PDF Electronics

I don't build amps kits but I found out about this neat place (Trinity) in Toronto selling 18W kits (and other great kits). Called them up in late July and ordered just a 18W turret board and chassis. Within three hours of getting the turret board I had completed it. Now I was stuck as I had nothing else I could really do besides wire the heaters and a few other little small things.

After three months of the amp sitting looking lonely I gave Stephen (head of Trinity) a call and ordered the transformers. Once I had the transformers it took me three more days and the amp was done. Called in an order at "the tube store" and got some tubes for this amp. Amp worked flawlessly first power up, no issues at all. Even better this amp is as quiet as a mouse, I guess my lead dress isn't so bad.

Sounded great through my "el cheap o" Celestion speaker but it really needed a cab and a speaker of its own. Put one finally call into Trinity and got Stephen to make me a cab. What a job he did, looks killer. I went to pick it up at his place and man the guys has a cool shop. I spent an hour talking with him while he installed the amp into the cab. Really cool guy and knows his amps/electronics.

While I was there he asked what speaker I am going to throw in the cab. I had to tell him I spent all my money on the cab and building the amp, so I had no funds for a speaker. So as I am leaving he says "Hey I just got these new Tone Tubby speakers in, check it out and tell me what you think". Tone Tubbys are these super cool handmade speakers from California made out of hemp (ya hemp). They sound amazing!

Some cool things about the amp...carbon comp resistors, really fancy SoZo and NOS Mustards capacitors, custom made and wound Heyboer transformers (they got paper bobbins and all that mojo jazz), plexi faceplate, Alpha pots, Switchcraft jacks.

It is pretty much an exact replica of the classic Marshall 1974x combo amplifier. It does have a neat unique feature though, a boost switch on the back which biases the first stage a bit differently and adds a bypass cap on the cathode to increase the gain of the stage. The switch adds a ton of gain, grit and volume when engaged. It's a neat idea, I've been using a similar idea in a pre-amp I am working on. It's great for getting that cranked, pushed saturated tube sound but at lower volume levels.

I tried a lot of tubes but ended up with a the following set...

Rectifier - EHX EZ81

Power tubes - Matched pair of JJ/Telsa EL84

Phase Inverter - EHX 12AX7 (matched/balanced triodes)

V2 - Reissue Mullard 12AX7

V1 - Reissue Mullard 12AX7

Photo album...