The Amp Garage

I use a lot of Mojotone chassis for my customer builds and have for years. Usually I have a few changes to a stock faceplate they offer for the various chassis they build and I always paid a "setup" fee in addition to any material cost for the engraving. I developed a logo that they would also put o...

Or you can buy them here: https://www.amazon.com/Dunlop-Super-Sol ... B078GX4SW6
For even more money.

Hi- I have been trying to log into CE Distribution (or its non commercial account site Antique Electronics known as tubesandmore.com) and I am having my browsers reject the access to the sites saying them are not secure as well as my NOD32 Antivirus blocking the sites. Is anyone else had this experi...

I have to mirror the experience of others here. Used to get fast service and answered emails for years. Now there is no reply to any attempt to contact them and orders status says April 17 delivery which is long past now. I have asked for refund and cancellation of order, hope it works. Amp Parts Di...

I thought I would come back and post the conclusion of this issue. I hate it when someone has a problem but it just never gets finished in the stream of posts trying to figure out what finally solved the problem. I have never actually seen this issue before but what I found was that the turret that ...

I just measured the voltage on pin 3...or should I say I tried to measure it but got 0 volts....All cathode resistors measure fine and there is a 10K unbypassed resistor on pin 3. per the circuit schematic. The only way there can be 0V across a 10k resistance is if there's no current flowing. It lo...

Such a high grid voltage seems more characteristic of grid leak bias; what is the cathode pin 3 voltage, and its measured resistance to 0V? I just measured the voltage on pin 3...or should I say I tried to measure it but got 0 volts. Switched to millivolts and still got zero. Pin 8 on the other sid...

So the board itself is not leaking DC. I am reading up to -1V on pin 2 of the preamp tube. This is the source of the DC making the pot scratchy. Its feeding that DC back to the pot. Today I did several experiments. I tried grounding the scratchy pot to back of pot rather than the buss ground. No dif...

Could be a layout issue ....I would separate the input signal from the signal going to the second gain stage...each should have it's own shielded cable ...the way it is ...could be what's causing the scratchy pot.... Yes- I have rewired the leads to their own shielded cable. I do have measurable DC...

Looks like a 2203. Check all resistor values that go to V1. Try running the volume pot ground to the back of the pot instead of the buss wire. Try seporating the signal wires that go to V1. Used individual shielded wire . Keith T Hi- Yes, its a 2204 circuit. I have changed out all the resistors goi...

I will try the cap trick. I have tried about 6 different tubes already. Some NOS, some new issue. It has not helped so far.

Thanks for the pointers however.

So I have been asked to track down a scratchy volume pot on a JCM800 clone circuit amp. Normally I suspect either just a pot that needs some cleaning or replacement or a leaky cap flowing some DC when it shouldn't. After cleaning then replacing the pot (this is the first volume pot, not the master v...

Not to hijack this thread but the other day I went to the CE Pedals website to order one of their chassis. They appear out of stock. So I sent them an email trying to find out if they are building more. No answer. The email contact form on their site, when clicked on, throws up a big Virus warning o...

Thanks so much for the schematic. I will pass this by the customer- I knew somebody must have done one of these over time.
I have built a few amps in my day. Thanks for the concern, I should be OK.

So I have a request to build a head that has two channels. One in the vein of a Fender Blackface "clean" style and the other more gain oriented in the Marshall style. Also reverb. Is there some prior art on this design somewhere already done by someone that is a known good circuit? I think ideally I...