Traynor tremolo issue

[Colas LeGrippa]

Hi , I have a Traynor Guitar Mate YGM2 which tremolo makes a constant noise even with speed and intensity knobs closed. Is there a way to shut it off completely without having to plug in the footswitch ? I'm not familiar with trem or rev circuitry but I've noticed that poking here and there with my meter ( one side to gnd ) was increasing the trem pulsation which prob indicates that being connected to gnd via the meter, the trem gets more strenght but I can't tell why. Thanks, here's the schem.


Colas

[jjasilli]

Maybe pull the trem tube. Make sure it's good.

If tube is good, smple approach to repair is to replace all the trem components.  Probly faster than diagnosing.

[sluckey]

Describe the noise it's making.

[Colas LeGrippa]

Hi buddy !


The noise is a weak pulsation but affects the overall tone, more or less like this:  shhh-shhh-shhhh-shhhh-shhhh-........


Happy new year


Colas

[sluckey]

That's what tremolo sounds like when the amp is just idling. Pull the trem tube or use a gator clip test lead (or something similar, maybe even just a screw driver blade) to ground the footswitch jack to totally kill the tremolo.

Setting the intensity pot to zero should kill that sound. Try this. Use a gator clip test lead to ground the wiper of the intensity pot. If the noise goes away then replace the intensity pot.

[Colas LeGrippa]

Ok thnx

[Greg]

Yes! If you are willing to make a small modification, you could replace the 250k linear pot with one that has a spst switch in the back. You will then have to solder a wire from the footswitch jack to one of the spst lug and a ground wire to the other lug. The switched potentiometer will click in the full CCW position and you will stop the oscillation instead of attenuating it.

[Colas LeGrippa]

very good idea indeed !


Happy new year


Colas

[Greg]

Dang. I made a stupid mistake. It won't work. The switch will have to be inserted between the speed pot and the junction of the two caps so it will «close» to start the oscillation, Sorry for the mistake.

[Greg]

Ok forget my two other posts! I just saw that the speed pot is one meg. I assumed it was 3 meg, just like in every other friggin fender amps. So now it's even better! Just replace the 1 meg audio pot with a one meg audio SPST (Doug has one in stock) and wire it like the small schematic below.

Happy New Year!

[Colas LeGrippa]

thnx

[PRR]

> I just saw that the speed pot is one meg.

Looks like FOUR Meg to me. And that would give a range 4.15Meg to 0.15Meg around the 1Meg of the other two resistors.

[Greg]

Thanks PRR, I guess the left portion of the "4" just vanished while messing with MS paint. Obviously, the LFO wouldn’t go slow enough with a 1 meg speed pot. In that case, going back to the previous idea of a switched 250k intensity pot that could open one of the phase shift sections or the cathode of the LFO will work.

[PRR]

> LFO wouldn’t go slow enough with a 1 meg

Counting on thumbs: It would be about 1.5X short of the original range. If he never uses the slowest setting, maybe 1Meg is fine. Or of course a 3P switch could throw-in 2X bigger caps and go even slower than stock. But if he's drilling a switch, it may as well be a trem-kill switch.

So several ways to go, depending on goals: keeping it original, making it work for the current user, who may want less or more range...

Lifting the cathode resistor *may* have the added advantage of faster re-start. Low-speed oscillators start slow. The open cathode will float-up over 5V. When the resistor is applied it will come down to 1V-2V. Depending where that cathode cap is wired (I'd have to think), this several Volt jerk may tend to throw the oscillator into action, reducing a long build-up time. Some fancy Fenders do this; another trick is dozens of V into the CRCRCR network to kick-start.

[Greg]

I was looking for the easiest and less invasive method to shut down the leaking traynor trem without the footswitch but yeah... Personnaly I'm a big fan of wobble, vibrato and tremolo. I would do all the mods you describe to extend its range. On my homebrew stuff, I even planned to build a wah wah pedal kit with its novelty 470k pot as a speed control by foot. I would have to scale the LFO accordingly. I don't know if this gimmick could be usable for guitar. Maybe for some ringing chords section in a tune.

[sluckey]

I still think the easiest and bestest solution is to fix the problem rather than just cover it up.

[Colas LeGrippa]

yep me too, so I'll redo the complete circuitry, so it'll be fine for another 60 years !


Thanx

[Greg]

I still think the easiest and bestest solution is to fix the problem rather than just cover it up

Of course but with respect Sluckey, I thought I was doing just that. I admit I got carried away. If a «bad» intensity pot has residual resistance, the best would be to replace it with a new intensity pot. Since the intensity pot doesn't kill/start the trem but only ground its signal, one might as well get one that has a switch to kill/start the LFO once and for all. The footswitch was intended for that duty but I must respect the wish of anybody who do not want to bring the footswitch, has lost it, or just don't care for the trem. I've measured pots with 10% of the total resistance at zero. This isn't a problem for a bass pot or a treble pot, but it might pass some trem wooshing with the amp idling and intensity pot set at zero.
 

[sluckey]

yep me too, so I'll redo the complete circuitry, so it'll be fine for another 60 years !

You don't need to redo the complete circuit. Did you even try my suggestion above? May not be your problem but it's very easy to check.

[Colas LeGrippa]

Yes I will try to replace the intensity pot rather than redo the whole circuit first. I will work on that today. Will get back with the results later this week. Thanx, brother.


Colas

[Colas LeGrippa]

Intensity pot good.
Inserted a 1/4 jack with tip soldered to gnd in the f/sw input.  Will tell my client to buy a f/sw for killing the trm noise when playing clean.
Thanx

Colas

[PRR]

Or butt-solder a small switch to a plug, so it can be switched without an actual foot-switch.