Tubes Asylum

Leaving 12AU7 on all day

108.41.115.249

bullethead

I think it sounds better now. I use a single 12AU7 tube in my DAC and it sounds better after leaving it glowing for days.
Yaqin DAC K-9
Oh man for $500. I bought another one on eBay used as well for a second system I am building. Second system is Harbeth Compact 7ES-3, PSaudio P-200 preamp, Bel Canto S300 amp.
Main system is connected to Bel Canto reference series equipment chain with internet streaming services.
Tubes man!

Edits: 03/08/14 03/08/14

Follow Ups:

RE: Leaving 12AU7 on all day - mhardyman 06:05:41 03/10/14 (0)
If I am home, and not galavanting about, all of my DACs are left on. All have only one tube of various designations. Preamp tubes will last a long time. Power tubes not so much. Audio Note specifically recommends that their DACs are left on 24/7. They do sound better and I have noted that all of mine seem to sound better once their operating temps have been reached. I don't know why this is so or which parts need to be nice and toasty warm!

I don't mind the power consumption aspect either. On/Off cycles are harder on equipment and tubes than anything else.

YMMV
RE: Leaving 12AU7 on all day, I wouldn't use a precious 12AU7 - Mechans 05:15:51 03/10/14 (1)
If you are ok with replacing it on a relatively frequent basis, then sure. I would opt for a really nice current production tube. What are you using now? I don't use current production 12AU7s so I can't offer an alternative but I hope other inmates will make some specific suggestions.

Steve
- RE: Leaving 12AU7 on all day, I wouldn't use a precious 12AU7 - bullethead 08:36:18 03/15/14 (0)
  I use electro Harmonix 12AU7. I was told it would be OK for thousands of hours as it is just a cathode follower. It sits inside the DAC. I started turning off when listening is over however.
  
  I will not use NOS in that configuration. I can see if it was for a preamp or something then yeah.
RE: Leaving 12AU7 on all day - BCR 13:33:25 03/09/14 (7)
Try a 12bh7, it can be used in place of a 12au7 and will last longer.
- Another vote for the 12bh7 used as cathode follower ... - beppe61 07:23:27 03/10/14 (4)
  it is really a great driver ... not that popular and i do not understand why. Why ?
  Kind regards,
  bg
  - RE: Another vote for the 12bh7 used as cathode follower ... - BCR 09:44:20 03/10/14 (3)
    I have been using them for years.As a matter of fact my Quicksiver amps come with 12bh7 tubes. When I asked why he uses them he told me they will last longer than a 12au7.
    - RE: Another vote for the 12bh7 used as cathode follower ... - beppe61 02:34:19 03/11/14 (2)
      Hello and thanks for the interesting information.
      I am not an expert but i have a humble and old preamp from Croft Audio where the line stage is just one tube connected as cathode follower, half tube for each channel.
      The phono stage is two ecc83.
      I took out the two ecc83 and put one 12bh7 in place of the existing 12au7.
      I know that maybe it is not optimized for the 12bh7 but the resulting sound is so more powerful and crystal clear that there is no discussion.
      I guess that a 12bh7 correctly used could be a spectacular line stage.
      If i were able i would build a line stage on the principles illustrated here ...
      http://www.altavistaaudio.com/SA-1000.html#lsp
      "... shunt more current through the line stage tube, lowering its output impedance so it can directly drive your power amplifier without that transistor sound.... Upgrading the resistors and capacitors in the line stage gives the tube the kind of support circuitry it needs to speak with exceptional clarity and purity; bypassing the output buffer eliminates solid-state colorations and lets you hear the tube.
      The whole effect is a richer, livelier, more detailed sound with more precise focus and timbral accuracy... "
      so apart a high output impedance there are no drawbacks.
      And i guess the resulting sound would be exceptional ...
      But i do not have the skills required to design this stage ...
      Just one 12bh7 ... and a pot before it ..
      Thanks again.
      
      Kind regards,
      bg
      
      Edits: 03/11/14 03/11/14
      - RE: Another vote for the 12bh7 used as cathode follower ... - BCR 06:43:19 03/11/14 (1)
        
        In Reply to: RE: Another vote for the 12bh7 used as cathode follower ... posted by beppe61 on March 11, 2014 at 02:34:19
        
        Hi, an ecc 83 is a 12ax7,an ecc 82 is a 12au7. The 12ax7 has lots more gain than a 12au7. As far as replacing a 12 type tube with a 6922 tube ,which is what you say you want to do, I think you would be wasting your your time and money. But that's up to you. Since you like the 12bh7 so much why don't you just stick with that?
        
        RE: Another vote for the 12bh7 used as cathode follower ... - beppe61 09:07:45 03/11/14 (0)
        
        In Reply to: RE: Another vote for the 12bh7 used as cathode follower ... posted by BCR on March 11, 2014 at 06:43:19
        
        I think i expressed myself badly.
        
        I am waiting to receive a tube buffer for the dac and this has only one 6922 or equivalent.
        
        The preamp instead is an old Croft Micro ...
        This preamp has two 12ax7 for phono and just one 12au7 as line stage (a buffer).
        I took out the two 12ax7 and replaced the 12au7 with a 12bh7.
        I liked the sound of the line stage section with the 12bh7 in place so much better.
        More powerful, crystal clear ... very very good even if i guess the circuit is designed for a 12au7 of course.
        And still the sound was much better to me.
        So they are two different cases.
        Kind regards,
        bg
- RE: Leaving 12AU7 on all day - Trouser Trout 15:52:11 03/09/14 (1)
  How about the 5814a?
  - RE: Leaving 12AU7 on all day - BCR 16:23:53 03/09/14 (0)
    You can use that also but I never have.
As I understand it, the tube is only used for the line out section... - Ivan303 06:03:03 03/08/14 (3)
Have you tried it using headphones?

If so, which ones and what do you think?

Not your planar speakers/headphones, real ones! ;-)
- I have no idea what you are talking about - bullethead 06:20:04 03/08/14 (2)
  I have no idea really. I don't see a headphone jack on it. That thing is IR...
  
  haha, another thing to fight against, IR distortion in high end equipment!
  - What, that black spot on the right side of the front panel is NOT a headphone jack? - Ivan303 07:02:52 03/08/14 (1)
    BUMMER!
    - it is good - bullethead 08:32:43 03/08/14 (0)
      I like it,

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