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DIY Stompboxes => Building your own stompbox => Topic started by: SonicVI on September 11, 2007, 02:46:08 PM

Title: Yamaha CMOS overdrive?
Post by: SonicVI on September 11, 2007, 02:46:08 PM
Anybody know anything about the Yamaha COD-100 CMOS overdrive?  I haven't been able to find a schematic.
Title: Re: Yamaha CMOS overdrive?
Post by: MartyMart on September 11, 2007, 07:20:19 PM
http://filters.muziq.be/model/yamaha/100/cod100

All I could find, there's one on Ebay Germany missing a knob but full function, i day left !

MM
Title: Re: Yamaha CMOS overdrive?
Post by: Mark Hammer on September 12, 2007, 02:10:15 PM
Boy does that writeup at filters.muziq.be ever scream 4049-based overdrive.  First off, the writeup from yamaha places emphasis on the tube-like characteristics.  Second, take a look at that current consumption; 32ma for an analog effect.  THAT's why EHX included an onboard transformer with the original Hot Tubes.
Title: Re: Yamaha CMOS overdrive?
Post by: SonicVI on September 12, 2007, 04:10:01 PM
That's my assumption, that it's 4049 based. I see them fairly cheap on ebay from time to time and have wondered how similar it is to the Hot Tubes or Tube Sound Fuzz, apart from having the two band eq.
Title: Re: Yamaha CMOS overdrive?
Post by: Steben on September 13, 2007, 06:59:56 AM
I recon if you could twist the overload of electronics (noise gate - compression), it would be a nice pedal. Many reviews talk about noise suffering at zero input, which typical for overbiased noise gates.
Title: Re: Yamaha CMOS overdrive?
Post by: SonicVI on September 25, 2007, 07:12:49 PM
I just picked up one of these pretty cheap on ebay and it uses a JRC NJU4069UBD, NE571N, and JRC4558SD (SIP, presumably driving the tone stack).   Soundwise it's definitely reminiscent of the Hot Tubes kinda overdrive, kinda aggressive with a tight bottom end and the dual band active eq allows for a pretty good range of tones but gets pretty noisy with too much treble as one would expect. The compressor circuit definitely needs some tweaking. I'm gonna have to learn up on the NE571.  When the gain is high the compressor pumps up the noise before reducing it again as the sustain decays. Not too bad but very noticeable and a bit unusual.  I'm gonna see if I can get a schematic from Yamaha. For the price ~$30 it's a pretty decent overdrive.
Title: Re: Yamaha CMOS overdrive?
Post by: SonicVI on September 26, 2007, 11:00:17 AM
oops, meant to edit not quote.    The edit was that there are actually three of the SIP package JRC4885's.