First Build Issue

[caesparza]

Hi everybody.

Last year I have the chance to buy a Peavey Classic 20 Chassis, cabinet, transformers and speaker. I decided to build a Marshall TMB 18W type of circuit using the original parts. The building process was very interesting and went smoothly. The amp sounded to bright to my taste, so I decided to upgrade the eminence speaker with a Celestion G10 Greenback, the result was phenomenal, the amp now sounds pretty sweet, the master volume is so versatile and it takes drive pedals very nicely.

The issue I have with this first build is that when the amp is cranked (volume and gain) it starts to interrupt the signal up to the point were the amplifier shuts down, so I have to wait a couple of seconds and put it on stand by and the amp comes to life again. Recently I have the opportunity to run some pedals in front of the amp and without having it cranked and with certain notes played on the guitar the behavior is the same, the amp shuts down and I have to wait and turn it on again. With this notes I get some sort of crackling sound out of the amp.

Its been more than half a year since I built the thing, and finally with all this crazy virus stuff I have the time to check this and tune up and finnish the build.

In the next link you can find the photos that document the process and the diagram I used to make it. Any suggestions related with the mentioned issue would be much appreciated.

https://www.facebook.com/pg/latienda...48578398549433



This is the layout I used.


Take care and be safe.

[The Dude]

Here's a tweaked schematic. Also, your layout link doesn't work.



Edit: This looks like the layout you used.

[caesparza]

Sorry and thanks, I always have problems with the attachments.

[The Dude]

Monitor voltages. Do any of the supplies disappear when the amp stops working? What is your bias current? Are tubes red plating?

[caesparza]

No red plating.

This were some voltages that I took before
B+1: 263
B+2: 245.9
B+3: 225.7
B+4: 180.3

I'll have to review all this again. Right now I had to go to my father's place to take care of the old man. I'll come back to you as soon as I can.

[caesparza]

I never post a closure message about this.

The problem resulted to be the fuse, here were I live the fuses are a tad shorter than the American ones. I changed the thing and it's working beautifully.

Thanks for the help.

Take care.