and temperature are concerned so, that extra 800ma may be the "Final straw that broke the camels back" the other issue may be with biasing, again, it will depend greatly on how your amp is biased, and if it can be adjusted to set a safe current draw limit, again, there are amps out there that will be able to take advantage of the extra power these valves have to offer, but i suspect most will have to be run at the same current draw parameters as the KT88 to keep them on the safe side,this would then mean that any benefits of using this valve instead of the KT88 will be somewhat limited solely on sonic differences and not power.
I hope this helps.
Anthony,TD...
...now as i said earlier, there are a lot of well designed amps out there that would cope fine [mine included]...
Nice one, mate - that's just the news I wanted to hear! :yay:
:gig:
Marco.
SteveTheShadow
15-09-2013, 10:33
I would certainly say that KT120s sound good in my own amp, which was designed and built from scratch to use them. But on a philosophical point, how do I know that it is KT120s that make my amp sound as it does? as said earlier, it's the sum of all the parts and how they interact that make an amp sound the way it does, not what flavour of the month power valves you use in it. You can make a great sound with EL34s, KT88s, 6550s and on and on, if the design is sympathetic to each one. So you cannot say that a KT120 sounds better than an EL34, it all depends as they say. The only thing we can be sure of is how a valve performs in our own amplifier, into our own speakers.
As I designed my amp around KT120s, there is no way it would take KT88s without blowing them up, so I have no desire to tube roll.
As for the KT150, I would love to try them, but if I did, I would rather design an amp around them than plug them into my KT120 amp and hope. £100 each is not a trivial sum to take a chance on, well not for me it isn't. I await with interest, the verdict.
the kt120 is a fine tube, and was my favourite in my rogue stereo 90. I did check with rogue before using them that there was was a sufficient margin in the winding to cope with the extra heater current. they sounded great but my residual oncerns were that they seemed to produce quite a bit more heat through radiation, and that I had to wind the bias pots almost to their limit to hold the bias at the recommended 40ma.
best to view them as ' somewhat interchangeable' with kt88/6550 types.
the Golden lion kt88s are an excellent valve too, just with a slightly richer bass sound, which I happen to like in that almost amp equally. our is just a different presentation.
best regards
Alex
Hi Steve,
I would certainly say that KT120s sound good in my own amp, which was designed and built from scratch to use them. But on a philosophical point, how do I know that it is KT120s that make my amp sound as it does? as said earlier, it's the sum of all the parts and how they interact that make an amp sound the way it does, not what flavour of the month power valves you use in it.
I couldn't agree more!
My eulogising of KT120s was not intended in any way to promote some superficial 'flavour of the month', but rather to relate my genuine experiences, accumulated over some time now of using those valves in my amp, to other members (such as Gary), who may own an amplifier that can take advantage of their benefits. After all, there must have been valid reasons why you chose to build your amp around KT120s, as opposed to KT88s ;)
Unlike yours, my amp wasn't built specifically for KT120s, simply because they weren't available to use at that time, but rather KT88s. However, when KT120s became available, I had the mains transformer of my amp (and all other necessary parts of the circuitry) upgraded to cope with their extra electrical demands, and so Anthony specified a mains transformer from Sowter that was as 'overkill' as possible for the job, and which would still fit inside the original casing.
Therefore, although my amp was not originally built for use with KT120s, it has since been modified to take full advantage of the extra power that they offer - and my goodness, you can hear it!! :exactly:
You can make a great sound with EL34s, KT88s, 6550s and on and on, if the design is sympathetic to each one. So you cannot say that a KT120 sounds better than an EL34, it all depends as they say. The only thing we can be sure of is how a valve performs in our own amplifier, into our own speakers.
Absolutely - and never at any point have I wrote anything to the contrary. Of course, as you know, much will depend on the type of sound you're after and the characteristics of the system and speakers you're using.
With the type of prioriities I have, I'll generally always favour using the most powerful push-pull valves available, which can thus exert the most 'grip' and control over the rather large 15" Tannoy drivers inside my Lockwood Majors, especially as the speakers are housed in a pretty small room, so bass grip and control are very important factors for me, as is my system having an effortless quality to play loudly and cleanly (with ALL types of music), with little signs of stress or listener fatigue.
Aside from the more subtle aspects of recorded music reproduction (which with the best systems I take as a given), I like recorded music to sound as 'real' as possible (in a physical sense), and for me that requires goodly dollops of power and the ability to shift plenty of air in as controlled a fashion as possible. Therefore, with KT150s fitted, my amp will effortlessly (and *that* is the key word here) deliver 60W of Class A into 95db efficient speakers, and I know that this will be an utter riot!! :fingers: :eyebrows:
Others may have different and equally valid prioriities, and that's absolutely fine.
As for the KT150, I would love to try them, but if I did, I would rather design an amp around them than plug them into my KT120 amp and hope. £100 each is not a trivial sum to take a chance on, well not for me it isn't. I await with interest, the verdict.
Indeed, although I can't see there being a problem if you've built sufficient 'overkill' into the circuit to cope with the greater current drawing demands of the KT150s. Anyway, I really love the look of your new amp and am sure it sounds fab. You have every right to be very proud of it!
I'll keep you (and everyone else) posted with how I get on with the KT150s, as soon as I have some to play with :cool:
Marco.
SteveTheShadow
15-09-2013, 11:34
Aye looks like you're the guinea pig then Marco. :)
Anthony,
So, a KT120 run at the same parameters as a KT88 in terms of B+, bias current and using the same output transformers will deliver the same power as a KT88 in the same.circuit, more or less?.
what affects power output when comparing tubes in the same circuit? id expect them to be largely the same, or does greater emission have an effect at the same voltages?.
also is the KT120 have greater headroom at the same operating parameters due to higher limits for plate dissipation compared to the KT88, and ttherefore potentially longer life, or is that limited by the life of the cathode?.
sorry for the thread highjack but we are discussing KT120s as a replacement for Kt88/6550 types.
cheers,
Alex
Aye looks like you're the guinea pig then Marco. :)
Lol - no worries. I'll probably wait until Anthony gets some in, and then I can take the time to assess them properly in the context of my own amp and system.
Therefore, bear in mind when I publish my findings, that they will be solely relevant in that context and not portrayed in any way as 'fact'. Hopefully I'll manage to get that across successfully to the more 'touchy' chaps amongst us, without having to scribble 'IMO', 'IMHO' all over my posts!! ;)
Marco.
SteveTheShadow
15-09-2013, 12:05
Indeed!
As your amp has been suitably modded to take KT120s I think you'd agree that push-pull amps designed around them are capable of kicking ass like nothing else, but also have the finesse to back it up.
Suave with a killer punch is a good description methinks.
This ought to bode well for those gherkins.
Indeed!
As your amp has been suitably modded to take KT120s I think you'd agree that amps designed around them kick ass like nothing else but also have the finesse to back it up.
Suave with a killer punch is a good description methinks.
Absolutely and utterly spot on, mate. We couldn't be more in agreement! :)
I remember Mo saying to me once, something along the lines of: 'All roads in hi-fi lead to single-ended valve amps and high-efficiency speakers'. Well, whilst I understood and appreciated where he was coming from, he was wrong.
As far as I'm concerned, the most musically entertaining roads all lead to (high-quality) high-power push-pull valve amps and high-efficency (big-boy, kick ass) speakers!! :exactly:
Anything less, for me, just doesn't cut it.
Marco.
SteveTheShadow
15-09-2013, 12:25
Well yes.
This business of hi-efficiency speakers with powerful amplification in an interesting one.
Can't remember where I read it as it was a while ago now, but there was a chap with Lowther corner horns
and a low power SET who swore by the combination, until he somehow ended up trying a big Audio Research 6550 jobbie into them. Stupidly over powered you would think.
Er....he ended up ditching the SET toot sweet as they say ;)
I had a similar epiphany with the present amp into my Metronomes. :lol:
Crazy.
Crazy, maybe, but it also makes perfect sense.
For me, the key is headroom; specifically in ensuring that there is enough 'on tap' (again think along the lines of 'overkill' here) for a system to successfully be able to reproduce a wide variety of music effortlessly and convincingly at 'real world' sound levels.
Think of it this way: in which type of car would you feel more comfortable in, cruising at high speeds on a motorway: a BMW, with 210bhp and a top speed of 150mph, or a Renault Clio with 60bhp and a top speed of 100mph? Both can do 70mph, but only one of them effortlessly!! Well, a similar principle applies with amplifiers, both valve and SS.
In that respect, 2 watts of SE just won't cut it (no matter the 'quality' of those 2W), even with high-efficiency speakers, unless you consider realistic scale and deep bass as an afterthought, and don't mind the sound of 'clippety clip', permeating proceedings, when the going 'gets tough'.....! :eyebrows:
The fact is that almost any system can sound good (read as: 'sweet and mellifluous') playing Alison Krauss at a barely louder than a whisper, but it almost certainly doesn't represent REALISTIC sound! ;)
Marco.
http://www.pyndt.dk/Tung-Sol%20KT150%20Curves.pdf
Lurcher posted that earlier, mate ;)
Marco.
The Black Adder
15-09-2013, 14:15
I am very tempted with the 150's I have to be honest.
Yup, but check with Anthony first for compatibility! :)
Marco.
The Black Adder
15-09-2013, 14:39
Yup, but check with Anthony first for compatibility! :)
Marco.
Hopefully it would be built to use them from the off if it's possible. Saying that, I'm sure the 120's will be more than adequate.
:rock::rock::rock::rock:
I agree with the high sensitivity speakers and high power providing it's valve power. High powered SS never sound as "right" hooked up to very efficient speakers, perhaps something to do with circuit performance at lower wattage output levels. My speakers are 92dB/1w and although I regularly drive them with a 15w SET amp, they sound far better with a 70w PP valve amp on the end. Not quite as incisive and revealing as with the lower powered Class A amp, but with a more natural balance and real authority when a higher powered amp is used. I've also heard 100dB efficiency horns driven with a muscle valve amp and the dynamics were incredible.
anthonyTD
15-09-2013, 16:50
hi Alex,
Pretty much so, there are a few things that will determine how much power you will get from any Tetrode, or pentode valve in an output stage, [while keeping the valve within its maximum operating dissipation] and they are, plate and screen voltage, ie, the higher' the more power potential, Dependant of course on the class the valve is to be used in ie; class A, AB1, AB, etc,,,Then theres bias [the amount of current the valve is set to draw with a given plate/screen voltage] and output transformer winding ratio, and speaker load match etc.
The power supply is very crucial in maintaining the desired voltage, versus current draw,; ie, the harder you bias the valve in Class A for instance, the more load you will have on the power supply, and therefore, the higher the potential for the power supply to sag, which is not what you want when the desired result is extra power...
This is i fear why a lot of amplifiers are biased into one of the lesser current draw mods such as AB1, AB2, AB, and at the extreme end for audio purposes anyway' class B, these classes allow for less standing current to be drawn, which in turn [and providing you have enough driver voltage swing] will allow the power supply and output valves time to recover and thus maintain a higher power output potential with [in many cases] a lesser/smaller power supply, however, the higher plate/screen voltage needed tends to cause more problems than its worth in my opinion, as the tendency for a valve to arc and short over due to the higher switching characteristics' is increased.
So, lets recap, if the desired affect within a class A output circuit is [using the same HT voltage] more power, the power supply must be large enough, and thus of a high quality to maintain the voltage required under higher plate current, otherwise, the results will be negligible as it will be a juggling act between plate voltage and plate current draw etc.
Hope this helps.
A...
Anthony,
So, a KT120 run at the same parameters as a KT88 in terms of B+, bias current and using the same output transformers will deliver the same power as a KT88 in the same.circuit, more or less?.
what affects power output when comparing tubes in the same circuit? id expect them to be largely the same, or does greater emission have an effect at the same voltages?.
also is the KT120 have greater headroom at the same operating parameters due to higher limits for plate dissipation compared to the KT88, and ttherefore potentially longer life, or is that limited by the life of the cathode?.
sorry for the thread highjack but we are discussing KT120s as a replacement for Kt88/6550 types.
cheers,
Alex
Thanks Anthony... Great answer.
Regards,
Alex
Cheers Anthony, good info.
I've emailed the manufacturer of my amp if they can shed any light on the suitability of the KT120's.
Big thanks to Ali Tait for taking the time to look at my amp.
Great that the voltages check out, good piece of mind.
Ali suggested some internal upgrades for me, caps, stepped pot etc, so know where I'm taking the amp next.
Sounds fantastic as is, upgraded will be a bit special.
Only question is what might have happened?
Amp sounds and measures fine...hopefully sweep this one under the carpet.
Got some new KT88's on the way just in case, Svetlana Winged C's, so should be good.
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