Epiphone Valve Standard Problems

[FreeMusicNo1]

After letting the amp warm up for about a minute, I hear a fairly loud popping/cracking sound, then the amp starts to make a hum that it usually doesn't. After about another minute and a few more pops and cracks the amp starts to make a very loud and horrible screeching sound (and messing with the volume knob doesn't change it) until I turn it off. If I turn it back on, the process repeats.

Any ideas what's going on? I'd really appreciate anything advice you guys can give me, as I really like this amp and hope I can get this fixed.

[Enzo]

Sounds like a failing power tube.

[bigjoe]

I had this same exact problem. It was a cap on the board that was in a spot marked for a jumper wire. I think its C7 after a bit of research on the wire diagram. Its between V2 socket and the pots if I remember correctly

I re-produced the problem with chassis out by tapping on the cap with a chopstick. It would work/not work after tapping on it.

Mine would just cut out after about 5 minutes, and come back with "fairly loud popping/cracking sound"

I also had another probelm were C27 went bad and it would have a high pitch squeal that was ear peircing. Both those caps are the same value/type. I have had probelms with 4 of them.

I have schematic if you need it.

[FreeMusicNo1]

I had this same exact problem. It was a cap on the board that was in a spot marked for a jumper wire. I think its C7 after a bit of research on the wire diagram. Its between V2 socket and the pots if I remember correctly

I re-produced the problem with chassis out by tapping on the cap with a chopstick. It would work/not work after tapping on it.

Mine would just cut out after about 5 minutes, and come back with "fairly loud popping/cracking sound"

I also had another probelm were C27 went bad and it would have a high pitch squeal that was ear peircing. Both those caps are the same value/type. I have had probelms with 4 of them.

I have schematic if you need it.

I just replaced the power tubes and it's sounding fine

[StandardPaul]

I have schematic if you need it.

I got a new Epiphone Valve Standard EPSTDSP from Thomann. But that amplifier has some disturbing noise and it comes from pre-amp. Can you help me with schematic?

[bigjoe]

SP

I can try and help you. I'm no guru at electronics. I was quite lucky with being able to find my problems so easily.

What specifically is the problem? How do you know it's coming from the pre-amp?

I got a lot of help from a guy on another website, that has an extensive post about valve specials and valve standards. I modified mine quite a bit, by removing the solid state effects and tweaking component values. It a straight tube amp now.

[StandardPaul]

Thanks for a good idea. I downloaded Valve Standard schematic from www.18watt.com and wondering that solution. DSP is continuously in the signal! I want to keep DSP unit, but it must work correctly and the signal must pass that when DSP is not in use.

[bigjoe]

I'm probably the one who posted the schematic.

As simple as it may sound your switch may just be bad. It's fairly easy to remove. Do you have a DSP footswitch? Or just the switch on the front of the amp. Ironically I removed the solid state from the circuit, now I have a footswitch with nothing to do.

I think even if the switch on the front of the amp were bad it would not matter if the footswitch were connected.

There is a small connector towards the back of the board close to the output jacks board (I think it has 2 small red, and one small black wire on it). I would pull that connector off the board and then see if your DSP turns off (do not have foot switch conncted when you do this). If your DSP is not on when you fire up the amp its probably a bad switch. Pulling that connector is like turning a switch off. When I first got mine and I was messing with it I accidentally left that connector off and my DSP quit working.

This isn't too complicated either. All you really ahve to do is take out the 4 screws on the top of the amp that holds the head in place and pull the speaker wire. you should have full access to the connector I'm talking about.

[DingDongDen]

Hi...bigjoe..

I have a valve standard and just got lucky with finding a space echo re201 in pristine condition..do you know if it is possible to remove the DSP on the amp and make this an FX loop so i can use the space echo?..any ideas gratefully received..

[alanhoggard]

SP

I can try and help you. I'm no guru at electronics. I was quite lucky with being able to find my problems so easily.

What specifically is the problem? How do you know it's coming from the pre-amp?

I got a lot of help from a guy on another website, that has an extensive post about valve specials and valve standards. I modified mine quite a bit, by removing the solid state effects and tweaking component values. It a straight tube amp now.

Can you please post the link to the other website you are talking about?
thanks

[DingDongDen]

Hi..Alan
I would like to know those links too...do you have any problems with the valve standard? I am wondering if there are any great improvements to make to this amp.

[alanhoggard]

i have just started looking, i have the hum

[DingDongDen]

Thanks Al...post on here any useful info you find..I will too.!!