Traynor YGM-3 undiscussed details

[Iplayloud]

I have a couple points I haven't seen covered in the dozens of other posts.

-The plate resistors of the first 2 gain stages are big. 220k and 330k. Ary reason not to change these to 100k and have a fatter clean sound like a Fender?

-Evrbody calls these a Deluxe Reverb with EL84s BUT... it's totally missing the 3rd gain stage after the reverb. More like a Tweed Reverb.

-The reverb recovery stage has a 470k plate resistor, dropping the plate voltage to 78v. Ain't that ridiculously low? I read a few places that under 100v, might as well put a transistor..

-The reverb driver is a 12ax7. We've been preached high and low that a 12at7 should be in that spot. Ok because no transformer?

-R13 and C11 do what exacly, like a presence pot halfway?

[The Dude]

Not to be a "Richard Noggin", but you'll get quicker and better response if you link or post a schematic with your questions so that people don't have to go looking for it.

[Enzo]

The first thing to do is decide if you like the way the amp sounds.

Any reason not to change them? My question is this: is there a reason TO change them. I always thought Traynor amps sounded pretty good as they were.

There is no "gotta do it this way" in guitar amps. The 12AT7 driving a transformer for reverb is pretty common, but so are many other approaches, including this one. Ampeg did something similar. Note the reverb pan is the highest impedance on the chart. SOme amps double up 12AX7 for transformer drive too. It all works.

Lots of tube circuits have under 100v on the plate. Not a majority by any means, but not uncommon. They are looking to maximize gain in the stage I'd wager. As to those other plate resistors, well consider the rest of their circuits. Your Fender example also used smaller cathode resistors. Different tone circuits too.

[g1]

These amps are very loved for their own sound. Many try to change them into Fender, or change the bigger Traynor's into Marshall's. I guess because they are cheaper than buying the real thing.
If you are totally unhappy with the sound, then carry on. But do it for the sound, not because the schematic is less familiar.
C11 is commonly called the 'presence cap' in these amps, and clipping it out is probably the most popular single mod done to them. R13 is required by the circuit.

[Iplayloud]

My understanding of larger plate resistors is that they're not the "proper" way to get more gain. The correct way to get more gain being to add another gain stage. Starving a tube for voltage creates more gain at the cost of a cold, compressed sound. I expected an answer more like yes dude if you're looking for a fat sparkling clean amp go for it. Over the last 20 years I owned 5-6 Traynors and always sell them back, they just sound a bit plainer than the others. With the ridiculous price of vintage Fenders I think I'm going to listen to myself and mod out some of what I think are bad ideas.

[Enzo]

OK, you don't need our approval to modify your amp. If you want to make it a Fender circuit, go ahead. But it isn't a matter of being correct or not. If Traynor got good results this way, they didn;t see the need to add another tube, socket, and all the support circuitry just for a reverb return. These are after all just guitar amps, not high-precision lab circuits. SO there is tremendous leeway in all the designs.

Traynors are my favorite chassis to use for building other projects. They are sturdy and well built, and most of the circuitry is already wired in useful manner. And they usually have TONS of room in them, so if you wanted to add a couple tubes, there is the space to do it.

[SoulFetish]

My understanding of larger plate resistors is that they're not the "proper" way to get more gain. The correct way to get more gain being to add another gain stage. Starving a tube for voltage creates more gain at the cost of a cold, compressed sound. I expected an answer more like yes dude if you're looking for a fat sparkling clean amp go for it. Over the last 20 years I owned 5-6 Traynors and always sell them back, they just sound a bit plainer than the others. With the ridiculous price of vintage Fenders I think I'm going to listen to myself and mod out some of what I think are bad ideas.

220k and 330k are not really that large for plate load resistors for a 12AX7. But, there are a lot of things here to touch on. Firstly, Enzo is right. It's your amp, no one but you is going to give a shit what you do with it. Second, as for the reverb circuit-I would like to see a schematic, but the signal voltage coming out of a reverb output transducer is extremely small. so, the special attention needs to be paid in the recovery stage to minimize noise and maximize gain. Thirdly, ...it's 3:50 in the morning and I'm too tired to get into the rest of it lets pick it up tomorrow. In the meantime, I would love to hear from Neumann and Irving on the subject. They have some great insight into the nuance of loading, bias, operating point, gain, etc in guitar amps.

[Iplayloud]

If we compare with the Fender AB763 (BF) range which you guys most certainly know by heart.. and on which the YGM are clearly based. Look at the 1st gain stage on a Twin, 260v on the plate, while a Princeton Reverb has 160v. Now the YGM-3 with it's huge plate resistors bring that down to 140v. This has an undeniable impact on clean headroom. These amps do sound particularly thin, will anyone just admit that yes it may be a good idea to put a 100k resistor?

[galaxiex]

Sure...

I did that.

This amp (1970 Traynor YGM-3) was hacked almost beyond belief when I got it.

It had...
an added mid pot in one of the 3 input jack holes
a pentode/triode switch on the back panel
an extra preamp tube 12ax7
a master volume on the back panel
a bunch of non-stock wiring to accommodate all the mods

I undid most/all of that and did some circuit re-wiring.
More notably the reverb circuit is now more fenderish.

Now it looks like this...



It sounds AWESOME!

Edit;
Celestion G12H in the cab.

Second edit;
Stock these amps have a presence cap in the feedback circuit.
Snip that out, really helps with the thin sound.

I think it's C31 on the original schematic.