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

[Rob Flinn]

I wish I could. I've been looking for a calibration procedure myself. Strange it wasn't in the Pye manual, etc.
My r52 trimmer isn't shorted. After calibrating it back up on the scope with the threshold cranked, it was probably about 2 or 3 turns in from the bottom click where the control spikes began to move upwards.

The other trimmers were left on suggested settings.

When you says suggested settings, you mean the fixed values that ABe seems to suggest next to the trimmer values on the boards ?

 

[desol]

Yep. The pre-trimmed values.

 

[Rob Flinn]

I have put jumpers in for R65 & R67, which makes the particular meters I'm using work much more responsively.  This effectively puts the circuit back to original specs.

I managed to get one channel working quite so it looks quite good on test gear. on the meter I'm struggling to get much more than 12dB of reduction to show. 

 

[Rob Flinn]

I got both channels working what looked like fairly well tonight.    I got the bit through for the stepped attenuators.  That seems to make things a bit more predictable.  WHat I was finding using 2 pots is that when you try to trim the things you have more variables which means there is a layer of randomness.    Unfortunately in my new workshop I don't have a monitor system just yet so this is all based on looking at it on a scope and milivlot meter & putting an audio signal in.  Really want a listen to this thing
Soon....

 

[desol]

Rob

What ever happened with the Pye? Did you get things sussed out with it....get a chance to try it on anything?

 

[Rob Flinn]

Rob

What ever happened with the Pye? Did you get things sussed out with it....get a chance to try it on anything?

Yes I did get it working & it did sound good on a couple of things I tried on on my work bench.    I am trying to get a proper front panel sorted. I'm using 6 pole 5 way switches so that the lim is on the same switch as the ratio.  I drew a diagram for it but have yet to see if it worksbecause I can't find my molex pins since moving my workshop.  I did thins to save space so I can use bigger meters than danderloo uses for his case.  If it does I'll post it here.  I have a bunch of the switches if anyone want some.

In the mean time one of my dogs has smashed up one of the original Pye meters I was using.  So I need to try and glue all the bakelight back together & get a piece of glass cut.    He's a very clumsy dog but has a lovely temperament.  It's my fault for leaving it underneath where his food is kept.  See pic of him sleeping on my tool bag .....

 

[Dreams]

I've actually picked this back up a couple days ago. The calibration is still somewhat mystery, but I'm plugging away. Any tips or procedures anyone feels like sharing would be v much appreciated. Getting the "threshold" correct seems to be my problem, but all the trim pots interact, so.

 

[Rob Flinn]

I've actually picked this back up a couple days ago. The calibration is still somewhat mystery, but I'm plugging away. Any tips or procedures anyone feels like sharing would be v much appreciated. Getting the "threshold" correct seems to be my problem, but all the trim pots interact, so.

The reality is that it is a lot easier to get going if you make the stepped in/out attenuator switch on a 2 pole 24way switch.  This automatically turns up the make up as it compresses more like on the API525.  It all looked very random before I fitted them.    I'm still not wildly sure exactly how all the presets should be set but it works & sounds fine.  I think most people are setting some of the presets to the nominal values on the diagram, which is what I did.

 

[Dreams]

Thanks Rob. I've got a 12 position switch rigged up for 2db steps, with build out resistors to make it go to 10k, if that makes sense? I'm building a single channel into 1 rack space, so that might be the best I'm gonna be able to do.

At the moment i have separate I/O controls because I'm trying to figure out how the gain works through it... if i was sure the transformers were correct, it would certainly narrow things down for me.

Anyway, I can get the thing to "work," but the measurements don't really make sense yet... I wish i could get my hands on an original for an hour!

 

[Rob Flinn]

You will find it very difficult to  figure the gain out unless you have both the in & out on one switch.  I spent months on & off trying to make sense of it.  It only came together when I had both on one switch.

 

[Dreams]

Haha fair enough, I'll throw it back in there now that I know the circuit is working as it should. I meant to say that in my last post...

Did you just leave the trimmers where they were? I was getting no change in pulse width at the chopper transistor with them set at the nominal values, but that also may have something to do with the sidechain transformer I'm using...

 

[desol]

He's a very clumsy dog but has a lovely temperament.  It's my fault for leaving it underneath where his food is kept.  See pic of him sleeping on my tool bag .....

He looks like a good boy! It looks like he knows he's in trouble..  ...and/or he's about to fall asleep!

@Dreams: I know for mine I just went with the pre-trimmed values printed on the board and everything seemed to look ok on the scope.

 

[Rob Flinn]

Haha fair enough, I'll throw it back in there now that I know the circuit is working as it should. I meant to say that in my last post...

Did you just leave the trimmers where they were? I was getting no change in pulse width at the chopper transistor with them set at the nominal values, but that also may have something to do with the sidechain transformer I'm using...

I just used a pair of cheap OEP transformers in the sidechain.  They are the 1+1:2+2 version, but are wired 1:2+2 to give me 1:4.  They seem to work fine.  For input I have a pair of Gardners 10k:10k, which are british vintage.  In trying to keep it an all British affair I was using some gardners 1:4 mic transformers on the output but whilst they seems t work well I wasn't sure they could handle the level so I subbed in some Edcor XSM 600:10k that were lying around doing nothig.  I might get some Carnhills to replace them.

 

[Rob Flinn]

I wish i could get my hands on an original for an hour!

You mean like one of these bad boys

 

[Rob Flinn]

Another shot

 

[Rob Flinn]

The other side.  After playing around for a while this afternoon, I would say the clones sounds remarkably similar.

 

[Dreams]

Awesome.

You gonna have it for a few days? I could use a few measurements....

 

[Rob Flinn]

I'm on site & don't have the time or test gear for measurements unfortunately.

 

[Grummy77]

Has anyone who's bought the Pye case, had an issue with the meter bezel(47mm) cutout, being too big? The cutouts on my case are 50mm...which leaves a 3mm gap.

I have the hairball 8027-wf 1ma meters.

Cheers and thanks.

Yeah mine don't fit. Also the faceplate on the case doesn't fit the rest of the case either. When I screwed it together it bowed the faceplate.

 

[eddie_ruff_]

I just bought the case and pcb from dan...nothing else yet. So the hairball meters do not fit, and the meter adjust hole has to be drilled?