[sdiy] Rising Realsitic Electronic Reverb prices and the urgeto modify...

Mon Apr 28 05:13:54 CEST 2008

> Did you also design the Radio Shack Stereo Synthesizer unit?

Wait. Do you mean the Archer Video Sound Processor? I buy those all the time 
on eBay. I use every part. I even have TWO heavilly modded (of course) units 
in actual use in a home theatre system ('78A's: the best version for actual 
use, although the '77 has it's merits - like a full steel chassis that works 
great for tube amps and a Reticon RD5106 and a handful of 4136's and an 
LM1894 DNR chip, etc. etc...) and I have a Pioneer receiver that has Dolby 
Prologic amongst other surround options (because I'm still too poor for a 
full fledged 5.1 or 6.1 system...). It's super-tweakable for a dork like me 
who instead of 2 or 4 good speakers has 8 middling ones and a bunch of chip 
amps from car stereos. (Soone to have a tube mono-block for my center 
channel and then maybe a stereo tube amp blah blah blah...)

I usually pass on the '78-NON-A's because they don't have the cool 
JRC4558DD's (that's right TWO D's!) and the PCB is majorly kludged - didn't 
think the grounding through ahead of time did we - with 2 DIFFERENT BBD 
clocks??? Maybe if the price is super low. Good for an MN3007 and an MN3006. 
The '78 was screaming for a redesign and I'm pretty sure that's what the 
'78A is. So I buy those and the '77's.

Counting the BBD chips I have it looks like I've gotten 8 or 9 of the '78's 
in whatever incarnation and 3 '77's. Sometimes they go for a lot and 
sometimes they don't. I always hoped I could keep 'em a secret so that 
nobody would buy 'em, but they do anyways. I mean I get email notifications 
and everything when one pops up on eBay. MN3011's too. That's how I got two 
for $0.03. Dammit I just can't stop gloating about that. Does it make you 
sick? What makes me sick is that since I have two, my designs for them 
always end up totally Byzantine: a complete modular synth just to run two 
brother-trucking multi-tapped BBD's!

Did Radio Shack ever have a unit that used MN3011's? Or MN3005's? Or even 
MN3205's for that matter???
And why the hell didn't Pansonic make an 8-pin version of the MN3004??? 
(Because I want to try replacing the MN3009's in my Roland MKS-50 and I 
think MN3007's might be too big, but maybe not... maybe if I jacked up the 
clock speeds I could get slide-whistle to go away?)

Frasier,
Anthony

> Cheers,
> Jeff
>
> -----Original Message-----
>>From: Paul Schreiber <pschreiber at sbcglobal.net>
>>Sent: Apr 22, 2008 9:37 PM
>>To: anthony <aankrom at bluemarble.net>, Synth-diy at dropmix.xs4all.nl
>>Subject: Re: [sdiy] Rising "Realsitic Electronic Reverb" prices and the 
>>urge tomodify...
>>
>>Jeez, I designed this thing in 1980 and it won't die :)
>>
>>Paul S.
>>
>>----- Original Message ----- 
>>From: "anthony" <aankrom at bluemarble.net>
>>To: <Synth-diy at dropmix.xs4all.nl>
>>Sent: Monday, April 21, 2008 1:13 PM
>>Subject: [sdiy] Rising "Realsitic Electronic Reverb" prices and the urge
>>tomodify...
>>
>>
>>> Hi guys,
>>>
>>> So I have one Realistic Electronic Reverb: the greatest effect to use 
>>> for
>>> not quite what it was intended for. This booger is a great noisemaker 
>>> and
>>> lots of fun with it's slider controls. It's even better with a few 
>>> tweaks
>>> to the circuit: more gain and high-end roll-off to the regen path, 471pF
>>> polytsyrene caps in place of the ceramic ones, JRC4558DD op amps in 
>>> place
>>> of the AN6550's, socket for the timing cap to play with different 
>>> values,
>>> adding 0.1 uF bypass caps here and there, and the latest greatest mod:
>>> popping in a BL3208A (normal 8-pin!) from Small Bear and WOW! I've 
>>> thought
>>> about wiring 2 or 3 in series, the BL3208A being something like $3.75 in
>>> price. Next planned mod is making the "DEPTH" control into a true 
>>> wet/dry
>>> crossfader, which is a non-trivial task, but not impossible: I think a 1
>>> uf cap and a couple 100kOhm resistors to put the bias in the right place
>>> again and cutting the traces on the PCB and rewiring accordingly.
>>>
>>> SO I've been trying to buy another one on eBay for what I got my first 
>>> one
>>> for ($12.00) and it's been a daunting task. People are catching on to 
>>> how
>>> cool these are.
>>>
>>> I'm not one to care much for collectability in gear because I like to be
>>> able to use my gear to the fullest. But I'm planning some more mods that
>>> will actuall involve cutting into the unit and I'm beginning to wonder
>>> whether I should. I wanted to add a DP3T selector switch to select 
>>> between
>>> various timing caps (if I can just find a good place on the front for a
>>> toggle switch to go...), and adding some brass body contacts to bring it
>>> (sort of) into the realm of circuit bending. I must admit that I don't
>>> actually hold to the philosphy of circuit bending although I enjoy 
>>> hearing
>>> some of the results. I don't think wiring various contacts and 
>>> capacitors
>>> to the timing cap connections could be considered circuit bending in its
>>> true spirit because they are not random bends, but carefully thought out
>>> connections. Putting your fingers across the timing cap terminals is 
>>> very
>>> fun: it depends on the pressure exerted so it has a playability factor 
>>> to
>>> it: you can quickly (or slowly) descend into the realm of 2 second 
>>> delays
>>> and back again. With the increased number of stages in the BL3208A, it's
>>> even better: repeats just go on and on without sounding like an
>>> oscillation, but it'll oscillate too - and how!
>>>
>>> So I'm wondering: should I do it? I mean even when they're going at $40 
>>> on
>>> eBay, it's not like I'm talking about circuit bending an Ibanez FL9 or
>>> something.
>>>
>>> Also, if anyone has DONE the wet/dry crossfade mod and would like to
>>> share, I'd appreciate that a lot. Thanx...
>>>
>>>
>>> Cheers,
>>> Anthony
>>>
>>> _______________________________________________
>>> Synth-diy mailing list
>>> Synth-diy at dropmix.xs4all.nl
>>> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>>
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