Diezel herbert noise on channel 3 with high gain setting

D

Dopamine

New member
I switched out all the tubes, biased and turned it on. Ch1 and ch2 works great, but whenever I raise the gain on ch3 to 9 oclock or so, I start getting this noise.
Here's a video with the noise. Halfway in I raise the gain to 9 oclock and the noise starts.
https://www.youtube.com/watch?v=XD-Ai1xXOOE
Am I right to assume that this is a faulty preamp tube? V2 at that, since it's only used by ch3?
 
Change the V2 preamp tube. That noise sounds like serious microphonics.

Also, when you bias a Herbert you have to go back and adjust each duet until all pairs read your desired mA.
When you adjust one duet, it draws more current and changes the bias not he other two duets.
I take it slow and make minor adjustments until each duet reads 35mA. It takes me 20 to 30 minutes, but the bias
also stays quite consistent for months.
 
Yes, I checked each pair three times when biasing. I put the old v2 tube back in, but the noise remained. I switched guitars from fender strat to gibson les paul, and the sound stopped. Switching back, I noticed the noise decreasing and then vanishing as I turned down the guitar volume. Could it be that the pickups are microphonic?
 
Perhaps I spoke too soon. I put the new v2 tube back in, and it seems to make no difference. This time however, I maxed the tremble/bass/etc settings, and begun to hear some noise even with the gibson. Bearing in mind that there was a lot of feedback, the noise seemed to be there, although not nearly as much as with the fender. Lowever in the settings to 6 oclock, which I had been using, pretty much eliminated the noise.

Heres a video, first part maxed, last part 6 oclock.
https://www.youtube.com/watch?v=lSaCFHdlTBI

Next, I'll try the old v2 tube once again and max the settings to confirm that I did not miss this the first time. After that, I'll try switching out the v1 tube. If the problem persist, should I keep switching out tubes? Could there be anything else that causes this?

Another thing.. I tried every possible setting on my marshall JVM amp, but could not get any noise from any of my guitars. If the pickups were to blame, wouldnt there be an issue with another high gain amp?
 
Is there any noise when you turn down the volume
on the guitar ?

Do sit in front of the amp ?

Do you have a power cable with ground ?

Thanks,
Peter
 
Peter Diezel":1uzzuw18 said:
Is there any noise when you turn down the volume
on the guitar ?
Click to expand...
No. I can even have some volume, and the noise peaks after about 8 or so.
Peter Diezel":1uzzuw18 said:
Do sit in front of the amp ?
Click to expand...
I recorded the last video standing about 7 meters from the amp.
Peter Diezel":1uzzuw18 said:
Do you have a power cable with ground ?

Thanks,
Peter
Click to expand...
Well the cable yes, but my house is only grounded in the kitchen if thats what you mean.

anyway, I've tried switched the tubes around a few ways:
new v1 & v2
new v1 old v2
old v1 new v2
old v1 & v2 (I had only one RUBY 12AX7 AC5 HG+, so I used a RUBY 12AX7 AC5 HG for v2)

While it might have sounded a bit different, there was noise every time. Very clearly with the fender. Here and there, sometimes hard to tell, with the gibson.
Do you think I should try switching out any of the other preamps? They are all RUBY 12AX7 AC5 HG+, with a balanced one on PI.
 
I had the same problem once when I used a speaker cable by accident instead of a guitar cable.

My Herbert still has the original preamp tubes and has never given me an ounce of trouble.

Hope we can figure this out for you.
 
Now I've tried switching out each of the 6 preamps, and while the noise was not exactly the same each time (nor when I tried changing v1 or v2 a second time) this seemed to have no real effect.
I dont think the gibson actually had that noise, at least I havent heard anything today while testing with the old tube on v3-v6. (also with all new) If I had another fender to try I could be sure, but it seems like the fender is the problem.

Unless there is something else I could try?
 
Any other guitars to try with the Herbert,OR a different amp with that same guitar?
That squeal/high pitch screeching sounds like the guitars pickups are not shielded.

ANY amp with have a higher noise floor when it's maxed out,BUT that really sounds tube and/or guitar related.
 
I tried with a Ibanez rg270, which has a single coil pickup like the fender, and there was no noise. Seems to be a problem with the fender at volume 9-10.
However, there is no noise with the fender playing through a marshall JVM, no matter what settings I use.
 
Dopamine":ff36r3f8 said:
I tried with a Ibanez rg270, which has a single coil pickup like the fender, and there was no noise. Seems to be a problem with the fender at volume 9-10.
However, there is no noise with the fender playing through a marshall JVM, no matter what settings I use.
Click to expand...
After some more testing, Im able to get this noise with the Ibanez as well. I have to max both mid cut settings, and change the bridge setting to left of middle (single coil + 1 humbucker pickup), and then it's there at volume 9-10.
 
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