Posted by rottenclam (A) on June 06, 2006 at 11:32:16

In Reply to: Joule Electra tube noise w/ Merlins (long question) posted by rottenclam on May 18, 2006 at 16:43:01:

Rich,

After speaking with another Joule customer that shares this same problem, he shared with me a technique for substantially lowering the noise floor:

1. Once the amps have warmed up, with no music playing, put your ear up to the speaker. Now, reach down and press the DC offset button (or any of the output tube bias buttons). Has a significant part of the noise/hum stopped? When you release the button does the noise return? If so, move on to step #2. If you hear no difference than this tweak is not for you.

2. Insert a toothpick between the button and the edge of the hole in which the button sticks through, with the button depressed, so it can be held down.

3. DO NOT, I repeat, DO NOT forget that you cannot have two buttons simultaneously pressed on one of the monoblocks. Jud Barber makes this very clear in the manual. Only put the toothpicks in when you're just about to sit down for critical listening. Take them out when not doing so. When the toothpicks are in, you cannot accurately adjust voltage, and you definately cannot bias any of the tubes.

Checking the DC offset does not have any effect on what you are hearing musically, other than dramatically reducing the noise/hum of the amp that ensues during basic operation. From what I understand, the communication between the display and the point in which you press the button are not in the musical signal path.

With that said, I have talked to Jud, and he has told me that he has shipped numerous versions of the Mark V iteration of the VZN-100, and he has not heard the kind of deep concerns that myself and this other customer have expressed. Maybe this noise/hum issue is relegated to mine and the other customer's OTLs only. Maybe we're just the ones that are most sensitive to it, and nobody else seems to be concerned. Either way, the "toothpick tweak" is an aural lifesaver for me. It may put the user at a disadvantage when trying to interface with bias checks, voltage checks, etc; but sonically, this, in my opinion, is the only way that I can listen to the amps now.

-Jake

• Re: An update! - Rich Brkich 13:00:25 06/06/06 (1)
  In Reply to: An update! posted by rottenclam on June 6, 2006 at 11:32:16:

  Very intertesting (and clever!)!

  This suggests to me that there must be something going on in the wireing to the bias controls that is injecting noise into the amps... something that I will have to talk with Jud about.... It can well be that RFI is sneaking in via the system that connects the amp to the built in LCD meter... loading it by pushing one of the bias buttons down may give the noise somewhere to go or prevents it from making its way in.
  Happy Listening,
  Rich Brkich
  Retailer & Audio Asylum Industry Liaison
  
  

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  • Re: An update! - tms0425 18:23:34 08/29/06 (0)
    In Reply to: Re: An update! posted by Rich Brkich on June 6, 2006 at 13:00:25:

    Just wondered if this was ever solved besides this little fix?
    
    I have the EXACT same behavior with my VZN100 MK V's and assumed they are all that way. I noticed it reduced the noise when the driver test buttons are pushed, but never even thought about operating it that way full time. The risk of screwing up and pushing a bias button simultaneously seems too great to me.

    I previously had Reimer Teton GS's which were 95db sensitivity and it was really intrusive with them on quiet passages. I didn't worry about it too much since I had VSM-MX's on order and after talking with Jud a couple of times I decided it was normal and I'd just have to live with it. With both my TSM-MX's and the VSM-MX's, the reduced sensitivity helped, but the noise/hum is definitely still there.

    These amps otherwise sound so terrific. Do I need to just get over it and enjoy them?

    Tom
    
    

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