Re: PYE Compressor/Limiter Thread *boards shipping* BOM up!
« Reply #760 on: April 21, 2017, 12:15:16 AM »
Well, it's quieter in that position.


aladan

Re: PYE Compressor/Limiter Thread *boards shipping* BOM up!
« Reply #761 on: April 21, 2017, 01:02:34 AM »
Well, it's quieter in that position.

It's OK, I was only kidding :)



Re: PYE Compressor/Limiter Thread *boards shipping* BOM up!
« Reply #764 on: April 21, 2017, 07:39:52 PM »
A relay is a relay; isn't complicated...all the hookups are labelled on the boards no/nc. Boards were off of Ebay...

http://www.ebay.com/itm/Two-DPDT-Signal-Relay-Module-Board-DC12V-Version-for-PIC-Arduino-8051-AVR-/130690277968?hash=item1e6dbf6250:g:1asAAOSwk5FUv7Nz


touane

Re: PYE Compressor/Limiter Thread *boards shipping* BOM up!
« Reply #766 on: April 22, 2017, 03:04:07 AM »
I've spent ridiculous amount of hours trying to get this compressor to work as it should. And I finally nailed what was the problem - one shorted trimmer on R44 position!
It has been very frustrating but it was worth every minute IMO.

Just follow the build guide and BOM provided by SR1200 and reference to the schematic file PYE3 14SCHB.PDF and you'll be good. They are both somewhere in this thread.
Luka

Great to hear another success story with this one! I've been following this thread for a while, and had a go myself but not 100% happy yet with the build. It does sound good, but craps out with max ratio, where I get a nasty thump as compression kicks in. Also, never gets to compress more than 10-12dB, despite what meter shows.

I'd love to ask you a few questions regarding calibration, in case you have a minute:

R23-->recommended 22R. Both in simulation and reality, it all sounds horrible with this value, and I ended up setting it around 68R, which is also the value appearing on the original schematics. Could you mention how you set this one?

Oscillator: I imagine you also used the 555. Could you mention which freq. and which duty cycle you ended up with?

Would love to hear more (if you recall) how you proceeded to set it up.

Thanks!

shot

Re: PYE Compressor/Limiter Thread *boards shipping* BOM up!
« Reply #767 on: April 22, 2017, 06:56:51 AM »
R23-->recommended 22R. Both in simulation and reality, it all sounds horrible with this value, and I ended up setting it around 68R, which is also the value appearing on the original schematics. Could you mention how you set this one?
I did readjust this one a lot, but after I found out my problem was elsewhere I set it back to around 22R. Since I have dual channel unit, I set those to match channel-to-channel gain exactly.
What I found out is that this trimmer simply sets the gain of the unit. But if you go with too much gain it can run the channel into shutdown. So you don't have unlimited range of gain setup.
Be aware that this compressor is feedback topology. If you raise the gain on R23 it affects the gain in the sidechain and that consequently changes the compression amount.
I think that you can set it at whatever resistance you feel it sounds good as long as sidechain is behaving properly!

Oscillator: I imagine you also used the 555. Could you mention which freq. and which duty cycle you ended up with?
I never had problems with oscillator. I built it with 555 and first I checked if it is getting proper supply voltage (in my case few mV higher than -12V). Then I used my cheap chinese Hantek to trim chopper pulses to the specified 250kHz. It was no big deal. Once done, I never had to go back to it.

Would love to hear more (if you recall) how you proceeded to set it up.
Problem with my dual unit was, as I mentioned somewhere before, with shorted R44 trimmer on one channel. It was manifesting as low output gain on that channel. I first went and tested main signal path on both channels. For it to be tested, I had to disconnect entire sidechain. It was messy since I didn't socket my transistors in the first place and solder pads on this pcb are very small with narrow holes. Disconnecting sidechain is done by lifting mid leg of the chopper transistor PN3640 and disconnecting interstage transformer's primary. That way you can test your input-to-output signal integrity.

I found out that when using BC550A on TR12, as recommended by Abe, is crap. I used 2N4124 as recommended by SR1200 and it performed well. As well, I did my first mistake not taking care when stuffing board in the first place so I put BC550C on that position! 550C has way too much gain. But then I got 550A and it didn't perform well either. When using 2N4124 it was all good.

:)

Luka

touane

Re: PYE Compressor/Limiter Thread *boards shipping* BOM up!
« Reply #768 on: April 22, 2017, 08:53:40 AM »
Much appreciated @ Luka, I'll take note for next time I decide to open that box!
Cheers,
M.

Re: PYE Compressor/Limiter Thread *boards shipping* BOM up!
« Reply #769 on: April 23, 2017, 12:19:14 AM »
i'd rather build my own pcbs

Yeah! I guess if you have the time it's a cool idea. Mdainsd sussed out most of the issues with this circuit and abe predefined everything as it should be. If people stick to what these guys did and found previously, you shouldn't have any problems.

If people start changing things, I'm assuming they will run into issues that are difficult to figure out. Also, there is no known calibration procedure. Abe spent 3 years? fooling around with this circuit, so rolling with the pre-trimmed values seems a wise idea.
« Last Edit: April 23, 2017, 12:24:00 AM by desol »