Roger Mayer RM57 build?

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Hey all, I have an rm57 , originally from the Record Plant ( it has some attack and release mods done for them), and the manual. It has the parts list, at least the caps/resistors/ VRs etc.  I scanned it for someone a couple of years ago, so it should be on one of my drives, and If it would be helpful, I'll be glad to send the scans to anyone who would like them.

Of course, if you would like to pay me an insane amount of $, you can have the thing.......( just kidding. I read through the posts, and saw that someone was asking 6K for one........ seems sort of nuts......, but hey, I can dream. can't I?
j
 
Hi Mark.
I gathered a fair bit of information on this unit - including the very useful stuff you had.
I still didn't find out about FET selection though.
I'm sure there must be some specific criteria for correct operation. (Pinch off voltage etc.)
As you know, the man himself turned out to be very rude obnoxious type who wasn't prepared to help in any way, and tried to make out that this unit couldn't be built these days - then went and revived the unit as a stomp box product! (check his website).

Anyway, I'll be very interested to see how you've got on with this.
 
I’m very interested in building this as anything Eddie Kramer uses or used I’m mad on!!
I built stereo version of the pie compressor and it turned out pretty good, I use it on over heads and acoustic guitar and it sounds fat and thick.
This could also be a great compressor for my studio.
I’ll take a look at the schematic and see if I can eagle something up and also track down what values are missing.
 
how does anyone feel about me making a parts list and as long as it can be done on single layer pcb, i can make the pcb and populate, bearing in mind i would need some support from people who can check through what ive done so i havent made any mistakes.

thoughts?
 
Well count me in of course.

There's this Italian company Side-B Studio in Italy (https://sidebstudio.it)
They've apparently managed to clone the RM57.
Looks like a single sided PCB too.
So it must be feasible.

Also the part count is so low and no transformers are involved.
This could be such  a fun project while being super affordable :)
 

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Gut shot of the "b-side studio" clone.
 

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thats great stuff could you also detail the power supply please and value of the VU meter?

also any higher res closer photos always help, need some values on a few things but let me go through it for a few hours and then i can put up a list of things to find.
 
ok well the first problem is that the first schematic is quite different form the last (scribbled) drawn schematic.
they share a few similarities but i'm going to stick with the first one for the time being, its on page 5 of the pdf.
 
Ok so far from page of the pdf I'm missing or not sure of the following values:

R34 is it 2.21 ohm or 2.21k?
C4 ?
Q6, Q7, Q8, Q9 transistor?
Q10 and Q14 fets?
Q15 ?

i can see the release is a lorlin with resistors for set release times, this should be fairly easy to work out.
Im going to check on the available parts for transistor equivalents and diodes, if someone could take best guess or check on a working unit perhaps?
 
right i've put the schematic in eagle and i will play around with layouts, just need to verify what transistors to use and what two JFET's are used or equivalents.

I have all the other information now i think.

regards

Spence.
 
here is a screen shot of the schematic laid out as per the picture of the insides, please let me know if you spot and issues or mistakes.
 

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