Harman Kardon HK 770

[argonrepublic]

This amplifier won't engage speaker relays or turn on meters until amp is warmed up. I am a novice but I am suspecting some worn caps. I can engage relays manually and no problem or warm up amplifier.

[Zen Mod]

replace C21, C22

[argonrepublic]

I am absolutely amazed that you know just like that. Thank you very much.
Are there any mods or other things I should take care of while apart?

[Zen Mod]

Originally posted by argonrepublic
I am absolutely amazed that you know just like that. Thank you very much.
Are there any mods or other things I should take care of while apart?

did you fixed it ?
after few decades in repairing biz , I had slight idea what's culprit

http://www.diyaudio.com/forums/showt...03#post1668203

[argonrepublic]

Yes. I was looking toward the power being insufficient. Am I understanding correctly that these caps caused an excessive load? I didn't touch the amp prior to getting advice although I opened it.
I saw the site the other day with the HK 770. I was thinking that the Mono amp would be a nice Match to run Subs if I can find one.
Very nice site BTW.
What is your opinion on the HK 770? I bought it to run nearfield monitors on my desk. So far I am pleased but I often wonder if I am only hearing what I want to hear.
Thanks again.

[argonrepublic]

Obviously you know these amps well. I am contemplating pulling the HK 700 from my studio. Not for lack of quality but for convenience. I am contemplating replacing it with ART SLA-1 because of gain controls and balanced inputs. Mostly the attenuation though. I don't like decreasing volume digitally and sometimes this amp is a little too loud for my desktop speakers. Any suggestions or opinion on 700 Quality versus SLA-1?

[Zen Mod]

I'm not familiar with these SLA amps , so it's best that you organize direct comparison between your HK and SLA

I'll make some modifications to my own HK , because I'm not so satisfied with sound quality;

but - it isn't so bad comparing to many commercial amps of these days ...... it's just bad comparing it to some of best amps available to diy

[mp9]

zen mod, i have a HK880vxi with a bad volume control which i'd like to replace with a alps, nobel or goldpoint but don't know what kohm to get. what would you suggest?

[argonrepublic]

Along those same lines. What can I install in series to attenuate HK-770 without signal degradation?
What mods will clean it up?

[Zen Mod]

Originally Posted by mp9

zen mod, i have a HK880vxi with a bad volume control which i'd like to replace with a alps, nobel or goldpoint but don't know what kohm to get. what would you suggest?

sorry - I can't find schematic of it , even with using already known trick with download link from HK ftp

I presume anything in range of 10-50K log will be adequate