Fender Deluxe vibrato problems
- Thread starter johnheath
- Start date
Help Support GroupDIY Audio Forum:
I looked at my notes on the ab763 vibro from my diy super reverb clone ...
There was a fender service note (which others have mentioned over the years) .. that adds a 0.01uF 450V mylar cap from the plate of the AX7 stage 2 to ground (osc gain stage). I tried 0.01uF to 0.022uF
I did that mod, and I found it reduced the 'osc punch thru' but did not eliminate it.
I also noted the noise was definately coupling from the B+ and super hi Z 10M resistor, bug 'hv side' area and that experimental 'wire lay' changes made a reasonable improvement ..
moving the wires closer to the chassis surface and 'holding them' in place ..
Maybe the fender 'old school wire-wrap-to-ground' around the most sensitive wires might help.
....
Here's a pic of the AB763 trem area wiring (not mine - tidier than mine!) .. maybe you can get some inspiration.
There was a fender service note (which others have mentioned over the years) .. that adds a 0.01uF 450V mylar cap from the plate of the AX7 stage 2 to ground (osc gain stage). I tried 0.01uF to 0.022uF
I did that mod, and I found it reduced the 'osc punch thru' but did not eliminate it.
I also noted the noise was definately coupling from the B+ and super hi Z 10M resistor, bug 'hv side' area and that experimental 'wire lay' changes made a reasonable improvement ..
moving the wires closer to the chassis surface and 'holding them' in place ..
Maybe the fender 'old school wire-wrap-to-ground' around the most sensitive wires might help.
....
Here's a pic of the AB763 trem area wiring (not mine - tidier than mine!) .. maybe you can get some inspiration.
Attachments
After that, I noted the 'neon' in the regular 'bug' wasn't helping .... so I made some led-based opto bugs of different types .. I ended up with a white led and original cs photoresistor cell in a black heatshrinked tube.
.. and tried different 'plate loading' schemes of the AX7 stage 2 ... 'lifting the 10M' helped to suit my 'led bug'.
I also slowed down the tremolo a bit by changing the osc caps to 0.02, 0.01, 0.02
and did some tube rolling for the AX7 till I found one that worked better ... but still when things get 'warm' in the chassis, the helicopters return occasionally .. but it's at a minimum.
That's been about 7 or 8 years like that now.
Next time I open it up. I'll swap to ceramic caps while I'm there, I think.
.....
Good luck !
.. and tried different 'plate loading' schemes of the AX7 stage 2 ... 'lifting the 10M' helped to suit my 'led bug'.
I also slowed down the tremolo a bit by changing the osc caps to 0.02, 0.01, 0.02
and did some tube rolling for the AX7 till I found one that worked better ... but still when things get 'warm' in the chassis, the helicopters return occasionally .. but it's at a minimum.
That's been about 7 or 8 years like that now.
Next time I open it up. I'll swap to ceramic caps while I'm there, I think.
.....
Good luck !
@ Alexc: Thank you sir...
The problem is solved by utilizing some shielded cable and wire layout... In this case I used the wires in the kit and it was the solid cables used in older Fenders... easy to solder but a bit stiff. They are however easy to dress if needed and in my case I tucked them pretty close to the tube sockets of V4 and V5... sort of separated them in to two groups.
And to experiment I added the suggested 22nF cap across the 10MEG resistor and the problem was solved. No, more ticking or flapping sound even on the highest settings.
Best regards
/John
The problem is solved by utilizing some shielded cable and wire layout... In this case I used the wires in the kit and it was the solid cables used in older Fenders... easy to solder but a bit stiff. They are however easy to dress if needed and in my case I tucked them pretty close to the tube sockets of V4 and V5... sort of separated them in to two groups.
And to experiment I added the suggested 22nF cap across the 10MEG resistor and the problem was solved. No, more ticking or flapping sound even on the highest settings.
Best regards
/John
Similar threads
