The Best 6SL7-type tubes ever made? An Update...

[Marco]

Guys,

A while back I wrote about some tube rolling I was doing, and that I found that the Brimar CV1985 was one of the best 6SL7 types I've heard, and also the amazing RCA/GE 5691 Red base:





GE branded version:




I use two of those bad boys in the line stage of my Croft preamp, and they are fantastic, however, I'd like to introduce you to another contender for the best 6SL7 ever made, and that's the equally amazing Tung Sol 6SU7GTY:





I've now fitted three of these NOS broadcast tubes in my preamp (one in the remaining position feeding the line stage and two feeding the phono stage section), and they are every bit as good as the 5691s, perhaps being marginally sweeter in the midrange, but not at all in a lush or 'syrupy' sense.

I've now been experimenting with all sorts of 6SL7s for the last three years, and in my opinion the American military types (particularly the premium versions from RCA and Tung Sol) are sonically head and shoulders above all others, as well as being heavier, significantly less microphonic and undoubtedly built from higher quality materials, as a result of being originally used in the demanding environment of military applications.

You just need to pick one up of either type and examine it to see the superb quality of the construction, particularly a 5691. However, these tubes are rather rare and somewhat expensive, but not crazily so.

They are however said to last almost forever, such is the high standards of construction and utterly strict quality control they were subjected to when being selected for military purposes.

For more info on the 6SU7GTY, check out this link and the video therein (ignore the fact that the guy is using them in his home-made guitar amp!) Trust me these tubes are truly superb in all audio applications:

http://www.tronbuilder.com/Tron-builder-6su7-review.php

So if you have any equipment that uses 6SL7s, and you want to give it a real shot in the arm, fit some RCA 5691 Red Bases or Tung Sol 6SU7GTYs!

Marco.

[Monjul]

Thanks for your post Marco. In fact, it was your words that pushed me to finally make a decision for replacement drivers in my Cary SLA 70A Signature amp.

Although my current Sylvania VT 229's are special tubes, they are somewhat forward although the soundstage is unusually wide (distortion maybe?). Forward enough to cause eventual fatigue unfortunately. Because of this, I was contemplating RCA's as they are described as smooth and laid back but some think they are too syrupy sounding. Not what I'm looking for.

The descriptions of the TS on the internet is that they are smooth tubes also, but no one has posted in any of my searches that they are dull and lacking detail so I decided to give the TS 6SU7GTY's a shot after reading your thumbs up review.

Wow. They are not only smooth and superbly balanced but render more than enough detail without sounding over etched These are certainly great tubes and if they sound even better after a bit of break in, I'm going to be a very happy audioholic.

[Marco]

Hi Armand,

Nice one - I'm glad they hit the spot

They certainly work very well in my Croft preamp. The TS 6SU7GTYs are very detailed and musical sounding, without specific emphasis on any part of the frequency range, which is just what I like.

The RCA 5691s are also very good, perhaps slightly more 'upfront' sounding (definitely not smooth and laid back) than the TS 6SU7GTYs - they create a very wide soundstage, and because they're amongst the least microphonic of their type, music emerges from an eerie 'blackness', which makes voices in particular sound magical.

What I like doing in a circuit with tubes is mixing and matching ones of the same type from different manufacturers, so that one specific sonic signature doesn't dominate the presentation. Ideally you want the sonic signatures of the tubes to complement each other to create musical synergy, and that's why I feel that the combination of RCA 5691s and TS 6SU7GTYs 'marries' so well.

Anyway, I'm glad that I've been of some help. That's what we're here for! Incidentally, where did you buy your 6SU7GTYs from?

Enjoy the forum. Btw, if you could do me a favour and pop into the Welcome area and introduce yourself to our members (check out the existing threads there to see what's required, stuff like system details and music tastes, etc), that would be great

Marco.

[nikonf]

Hello Marco,

Can you suggest any reliable sources for the Tung Sol 6SU7GTY ?
I would like to try these in my input to my Antique Sound Labs 845 Monoblocks.

Currently, I am using Adzam 6SL7GT - 1950's vintage from Philips Holland.
I find it has an over-emphasized top end, which I do not particularly care for in these amps.
I would like something neutral or perhaps adding a little emphasis to the mid-range.
The Adzams have great detail, I just don't like the top-end with these amps.

Do you know of a reliable source?

Many thanks!
Mike

Hi Armand,

Nice one - I'm glad they hit the spot

They certainly work very well in my Croft preamp. The TS 6SU7GTYs are very detailed and musical sounding, without specific emphasis on any part of the frequency range, which is just what I like.

The RCA 5691s are also very good, perhaps slightly more 'upfront' sounding (definitely not smooth and laid back) than the TS 6SU7GTYs - they create a very wide soundstage, and because they're amongst the least microphonic of their type, music emerges from an eerie 'blackness', which makes voices in particular sound magical.

What I like doing in a circuit with tubes is mixing and matching ones of the same type from different manufacturers, so that one specific sonic signature doesn't dominate the presentation. Ideally you want the sonic signatures of the tubes to complement each other to create musical synergy, and that's why I feel that the combination of RCA 5691s and TS 6SU7GTYs 'marries' so well.

Anyway, I'm glad that I've been of some help. That's what we're here for! Incidentally, where did you buy your 6SU7GTYs from?

Enjoy the forum. Btw, if you could do me a favour and pop into the Welcome area and introduce yourself to our members (check out the existing threads there to see what's required, stuff like system details and music tastes, etc), that would be great

Marco.

[Marco]

Hi Mike,

Welcome to AoS!

I got mine from here (helpful chap and very prompt and reliable service): http://www.audiotubes.com/6sl7.htm

If you scroll down the list, you'll see that he's got some of the tubes you're looking for in stock. Let me know how you get on

Marco.

[nikonf]

Hi Marco,

Thank you so very much for your most prompt reply!

I like your system and I am looking for a Technics SL-1210MKG. I heard one at a dealers shop and it sounded amazing on a horn speaker/vacuum tube system.
Is it possible to easily have the stock tonearm replaced? Which tonearms do you recommend with the SL-1210?

Happy listening,
Mike

[Marco]

Hi Mike,

Best to start a separate thread on that one in 'The Techiepedia' section of Analogue Art. I'll nip along when I get a chance

Marco.