12AT7 Tubes

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martyo

Re: 12AT7 Tubes
« Reply #20 on: 14 Dec 2011, 09:46 am »
Sweet. I have many of the same and a few others (Sylvania GBs, Siemens triple micas, RCA black plates).

The triple mica Siemens were what I first used in my 550 until the TFK's showed up. And before I got the T8 I had the Valvos ready to go in and then Frank changed to the 6N1P's. (All under Mark's tutelage  :P)

ricmon

Re: 12AT7 Tubes
« Reply #21 on: 14 Dec 2011, 06:39 pm »
The triple mica Siemens were what I first used in my 550 until the TFK's showed up. And before I got the T8 I had the Valvos ready to go in and then Frank changed to the 6N1P's. (All under Mark's tutelage  :P)

Are there any makes of the 6N1P that have the reputation of the Telefuken's?

Ric

avahifi

Re: 12AT7 Tubes
« Reply #22 on: 14 Dec 2011, 06:47 pm »
Just a quick mention that if you have the Exicon 10P20 upgrade done to any of our hybrid preamps, this will be more of a major musical improvement than your choice of any of the tubes discussed herein.

Based on the observation that a clever thing to do is to locate and fix the worse case problem first, it certainly appears now that the Hitachi J79 was the worse case problem previously.  It took lots of years to find something a lot better, and now, unfortunately, the 10P20 plastic case device is out of stock for probably four months.  We have adequate inventory for new products, but not for any more preamp or DAC upgrades until they are available again.  I wonder if they are a victim of the SE Asia horrible floods this winter?

Frank

coldfogey

  • Jr. Member
  • Posts: 62
Re: 12AT7 Tubes
« Reply #23 on: 28 Apr 2013, 02:29 pm »
I am interested in a Amperex 12at7/6201 PQ w/gold pins,  I believe it is classified as a E81CC.  Is this ok to use in my 600R?  If it is, has anyone used it?  What is your impression of this tube?  The reason for the question is that the 600R instruction only stipulates ECC81.  Thank you.

avahifi

Re: 12AT7 Tubes
« Reply #24 on: 28 Apr 2013, 08:36 pm »
Since the 6201 has identical specifications as a 12AT7 tube, they should work in a Fet Valve 600R amplifier.

HOWEVER since I have seen far too many defective so called new old stock tubes, I strongly urge that you try them first in a less valuable piece of equipment before risking a 600R with defective tubes.  If you notice a heat sink getting hotter than normal when you switch to a different brand of 12AT7 tube or an "equivalent" then at least a re-bias is needed and that is a job for us.

By the way we now have good inventory of the 10P20 Exicon mos-fet we use to upgrade the old Ultra and Transcendence Seven preamps.

Frank

medium jim

Re: 12AT7 Tubes
« Reply #25 on: 28 Apr 2013, 09:19 pm »
Since the 6201 has identical specifications as a 12AT7 tube, they should work in a Fet Valve 600R amplifier.

HOWEVER since I have seen far too many defective so called new old stock tubes, I strongly urge that you try them first in a less valuable piece of equipment before risking a 600R with defective tubes.  If you notice a heat sink getting hotter than normal when you switch to a different brand of 12AT7 tube or an "equivalent" then at least a re-bias is needed and that is a job for us.

By the way we now have good inventory of the 10P20 Exicon mos-fet we use to upgrade the old Ultra and Transcendence Seven preamps.

Frank

The answer or must have for anyone who tube rolls, is a tube tester in good working order.  At minimum, one that checks for leaks, shorts, and for mutual conductance.

Jim

tonyptony

Re: 12AT7 Tubes
« Reply #26 on: 6 May 2013, 12:08 am »
Well, I finally got my hands on a pair - pinched waist Valvo Blue Label, triple mica 6201 tubes. Among the rarest of the rare, almost the Flying Dutchman of tubes. With any luck I'll be testing them on my tube tester tomorrow evening. If they check out okay I'll have to plan for a swapout.

mark funk

Re: 12AT7 Tubes
« Reply #27 on: 7 May 2013, 10:40 pm »
Tony, check these out,











                                                                                                                                              :smoke:

tonyptony

Re: 12AT7 Tubes
« Reply #28 on: 8 May 2013, 12:06 am »
Ah, nice.

avahifi

Re: 12AT7 Tubes
« Reply #29 on: 8 May 2013, 12:39 am »
Don't zap yourself installing them in a Fet Valve amp.  The black heat fins on the vertical power supply board have 275V DC on them when the amp is energized or even turned off until the supplies slowly decay.

Frank

mark funk

Re: 12AT7 Tubes
« Reply #30 on: 8 May 2013, 09:55 am »
Hay Frank, I don't roll tubes in my amp or my DAC any more they run on Telefunken's. When I do roll some tubes its in my T-5 pre amp like now I am running a pair of ECC81 1955 Valvo sounds good :thumb:



                                                                                                                                           :smoke:

martyo

Re: 12AT7 Tubes
« Reply #31 on: 8 May 2013, 01:44 pm »
Hay Frank, I don't roll tubes in my amp or my DAC any more they run on Telefunken's. When I do roll some tubes its in my T-5 pre amp like now I am running a pair of ECC81 1955 Valvo sounds good :thumb:



                                                                                                                                           :smoke:

What do you mean, you were rolling tubes in your HumDinger! :lol: 8)

adrianc

  • Full Member
  • Posts: 356
Re: 12AT7 Tubes
« Reply #32 on: 8 May 2013, 03:00 pm »
You will never know how good a Ecc81 can sound if you never try these Mullard earliest version,


mark funk

Re: 12AT7 Tubes
« Reply #33 on: 8 May 2013, 10:40 pm »
I only have three pair,





                                                                                                                                      :smoke: