Got Onkyo M-504 amp out of repair yay! 2 Q's


2006-05-12 11:17 pm
Hello, I don't know if you guys will remember but I found an Onkyo Integra M-504 dual mobo power amp at goodwill for 20 dollars in like new condition and couldn't get any output. I took it to Innersound in Portland and they desoldered and reflowed the the entire board. That's all it needed, 140 dollars. They then checked every thing else and said all looks mint. It sounds incredible, best amp I have owend.

First question: I don't have a preamp so is it save to plug my ipod into it until I get one?

Question 2: The amp is rated at 165 watts rms at 8 ohms, would someone be able to tell me what it might be rated at 4 ohms. If any additional info is needed let me know because I would really like to know.

Thank you all for any info
Dan you lucky b...... :D

This was a very famous amp way back (and good looking).

As I recall, the only major problem with this amp is that the max Working Voltage of big power supply caps is almost the same as the rail voltages which have coused several caps to blow up :hot:

Many have replaced these to ones with higher WV and higher capacity with good result ;)

Ian Finch

Paid Member
2010-04-11 4:22 am
Coffs Harbour, NSW
4R power rating

You can use most solid state amplifiers down to very low impedances - but not at higher power. (like say, twice the 8R power.)
You are limited by expensive parts like the power transformer, number of output devices and heatsinks, so it was not unusual
to go for just 8R power and sacrifice maximum 4R power at a time when it was not so commonly needed in domestic use.