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

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Mmt50816

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1) I was wondering did anyone ever try to put the missing 100k resistor back in the circuit and did it change anything?

2) Are you guys grounding the case and shield of the input cinemag and did it help noise?

 

Rickstar44

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Jan 31, 2017
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JoBe76 said:
I was wondering does anyone have the full documentation for this project?
The Help docs on collectivecases.com has no schematic on the U7 Daughter Board, all other links I have found are dead.
I would be incredibly thankful for any additional documentation anyone could share.
All the documents needed are in the thread,
gotta go through and read all pages.
the U7 is not documented
 

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jplebre

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Have a pair of stuffed PCB, with a couple of other things like neutrick plugs power trafo knobs etc etc etc for sale on Black Market.

I haven’t had the time to do any DIY projects in years and I don’t see that changing. I’d rather these pye were being used to make music :)
 

dogears

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Does anyone have any information on how the 555 is configured in this application? Anyone able to snap a photo of the 555 daughter board?
 

scott2000

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Next to last post here has a schematic  of something....Not sure if it's helpful....

https://groupdiy.com/index.php?topic=43351.380

found this too...

https://web.archive.org/web/20160420075209/http://collectivecases.com/?product=ac-sound-pi-3141-vintage-pwm-compressor-circuit-board
 

JMan

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What are you all doing about the PN3640 transistor?  I can't find them for sale anywhere, and I don't know enough to confidently identify a replacement.  It seems like they have been obsolete for years now, so people MUST be building this without them, so what are you using instead? 

(And sorry if this has already been covered, I scanned the thread but only saw it mentioned way back in 2014 and in that case the guy was eventually able to get his hands on some.  If there was more discussion, I missed it.)
 

desol

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Spencerleehorton said:
Would be really helpful to have a proper setup procedure

Hopefully someday there will be. Would be nice to see the original designer back on here and offer a proper setup. I have the schematic and build guide for this. Here:
Schematic:
http://s000.tinyupload.com/?file_id=02106532008809327609
Build Guide:
http://s000.tinyupload.com/?file_id=59000528885487538057
 

Ilya

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dogears said:
Still hoping someone can shed some light on the 555 use.  :-\

What is the question of the 555 use you want to ask?
From my experience, 555 doesn't work the same as a discrete oscillator. You won't get a "real PYE" with 555, although it still will be a PWM compressor.
 

JMan

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Ilya said:
What is the question of the 555 use you want to ask?

Wondering the same.  In your earlier post, you asked about how it is "configured."  Are you just asking about its orientation on the daughter board?  From there it should be easy enough to trace the rest of the path, I think.
 

desol

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Ilya said:
What is the question of the 555 use you want to ask?
From my experience, 555 doesn't work the same as a discrete oscillator. You won't get a "real PYE" with 555, although it still will be a PWM compressor.

I remember I asked the designer when he built his and he said the 555 didn't make that much of a difference in sound. His unit is here, and sounds pretty amazing. https://www.youtube.com/watch?v=RxyLcNF9-JI

I think he may have had an original to compare to.

With the 555, I just hooked up a digital meter to it and dialed in 250khz.
 

Ilya

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desol said:
I remember I asked the designer when he built his and he said the 555 didn't make that much of a difference in sound. His unit is here, and sounds pretty amazing. https://www.youtube.com/watch?v=RxyLcNF9-JI

I think he may have had an original to compare to.

With the 555, I just hooked up a digital meter to it and dialed in 250khz.

Well, I've made measurements with discrete oscillator vs 555 circuit and they behave differently. They both compress. But do it differently. I don't have original at hand, so I have no idea how that compares to original. But I won't say that they are the same and sound the same (while in compression).
 

dogears

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I haven't been able to find a schematic of the 555 configuration or the daughterboard. As in, a complete schematic of how the 555 is used in this particular circuit.
 

Dreams

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The 555 board is pretty much a copy of the datasheet circuit. I have a schematic somewhere but you could probably trace it out in less time than it would take me to find it. Power, ground, osc out, not much going on
 

AW

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Feb 15, 2021
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Hi

Does anyone have a mouser BOM they can share for this project

Thanks, Tony
 
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