abechap024
Well-known member
Well let me give some more updates on exactly what happened:
I got everything together, first power up there was only a faint weak trebly distorted sound coming out...after many hours of angry words I finally realized, stupidly I didn't have it grounded correctly. So grounded it and it started producing some real sounds.
At first I had the two stages connected to a 10k dual ganged pot. But for testing purposes I un hooked them and used different pots for input/makeup gain. that stages seem pretty immune to using different values, I think right now I have a 10k pot with a 3k resistor on the leads and the a 50k pot on the makup stage, I'm sure it could probably use some tweaking later.
So next power up the side-chain was acting funky....with no signal the meter would sit around "0" (i just had a vu hooked up to it but I think it requires a 1ma DC meter) but its seemed to respond correctly...the meter was bouncing to the music, just was off...
So come to find out, I had the decay switch rotated one notch to far to the left when I soldered it in, and also a 2n4124 transistor was burnt out probably from me messing with some of the trim pots and maybe turning them too far to one side (just a guess).
Mind you during all this the oscillator was not working and the 100 ohm resistor by the oscillator was getting hot to the touch.
Well I switched out different hand wound transformers....getting very discouraged, thinking well this is crazy....Its not going to work...so I just took the little transformer out (i tested about 5 different ones up to that point).
And well then I made those changes as stated before, and other fiddlings and well installed one final little hand wound transformer....(mainly to get the meter to sit at "0" because I found it doesn't with no transformer installed)
But low and behold!! WE get signal!
There is a waveform that very closely matches the pictures I was sent of a working pye. You can imagine my excitement... So next thing is to probe the base of the chopping transistor.....and by turning the ratio switches I can artificially trigger the side-chain...and what do a see on the oscilloscope? These amazing waveforms! They get wider during peak reduction and smaller during less reduction, just like the manual states! I was blown away, I have no Idea how it does it but it does, it was very beautiful to see (I had been staring at a blank oscilloscope for many hours....that could be why
)
Well anyway, very excited its working, I do a few more tests, also the side-chain isn't detecting audio correctly (like it was) and I have to move wires and what not to get it to work intermittently. But I'm very confident I will get the problem sorted, as it was responding correctly before, and the only big issue in my mind was getting the oscillator to work, and I think its easier to get to work than any of us could of imagined.
My oscillator is running at 500khz so I need to tweak the transformer etc....
anyway very excited how this is turning out, my oscilloscope broke (how ironic!) so I've stopped working on it for the time being, otherwise I (hopefully) would of brought news of a completely working unit.
Going to continue progress today. Either by fixing mine, or borrowing a friends down the street.
Thanks for bearing with my long post, hopefully someone finds this helpful (and not radial! )
Cheers,
Abe
I got everything together, first power up there was only a faint weak trebly distorted sound coming out...after many hours of angry words I finally realized, stupidly I didn't have it grounded correctly. So grounded it and it started producing some real sounds.
At first I had the two stages connected to a 10k dual ganged pot. But for testing purposes I un hooked them and used different pots for input/makeup gain. that stages seem pretty immune to using different values, I think right now I have a 10k pot with a 3k resistor on the leads and the a 50k pot on the makup stage, I'm sure it could probably use some tweaking later.
So next power up the side-chain was acting funky....with no signal the meter would sit around "0" (i just had a vu hooked up to it but I think it requires a 1ma DC meter) but its seemed to respond correctly...the meter was bouncing to the music, just was off...
So come to find out, I had the decay switch rotated one notch to far to the left when I soldered it in, and also a 2n4124 transistor was burnt out probably from me messing with some of the trim pots and maybe turning them too far to one side (just a guess).
Mind you during all this the oscillator was not working and the 100 ohm resistor by the oscillator was getting hot to the touch.
Well I switched out different hand wound transformers....getting very discouraged, thinking well this is crazy....Its not going to work...so I just took the little transformer out (i tested about 5 different ones up to that point).
And well then I made those changes as stated before, and other fiddlings and well installed one final little hand wound transformer....(mainly to get the meter to sit at "0" because I found it doesn't with no transformer installed)
But low and behold!! WE get signal!
There is a waveform that very closely matches the pictures I was sent of a working pye. You can imagine my excitement... So next thing is to probe the base of the chopping transistor.....and by turning the ratio switches I can artificially trigger the side-chain...and what do a see on the oscilloscope? These amazing waveforms! They get wider during peak reduction and smaller during less reduction, just like the manual states! I was blown away, I have no Idea how it does it but it does, it was very beautiful to see (I had been staring at a blank oscilloscope for many hours....that could be why
)Well anyway, very excited its working, I do a few more tests, also the side-chain isn't detecting audio correctly (like it was) and I have to move wires and what not to get it to work intermittently. But I'm very confident I will get the problem sorted, as it was responding correctly before, and the only big issue in my mind was getting the oscillator to work, and I think its easier to get to work than any of us could of imagined.
My oscillator is running at 500khz so I need to tweak the transformer etc....
anyway very excited how this is turning out, my oscilloscope broke (how ironic!) so I've stopped working on it for the time being, otherwise I (hopefully) would of brought news of a completely working unit.
Going to continue progress today. Either by fixing mine, or borrowing a friends down the street.
Thanks for bearing with my long post, hopefully someone finds this helpful (and not radial!
)Cheers,
Abe
