[whirlwind]

  Hey guys...how does a GEC/Osram, brown curved-bottom base A1834 (6AS7G) NOS for £65 sound to you?...Unbelievable?...YES!!
 
On this Halloween day, the Gods have indeed (at last!) smiled upon me. Following "mordy's mantra" when searching for bargains - plus my own addition : luck, luck and more luck! - I have indeed managed to bag aforesaid tube, lol!!

...how?...by searching on a specific ebay site, rather than just my UK or .com - ie. ebay.de (Germany) - and searching for just "6AS7G", I could not believe my eyes when I saw the very tube I mentioned a while back that a lucky member on 'For 6AS7G rollers here' discovered...ie. a Haltron 6AS7G. Usually these rebrands are the cheap Russian variant, hence not too many probably bother with them. But its "smell" was pure GEC - especially when a close look at the brown base showed it to be curved!
Well, when I saw the early bids at 3 Euros, I couldn't believe my luck - it appeared possibly no-one had yet recognised just what it was!
 
Anyway, as the bidding was still not very high minutes before the end, I whacked in a max bid of 120 Euros in the last seconds...and got it!!!...Edit : for 90 Euros!
 
I am so sorry if I beat anyone here to it...but I just had to try lol! And so, folks, this just shows that miracles can happen...if you're very lucky! OK, so I didn't get it for $15....but you ain't NEVER gonna get one of these rare beauties NOS (or used!) for that...no matter how lucky you are, methinks...the item in question...
 

 
Better get some dinner under way...almost too excited to eat though!!! 

 

Great snag.....these are wonderful tubes, to say the least.

 

[nephilim]

Congrats H1! Great deal
 
I just tried the FDD20/ECC31 combination together with the 5998... and I immediately felt that the ECC31 channel has much more bottom and sounds juicier. Towards the upper frequencies the differences are less pronounced and yield a nicely expanded soundstage with a pretty sparkle. However, I always think that the FDD20 ear is half-deaf due to the leaner bass... Maybe the FDD20 is simply not burned in enough?
 
Anyway... going back to the Mazda tonight (before Elise's short vacation in Poland). The first(!) impression was that they seem to be more bass-heavy than the FIvre - a bit like the ECC31 with a sledgehammer behind the back.

 

[UntilThen]

H1 Nep, if you're grounding via the left RCA connection, be sure that the RCA plug is fully in. It can be tricky now with the ground wire in it to make contact fully. That is my observation. If it's not contacting properly, you get no sound on left channel, if it's contacting but not fully, your left will sound softer. What I did was use a thinner ground wire.
 
However if you're not grounding in that manner then it's interesting you're hearing differences because I detect no differences other than a stereo image. In fact you can clearly hear instruments from left centre right and picture where all the musicians are standing.
 
My FDD20 has less than 20hours now but it's not showing any of that effects. I try a great variety of songs. I shall do a more thorough listen.

 

[UntilThen]

Alright I just did a Channel ID / Phase test and Balance test and Subwoofer crossover test using my Chesky Records 10 Best album.
Yes I do a lot of such testing when I was competing in car sound system. Even have 3 trophies LOL.
 
If you have such a test album try it. My test has conclusively proof that:-
 
Channel ID / Phase Test - Passed
Balance test - Passed
Subwoofer crossover - OMG these are not subwoofers but sure feels like one

 
 
This album:-
Track 12 - Channel ID /Phase Test
Track 13 - Balance Test
Track 14 - Pink noice (~20 dBFS)
Track 15 - Subwoofer crossover test
 

 

[nephilim]

Hmm, I have no additional ground wire - just the plus & minus from the 12V supply, where the minus is already linked to earth. I also did not notice that something is missing when I have both FDD20 running - it's just the slightly leaner bass of the FDD20 channel compared to the ECC31 channel which shifts the lower end to the ECC31 ear. I will swap FDD20 & ECC31 to check if the impression follows the channel change. Interestingly all of us put the FDD20 to the left channel

 

[UntilThen]

I did mine to the left because it's a shorter route to the RCA connection. I have to ground too or else I get hum.

 

[hypnos1]

Thanks guys...I must admit I never dreamt this kind of thing could happen again - especially with this particular tube being the Holy Grail of Holy Grails lol!! (Even if some would say the curved-bottom base tube sounds no different to the straight-bottom!).
 
So have a go using these strategies...you never know your luck!! 

...

 

[nephilim]

Just swapped channels... and the bass moved towards the other ear, too. It's more centered now than before - obviously my ears are not identical

 

[UntilThen]

Which song do you listen to for that test Nep? I'll try it too. I wouldn't be surprise if for most of us our ears are not totally identical in sound reception. A check with the specialist will prove that.

 
This is why I think the La Figaro 339 is great. It's dual mono. You have right and left channels volume controls.

 

[hypnos1]

  Congrats H1! Great deal
 
I just tried the FDD20/ECC31 combination together with the 5998... and I immediately felt that the ECC31 channel has much more bottom and sounds juicier. Towards the upper frequencies the differences are less pronounced and yield a nicely expanded soundstage with a pretty sparkle. However, I always think that the FDD20 ear is half-deaf due to the leaner bass... Maybe the FDD20 is simply not burned in enough?
 
Anyway... going back to the Mazda tonight (before Elise's short vacation in Poland). The first(!) impression was that they seem to be more bass-heavy than the FIvre - a bit like the ECC31 with a sledgehammer behind the back.

Hi neph.
 
I personally found it took quite a long while for the bass to even out. Also, I found I had to change my first ECC31 for another, as it was obviously a very strong tube and was dominating the FDD20. Once these two factors were resolved, I found no imbalance at any end of the frequency range.
 
ps.  I have in fact found more imbalance between two of my 31s, compared to the 20/31 combo!
 
Hope you manage to even things out in your own system...but remember it might well take up to 100+ hrs to get there, lol!

 

[hypnos1]

  Just swapped channels... and the bass moved towards the other ear, too. It's more centered now than before - obviously my ears are not identical

I suspect very few people's ears are in fact identical, n!

 

[UntilThen]

This is another CD for testing purposes. It has left / right channel test and the various Hz test. Also a piano chord in mono. I'll do more testing for sure. Now I'm even more keen to dig deep into this.
 

 

 

[hypnos1]

  Which song do you listen to for that test Nep? I'll try it too. I wouldn't be surprise if for most of us our ears are not totally identical in sound reception. A check with the specialist will prove that.

 
This is why I think the La Figaro 339 is great. It's dual mono. You have right and left channels volume controls.

Yes indeed UT...a very useful feature of the LF!
 
Mind you, with probably all our 4 tubes hardly ever in exactly even strength, a judicious swapping around in trial and error would probably do the trick in most cases, I suspect.
 
This is obviously what the Feliks-Audio guys do (but using more scientific measurement, lol!) when numbering the specific position for each tube...is that service above and beyond the call of duty, or what?!

 

[UntilThen]

 
Yes indeed UT...a very useful feature of the LF!
 
Mind you, with probably all our 4 tubes hardly ever in exactly even strength, a judicious swapping around in trial and error would probably do the trick in most cases, I suspect.
 
This is obviously what the Feliks-Audio guys do (but using more scientific measurement, lol!) when numbering the specific position for each tube...is that service above and beyond the call of duty, or what?!

That's so true what you said H1.
 
Now there's clearly a reason why Feliks Audio so painstakingly numbered those tubes and numbered the sockets for it to go into. I knew there had to be a reason.
 
Also with 2 ECC31 one would assume they are 100% identical but are they? A look at some test results for tubes show different strength. Not just ECC31, for that matter any other pairs. If really critical then yes go for matched pairs however I have not felt the need. My ears are more forgiving BUT if the difference is a lot I would have heard it.
 
With FDD20/ECC31 what I'm hearing now is superb imaging and clarity. Annie Lennox voice is right in front me. Vocals are projected forward and commanding. Backing singers to the left and some instruments to the right. Mid bass is pounding in my chest dead centre and sub bass is simply felt. This is 'Whiter Shade of Pale'. Incredible.
 
Sub bass is not localised. That's why you need not place your subwoofer in the centre. It can be in the left or right corner and you will feel it. My Definitive Technology 12" sub in the right corner caused my wall clock to come tumbling down and crash watching 'Saving Private Ryan' !!! Maybe I should wire the sub to my headphone.

 

[UntilThen]

RCA JAN 1635 / Chatham 6AS7G
 
For a start, this is a no, no. I have to crank the volume knob to 4 o'clock to get a satisfying listen. It actually sounded OK at that volume. I have to thank this tube though because with it I was able to crank Elise to 5 o'clock which is where it starts to distort and obviously at max it distorts badly...buzzing sound creeps in. So there you have it. Don't use 1635 or else you might blow Elise up with that volume setting at extended listening sessions. With all other tubes, even with 2 ECC31 and 5998 on HE560, I've never gone beyond 12 o'clock(LOUD). With HD650 the max I can go to is 10 o'clock(LOUD). Anything more will surely damage my ears.