Snider Prototype (Traynor YGM-4)

[sonicmojo]

I mentioned my Snider modded YGM-4 amp in xtian's thread about his Traynor. Curiosity got the best of me and I traced it out. I believe this amp is an early prototype for the Jeff Snider "California" and "Chicago" amps that I don't think are currently being built as the Snider website is gone. There is no information out there that I can find and I'm planning to tweak some things in it so wanted to get a good trace of it first.

It is a nice sounding amp, tons of gain and the reverb doesn't overpower things when you play but comes in nicely after chords and notes. Snider described this as "ducking" reverb I believe. I want to tame the gain control as it gets blown out pretty fast (IMHO) but the amp sounds very good to me when gain is dialed up just a bit. What I find interesting is the .001 coupling cap on V1 but this amp has tons of bass on tap regardless.

I have no clue what transformers are in it as the codes don't match anything I can google. I'm pretty sure they are not Traynor stock plus it has a choke.

Excuse the sloppy Visio since this is my first attempt with an amp layout. It took me way too long to draw but I've been wanting to improve my Visio skills. Enjoy!




Edit: Corrected layout error on 4-19-2017

[joeboo88]

Thanks for doing this sonicmojo, nice work. I'd like to try this out, with 18 watt iron that I have.
Are your voltages as high, as on the YGM3? like Xtians?

[sonicmojo]

Are your voltages as high, as on the YGM3? like Xtians?

Yes, plates exactly at 398V.

[pompeiisneaks]

The layout looks great!

[sonicmojo]

I found an error in my layout. I put a date on the drawing so you can tell if I update it.

I swapped in a 1M Audio gain pot and I think it makes the control more usable. The tremolo is a little fast so I'll probably swap in .02 caps instead of .01 for the oscillator.

In addition, the 330K resistor between V1 and V2 isn't connected to anything. I think part of the original Traynor reverb circuit was borrowed for the gain control so I think this resistor is just a leftover part.

[studiodunn]

Thanks for this!

I've owned 3 (currently a 484) Sniders and Jeff can make El84's sound massive.
His amps can be wild, but the touch sensitivity and response is just amazing.

I've owned lots of amps with 5x the knobs that couldn't be as versatile.

[tictac]

Is that 10k plateload on V1B a typo? Color code looks like 100k....

TT

[sonicmojo]

Is that 10k plateload on V1B a typo? Color code looks like 100k....

TT

Definitely a 10K. I measured it too. I actually was experimenting with changing that value up but it didn't seem to affect the reverb much.

[tictac]

Oh now I see what he's doing, it's a cap-coupled reverb driver. Slick tapping the reverb input signal off the treble cap

TT

[sonicmojo]

I think I'm going to use some of the ideas in this amp and make a smaller hot rod Princeton Reverb style amp with 6V6s (omit Mid and Master controls).

[10thTx]

Here is a DRAFT schematic that likely contains errors. CHECK for ERRORS!

I gave up trying to draw the tone stack from the layout and just drew something I was familiar with.

I also gave up trying to figure out some aspects of the B+ rail.

So please assume there are errors around the tone stack and errors around the B+ rail at the minimum. There could be other errors also?

With respect, 10thtx

SonicMojo, ........... IF you would edit this and repost a correct schematic, I would appreciate that. I've attached an editable ExpressSCH file ...... OR you can use PAINT with the GIF file to edit this.

I would note that the 398v on node A means the PT probably is a 285-0-285 using solid state rectifier. IF I was going to build this with solid state rectification, I would want to use a PT that has 250-0-250 .......... OR use a 5Y3GT and use a 300-0-300 PT.

With respect, 10thtx

[10thTx]

I also should add that I am not sure about V1a with the reverb. I am thinking there should be a cap of 500p to .001 value and a grid resistor of 1M to ground?

With respect, 10thtx

[sonicmojo]

Thanks 10thtx! Thanks for the work on this and suggestions and I'll try to complete the schematic. I don't see the sch file, maybe you can PM it to me? I have ExpressSCH and can work with it. The reverb circuit is funky but does work. I'll also pull out the tank to verify which model - just need to remove about 50 screws on the Traynor cab to do it.

[10thTx]

Sent a PM with ExpressSCH file.

Thanks for being willing to do the corrections. With respect, 10thtx

[sonicmojo]

Verified the tank as Accutronics 4FB2A1B. Updated the layout. Reducing or eliminating the 330K resistor off the reverb pot will increase available reverb.