PYE Compressor/Limiter Thread *boards shipping* BOM up!

Hello there

back on the thread - I never received any comments on my PNP replacement comments... I went ahead and mounted those cans I had and we'll see how they do....

In the meantime I had a nice talk with David at Cinemag, ordered some trafos from him - of course the Input CMLI 15/15BPC but also a 600:15k 1:2 high quality OUTPUT and a less expensive option for the SIDE CHAIN OUPUT which I am not sure I will be using as much.

Once I receive them I will post so if anyone else wants an alternative to Edcor will have the exact model number to order from Cinemag - given we picked the right ones...

More soon...

Sage

Are there any self-etch files for these boards floating around? I noticed abechap024 said they'd offer them eventually.

trashcanman said:

Are there any self-etch files for these boards floating around? I noticed abechap024 said they'd offer them eventually.

Click to expand...

Did you look here http://collectivecases.com/?product_cat=pcb

Hi, So i finally got myself a pair of boards and got one stuffed but it doesn't quite seem to be working correctly. Is there anyone who has a completed one able to post some typical voltages on the most recent schematic to help trouble shoot?

Im keen to contribute to this thread as much as possible, my unit seems to drop quite a lot of level by the time it reaches TR5 and i find myself having to trim R23 a lot to stop it from clipping. I also seem to have a problem in the Control circuit because when i have the base of TR11 in circuit the level is reduced to almost inaudible. I can only get my TL555 to 268Khz, I'm not quite sure what its supposed to be but i don't think this is causing my problems so far. I trimmed all the trimmers to their suggested value and have opted for the higher voltage rail of -22v. To test the input and output amplifiers i have to take TR5 out of circuit.

Im currently using a That 1240 as my input buffer and no output transformer as my budget is a bit tight at the moment. However I'm pretty sure i should be able to at least get the circuit functioning correctly like this don't you think? I shall post updates if i get any further but if anyones got any ideas that could help me along that would be most appreciated.

It's coming along... 24v/12v power all hooked, bypass boards working....wiring coming along. 12v power supply took FOREVER to come in.

Coming along, coming along...

Hey guys. For anyone that's done the relay bypass, should my bypass routing go straight from in to out? Or do I want to keep any of the transformers in bypass?

The way I have it hooked at the moment, it's bypassing from in straight to out.

That 's the interest of a "true" bypass
Straight wire! I'd keep it this way

If you can have it so that the comp side chain is "off" then that is generally the other type of bypass that uses the circuit and not "true" bypass.  The more modern things seem to follow the way you have it wired.  Seems to me you can have the best of both worlds if you can set it not to compress much of anything.
Patrick

Hey guys..

Thanks for your reply. That what I originally thought would make more sense, to bypass the sidechain leaving the transformers in. I think the way I have it now, in-out will be fine....and a bit less stuff to figure out to.

Im pretty sure that is what the 1:1 compression setting is for, on that ratio there will be no compression so effectively you are using it as a line amp and not a compressor. Alternatively you could put a switch in at the base of TR11 which will stop the Control voltage but i have not got mine fully up and running so i can not be sure this doesn't effect the circuit. This is what i did so that i could test the line amp side of the circuit.

That makes sense on the 1:1 compression setting...i didn't think of it that way before. ? Hmph. I'll have to look more into that later.

Hi, So update on where I'm at. I didn't read the Build Manual so i had TR16, TR18 and TR12 the wrong way round. After switching this around i was still not getting compression however i found out that i needed the side chain transformer the other way around.(Im just using a cheap microphone 1:4 transformer) As I've read this really does make a big effect on the threshold. At some point I'm hoping to do some more in depth testing so i can understand it better.

My distortion level is pretty high and i can't seem to get it lower. With a 1Khz Sine wave i have -10db on the output at the fundamental and -35db as the first harmonic, i haven't done the sums but that seems far too high. I have played around with R23 but it doesn't seem to have too much effect on the THD when its roughly in the right place, i have used this trimmer to adjust for the highest level going out at C19 to lower the threshold as much as possible so that i don't have to drive the input as hard.

My meter is going the wrong way but this may be because I'm using a hairball meter that is meant for an 1176, i have tried switching the polarity but that doesn't effect it. More investigation needed.

Question regarding using a stepped dual attenuator or a dual potentiometer, Did you leave a resistance at the minimum for the output/input? Because obviously when you have the output at 0 you have no output so I'm wandering if its worth leaving a bit of signal going through and then adding a gain stage so that you can really get this compressor slamming. Or is this threshold potentiometer supposed to work so that with no compression (1:1) it should be hold its gain level regardless of where you have the knob set?

Just to Reiterate i currently am running this transformer less with Line drivers and receivers and it's currently laid out on my bench and not in a chassis yet. That will be my next step. I hoping once i get it fully functional i will borrow a real one and run some tests together…..i will of course post any findings i have.

EDIT: I had my output from sound card turned down which is why i was having to push it hard to get 15db+ compression, now i can seriously slam it before the output reaches 0. 

jonathanmorbin said:

Question regarding using a stepped dual attenuator or a dual potentiometer, Did you leave a resistance at the minimum for the output/input? Because obviously when you have the output at 0 you have no output so I'm wandering if its worth leaving a bit of signal going through and then adding a gain stage so that you can really get this compressor slamming. Or is this threshold potentiometer supposed to work so that with no compression (1:1) it should be hold its gain level regardless of where you have the knob set?

Click to expand...

IIRC I used 40dB stepped switches, 21 position, 2dB/ step, one forward, one backward.  I have a spreadsheet somewhere. .......
Best,
Bruno2000

Hey everyone,

Does anyone have a good Mouser project for this? I swear I saw one but dug through the thread with no luck...

Thanks!!

E

I have one, but it needs a few changes...

bruno2000 said:

jonathanmorbin said:

Question regarding using a stepped dual attenuator or a dual potentiometer, Did you leave a resistance at the minimum for the output/input? Because obviously when you have the output at 0 you have no output so I'm wandering if its worth leaving a bit of signal going through and then adding a gain stage so that you can really get this compressor slamming. Or is this threshold potentiometer supposed to work so that with no compression (1:1) it should be hold its gain level regardless of where you have the knob set?

Click to expand...

IIRC I used 40dB stepped switches, 21 position, 2dB/ step, one forward, one backward.  I have a spreadsheet somewhere. .......
Best,
Bruno2000

Click to expand...

Found the spreadsheet.  PM me with your email if you want it.
Best,
Bruno2000

Can I also get a spreadsheet for switches?

Or better yet, is there a calculator to determine what resistor values to use when using 23 step switch?

I already have 23 pos. switches so I'd like to use them. I'll ditch the potentiometers since this compressor really is a beast and I want to use it not only when mixing but also in mastering. And for that, since recallability is a must, I should have ins and outs on switches...



Luka

desol said:

Hey guys. For anyone that's done the relay bypass, should my bypass routing go straight from in to out? Or do I want to keep any of the transformers in bypass?

The way I have it hooked at the moment, it's bypassing from in straight to out.

Click to expand...

Looking good! You laid yours out just about the same as mine.

Mine bypasses in to out direct.

Hey guys.

Can anyone offer any advice on how to go about calibrating the oscillator? I have a scope and sig gen, but not a lot of exp using them. A little more detail on the process would be awesome.

Thanks and cheers!

hey
im about to give this build a shot. im a bit confused about transformers though. can i use any of the old british iron i have lying around? :

- marinair 10k:10k
-gardners that can be wired either 600:600, 600:1200 or 600:300

id really appreciate if someone smarter than me can tell if i could use those for in- and output....