Herbert Preamp tubes / Hum on Ch 2 and 3

[TOOL_5150]

I very recently bought a Herbert. I went to crank the gain on ch 3 and it hums pretty bad. Is this normal? Is it wired to provide DC to the filaments? I ran guitar straight into the head to make sure it was not any effects. Is there a way to find out what year this amp was built? It has ruby tubes in it - possibly original?

Thanks,

~Matt

 

[RedB4Black]

When you crank the gain getting a little hum is normal. What is the serial #? The Ruby's are likely the stock tubes.

 

[Peter Diezel]

It sounds like a bad preamp tube. If it´s also
on channel 4 You have a bad hum pot.

 

[TOOL_5150]

It sounds like a bad preamp tube. If it´s also
on channel 4 You have a bad hum pot.

As you can see Im new to the forum [post #2 right here!]

Wow, an answer from 'the man' himself. Im honored! I will check for microphonics tomarrow. I should check V1 and V2, correct? One thing though Peter, please excuse my ignorance, but is there a channel 4 on a Herbert?

~Matt

 

[KillDivision]

It sounds like a bad preamp tube. If it´s also
on channel 4 You have a bad hum pot.

Peter, stop drinking the cheap stuff.

 

[Peter Diezel]

Oooooooooops, it´s a Herbert

Anyway, only good stuff at home

 

[TOOL_5150]

001/457 Is the serial # - What year was it made?

It has external bias points, So I would guess its a newer herbert, right?

As far as checking the preamp tubes - how many do I need to check it? Just replace the first 2?

~Matt

 

[duesentrieb]

I'd swap them first.