# Traynor YGM-3 Reverb Tank help



## sj250 (Oct 26, 2010)

Hey guys, I just picked up a '74 YGM3. It's a bit of a project as it was chassis and tubes only. I'm going to build a head cab for it and run it through my 2x12 with Scumback M75 PVC's. I fired it up the other night for the first time and it worked decent, was surprisingly quiet with only a moderate amount of on with the volume on 10. The issues are the Trem didn't seem to work very well and the reverb was non existent and only added huge noise the higher you turned it. I pulled the tank and found the ground on the output had snapped inside the tank. It's not really a repair worth attempting given where the wire snapped. I pulled the plugs from the tank and left it off. Ahhhhh, the glorious trem that ensued was everything I'd heard and hoped for from this amp. The whole amp seemed to sound better after getting rid of the tank. 

My problem now is there is not a modern reproduction I can find that matches the impedences required as well as the configuration of grounded/non grounded for the input/output. I'm wondering if any of you knowledgeable people have any suggestions on what tank you're using or if they're is something that I haven't found from the suppliers I've checked? I know I can just add a 'verb pedal but I'm to picky and if it is supposed to have reverb I'd like to get it working!

Thanks everyone!


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## nonreverb (Sep 19, 2006)

Where'd the wire snap?


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## sj250 (Oct 26, 2010)

Right at the coil, there's not enough sticking out to do anything with. It's also a tiny little tank on there. Seems most of the specs call for the 4FB2B1B but this one is only about 9" so I'd like to add a longer tank anyways.


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## Wild Bill (May 3, 2006)

sj250 said:


> Hey guys, I just picked up a '74 YGM3. It's a bit of a project as it was chassis and tubes only. I'm going to build a head cab for it and run it through my 2x12 with Scumback M75 PVC's. I fired it up the other night for the first time and it worked decent, was surprisingly quiet with only a moderate amount of on with the volume on 10. The issues are the Trem didn't seem to work very well and the reverb was non existent and only added huge noise the higher you turned it. I pulled the tank and found the ground on the output had snapped inside the tank. It's not really a repair worth attempting given where the wire snapped. I pulled the plugs from the tank and left it off. Ahhhhh, the glorious trem that ensued was everything I'd heard and hoped for from this amp. The whole amp seemed to sound better after getting rid of the tank.
> 
> My problem now is there is not a modern reproduction I can find that matches the impedences required as well as the configuration of grounded/non grounded for the input/output. I'm wondering if any of you knowledgeable people have any suggestions on what tank you're using or if they're is something that I haven't found from the suppliers I've checked? I know I can just add a 'verb pedal but I'm to picky and if it is supposed to have reverb I'd like to get it working!
> 
> Thanks everyone!


Well, there are some sources like Antique Radio or VibroWorld but they don't appear to stock the Traynor exact model.

Why don't you go to http://www.accutronicsreverb.com/ and try there?

When you click on ordering they try to push you off onto one of their distributors but this will be a special order anyway. It says you can order direct so why not?

Wild Bill

L4FB2B1B


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## sj250 (Oct 26, 2010)

Hi Bill, I've already emailed Mod and Accutronics directly but haven't heard back from Accutronics. Mod sent me an email saying the closest they had was 4FB3D1B. So the only difference is long delay instead of medium and the D instead of B so the input/output grounded/isolated setup is different somehow. Is it feasible to modify a tanks connectors to match the requirements of an amp? I'm not opposed to modifying parts at all if it will make it work. 


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## Wild Bill (May 3, 2006)

sj250 said:


> Hi Bill, I've already emailed Mod and Accutronics directly but haven't heard back from Accutronics. Mod sent me an email saying the closest they had was 4FB3D1B. So the only difference is long delay instead of medium and the D instead of B so the input/output grounded/isolated setup is different somehow. Is it feasible to modify a tanks connectors to match the requirements of an amp? I'm not opposed to modifying parts at all if it will make it work.
> 
> 
> Sent from my HTC One using Tapatalk


The input/ground isolation thing is not a big deal. It might even work as is!

What happens is that sometimes with a common ground between the two connectors on the tank you get a ground loop, which causes unwanted hum. The easiest way to get rid of that was to kill the ground at ONE of the connectors!

Both cables are still grounded at the OTHER ends, of course!

Even a lot of so-called techs don't understand that with high impedance, high gain circuits like within a tube guitar amp you can't just ground anywhere and as often as you want. It's not like lights in your car, where anywhere you can find bare metal is fine to put a ground return.

It is common practice when using shielded wires within an amp to only ground the shield braid at one end. This prevents any ground loops.

That being said, you still have to make sure that input and/or output tank coil has a ground return. As long as you understand what's going on and why the connectors are wired the way they are, it's easy to just change the connections to any way that works!

Wild Bill


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## jb welder (Sep 14, 2010)

If you are getting a MOD tank, they have a solder bridge jumper at each jack so you can configure the grounding scheme how ever you want it. 
What is more of a concern it your description of the change in tone with the tank removed. I'm not sure why this would occur, but won't putting a tank back in make it sound like it did before you removed it?


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## sj250 (Oct 26, 2010)

I've only recently started really looking into these amps but I believe the trem and Reverb share part of the schematic somewhere along the line. I'm merely guessing the noise from the broken Reverb was affecting the trem somehow. It honestly could just be a placebo affect with any change in the rest of the amp. Just like changing a preamp tube to the same thing, you know you changed it so it must sound different right? 

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## dtsaudio (Apr 15, 2009)

> trem and Reverb share part of the schematic somewhere along the line


The output of the reverb, and the tremolo oscillator are the same tube, however they are separate triode sections, and are quite isolated from each other.


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## sj250 (Oct 26, 2010)

Ok that makes sense. Honestly I got the amp home cleaned all the tube sockets and pots fired it up and found the Reverb pot did nothing but add noise so maybe I just didn't play with it enough to get a feel for the trem. 

On a side note any input or tricks you guys have for ways to improve the amp, I'm all ears. I already watched Pat Furlans vids and clipped the presence cap. Next step is changing that first coupling cap which I believe changes the bass frequencies as I've already found in a hurry there is just too much low end. On the other end I find the treble is either not enough at about 2-3 or too piercing at 4-5 and up. I have the 2 input model with the treble boost. I've heard of a bright cap on the volume knob, not sure if it applies to this model but I was gonna have a look at it. I'm always open to suggestions. This one is by no means a museum piece so I have no issues changing and trying things. 

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## sj250 (Oct 26, 2010)

As a follow up I thought I'd post this for anyone else that might stumble on this post. Traynor apparently uses the same tank in the reissues and although you can't find it at any suppliers it can be ordered through any Yorkville Sound dealer. Part no 9945

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## jb welder (Sep 14, 2010)

sj250 said:


> Traynor apparently uses the same tank in the reissues and although you can't find it at any suppliers it can be ordered through any Yorkville Sound dealer. Part no 9945


 I tried to get one of those a year or two ago, they said they were all gone and they couldn't get more, so they were subbing something "close". 
So check with them if it is really a 9945, and what the accutronics code number is.
I ended up using the MOD 4FB3A1B and adjusting the ground jumpers. The only difference was that the original was medium decay and the MOD is long decay.


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## sj250 (Oct 26, 2010)

Hmmm, good to know. That was just the info I got from Yorkville Sound through email. I think I'll just go with the Mod as I need to order one for another amp anyways and they are half the price of the Traynor part. 

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## jb welder (Sep 14, 2010)

Yes, the MOD are a lot cheaper, although the Yorkville may be real Accutronics parts.
Looking at the current Yorkville parts cat. and their parts search function on the website, the only thing close they have listed is 4EB3C1B, their part #3537. I think if you checked with them that is what they are probably subbing for the 9945.
So that is the longer delay, but also lower input impedance. So the Mod may actually be closer to the original.


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## parkhead (Aug 14, 2009)

yorkville is stocking the one for the re-issue 
the impedance should be the same 

p


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## jb welder (Sep 14, 2010)

parkhead said:


> yorkville is stocking the one for the re-issue
> the impedance should be the same


Thanks for that. They do indeed have the 9945 tank used in the re-issue in stock.


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