rabski

EAR834 tube rolling

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4 hours ago, Maverick said:

not sure on your country but try Watford Valves site

Well, the price is so reasonable and their information is so clearly! 

Thank you for that!

tungh

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After trying some ways with some tubes and I found the 6211 (12au7) gold pin from Telefunken was the best (may be) with my system. I replaced the V3 and then V1, I'd love V1 rolling. Sound stage was opened and larger, the 3D effect was clearly, more details and balanced.

I'm waiting for the Siemens 12au7 and 12ax7 long plate and try again to find the best.

Thank you for your advice!

tungh

P/s: The Telefunken 6211s are too expensive now, you can find them on eBay.

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Super Wammer
On 28/02/2017 at 09:29, mr.me said:

Although I don't own an EAR I would recommend using a lower gain, low microphonics 6072A in place of the 12AX7 

I've ordered one to give it try thanks

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4 minutes ago, Maverick said:

I've ordered one to give it try thanks

So please tell me which brand is the best?

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10 minutes ago, Maverick said:

I've ordered one to give it try thanks

I should have added that nos tubes and not the new production EH or JJ. Sorry  :oops:

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Super Wammer

bit like speakers, depends upon rest of system and personal preference

IMHO any differences between brands are personal not "night and day", but in this hobby so much is . . . . 

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Super Wammer
5 minutes ago, mr.me said:

I should have added that nos tubes and not the new production EH or JJ. Sorry  :oops:

bugger, not much £ to try

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Well my take on it is there is a big difference between the GE or Sylvania 6072A than the new production tubes and you will see that in the prices that they sell for.

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My 3 pence worth on the 834p. I have tweaked a few now. V1 which I will assume is the input valve runs open loop, and I select for the lowest noise and best channel balance. V2 does all the gain, and is essential for the correct operation of the feedback riaa. I select the highest gain for this position. Not all ecc83s are created equal. The original has a gain of 100, but some of the newer ones are nearer 90. I even measured a 12ax7wxb iirc as 130. It is my observation that too lower gain gives the more muddy sound in the bass. V3 is a cathode follower inside the feedback loop. I put ecc81 in this position, but I did half the cathode resistors, to increase the cathode current so it has a bit more welly. Unfortunately selecting valves needs some specialist gear, some of which I have, or with a bit of practice they can be tested in the unit.

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