Korg Poly800/EX800 Users

Hi p9,

that could be interesting, but can you please describe the effect more
exactly?
Is it a noise reduction or does it make brighter sound (more hurting
resonance sweeps, for example)?
If also the effect of some "flanging" or "phasing" noise, I think it's
caused by the chorus, but I'm not really sure. Is it reduced by your
modification?

Would be helpful, thanks,

Olaf


----- Original Message -----
From: "plutoniq9" <Plutonique9@...>
To: <korgpolyex@yahoogroups.com>
Sent: Saturday, May 04, 2002 3:39 AM
Subject: [korgpolyex] Noise & Bandwidth Modification


> The final audio stage of the Poly 800 goes through a NJM4558 OpAmp.
> The slew rate for this OpAmp is a little to slow to achieve a 20hz-
> 20khz Bandwidth reproduction, and normally when these are used for
> audio, compensation capacitors ar used to make up for it's lack of high
> end. The Final Opamp stage doesn't use these caps though, so it's safe
> to say that the high end freq. responce of the audio outs are capped.
>
> Well, no point in adding the compensation caps, may as well remove the
> OpAmp and replace it with a socketed higher performance audio opamp
> that doesn't need 'em, one also that has a higher Signal to Noise
> ratio. So, Dis is how;
>
> What you'll need;
>
> -Solderin' Iron (30 watt or so)
> -Solder, Desoldering Braid
> -8 Pin IC Socket
> -NE5532 Dual Opamp (Pin 4 Pin replacement of the 4558)
>
> Ok;
>
> First you need to locate "IC2" on the KLM-598 Circuit Board (This is on
> the top half of the Poly 800 synth). Unscrew the KLM-598 board from the
> Poly 800 casing and remove the ribbon cables from the sockets on the
> board(This will allow you to completley remove the circuit board out of
> the synth to work on). Using the delsolder Braid, desolder all the  8
> Pins of IC2 (NJM4558) and remove part from the board.
>
> Next, Solder in an 8 Pin IC Socket where you removed "IC2", make sure
> the IC socket is facing the right direction (matching up with the
> drawing on the circuit board). Now, carefull insert you NE5532 Opamp
> into the IC socket (The dot representing Pin 1 of the NE5532 should be
> inserted into the socket so that it is on the side of the IC socket
> with the Dip in it).
>
> Now screw the KLM-598 board back into the Poly 800 casing, reconnect
> all the ribbon cables, screw your synth back together....and your done!
>
> Hope it sounds all the more sweeter. If ya find you prefered the ol'
> noisy low-bandwidth NJM4558, hey it's easy to remove the NE5532 and
> stick the old one back in there, no harm a done :)
>
> Seeya
>
> P9
>
>
>
>
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