Slowly obtaining a spare set of valves for my Croft preamp and TD Copper amp

[The Grand Wazoo]

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

[Marco]

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!

Marco.

[Mike]

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!

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!

[Marco]

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]

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.

[Marco]

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.

[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":





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?

I'd love to try one!

Marco.

[Mike]

Good luck with that...

http://cgi.ebay.co.uk/1-NOS-12AX7-GE...item45f96943f3

There's always the re-issue. Won't be the same though.

http://cgi.ebay.co.uk/Genalex-Gold-L...item256218f590

[Marco]

Oh FFS!!

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

Might try the reissue for a giggle - we'll see!

Marco.

[Mike]

I can't even remember why now, but the ECC83 family was (is?) a bit of a "hobby horse" of mine.

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!

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....