If you are interested in this topic more, please look up a good book, such as Audio Power Amplifier Design Handbook by Douglas Self. That is not the purpose of bias! The purpose of bias is to set up the amplifier in order to minimize crossover distortion. The quiescent current/voltage adjustment on the output devices influences the DC offset (as you have seen empirically for yourself), but we don't want to be setting the DC offset by manipulating the bias. I came across your posting because I was researching this amplifier a little bit (thinking of maybe buying one from someone). Many thanks in advance, and have a peaceful Palm Sunday! :taps2: They're not my actual unit, but mine is exactly the same, but less dusty. Let me know if you want me to upload an english copy of the Owner's Manual, it has a better schematic in it all on one page, easier to read. I'm wondering, will I damage anything doing this, should I put them back to where they were? I compromised at 20 mV BIAS for both channels, and now the DC offset is 50 mV for L, and 5 mV for R, which is better, less than half what they were.
Is there something wrong here? I tried carefully adjusting them, but they only go to 30mV with the pots fully on, this doesn't seem right to me.
LEFT CHANNEL ONLY BIAS AMP 2 MANUAL
In the manual it says should be 40 mV.(!). So I hooked up my voltmeter to the test points, and I got 4 mV on the L, and 8 mV on the R. On a related issue, in the service manual I found the section on BIAS adjustment, and I read online how it can affect the DC offset. Am I right in saying that to fix this I'd have to replace the output transistors? I understand this isn't so good for the L channel at least, but unfortunately this amp doesn't have any DC offset adjustments. I checked the DC offset at the speaker terminals, and the L channel said 100 mV, while the R was 25 mV. Upon using it a bit more, I noticed a bit of distortion at high volume, more so in the left channel. Last week I picked up a nice Kenwood KA-3500 40watt intergrated amplifier in pretty good shape.
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