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

[Niketouille]

Got my pcb this morning with...the annual tax !!!
Does someone know something about the others transformers (input/output/sc ) ? Some mesures would be great...

 

[abechap024]

Glad you got it!

Some measurements of an actual unit would be great. But because of its low -16V supply rail, someone was saying that we will need at least 1:3 3:1
(more like 1:4 4:1) on input and the opposite on the output.
I believe for the side-chain is just a 1:1, but would be nice to have some conformation on this. I bought some from edcor for the project, a 10k:600 on the input, 600:10k output and 1:1 sidechain. I'll let you know how it goes...

 

[abechap024]

Also found some torroids that look like the original....found them on the bay..just by chance!

 

[Hank Dussen]

Some members here own or have access to these compressors.
Surely it can't be that hard to measure the ratios...

 

[Rob Flinn]

Some members here own or have access to these compressors.
Surely it can't be that hard to measure the ratios...

It's not that difficult to work out how many turns the primary & secondary are.  If you look at the 2nd circuit board pic I posted you can see the transformer about 1" in from the left where there is an E printed on the board.  It's something like 3 turns &  the other winding 5 turns.

 

[Niketouille]

R33 should be 8,2 ohms right ??? not 8,2k ?

 

[abechap024]

Ops! Yes your right. Good catch. Looks like I have some un-soldering to do...


Oh wait, on the original schem it says 8.2 ohms but on the original parts list it says 8.2k - and my gut goes with the parts list cause 8.2k is quite more common then 8.2 ohms...
But I had someone tell me it probably is 8.2 ohms...so I would go with that.

But who knows....Just try and see I guess. I 'll try 8.2k first since thats whats in there already

 

[leadbreath]

hey abe

got my pcb's, nice work! im loving the "playground"!!

thanks
mick

 

[Niketouille]

8,2 ohms is much more logical than 8,2k.
8,2k induce a lots of nfb and therefore a very low output level. I mean that's what my over-excited brain first thought....

 

[abechap024]

Okay, well that is what someone was telling me too. Which makes a lot of sense now I need to learn more about all this !
So first errata!!

r33 is not equal to 8.2k
r33 is equal to 8.2R

First of many I suspect!

Cheers,
Abe

 

[reanimatorstudio]

For many reasons (feedback, output impedance, output level, power of the resistor, relation to other components,...) I believe R33 is 8,2 ohm

 

[Rob Flinn]

If you look at the 2nd circuit board picture I posted.  On the bottom edge below one of the inductors is a large 8R2 resisitor.  Whether this is R33 I have yet to find out but ...............

 

[Niketouille]

2N4124 quantity is 2 in the bom instead of 1.

 

[Niketouille]

and R52 is a trimmer not a fixed resistor...

 

[Niketouille]

Add a 1k resistor in series with the meter ??? I'm refering to the pye manual.

 

[Niketouille]

About the dual 330 ohm pot I will use a dual 2,2k lin pot with a 390 ohms resistor in between the wiper and the bottom legs.
... too much post today !!!

 

[abechap024]

Add a 1k resistor in series with the meter ??? I'm refering to the pye manual.

You need a 1k in R1 if not using an external meter.

Good stuff! Updating BOM

THNX!

Hows your build going? I have mine about 3/4 stuffed with just random parts around....also 550/560 *should* work in lue of 549/559 I had some laying around we'll see!

I hopin they at least do somthin!

EDIT: found another error, BOM should have TR18 as BC559A

 

[Rob Flinn]

About the dual 330 ohm pot I will use a dual 2,2k lin pot with a 390 ohms resistor in between the wiper and the bottom legs.
... too much post today !!!

It's not a dual 330R pot !  It's a dual rotary switch.  I'm hoping to visit my friend soon & measure what the steps are.  I suspect that you may manage to get something happening using your 2K2 pot and 390R, but the rotary switch automatically gives you the correct make up gain like on an API 525, so it may not work correctly.  I will post some more on this as soon as I have the information.

If you look at the 2nd circuit board picture I posted.  On the bottom edge below one of the inductors is a large 8R2 resisitor.  Whether this is R33 I have yet to find out but ...............

Can confirm that this is correct & that R33 is 8R2, & it looks to be at least 1/2Watt

 

[abechap024]

Great thanks for confirming. I updated the BOM.

Also some of the resistors look like they are 1/2 watt...I think that is a bit of overkill though....if a 56ohm resistor was connected to the -16 rail straight to ground it would only dissipate a little over 1/4watt. And the output section will probably be using the most current and its all connected with 56ohm...


....Long story short, My bets, we will be fine without cumbersome 1/2 watt. If not I'll buy everyone a Sparkling water!

Abe

 

[Niketouille]

Didn't know it is a stepped pot, so I will wait until you could mesure it. Schematic is a bit unclear about that.
I'm still waiting parts for this project so nothing is soldered yet...