pkquat

The manual can be found here: https://www.hafler.com/pdf/archive/DH-220_amp_man.pdf The DC offset and bias are covered at the top of page 11. It's been a while so I don't remember the details. diyaudio.com has a few threads on the subject. There is some good info there. For what you are replacing, I don't think values will change. Only make adjustments if the DC offset is over 50mv if I recall correctly. And if the amp is evenly warm, no real need to play with the offset. Too high a bias and you can burn out the transistors. I disagree with the manual about the settling time. It's more than a few seconds. I was also told later that two calibrated MM's make the job easier.

  • Re: Mass Loading "Ultimate Foundations" Stands

    pkquatpkquat
    I'm not sure of the ratio of shot to sand. If its mostly shot the sand will fill the small voids. Depending on the vibrations and the volume at the time the shot could rise instead as the fines …
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  • Re: SDA 1C vs SDA SRS 2

    pkquatpkquat
    A small FYI, while it does depend on the material, IMO if stuff starts to sound too much surround sound like you are getting too many reflections off side walls or objects. Looking at the room, there…
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  • Re: Might pull the trigger on Hafler Amps

    pkquatpkquat
    The P230 is the later version of the "professional" rack mount version of the DH-220. The early version was the P225. According to Hafler the P230 has additional MOSFETS and larger power su…
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  • Re: Check your MW screws

    pkquatpkquat
    Did you glue the hurricane nuts as well? Are you sure they were drawn in all the way initially? I have heard people having issues if they didn't get them seated enough. I had to make a washer se…
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  • Re: Polk monitors 10 B

    pkquatpkquat
    You should also replace the sandcast resistors with Mills. They are also available from soniccraft. I assume you have the SL2000 tweeters and a polyswitch. The polyswitch should be replaced with a 0.…
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