Mod a Marchand XM9 Electronic Crossover

[slhijb]

Please be patient, I’m new to electronics. Want to modify a Marchand XM9 electronic Xover. Great unit, but a little bright in the treble region for my tastes. Looking at changing the opamps & would like your suggestions:

Currently using Dual Bi-Fet LF353. Possibly change to:
OPA2134
OPA627 or
LM4562

Any other suggestions on how best to upgrade or modify the Marchand XM9 are greatly appreciated.

XM9 Schematic: http://www.marchandelec.com/ftp/xm9man.pdf

 

[slhijb]

Anyone out there modded or upgraded a Marchand?

 

[planet10]

I had one. I got the suggested upgrades from Marchand.

I thoy about a much better dual mono supply, but ended up selling it before i did any serious mods.

dave

 

[djk]

Years ago I stuck OPA2604s in one instead of the LF353s, it made quite an improvement.

You may have some off-set with non-fet input opamps (LM4562) because of the lack of impedance matching on the IC inputs (not needed on FET inputs).

You might consider the AD823 too.

 

[slhijb]

Thanks Dave & DJK for the responses. I've continued research based on your comments DJK and think I'll try the AD825 J-FET Dual amplifier surface mount. Seems to be pretty much a drop in replacement and has good reviews.

http://www.referenceaudiomods.com/M...reen=CTGY&Store_Code=RAM&Category_Code=OPAMPS

Also, any thoughts on cap or resistor upgrades? Is it worth my while?