Amps and effects
Work in progress
Retro Sonic Vintage Vibes
The MN3002 BBD in a Retro Sonic Vintage Vibes started making noise. All working conditions are in order so the guess is the BBD chip is not as it should.
The BBD is a MN3002.
Since the MN3002 BBD is hard to find, an extra adjustable low pass filter stage is installed. Allowing the user to set the cutoff frequency. Accessible with the bottom lid of next to the input jack.
A Boss DS-1 in need of service.
It got fed 18V instead of the usual 9V, bypass is working fine but quiet when effect is engaged.
A voltage reading of the op-amp indicated it was fried, +9V on all the pins but the GND connection. Here replaced with a JRC4558, also take a look at the bigger 100uF capacitor to the left.
Here it is desoldered. It did not survive the 18V it was feed. Replaced with a new one and the circuit is working again.
A Supa Tonebender in near mint condition, giving a very weak output signal.
Guts reveals what appears as all original.
Signal generator and a scopemeter isolated the problem to the bypass switch.
Not the typicall bypass switch construction. Note the date stamp 10 MAY 1976.
However a construction that is easy to service.
After a cleanupof the switch and the Radiohm potentiometers, the pedal is back in working condition.
My favorite chorus pedal the Boss CE-2 on the workbench for an ACA to PSA mod and a recap.
Solder side of the circuit board.
Component side.
For the ACA to PSA mod we want to remove D5 and R53 and jumper them.
Component side after the recap and ACA to PSA mod.
Trying a new circuit, a low gain overdrive with an interesting tone control.
Circuit board for the Lady Luck tube vibrato pedal.
A customer sent a mail with a picture of his pedal board.
There’s four zeta sound pedals on the board. At the top left Eko, a custom orderd analog delay pedal, bottom left Magic Drive another custom order, bottom middle the Turtle Clipper and on the bottom right a zeta sound clone if the R.M Octavia.
A nice vintage fOXX Fuzz & Wa & Volume pedal on th workbench.
Previously modified with an added bypass switch, and a DC jack.
The guts.
Solderside of the circuit board.
View of the potentiometers.
A customer asked for a mod of the bypass switch for the wah circuit, omitting the volume function when the wah is set to bypass, and service in general.
Cleaning the wah pot, recapping the circuit board and rewiring the wah/volume switch and the pedal is as new again.
Saving a vintage wah pedal.
A vintage Vox wah pedal giving no effect. The pedal had the jacks, bypass switch and the potentiometer changed before it was sent to Zeta Sound.
Has the number 250.049 at the bottom lid as the only identification about what model it might be.
The bypass switch was replaced with a new DTDP switch, although wired wrong. Got it rewired correctly, but the pedal did not give any effect. The problem was the new potentiometer, too much heat when soldered had caused the wiper soldering lug to lose its contact. By taking the pot apart and reattach the rivet it could be saved.
Rewired with a new battery clip installed.
Also replaced the old 4,7uF capacitor, for some reason it had a non polarized version.
