Marantz PM7200 UPGRADES

vpceb2c5e — Sun, 14 Dec 2014 05:14:22 +0800

I'm new to the forum and it's my first post- so go easy on me.

After looking around online I found a couple of posts relating to the Marantz PM7200 inteintegrated amplifier. It was an award winner back in 2004 and I sold my last one to upgrade to a home cinema system - but the sound quality did not improve, there was just more of it!

Anyway, seeing how good my old PM7200 was, I bought a 2nd hand one cheap, and have given it a service and upgrade. This has consisted of:

Replacing all power amp pcb capacitors.
Replacing volume board audio circuit capacitors.
Replacing main power supply capacitors.
Replacing opamps for tone, balance and main volume.

Essentially, I've replaced all the caps due to aging, it doesn't help that this amp runs hot, especially in Class A, I wouldn't expect the caps to last long they are only 1000 hour rated at 85 degrees C. The original Elna silmic and roa types were ok in terms of quality, but there are better alternative now, such as Elna Silmic II and Nichicon FG.

The opamps were upgraded to FET types from Burr Brown.

It cost about £60 in parts, and a few days work.

I also replaced the power amp trimpots with multiturn types, and realigned/rebiased.

The amp was run in and everything worked, there is a lot less noise, I can turn it to 4 O'clock before I can hear any hiss. The sound improvements though are amazing, and I'm really glad I took the DIY route and didn't spend £800+ on a new amp.

The new main volume opamp is a opa2164, replacing a JRC2114. The opa2164 has lower noise & higher slew rate in particular that translates to much faster attack and decay and better sense of timing for the sound, really an incredible improvement on an already good home amplifier.

I wonder how everyone else has got on with their PM7200 mods and upgrades?

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Marantz PM7200 UPGRADES