bias wiggle trem tick solution

[StrummersOfThunder]

Also while im at it , im about to re-embark on the well trodden path of trouble shooting a ticking fender trem.
Ive done this with success in opto coupled circuits but the 6g9b has a bias wiggle trem.
Any of the amp boffins want to throw their hat in the ring and give me some pointers here?
Many thanks

[RectifiedAmps]

Could be as simple as a ‘lead dress’ issue- the wires from each preamp gain stage (pins 1,2,3 vs 6,7,8) should be bunched together and kept as far away from others as possible, especially those from the tremolo tube socket V3. The wires to the tremolo controls (if it’s not a PCB reissue) should also be dressed together and away from from the tone controls. I’ll try to dig up a photo later!

[StrummersOfThunder]

Could be as simple as a ‘lead dress’ issue- the wires from each preamp gain stage (pins 1,2,3 vs 6,7,8) should be bunched together and kept as far away from others as possible, especially those from the tremolo tube socket V3. The wires to the tremolo controls (if it’s not a PCB reissue) should also be dressed together and away from from the tone controls. I’ll try to dig up a photo later!

nope its an original 62
ill take some photos later today
thanks very much for the advice. i havent actually 'properly' inspected the amp internally so today is the day.

[StrummersOfThunder]

Could be as simple as a ‘lead dress’ issue- the wires from each preamp gain stage (pins 1,2,3 vs 6,7,8) should be bunched together and kept as far away from others as possible, especially those from the tremolo tube socket V3. The wires to the tremolo controls (if it’s not a PCB reissue) should also be dressed together and away from from the tone controls. I’ll try to dig up a photo later!

lead dress looks pretty good
poked around with a chopstick and couldnt get any changes
just uploading an image or two but its taking a long time.

other thing is the trem seems super fast and probably lacks a little depth.

[RectifiedAmps]

Ok. Both the ticking and especially trem depth can be affected by the bias point of the output tubes. Cooler bias usually results in a deeper trem effect but Im not sure if it’ll help or worsen the ticking.

You could also try swapping the V3 12AX7 with one of the others- V1 or V2. Weak tremolo can be a symptom of a weak tube.

The ticking might be a dirty socket contact but I doubt it- most likely to be capacitative induction of noise from the trem wires into other parts of the preamp. With the ticking happening, you could pull V1, then V2 to see if it goes away.

[StrummersOfThunder]

Ok. Both the ticking and especially trem depth can be affected by the bias point of the output tubes. Cooler bias usually results in a deeper trem effect but Im not sure if it’ll help or worsen the ticking.

You could also try swapping the V3 12AX7 with one of the others- V1 or V2. Weak tremolo can be a symptom of a weak tube.

The ticking might be a dirty socket contact but I doubt it- most likely to be capacitative induction of noise from the trem wires into other parts of the preamp. With the ticking happening, you could pull V1, then V2 to see if it goes away.

well, please tell me if this is an unstable fix but i seemed to have completely resolved the issue.
after a bit of reading on tdpri i found a discussion suggesting a diode across the outer lugs of the intensity pot https://www.tdpri.com/threads/filtering ... n.1026286/

Just so happen to have some to hand so ive soldered one across and it worked.
The trem sounds deep and full. Still a tad fast if you go above 3 -4 but totally useable. No ticking!

[RectifiedAmps]

Awesome- if it sounds good, do it!

[sizzlingbadger]

You nan add another 0.01uF cap in parallel to either/both of these to slow the tremolo down.

Screen Shot 2021-01-22 at 2.09.14 PM.jpg (308.78 KiB) Viewed 1766 times

[StrummersOfThunder]

You nan add another 0.01uF cap in parallel to either/both of these to slow the tremolo down.


Screen Shot 2021-01-22 at 2.09.14 PM.jpg

Nice. I believe I have a stash of those..may just do that.
Thanks !