Maxon - OD-9 Pro Plus

All about modern commercial stompbox circuits from Electro Harmonix over MXR, Boss and Ibanez into the nineties.
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roseblood11
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Post by roseblood11 »

I just bought a Maxon OD-9 pro plus, just to see what's inside - have to send it back in a week... I will post gutshots and parts values tomorrow, but I won't have the time to do the retracing myself.

Or does anyone already have a schematic?

It's just a variation of the tube screamer, but a good sounding one. Opamps as input and output buffers (like vintage OD-808) and the power supply looks very similar to the OD-820.

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Dirk_Hendrik
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Post by Dirk_Hendrik »

Still looking forward to those gut shots!
Sorry. Plain out of planes.

http://www.dirk-hendrik.com

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Post by czech-one-2 »

Wait, you just bought it to trace it, then your returning it? I hope I miss-understood :scratch:

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Post by roseblood11 »

Dirk_Hendrik wrote:Still looking forward to those gut shots!
I hope that I can take the pictures tomorrow. My son is ill and I don't get much sleep at the moment...

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Post by roseblood11 »

Just uploaded the pictures to my flickr account:
http://www.flickr.com/photos/57866822@N ... 699760166/

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Post by roseblood11 »

parts values:

R01 1k
R02 510k
R03 10k
R04 1M
R05 4,7k
R06 12k
R07 jumper
R08 10k (DMM says 4,9k)
R09 1k
R10 100k
R11 33k
R12 10k
R13 jumper
R14 100k
R15 470R
R16 4,7k
R17 10k (DMM says 4,9k)
R18 1k
R19 1k
R20 220R
R21 2,4k
R22 1,2k (for status LED)
R23 2k metal film
R24 180R
R25 brown-orange-violet-red-brown = 13,7k (or127k?), DMM says 7,3k – metal film
R26 11k metal film
R27 4,7k
R67 (sic!) 1,3R (looks like brown-orange-gold-gold, but it‘s almost not measurable with my DMM)

C1 22nF film
C2 1µF elec
C3 47nF film
C4 56pF (?-“560“) mica or hv cera
C6 100pF cera
C7 10µF film
C8 1µF elec
C9 68nF film
C10 56pF (?-“560“) mica or hv cera
C11 22nF film
C12 220nF film
C13 220nF film
C14 1µF elec
C15 1µF film
C16 220µF elec
C17 150pF film
C18 22µF elec
C19 22µF elec
C20 220µF elec
C21 220µF elec
C22 1µF film
C23 1µF film
C24 100µF
C25 100µF
C26 22µF
C27 22µF
C28 33µF elec
C29 33µF elec
C30 100µF elec
C31 100µF elec

D01 1n4002 polarity protection
D02 si rectifier diode?
D03 si rectifier diode?
D04 silicon blue band
D05 si rectifier diode?
D06 si rectifier diode?
D07 silicon blue band
D08 si rectifier diode?
D09 silicon blue band
D10 silicon blue band
D11 silicon white band (clipping?)
D12 silicon white band (clipping?)
D13 silicon white band (clipping?)
D14 silicon white band (clipping?)

ZD01 ?? Zener (for status LED)

L01 100mH ? („101“)

IC01 4570C (NEC)
IC02 4558D (JRC)
IC07 23744D (JRC)

Q01 2SK246

L01 indicator LED for 9/18V
L02 status LED

SW01 1pdt (boost / normal)
SW02 1pdt ( switches between 9V and 18V)

VR01 ?? measured 130k, „50 4A 14 5C“ (Drive) ? 500k log???
VR02 ?? measured 93,6k, „10 4B 14 5C“ (Level) ? 100k lin?
VR03 ?? measured 17,9k, „20 3W 14 5C“ (Tone) ? 20k w-taper?

I could upload a zip-file with all the pictures to my dropbox, if it's really needed - but I think the pictures at flickr should be good enough.

This is a good pedal and I hope that someone will retrace it. The overdrive is smoother than a standard Tube Screamer and it has more headroom. The power supply is very well filtered, this part of the circuit could be interesting for other pedals as well.
I won't do the retracing myself, because I don't need another overdrive and my "Rose Screamer" can cover every sound that the OD-9 produces, and many more.

The pedal will leave me tomorrow, so if any more pictures are needed please tell me today.

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Post by roseblood11 »

Nobody interest in retracing this?

Power supply section should be similar to this, maybe the gain stage around the 4558 as well:

http://www.dirk-hendrik.com/maxon-tod-9.pdf

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tube-exorcist
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Post by tube-exorcist »

The value of C5 is missing - probably 220n
"I've noticed there's an inverse relationship between cost of gear and talent. If you need the most expensive gear to get decent tones, then you suck as a player."

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Post by KHELSTROM »

Anyone have pictures of the board for this etc... The link roseblood11 posted is now dead

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