I’ve fixed one issue with the speed preset switch, it could sometimes skip one of the three speeds, jumping from slow to fast skipping medium. It now goes steady from slow (1Hz) -> medium (2Hz) -> fast (7Hz).
I’ve made the depth trimmer available from the bottom lid and added a trimmer for the fast speed as my client requested, adjustable 3- 7Hz.
So lets try to list what differs from the original.
I’ve used 2N5952 fets instead of the 2N4303.
It’s got a new input buffer suited for guitar.
It powerded by 9VDC.
Adjustable high speed.
The speed selector circuit, tap the switch and change the speed.
Finally found the time to finish this phaser. Replaced the electrolytics, adjusted bias for the fets and it sounds as good as new. I really like the off board wiring done to it. Shielded wires for everything in the signal path.
The opamps have sanded but they are all seem to be LM1458:s.
The bypass switch is a nice, non-clickinging type. Never encountered them before. It’s not wired for true bypass.
The pedal works of a 9VDC battery but also have a DC jack, though the circuit uses +/- 4,5VDC from the power source so it can’t be daisy chained.
Got hold of this old phaser in a no working contition.
Tried to power it up but found that it’s short circuited. The problem was not located in the circuitboard, found that one of those blue old tantalum caps on the power inlet for the DC-jack was shorted.
I had them replaced and yes! There’s phasing. However it seems that it’s in need some more tending to, it’s way to noisy. Lets see what a total recaping can do for that.
So I finally got the fets matched and ready to go into the circuit. It all seems to work as it should. Here’s a short soundclip recorded as I take it through the presets, slow, medium, fast and then back to medium and slow. Poor quality on the recording though, using a tone generator and cellphone for recording.
You can hear the nice feature of the ramp working.
Now the work continous, it’s time to modify. The input buffer needs some tweaking and the I’ll have to decide how to the speed presets will be set, who knows were it will end.