Help! No Sound! Valve 3 circuit problem!

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Edit: I've since found roughly where the problem is, see further down to skip the intro waffle!

Hello!

Played a gig, amp was fine. Plugged in a minute ago and there's no sound. Any ideas?

I've unplugged all FX. Tried different speaker lead/cab. Tried different guitars/leads. Makes usual power amp hum, and also FX unit in parallel loop doesn't see any level when plugged in. Therefore I assume the power amps working fine, just not getting any signal from the preamp (except a REALLY REALLY quiet sound when on distorted and quite loud). Is there anything in the preamp to check? Preamp tubes are all glowing. Help! :(
 
Nope! Tried toggling it too, and the switchable loop, and tried the old off and on again trick in case some of the relays "stuck".
 
Could be a midi problem (did you gig with midi gear?). Try to set the amp back to omni mode - and make sure all the tube lits on the back (if you should have them) are NOT on.

What happens when you plug your guitar into the non-switchable (!) return?
 
Yeah, I used midi stuff, but the MIDI foot pedal still changes channel, and the midi doesn't control volume (except mute which isn't on) so I don't know why it would be midi related? I can try it if you think it's worth a go though?

No tube lights are on. I played the gig with 4 tubes cuz as I mentioned a few weeks ago I'm trying to get hold of a fuse holder as I lost it when a fuse blew. It worked fine at the gig though on 4 tubes so I don't know why that should be a reason either. Should I not have a blue light for the one without the fuse in though????? :confused:

And there's no signal coming out the parallel FX loop send anyway - hence why I think it's preamp.
 
Does that mean it's time to turn my house upside down looking for old preamp tubes, or does it mean taking it out the rack and looking inside. :cry:
 
Which tube does the serial loop come back to? Then I know it's nothing after them....
 
serial loop doesn't go back to any preamp tube i believe just straight through the power amp
 
Herbert right?

Herbert:

V1 Used by all channels

V2 Used by channel 3

V3 Used by all channels

V4 Mixer & Loop Driver

V5 Return Driver

V6 Phase Inverter
 
If you have a clean channel by chance then it's v-2 or v-3. But I would say myself it's most definitely a pre tube (98% sure) because I had the exact same thing happen awhile back. Chinese tubes don't travel well for some reason, but are cheap and sound great, so I get doped back into them even though that's happened to me twice already... in different amps.
 
I might just re-tube the whole thing with non-chinese tubes. This amp's been the most unreliable amp I've ever owned and it ALWAYS THE F**KING TUBES, never the amp itself!!!! :cry:

Is the Phase inverter an 12AT7? The manual says so, but I've heard varying accounts. Is a 12AT7 the same as an ECC81? or ECC82?
 
Ailean":14dapisr said:
12AT7 is the same as ECC81 but not ECC82.
Click to expand...

Hello fellow southamptoner!!! :)

Is it definitely a 12at7 then, not 12ax7 for phase inv?

(edit: it's a Herbie btw)
 
herbert uses all 12ax7 tubes no 12at7 at all i made that
mistake once and peter corrected me
 
Doh! Too late, I already ordered.

Should just make the output distort later, so I may try it and if not switch to another of my ECC83s. I guess it should just mean that instead of the amp not getting any louder after about 1 o'clock, the same thing happens but at nearer 4 o'clock, and my master volume knob is less sensitive. Am I correct? :confused:
 
This is taken from the Herbert manual on the factory website:

The pre-amps are equipped with 12AX7 tubes in all positions, except the phase inverter, which is a 12AT7.
Click to expand...

Hello Me! Yeah I noticed you were a Southampton lad, where abouts? I'm in Shirley.
 
Ailean":2yazqofb said:
Hello Me! Yeah I noticed you were a Southampton lad, where abouts? I'm in Shirley.
Click to expand...

Woolston! Are you in a local band?
 
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