Peavey Classic30 troubleshooting help please

[kate033]

Hi guys
I have a peavey classic 30 combo and would truly appreciate any troubleshooting advice you can give.

The amp works perfectly on the first channel. When you switch to channel two everything works normally except there is no increase in gain/overdrive when you crank the post knob. In fact you can have all the knobs on twelve except he master vol and there is still no gain. There is no hum or scratchyness an all the pots seem to work properly.

I assumed it was a badpreamp tube so I replaced all the 12ax7's wih new jj's with no change.

I brouht it to the local shop to have a tech look it over but when they plugged it in it worked 100 percent fine?!? Very frustrating! They said it must be my cable or voltage issue at my house, but i brought in my own guitar and cable to the shop and eliminated that possibility. Tried it at my neihbors house wih same problem.

Any suggestions on what might be wrong? The only other repair shop around is sam ash. I hate to spend a fortune on it there. At this point im wondering if id be better off just buying an od pedal and ignoring the 2nd channel

Any suggestions? Much thanks in advance!

[Jazz P Bass]

Classic 30

What volume level are you testing this at?
Channel #1 is the "clean" channel. Set the volume at "5".
Channel 2 is the "lead" channel. Set the "pre & post" at "5".
When you change channels is there any difference?
There may be a "boost" switch. Does this change anything?
Channel #1 only the "normal" pot works.
Channel #2 only the pre & post work.
On channel #1 select, a relay grounds out tube V2 & enables the normal pot.
If you are diming everything you may not get what you are after.

[kate033]

What volume level are you testing this at?
Channel #1 is the "clean" channel. Set the volume at "5".
Channel 2 is the "lead" channel. Set the "pre & post" at "5".
When you change channels is there any difference?
There may be a "boost" switch. Does this change anything?
Channel #1 only the "normal" pot works.
Channel #2 only the pre & post work.
On channel #1 select, a relay grounds out tube V2 & enables the normal pot.
If you are diming everything you may not get what you are after.

Thanks.

I usually keep the volume around 3-5 for home use. I do clearly understand hoe the pre post and master volume controls work. I had this amp for a year or so w/o any trouble before this....never gigged or abused.

Typically when on the lead channel as you turn up the post the gain will increase. Now, it does not. There is a slight increase in volume only - no gain. The boost still works same as new. Essentially, the lead channel sounds identical to the "clean" channel w/ the exception of the pre knob contolling vol instead of the master volume. The new 12ax7's did not make any difference.

Also, Ive never had the footswitch so that is not a factor.

Any ideas?

[Jazz P Bass]

Classic 30

Just checking that we are on the same page here.
I am looking at the owners manual. Maybe you have an older amp.
It shows, left to right: Normal, Pre, Post, then the tone controls.
I do not see a Master Volume.
Normal is your clean volume.
Pre is your lead channel gain.
Post is your lead channel volume.
If this does not help. you need a tech.
I counted 18 parts in the lead circuit besides tube V2 & the relay.

[kate033]

Just checking that we are on the same page here.
I am looking at the owners manual. Maybe you have an older amp.
It shows, left to right: Normal, Pre, Post, then the tone controls.
I do not see a Master Volume.
Normal is your clean volume.
Pre is your lead channel gain.
Post is your lead channel volume.
If this does not help. you need a tech.
I counted 18 parts in the lead circuit besides tube V2 & the relay.

Yes, that is correct. My apologies, I was refering to the normal as master vol. Im using my iphone instead of the laptop tonight so my typing isnt quite up to speed with my thinking. Sorry for any mixups or typos!
I was hoping there might be any easy fix but i dont want to do any srious digging in the insides. With the pcboard and complicated circuit i'm not qualified to safely get in there.

Thank you for your help! Will have to try to find a better qualified tech this week!

[bluesfreak]

Since the Channel Switching is done via relay there could be 2 issues:
1. No Voltage to relay => not likely because the switching Voltage is generated by the Heater/Bias supply so if any fuse (F3) is blown there will be no output from the amp but your amp is still working normally
2. Relay bad => Check K1A if it is taking the additional system of V2 into the circuit. Is a clicking noise noticeable when you switch into drive channel?
3. Broken solder joint =>Sometimes the flex wires connecting the PCBs in this amp do go bad and cause funky behavior. then you either have to trace down where the break is or just resolder all the connection wires between the PCBs...

[Jazz P Bass]

PC board connectors

Yeah, these amps are a real joy to work on.
My hat is off to the engineers for fitting 3 boards together like that.

[crowguitar]

These amps suck to work on.. I have a decent amount of experience modding and repairing amps/effects, but this amp is ridiculous. I've owned my Classic 30 for 10 years now and cringe when/if anything goes wrong. I've had to replace a Pilot light, fix the reverb's board connection, and replace some minor components but the layout and how crushed together everything is makes it anything but a breeze job...no matter how small.

If you're not experienced with this, I really suggest locating a good tech. Not even just because of the tiny squished pcb boards but also because these boards are so close together, you can easily accidentally touch a Voltage loaded cap and fry yourself.

[Enzo]

It works then it doesn;t then it does.

Turn the reverb down, then ball up yout fist and whack the top of the amp hard. Does that make the symptom either stop or start?