The Amp Garage

WhopperPlate wrote: ↑Tue Oct 24, 2023 4:27 pm Love the look of those old behemoths

They do look cool but they are a beast to haul around.

Stevem wrote: ↑Tue Oct 24, 2023 10:12 am Yes, that's a code number of manufacturer.
It was made on the 36th week of 1979.

Thanks much for the info. I put the EV in a 1-12 cabinet I have.

I bought a very old EVM12-L from a guy I worked with years ago. There is no decal on it but I've owned other EVM12-L in the past. It has a heat sink screwed to the back. The only marking on it is 936. The frame is painted black. Since it's a 200 watt speaker and I don't have any amp over 100 watts I...

I know that there are maximum filter capacitor rules when following a rectifier tube. My current project will use a 5AR4 and 60UF is the recommended maximum capacitor immediately following it. Are there any "rules of thumb" regarding the maximum capacitor values down line from the plate supply?

Yes I've picked out the transformers. I'm using Hammonds, 270FX PT, 1760J OPT. Also a 194D choke I got for free when I worked at AES, still in the box. I've got an amp I built 20+ years ago based on the Matchless Spitfire preamp with a parallel 12AX7 triodes for the first gain stage. That feeds a si...

Thanks pdf64 for your input and schemo. That's a great solution for me. Littlewyan. I'm designing this amp with lower plate voltage than a JTM45. I'm using 6AQ5/6005 tubes because I have a 20+ NOS stock of them I got for $1 each around 1990. I recently had them tested (https://arizonatubesupply.com/...

I'm drawing up a schematic for a JTM45 style amp with a matched quad of 6AQ5 output tubes for a "Mini Marshall" type amp. I've previously built a JTM45 clone that works well. I'm using a smaller chassis than a standard JTM45 chassis. Looking at the traditional 4 jack inputs, I want to reduce it to t...

Today I had a chance to plug this JTM45 clone into my 2-12 cabinet. I cranked it and experienced no microphonics from the preamp tubes. I controlled the volume from my Les Paul and it was quite nice. I got typical 70s Marshall crunch, Clapton "woman tone" on the neck pickup and nice full clean tones...

I find silver micas to be even more microphonic then ceramic disc caps many times. I encase mine in clear silicone. The distortion factor that carbon comp resistors display over metal film caps takes place only once the voltage applied to them gets up near 300, and for a common 1/2 watt resistor th...

Yes, I noticed that. MO are great in power applications, where any resistor resistor noise gets decoupled, but their noise specs typically aren’t their strong point, so rarely used in the signal path, especially early stages. This isn't a real noisy amp, but I will tuck that info away for possible ...

picture shows many metal oxide resistors. try carbon film plate resistors for that famous plexi tone I had a large number of MO and MF resistors in my stock so I used them because I had them and because the 1/2 W carbon film leads were too short to make a full span across the turret board. I didn't...

I built a JTM45 clone 6 years ago. I made a few changes to the original circuit. The screen grids are 1K 5 watt and I put 1.5K grid stoppers in directly on the output tube pins for stability. I also used carbon film or metal film resistors instead of carbon composition and silver mica caps in place ...

I hope it doesn't go away. I have read so much good information there and collected a bunch of schematics through the years. Enzo was an amazing wealth of knowledge by himself. Sadly, he passed away not too long ago. He personally helped me many times, in particular with my beloved SWR Super Redhea...

I'm going to wait until it's known safe. Mostly I was checking to see if it was still a going concern. When it was still accessible last year I noticed they'd closed down some of the forums. Many of the regulars dropped away.

Anyone know what happened to Music Electronics Forum, PKA Ampage? When I try to go there I get a security warning that the connection isn't secure. Haven't been able to access it in months.