The Amp Garage

martin manning wrote: ↑Thu Dec 28, 2023 1:11 pm Still not sure exactly where the feedback loop is

Fender reverb circuit has some feedback. If there's 20mV signal on the recovery tube grid and the reverb pot is fully turned up then about 1mV gets fed back to the reverb driver tube grid. Even small changes to the circuit can make it oscillate.

Nice build. Lundahl transformers are a rare sight in guitar amps.

I was testing Neural Amp Modeler and creating models for it from my amps. I had an idea what if instead of using a real amp to create the model I would just use LTspice for it. I ran the WAV file that is used to create amp models through 5E3 LTspice simulation. It took about 6 hours and then I used ...

I was intending on using the relay boards from Headfirst amplification that I purchased and they are layed out to use those Omron G5V-2-DC12 kind of relays. They happen to be upwards of 40mA so 3 of those are looking at 120mA activated. Yeek, its a bit. There are probably some lower power relays to...

Transistor is used if you need to switch multiple relays from one switch. Also you can use LED indicator either in the amp or in the pedal without needing any additional circuit. Just connect a LED from CTRL to ground and when you short CTRL to ground the relay switches and led turns off.

It's a board for a DPDT relay so yes it can be used for Clean/Overdrive switching and PAB switching.

Here's a couple more

Here's a bunch of KiCad design files for several different projects for anyone who wants to use them.

At full power output the screen grid current for two 6L6GC tubes at these voltages is going to be about 25mA probably even less. So let's say the current through the 1k power supply resistor is 30mA. Oh noes that's 0.9W dissipation in that resistor. How in the world will a resistor survive such a he...

6k6 load with those voltages is not risky in any way. As load impedance gets higher plate current goes down and screen current goes up. With 1k screen node resistor and series resistors with screen grids there's no way the screen dissipation will ever get too high.

did you realised increased attack on strings when using Toroid for the main tranformer? this is the reason i have quit with them long ago.. sound was just jumping out "before time", it was annoying so i have replaced all toroids with normal EI over time and fixed that "problem". i mean strat was so...

My latest build is a 3 channel 35W guitar amp with tremolo and digital delay. I used Electro-Smith Daisy Seed for channel switching and for the delay effect. First channel and the power amp are pretty much the same as on my Echosonic build. Second channel is a bit different from usual. EF86 is used ...

Datasheet of those capacitors has no mention of load life. Does it mean snake oil lasts forever?

I'm not sure but those probably are 6P3S or 6P3S-E tubes. Try it with 6L6GC power tubes and measure the voltages again.