The 6SL7GT valve & It's variants - MY ADVENTURES!

[Wakefield Turntables]

Part 1 - Intro!

This year I decided to properly get into tube rolling on the Croft pre-amp.

I decided to embark on some adventures with the 6SL7GT so far I have tried the following

Mullard 6SL7GT - UK
RCA black base 6SL7GT (AMERICAN)
Reflector 6H9C (Russian) - Non military version
Sylvania black base 6SL7GT - USA

On order

MELZ 6H9C Metallica base
MELZ 6H9C Black base

Currently trying to do a deal on some General Electric (USA) 6SL7GT'S :D

I'll post some pics and findings as I get time.


So my first valve. The Reflector 6H9C (NON MILITARY version)

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This is not my image. My camera's battery was exhausted. These can be purchased very cheaply from Russia or Watford valves if you don't want the hassle of e$cum. I would heartily recommend trying this valve out purely for so you get some idea of how the valve can be bettered. It's only when you hear a so-so valve do you then start to appreciate just how good things can be. It's an inoffensive valve which is pretty much middle of the road. It's not very detailed when compared to the Sylvania's and Mullard's of this world but for a cheap starter it's perfectly ok. I'd probably keep a set of this in my box as spares when testing out new amp purchases when I dont want to put additional hours of some of my rarer valves. It's not particularly good at soundstage depth or instrument separation and timbral detail is severely lacking. This valve is magical in being a benchmark of how crapiness (sic). But, as stated if you learn it's weaknesses you can then appreciate a really good valve.

STAY TOOBED! :)

[sjs]

my favourite 6SL7 are the Sylvania 6SL7WGT brown base

https://tctubes.com/images/products/detail/659_6SL7WGT_SYL_800.JPG

best of luck
Simon

[Wakefield Turntables]

Simon,

Thanks for replying. I've seen these over on ebay.com and they are getting more expensive as each month goes by! I'll be dipping my toes into the Russian variants at the end of this month. I have some Melz coming. I'm listening to to Sylvania black base 6SL7GT's at the moment and so far they have been excellent. Prior to those I had some Mullard's in which were simply sublime. The Sylvania's are stopping in until the Melz turn up and then I'll write some words on my findings.

Thanks

A

[Wakefield Turntables]

Hmmmmm not liking the Sylvania black base 6SL7GT as much as the Mullards. More details tomorrow when I plonk the Mullards back in for comparison.

[Wakefield Turntables]

Pt II - Sylvania Black Base 6SL7GT

WOW, what a valve. Very very detailed. A massive improvement over the Sovtek 6H9C valve. The soundstage is very cohesive in fact it's the first thing that strikes you when you try them out. The Sylvania does lose out however to my Reference valve which is the Mullard 6SL7GT in that piano presentation is a little lacking in end note decay in that you can hear the note "wobble" as it decays. This is something that I don't get with the Mullards piano notes are sharp and crisp and have a very sharp leading edge. The Sylvania's have less end note decay and notes don't seem to "float" as well the Mullards. Percussion work on the Sylvania's is excellent but again the Mullards just seem to ace them again. I have to say that the Sylvania's are very very good at findings those little extra details in the background of live recordings. Cal Tjaders Session Live record being a good example. You can hear several members of the audience getting up out of seats whilst talking to each other and squeaking floor boards as they move around. All excellently rendered by the Sylvania's. All in all a very very good valve but I'm glad I have my Mullards back in. I'll give these a score of 7/10.

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For a little fun I've decided to have a 6SL7GT shoot out list, so here goes.

1. Mullard 6SL7GT 9.25/10
2. Sylvania 6SL7GT black base 7/10
3. Reflektor black base 70's version 5/10

[Jimbo]

Any chance Andy of a picture of the valves in situ in the Croft preamp?:)

[Marco]

my favourite 6SL7 are the Sylvania 6SL7WGT brown base

https://tctubes.com/images/products/detail/659_6SL7WGT_SYL_800.JPG

best of luck
Simon

Hi Simon,

I agree, but for best sound, it's got to be the 1950s vintage ones, which look like this:

https://imagizer.imageshack.com/v2/1024x768q90/923/Lh4IMN.jpg

Those sound stunningly good! :)

Marco.

[Wakefield Turntables]

Any chance Andy of a picture of the valves in situ in the Croft preamp?:)

Will see what I can do.

[Marco]

Interesting thread, Andy. As you know, I've been here many times before, but it's always fun to revisit these things again. Aside from the valves you've listed, I thought you also had some Mullard ECC35s, which I recommended to you last time?

The 1950s 'Tall Boy' narrow brown-base versions are the ones you want.

Those are probably the best (albeit also most expensive) 6SL7 types you can buy. Another beauty is the RCA 5691 red base, which is also a sonic stunner (huge, expansive sound, super-airy top-end, crystal clear mid, and massive, 'blow your tits off' bass!)

Other 6SL7s I rate are: military spec Raytheon VT-229 (with smoked glass), the Russian Melz you mention, but they must be the ones with holes in the anodes, from the 1950s, and military spec Tung Sol 6SU7GTY (6SL7 equivalents), like these, from the 40s to early 50s:

http://i665.photobucket.com/albums/vv12/Getgaff/0adbadb08c3bc91e0bf2cc06af835302_zpsgwjtmxo3.jpg

Awesome sound! :cool:

Marco.

[sjs]

Hi Simon,

I agree, but for best sound, it's got to be the 1950s vintage ones, which look like this:

https://imagizer.imageshack.com/v2/1024x768q90/923/Lh4IMN.jpg

Those sound stunningly good! :)

Marco.Marco

Aren't they the same ones? ;-)

There are some 6SN7s which look v similar and they are also v nice

Simon

Sent from my SM-G930F using Tapatalk

[Marco]

The 50s ones have dark black anodes, not grey :)

Marco.

[sjs]

The 50s ones have dark black anodes, not grey :)

Marco.I think it's just the lighting on the photo I chose from Google :-)
The one I have had always had gloss black anodes. :-)


Sent from my SM-G930F using Tapatalk

[Marco]

Fairy muff :)

Marco.

[Wakefield Turntables]

Jim, this is for you!

A shot of the 5 valves which control the MM stage, the tape/in out, aux and also L+R channel out to power amp.

A few mods. We have Yannis Tome intrinsic wiring to the MM stage and the L+R output channels. Finally silver WBT RCA;s. The far right valves (last two) are the Mullard 6SL7GT which I re-installed. All the other goodies are elsewhere in the amp!

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These have just come out of the pre-amp RCA 6SL7GT not sure of the vintage. Some notes coming up at some point.

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Enjoy.

[Marco]

Hi Andy,

Those other valves in your amp with black bases (not the Mullards) are fairly generic Russian valves, which are ok, but nothing special. You can do considerably better! What you need are these boys, proper 6H8C (the 6H9C you need look identical), made in the Melz factory during the 1950s:

https://imagizer.imageshack.com/v2/1024x768q90/924/hTPGKj.jpg

The thing to look out for are the distinctive holes in the anodes... Those are stunning sounding valves, with really airy highs and superb dynamics.

Also, the Mullards you're using are also fairly generic, and I suspect simply re-badged Sylvanias. What you need are these, 1950s 'Tall Boy' brown short-bases:

https://imagizer.imageshack.com/v2/1024x768q90/923/8iuZGq.jpg

Themz PROPA! And a totally different ball game to what you're using.

Trust me, if you can find what I've recommended above, and fit them in your amp, you'll be blown away by what you hear! :)

Marco.

[Wakefield Turntables]

Marco,

The left three valves are all non-military spec Reflektor valves which came with the amp. The other two could well be re-badged Sylvania's but they sound so different and better to the two which I've just removed. I have a two types of Melz coming from our Russian friends and for the price I'm not complaining. I'm probably going to get a lot of enjoyment trying the Russian valves and it works out cheaper than a night on the tiles (but without the hangover)! I'm working on sourcing a pair of Mullard brown bases and also a pair of Brimar 6SL7GT's! All good fun. Just out of interest, I have a question for you regarding the left three valves. The far left valve is for the MM stage (which I don't use), have you any idea which of the remaining two controls the AUX RCA input? I'm thinking on experimenting with this valve as I think I can get more from the pre-amp this way .

[Jimbo]

Jim, this is for you!

A shot of the 5 valves which control the MM stage, the tape/in out, aux and also L+R channel out to power amp.

A few mods. We have Yannis Tome intrinsic wiring to the MM stage and the L+R output channels. Finally silver WBT RCA;s. The far right valves (last two) are the Mullard 6SL7GT which I re-installed. All the other goodies are elsewhere in the amp!

22541


These have just come out of the pre-amp RCA 6SL7GT not sure of the vintage. Some notes coming up at some point.

22542

Enjoy.

Thanks Andy, those valves are quite big beasts! Need to see the rest of the amp!:)

[Firebottle]

The far left valve is for the MM stage (which I don't use), have you any idea which of the remaining two controls the AUX RCA input?

It's much more likely that the first two valves are for the MM, the same as Croft amp using the smaller 9 pin valves.
The third could well be a cathode follower also associated with the MM input, I haven't had direct contact with this type of pre.

To prove it you could take out these two (3) valves and see if the Aux still functions.

[Wakefield Turntables]

It's much more likely that the first two valves are for the MM, the same as Croft amp using the smaller 9 pin valves.
The third could well be a cathode follower also associated with the MM input, I haven't had direct contact with this type of pre.

To prove it you could take out these two (3) valves and see if the Aux still functions.

I did think of this about 30 seconds after I posted. :doh:

[Wakefield Turntables]

PT III - Valve madness

OK, The Melz have arrived and I have now just purchased these badboys

I managed to find one of these for £13!!!! Now just need to find another. I'm in no rush.

https://i.ebayimg.com/thumbs/images/g/SDcAAOSwxOFaUhUi/s-l200.jpg

I also pushed the boat out and got a couple of these

https://i.ebayimg.com/images/g/C6sAAOSw4DJYivJq/s-l500.jpg

I also have a single Brimar 6SL7GT on its ways. So it looks like the Melz going in this weekend.

Stay tuned

[Wakefield Turntables]

PT IV - MULLARD MAGIC - The Mullard 6SL7GT

This is a bit arse about tit, but these are my current reference valves, so far I've not heard better in my limited experiments.

http://theartofsound.net/forum/attachment.php?attachmentid=22541&d=1516479480&thumb=1

These valves major on detail and a good solid 3D soundstage. They are especially good with Jazz and vocals. They seem have a magical quality all to themselves when it comes to portrayal of note decay. I particularly like the snap and attack on drums, cymbals shimmer like no other valve that I have heard.
There is plenty of space between instruments. The real magic of the Mullard is it's midband it's simply the best I have ever heard, I've never heard Miles Davis or Wayne Shorter sound as good. These valves when given a good recording can make a soundstage appear to float above, beyond and to the back of my Tannoys. All in all a very enjoyable valve, heartily recommended.

Next - MELZ!

[Wakefield Turntables]

Pt V - More stuff into the mix.

It's Saturday and there are two packages waiting for me at work. The first has my Tung Sol's (which I'm now listening to).

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A shot of the Tung sol's in the Croft.

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I'm now slowly removing the other Sovtek 6H9C's out of the amp and I will eventually run just three of my chosen valves.

I bought a single Brimar NOS 6SL7GT, now I just need to source another and we can have some fun.

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I was supposed to be reviewing the Melz 6H9C this weekend but I decided to chuck the Tung Sol's in. :eek: I've also been informed that I have another package waiting for me from the US of A with some WWII NOS 6SL7GT (General electric) I think.

Stay tuned. :cool:

[Wakefield Turntables]

Pt VI - The Tung Sol 6SL7GT

Just a few notes on these fantastic valves.

2259822599

Miles Davis - So What - Kind of Blue

- Very muscular double bass, with improved timbral detail. Paul Chambers Bass never sounded as moody.
- A much fuller, midband. There was more of John Coltrane's sax just sounded so full, effortless.
- Slightly more snap to drums with the cymbals have a little more sparkle and shimmer, Jimmy Cobb's delicate touch came forward.

Cal Tjader - S'Wonderful - Sessions

This 1957 recording by Chris Conner is a very close mic performance which suffers from dreadful sibilance but boy can
she sing! I use this record more to assess the ability of a valve to dig out performace in the background. This is usually
a very pleasent track but today I was very irritated buy the increased amount of audience noise, someone closing a door,
someone walking across a squeaky floorboard, all details I had not heard before.

Miles Davis - Nefertiti - Nefertiti

Brush work on this track is to die for, again a completely sublime midband and a very muscular power bass. This
recording really shows how cymbals can shimmer and sparkle. Plenty of space between the instruments. A very wide and
expansive sound.


All in all the best 6SL7GT I've heard yet, they surpass the Mullards and go top of the list. So, here the current shoot out results.

1. Tung Sol 6SL7GT (Orange base) 9.5/10
2. Mullard 6SL7GT (Black base) 9.25/10
3. Sylvania 6SL7GT black base 7/10
4. Reflektor black base 70's version 5/10

The Tung Sols have now replaced my Mullard black base 6SL7GT as my reference. :eek:

Stay tuned.

[Wakefield Turntables]

Pt VII - More Sylvania. 6SL7GTY

This is a new one to me and will be going in the pre-amp this Sunday for evaluation. Ex military stock from the 1950's. They REALLY knew how to make valves back then. Should make for an interesting comparison against my favourite Tung Sols.

22618

:D

[Marco]

Oh, FFS..... :doh:

Please tell me, DAFTEE, you've posted the wrong picture of what you've actually bought... IF NOT, and that's exactly what you've bought, then they are THE WRONG VALVES!!.

Look what is says on the boxes in your picture above: 12SK7GTY

Also, look at the construction, compared with the other 6SL7s you're using. It's completely the wrong item. You've bought this (a PENTODE remote cut-off valve):

http://www.r-type.org/pdfs/6sk7.pdf

Instead of this (a TWIN TRIODE):

http://www.williamsonic.com/TubeDI/6SL7GT.pdf

What you probably thought you were buying, was what I recommended earlier, which were these:

http://i665.photobucket.com/albums/vv12/Getgaff/0adbadb08c3bc91e0bf2cc06af835302_zpsgwjtmxo3.jpg

6SU7GTY - a totally different animal....!

Andy, DO NOT ATTEMPT TO PUT 12SK7 VALVES IN YOUR AMP, even if they fit, as if switched on, you might destroy it and/or the speakers connected to it!! :no::nono::nono:

Marco.

[Firebottle]

Oh dear :doh:

[anthonyTD]

From the datasheet, the 6SU7 is a close substitute for 6SL7.
I WILL CHECK AGAIN THOUGH.

http://tdsl.duncanamps.com/show.php?des=6SU7GTY

https://frank.pocnet.net/sheets/127/6/6188.pdf

[Marco]

Hi Anthony,

The 6SU7 is a close substitute, as I use them in the Croft, and they're great. The problem is, Andy appears to have bought 12SK7s.............!!

Scroll up mate, and read what's been posted again, particularly see the picture in post #24.

Marco.

[Wakefield Turntables]

Whoa, calm down! It's the wrong picture! I've saved numerous pictures from ebay to make comparisons with respects to the various valve vintages and variants. I've not purchased a pair of 12SK7GTY's so you have nothing to worry about although I'm flattered you took the time to point out my potential f*** up.

[Marco]

Whoa, calm down! It's the wrong picture! I've saved numerous pictures from ebay to make comparisons with respects to the various valve vintages and variants. I've not purchased a pair of 12SK7GTY's so you have nothing to worry about although I'm flattered you took the time to point out my potential f*** up.

Lol - thank fuck for that! :D

I thought that might've be the case, hence why I mentioned it. So..... What did you *actually* buy, and could we have a picture of that instead? :)

Marco.

[Wakefield Turntables]

Sure pics when I have a little time. I 'm playing with a new valve MM stage at the mo!

[Marco]

Cool beans, keep us posted :cool:

Marco.

[Wakefield Turntables]

Pt VIII Melzdown

I intended reviewing the Melz 6H9C


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So, I get them installed only to find that one is completely knackered, supposed to be matched pair testing strong, hollocks! Never mind they cost about £30 so not a massive loss but still annoying. I did managed to snag a pair of General Electric 6SL7GT and here is a picture of the very valves. These are coming from the US of A.
22648
I also managed to snag another Brimar NOS 6SL7GT. I now have a pair of these and shall be testing them soon!


22647

Finally, I have tracked down the valve controlling line in to the RCA's from the phonostage which means that I can also start experimenting with valves here. I have been using a Reflektor 6H9C and whilst it's a great valve I feel that more could be had from the Croft. So, I''l be plonking in some bits and pieces in here to see what happens.

Stay tuned.

A

[Wakefield Turntables]

PT IX - Mini mini update!

These bad boys are coming from the USA.


22733

Shaded 6SL7GT 1942-1945 vintage. Tung-Sol seem to have produced some of the best sounding valves EVER most people seem to agree!

Anyway I now have a pair of Brimar's to install and listen.

[Wakefield Turntables]

Currently undergoing extended listening.

22751

Very detailed! More over the weekend!

[Wakefield Turntables]

Pt X - Brimar 6SL7GT - Mullard's poor cousin?

22775

I waited for some time to put these into my Croft and after several weeks finally got around to listening to them. I'd heard good things about this valve, so here we go!
These valves are a bit of a mixed bag in that they seem to excel in some areas whilst sound poor in others. Overall they are a step up from my Original Reflektor 6SL7 that I'd been using. These valves are not very good at producing female vocals but they do seem to excel in being able to see right into the mix of a record. They seem to be extremely good at extracting the smallest scintilla of detail. I tested the valves on the usual Jazz suspects that I listen to and seemed to notice a whole new level of detail and definition to the open double bass of So What on the Kind of Blue Album but this was juxtaposed against a terrible rendition of Cal Tjader album. What should have been a very intimate female vocal from Chris Conner sounded very flat, recessed and just not right. John Coltrane's sax did sound sublime and then the realisation kicked in. This valve is probably going to be great if you listen to nothing but stringed instrumental or brass based music and then fall flat on it's backside for anything else. This is a real shame as I had high hopes. So, I've given this one a 6.25 on its strengths of reproducing amazing detail when listening to instrumental music. It's a one trick pony and not an all rounder. I can highly recommend this valve for strings and brass otherwise do some more tube rolling.

Here's how the shoot out list looks after 5 lots of tube rolling.

1. Tung Sol 6SL7GT (Orange base) 9.5/10
2. Mullard 6SL7GT (Black base) 9.25/10
3. Slyvania 6SL7GT black base 7/10
4. Brimar 6SL7GT (black base) 6.25/10
5. Reflektor black base 70's version 5/10

So what's next? Well we have some lovely General Electric 6SL7GT'S plumbed in, freshly picked from the US of A.

22776

22777
Expect some scribbles soon! As ever, stay tuned! :cool:

[Wakefield Turntables]

Pt XI - General Electric Black base 1970's.


22795

22796
I've had these valves for quite some time and thought it about time that I plumbed them in and have a listen. Well, they were an instant improvement over the Brimar 6SL7GT's that I last had in. These GE valves are cheap, plentiful and make for an excellent valve. These came from the USA as most of my stock usually does. The GE 6SL7GT is an extremely detailed valve which is rich and fulsome. It gives little away to some of the valves at the very top of my list but dosen't quite have the magic of the black base Mullard or the rare military spec Tung Sol from 1963. The valve is prone to enhancing any transformer hum that your valve amp may have but this is a small gripe as the soundstage that I'm used to was slightly spoiled by a little extra transformer hum. The GE 6SL7GT has all the strengths of the Mullard and the Tungsol but to a slightly lesser extent. Reading the reviews for these two valves will give you some idea of how this valve sounds. On that merit alone I would give this valve a good solid 8.5/10 but because the valve is extremely plentiful and good value for money I'll rate it a 8.75/10.

Here's how the shoot out list looks after 6 lots of tube rolling.

1. Tung Sol 6SL7GT (Orange base) 9.5/10
2. Mullard 6SL7GT (Black base) 9.25/10
3. General Electric GSL7GT (Black base 1970's) 8.75 / 10
4. Slyvania 6SL7GT black base 7/10
5. Brimar 6SL7GT (black base) 6.25/10
6. Reflektor black base 70's version 5/10

I've now nearly run out of valves! But, these beauties are not sitting in the Croft. More when I have time. :D

22797

Stay tuned. :cool:

[Wakefield Turntables]

Pt X - Ken Rad 1945 Black base - Military grade

Been a long time since I played around with the 6SL7GT's, so snagged these from the US of A. Never tried Ken Rad so should be good fun!



2326223263

[Wakefield Turntables]

Pt XI - Tung Sol (1945 Era) Black bottle VT229 6SL7GT

This is another score from the USA. This pair was made circa 1945. Tung Sol happen to be my favourite American valve maker and I highly rate their brown/orange based 6SL7GT valves from the 1950s and 1960s, so I was hoping that this valve would be something really special when I plugged it into the Croft pre-amp. I started by listening to a new pressing of Time Out (The Dave Brubeck Quartet) which I purchased in Huddersfield at Vinyl Ta, this pressing was released on the Not Now label and is highly recommended. Initial impression of the Black Bottle's where good. Eugene Wright's double bass had oodles of timbral quality and sat right in the middle of the soundstage. The drums of Joe Morello produced plenty of snap when playing Take Five and Dave Brubecks piano notes seemed to start and stop on a penny. The black bottles produced a fantastic wide soundstage, maybe not quite as deep as some the valves in my collection but still pretty impressive. The black bottles also seem to amplify less surface noise from the vinyl and have reduced some of the transformer hum through the speakers so the soundstage is blacker and boy you can tell.


23284

Listening to the LLoyd McNeill Quartet is a real treat when they perform the Washington Suite. Each member can be clearly heard and maybe a little definition is lost in the vibes and oboe when compared to my Reference Tung Sol's but these black bottle are not that far behind. So far, so good. They are proving to be a real gem and certainly one that I'm keeping. I must say that double bass is probably one the Black bottles weaknesses as I've heard a few records now and it dosen't seem to produce quite as much detail as my Reference Tung Sol's this is also evident on the opening track of Kind of Blue "So What" where the double bass looses some of it's definition and reverb. The midband is perhaps a little recessed and not quite as sharp in definition as my other Tung Sol's but I am being quite picky. The opening track of Nefartiti highlighted this point very clearly.

OK, so where do they rate ? Well contrary to what I've written I actually really really like these valves and make a really nice change from some of the valves that I've heard over the last few weeks. The black bottles are quite rare but do seem to crop up every so often on ebay.com. I'm going to give them a solid 9.1/10. They are not quite as good as my black base mullards or Orange base Tung Sol's but they do rate very very highly and can heartily recommend them. So, here's the shoot out now after 7 valve reviews.

1. Tung Sol 6SL7GT (Orange base) 9.5/10
2. Mullard 6SL7GT (Black base) 9.25/10
3. Tung Sol 6SL7GT VT229 (Black bottle) 9.1/10
4. General Electric GSL7GT (Black base 1970's) 8.75 / 10
5. Slyvania 6SL7GT black base 7/10
6. Brimar 6SL7GT (black base) 6.25/10
7. Reflektor black base 70's version 5/10

Next some Ken Rad 6SL7GT'S from 1945.

[Wakefield Turntables]

Pt XII - Ken Rad Black Base 6SL7GT (1945)

Yet another score from the USA. This time I decided to try some Ken Rad valves. This is a brand that comes up from time to time and I've had to wait for ages for a matched pair to surface. This pair date back to the first few weeks of 1945 making them 73 years old! I've not heard a great deal about these valves before but I plumbed them into my Croft Epoch and boy did I get a shock :wowzer:.

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I got one of those WOW moments the first time that I heard these properly. I've done quite a fair old bit of tube rolling over the last few months and these babies equal my reference Mullard and Tung Sols. They are every bit as good as the Tung Sols and Mullards but just lack a little of the "bite" that the other two demonstrate. They produce a wonderful wide soundstage with very defined instruments with plenty of time, space and decay in the soundstage. The double bass detail on some of my Jazz recordings is fantastic, really great timbral presentation with lots of detail as several musicians work the fret board. The mid-band is equally on a par to anything that I've tube rolled so far. Drum work, especially brush is so delicate it shocks. Saxophone is just amazing, I'm hearing more reverb than ever and I'm getting a better idea of how the Sax reacted in the room of the recording, the detail is that good. :trust:. So, the next question is just where do they rank of the shoot out table? A bit controversial but I think they rate 9.25/10, same as the black base Mullards. I could quite happily replace these with my Mullards and never listen to the Mullards again, but for the time being, I'll keep a hold of them. ;)

1. Tung Sol 6SL7GT (Orange base) 9.5/10
2. Mullard 6SL7GT (Black base) 9.25/10
2.= Ken Rad 6SL7GT (Black Base) VT229 9.25/10
3. Tung Sol 6SL7GT VT229 (Black bottle) 9.1/10
4. General Electric GSL7GT (Black base 1970's) 8.75 / 10
5. Sylvania 6SL7GT black base 7/10
6. Brimar 6SL7GT (black base) 6.25/10
7. Reflektor black base 70's version 5/10

Next time, more Tung Sol loveliness with a pair of 1960's (I think) Orange micanol bases.

[Wakefield Turntables]

PT XIII - New Reference. Tung Sol black Bottles - 1940's vintage.

Say hello to my new reference valves. Yet another score from USA. A beautiful light airy mid range. Piano playing is crisp and exact. Soundstage is wide and 3D in nature with very carefully positioned band members. It is with extreme ease that I can follow every band member and not in a rushed manner, the music just simply flows with great clarity and with a timeless manner. Drum work is fast, snappy, accurate. These valves have no problem in transcribing complex jazz passages. Every note just seems to start and stop with pinpoint accuracy. These valves are a little strident and female vocals can appear a little shouty but in all honesty it's something I can live with. These valves are sure packed with an addicitve factor. It's been quite some time that I've wanted to try so many pieces of vinyl to see how a pair of valves perform. My only gripe with these valves is that they take quite a while to warm up, but boy once they are warmed up they perform, and perform well! I have to say that in all the valves that I have reviewed TUNG SOL seem to produce the best to my ears. I'm now running out of 6SL7GT's and shall
be starting with the 6SL7GTW's, I've ventured into the VT229 territory and if my wallet can handle it, the ECC35 and
5691 variants. The USA seems to be a fertile hunting ground for these valves.



2358423585

So how do these fair on the shoot-out table?
1. Tung Sol 6S7GT (Black Bottle) 9.6/10
2. Tung Sol 6SL7GT (Orange base) 9.5/10
3. Mullard 6SL7GT (Black base) 9.25/10
3.= Ken Rad 6SL7GT (Black Base) VT229 9.25/10
4. Tung Sol 6SL7GT VT229 (Black bottle) 9.1/10
5. General Electric GSL7GT (Black base 1970's) 8.75 / 10
5. Slyvania 6SL7GT black base 7/10
7. Brimar 6SL7GT (black base) 6.25/10
8. Reflektor black base 70's version 5/10

Next time, we shall be looking into the more exotic 6188 and 5691 variants!:eek:

[Wakefield Turntables]

Pt XIV - Bendix redbase 5691 - Or in other words the legendary rebadged RCA redbase

This valve is legendary and a very very special version of the 6SL7GT everything about it has been massively over spec'd and it shows! I've not exhausted teh list of 6SL7GT valves out there but I was getting a little bored and decided to try something rare and exotic. This valve has met all my expectations and surpassed them. I'd done a lot of reading around the 6SL7GT and this variety was supposed to be at the top of the tree. My favourite 6SL7GT's have always (so far) been manufactured by Tung Sol. I've tried the black base RCA 6SL7GT and found it to be ok, not the best in the world but certainly not the worst. The Bendix seems to add a little gain and the soundstage is truly wide, cohesive, and everything that makes the best Tung Sol valves sound so good. The Bendix majors on micro-detail and really really digs deep into the groove of any vinyl recording and produces more detail than I have ever heard before from any valve that I have tried. This valve has gone straight to the top of the pile and has replaced the Tung Sol black bottles as my new reference valve.

23631

So, the shoot out now looks like this

1. Bendix 5691 (Red Base) 9.75/10
2. Tung Sol 6S7GT (Black Bottle) 9.6/10
3. Tung Sol 6SL7GT (Orange base) 9.5/10
4. Mullard 6SL7GT (Black base) 9.25/10
4.= Ken Rad 6SL7GT (Black Base) VT229 9.25/10
5. Tung Sol 6SL7GT VT229 (Black bottle) 9.1/10
6. General Electric GSL7GT (Black base 1970's) 8.75 / 10
7. Slyvania 6SL7GT black base 7/10
8. Brimar 6SL7GT (black base) 6.25/10
9. Reflektor black base 70's version 5/10

Next time something from pentalabs I think....

[Wakefield Turntables]

Pt VX - The future...

I've tried many valves now and I think I've come to the conclusion that RCA and Tung Sol probably produced the best 6SL7 valve. I've yet to try everything and there are still one or two that I'd like to try, these being the Brown / Black base Mullard ECC35's, the 5 holed Melz, and maybe some of the more weird and wonderful VT229's kicking around. I may even try some of the newer 6SL7's doing the rounds at the moment and perhaps this could another area of future research. So, for the time being this thread will be taking a break.

[Wakefield Turntables]

Oh dear looks like the tube rolling bug has struck again.

[karma67]

lol have you tried any 6F8G's? no going back for me since hearing smoked tungsol's

[Wakefield Turntables]

6F8G's?

No! Please don't send me down a rabbit hole!!

[da2222]

lol have you tried any 6F8G's? no going back for me since hearing smoked tungsol's

Different tube Jamie, though sometimes it can be used in place of 6SL7s.. The 6f8g is a direct equivalent of the 6SN7 and has lower gain than the 6SL7:-) A marvellous tube it is too!

[da2222]

However, re 6SL7 types, IME the 1940s black glass Tung Sol 6SU7GTY is the ultimate...

[karma67]

Different tube Jamie, though sometimes it can be used in place of 6SL7s.. The 6f8g is a direct equivalent of the 6SN7 and has lower gain than the 6SL7:-) A marvellous tube it is too!

yep my mistake,your right.

[Wakefield Turntables]

Phew dodged a bullet!

[da2222]

Phew dodged a bullet!

Not necessarily... It may well be compatible in your setup;)

[Wakefield Turntables]

PT XVI - RCA Red base 5691


27429

Sometime ago I heard about the RCA redbase 5691. There's plenty of information on the internet about them. They are perhaps the ultimate variant of the 6SL7 valve with many improvements over standard 6SL7'S. I liked this valve so much I had the Croft pre-amp modded to specifically run from them and I still have the flexibility to run all the old 6SL7 and GT / GTY variants as well. This valve put quite simply is the best thing I've ever heard in my Croft Pre-amp. Even though I have a pair of Bendix Red Base 6591 which I used for quite a while until they went tits up and then I got the RCA's. They are the same spec wise but the RCA's just seem better, it's probably down to them being a strong tested pair. They are very holographic and ideal for Jazz they have a midrange that beats anything that I've heard before. Vocals are also life like. Overall I think these are probably not going to be bettered, but I'll try!! I've still not heard Mullard ECC35's or the Melz 5 hole variants. So, these are now my new reference valves. Here's how things look now with the shoot out results.


1. RCA 5691 (Red Base) 9.75/10
2. Bendix 5691 (Red Base) 9.75/10
3. Tung Sol 6S7GT (Black Bottle) 9.6/10
4. Tung Sol 6SL7GT (Orange base) 9.5/10
5. Mullard 6SL7GT (Black base) 9.25/10
6. Ken Rad 6SL7GT (Black Base) VT229 9.25/10
7. Tung Sol 6SL7GT VT229 (Black bottle) 9.1/10
8. General Electric GSL7GT (Black base 1970's) 8.75 / 10
9. Slyvania 6SL7GT black base 7/10
10. Brimar 6SL7GT (black base) 6.25/10
11. Reflektor black base 70's version 5/10

Until next time.

[da2222]

The RCA red base 5691 is indeed an excellent tube- I used these for some months till finding and settling on the smoked glass Tung Sol 6U7 gty. I find the latter more rounded and 'ballsy' and not quite as dry sounding

[Wakefield Turntables]

PT XVII - RCA "coin" base 6SL7GT

28965

I'd never even heard of this one until Marco bought a pair. I decided to follow suit and see if they could usurp my 5691 reference valves. The "coin" base is very well made and dates from the 1970's. It's an extremely articulate valve. It demonstrates excellent timbrel decay and female vocals sound amazing. This valve produces a very well defined and powerful bass and it demonstrates amazing insight into recordings. It's a great valve and one that I'd quite happily live with but it does have it's issues. It produces a muted top end treble and looses out some of the clarity and precision of the 5691 I noticed this on the production of rim shots that were less well defined. I also noticed that this valve had no "air". Notes hang around in the soundstage with the 5691's this was not apparent with the "coin" base RCA's. I'd also say that the 5691 has a tad more delicacy than the "coin" base. Overall a great valve, the 5691 is still king of the tower. I'm going to give this one a 9.6 it's not as good as the Tung-sol black bottle so it can sit in the No 4 position.

1. RCA 5691 (Red Base) 9.75/10
2. Bendix 5691 (Red Base) 9.75/10
3. Tung Sol 6S7GT (Black Bottle) 9.6/10
4. RCA 6SL7GT (Coin base" 9.6/10
5. Tung Sol 6SL7GT (Orange base) 9.5/10
6. Mullard 6SL7GT (Black base) 9.25/10
7. Ken Rad 6SL7GT (Black Base) VT229 9.25/10
8. Tung Sol 6SL7GT VT229 (Black bottle) 9.1/10
9. General Electric GSL7GT (Black base 1970's) 8.75 / 10
10. Slyvania 6SL7GT black base 7/10
11. Brimar 6SL7GT (black base) 6.25/10
12. Reflektor black base 70's version 5/10

Next time around I will be looking at a very special 6SL7 variant the Black Bottle Tung-Sol 6SU7GTY from the 1950's.

2896628967

Until next time.... :cool:

[Filterlab]

I certainly agree with your top placing. Superb valves.

[Wakefield Turntables]

I certainly agree with your top placing. Superb valves.

Yep they are superb, maybe the 6SULGTY's will beat them, we shall have to see. :christmas:

[Filterlab]

Be interested to read your findings.

[Wakefield Turntables]

I've got big expectations now that Marco bigged 'em up.

[Wakefield Turntables]

6SU7GTY - Have landed today from US of A, I shall be installing these over the next few days for evaluation. :eek:

[Wakefield Turntables]

Just out of interest I found this on a website and thought it might be useful for those of you that dabble with these valves. THIS IS NOT MY TEXT!



The 6SL7 is a high-mu twin triode in an octal based glass package. To my knowledge, there were not any metal shell versions made. Each triode section operates as a

class-A amplifier. This tube has much higher mu than it's cousin, the 6SN7. It's factor is 70, whereas the 6SN7 is only 20, therefore these two tubes are not

interchangeable. There is still a good population of hi-fi and musical instrument amps using this tube in the preamp stage out there, and these tubes are still

available. The 6SL7 was never as popular as the 6SN7---due to the 6SN7's widespread use in television chassis design---so this tube does not turn up as often whenever

vintage tubes are being sold. It is, in the proper circuit, a wonderful sounding tube, and audiophiles would do well to try the NOS vintage 6SL7 tubes before buying

anything currently made today.

These tubes come in glass packages, and have envelope sizes similar to the 6SN7 family. GE usually used a short glass shell, RCA used the medium, and Sylvania,

Westinghouse, and Raytheon often used the "tall boy" style. There are many variations among brands, and even within brands. Here is a summary of what is most often

available:

6SL7GT / G:
This is the standard version of this tube produced by most USA makers. Nearly all have a pair of cylindrical plates, usually mounted low in the tube. Early versions

have an RF shield sprayed on inside the glass (greyglass), and then since about 1952 were made of clearglass. RCA used the famous blackplates and a bottom getter, as

did early Sylvania. In the 1950s, Sylvania went to a top getter, called chrome tops, and used both a short and a tall boy style. General Electric used a short glass

envelope, bright nickel plates, and a side mounted getter. They also made tubes for other brands. Whenever you see the bright plates, even in tall boy glass with

bottom getters they were most likely made by GE. Ken Rad tubes are just like GE. Early Tung Sol tubes looked like RCA, but later went to small grey rectangular plates

that looked like tiny 6SN7 GE plates. Tubes made after 1975 used the coin or wafer base. These are all great vintage tubes.

5691:
This is the "industrial" version of the 6SL7, and has premium qualifications. These include a long life heater, extra thick mica spacers, extra support rods, and often

a low loss micanol base. RCA made these in their famous "red base" line, identified by their red marbled micanol base. Other brands sold a 5691 with brown or black

bases, but virtually all were made by RCA. The early versions have dull blackplates and the old circle RCA logo on the base and/or the top of the tube. Later versions

have greyplates, and the modern RCA logo in orange on the redbase. Both sound and perform identically. Since the greyplates are usually easier to find, they are

usually priced lower, giving a great opportunity to own a real 5691 at a savings. These tubes are great, and last a long time. They have also nearly disappeared. Their

high price is justified by their high quality and demand in the market. The military versions of the 6SL7 are often just as good, so don't despair if you can't find

5691 tubes!

ECC35:
A very rare European type of 6SL7. Philips are what are mostly seen, if rarely. The Holland made versions are similar in size to the "tall boy" USA types. These

usually have high-mounted cylindrical plates, and brown micanol bases. These are sweet and rare versions of the 6SL7, and are plug and play compatible with any 6SL7 or

5691 type tube. Some say they have all the best attributes of the 5691, with better richness and vocal clarity. Very hard to find in the USA, and worth grabbing

whenever you can find them!

JAN 6SL7GT, JAN 6SL7WGT, VT229:
These are the military versions of these tubes. The Joint Army-Navy used the term "JAN", sometimes (but not always!) with the letters WGT, and / or (but again, not

always!) with the designation of VT229. A true military tube will always be marked "JAN". They may or may not have listings such as "WGT", which is mil spec

ruggedized; or VT229, which is the military type number of this tube. A common belief is that VT229 tubes are better than JAN or WGT types. Not true! These ARE ALL THE

SAME TUBES. They may or may not have brown micanol bases. All have extra support rods and mica, and are very rugged tubes that sound wonderful. The RCA, Sylvania, Ken

Rad, and Tung Sol JAN blackbase tubes look much like their civilian counterparts. JAN Sylvania, Tung Sol, GE, and RCA also made versions with brown bases, mostly with

short glass envelopes. The JAN Sylvania have a light marbled base, and the plates inside are very short black cylinders. These milspec versions are an endangered

species, and stocks may be wiped out when the 5691 series of tubes vanish. Prices are on the way up because of this.

6SU7GTY / 6188:
This is a premium version made by Tung Sol, possibly made by them for other brands as well, as GE lists it in their own "Essential Characteristics" book. It has a

brown micanol base and the triode sections are factory matched. Sometimes the tube is listed by the industrial number of 6198, some military types list both numbers on

the tube, and yet some don't use the industrial number. It's the same tube regardless. These are great 6SL7 substitutes said to sound sweet, but are rare.

[Filterlab]

I’d definitely agree with trying NOS vintage over new. The new valves I bought, badged as Tung-Sol, were absolute rubbish. Dull, lifeless, rolled off, pathetic.

There’s no comparison with those and my 5691s / 6H9Cs / Sylvanias. The vintage valves are leagues ahead!