Marantz 2245, power supply, DC Offset and Bias done.

Video showing some of these things being done. I messed up at first on the power supply voltage pins.

[@CM-dw3gh]

..I think after watching this I'm gonna do the same with my marantz pm4001 OSE. It's an amp that sounds great until past 9 and then distorted. I'm sure this isn't how they intended a 40w amp to sound at that level. Got some great Elna caps in it too

[@CM-dw3gh]

Hello. If the offest has a recommendation of '+-50mv' is it saying anywhere just between -50 and 1v?

[@bfpsa64]

Not really. 1volt would be 1000mV which is way to much. Your speakers would be pushed out when you turn on your receiver. Try to get it as close to Zero as you can. Usually the Biasing will be set to 30-50 mV depending on your manufacture. Hope this helps.

[@CM-dw3gh]

@@bfpsa64 the marantz terminals were both around 14mv. Should I lower them to 30-50 range?

[@bfpsa64]

@@CM-dw3gh Are you talking DC voltage or your Bias settings? DC voltage at the speaker terminals should be zero. Bias Offset should be i the range that they list in the service manual. IF the bias is 30-50mV then set it in that range. Then use a dummy load and 1K signal and check how it scopes out. If you see distortion before listed wattage you need to adjust or see what else is drawing it down. Hope this helps as it is hard to trouble shoot without really seeing what is going on.