Harman-Kardon HK825 preamp serviced in working order hk 825 sounds good

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  • Item Category: -
  • Source: eBay
  • Sold Date: Nov 05, 2011
  • Channel: Auction House
Harman/Kardon HK825
This is a Harman Kardon HK-825 preamp from the early '80s. I cleaned the controls, which were a little noisy. The volume control has a little noise, but tracks good and didn't seem intermittent. I could not lube the volume control (it is sealed). The output relays got stuck the first time I warmed it up on the variac, but after turning it off, then back on, it worked just fine. I think regular listening will be good for it. It had been unused for some time (maybe 10 years). The previous owner had used some audiophile wire and capacitors to improve things. Sound is very good given that it's an early '80s preamp. The circuit is very good: lots of FETs. There aren't a bunch of OP-Amps. This design is geared up to high quality sound without shortcuts (op-amps). There is a large (for a preamp) heatsink that generates some heat, which is VERY unusual for a transistor preamp.
Notable features include headphone output, defeatable tone controls, two phono inputs, built-in phono pre-preamp (for moving coil cartridge), and adjustable cartridge loading from the front panel. There are numerous polystyrene capacitors in use. Electrolytic capacitors, though getting long in the tooth, all look like they are in good condition and were several levels better than the majority of capacitors I see from that era. None were
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