The Amp Garage

I think it’s more about the ratio of the anode resistor to cathode resistor. Taking the anode resistor up to 330K would bring the cathode resistor up to 5K to maintain the same ratio of 100K:1.5k. Any cathode resistor lower than 5K (with a 330K anode load) will increase gain. Someone, please stop me...

If my understanding of High Plate is correct (and it may very well not be), the High Plate models have higher values of plate load resistors in the preamp stages (when compared to the standard Fender value of 100K). This increases gain in the preamp stages.

Hi Phil,

I’m curious where the od entrance trimmer is set. With power off & caps discharged, can you measure the resistance from the center pin of the trimmer to ground?

Over the years, I have developed a few unconventional solder sucker strategies that prove useful, time and again with regards to stubborn holes. When you use the solder sucker in the conventional way, as you do in your video, you are fighting (John Meyers) Gravity, pulling the solder upwards. To all...

Okay, It took me a bit longer than I had expected to work through this. In a nutshell, you are correct, Phil; the "SEND" and "RETURN" labels in the silkscreen are swapped. I apologize for my oversight and I hope it didn't cause too much rework pain. I will be sending out a revised schematic, noting ...

Hey Phil,

Just got out of a physical therapy appt. i missed a whole bunch of discussion! I’ll be home in about an hour, and I will verify the incorrect labling on the board. Thank you for catching this!

Lou

Plugging a cable into the efx send jack does not interrupt the signal chain. This allows you to use just the send jack as a preamp output, which is useful for a number of applications. Plugging a cable into the efx return jack will interrupt the signal chain. Also, if you pick up the other end of th...

Ah, okay - it had slipped my mind that you were building a 183. I think I would leave your NFB circuit as-is for the time being, and look elsewhere for the oscillation. A few questions / suggestions: - When the oscillation occurs, can you affect it’s frequency by changing the positions of the volume...

Hi Phil, Looking at your pictures, I see a few things: - R51 should be 100K, it looks like you’ve got 4.75K in there? Am I reading that right? EDIT: I am not seeing R52 in the pictures, but that is the one that should be 4.75K - is it possible you swapped the value of these two parts? - the global n...

Hi Phil.

How long are the wires between the bright switch and the board? Shielded, or unshielded?

Thanks,
Lou

I Know that using the passive Dumble loop into pedals kills your tone regardless of buffered pedals. :D This has not been my experience. p.s. Lou , yes you wont destroy a 9v pedal but they sound like shit without the proper gain staging/matching of a Dumbleator. Gain staging is an important ingredi...

I Know that using the passive Dumble loop into pedals kills your tone regardless of buffered pedals. :D This has not been my experience. p.s. Lou , yes you wont destroy a 9v pedal but they sound like shit without the proper gain staging/matching of a Dumbleator. Gain staging is an important ingredi...

While I see your point, Erwin, I can also state that I have never heard of anyone destroying a 9V powered pedal by using it in a passive effects loop. I can also state that, at lease for the pedals I have designed, a clamping circuit was employed at the input jack to prevent such damage. It’s just g...

Phil, you are correct; a buffer is a buffer, which is a unity gain amplifier that lowers the source impedance of a signal. I think norbury may be confusing a buffer with a recovery amplifier.

I’d swear I heard the cat say: “Oh boy! Daddy dropped a toy for me to bat around!”