New Harman Kardon project
- Thread starter rossm
- Start date
Thanks, lots of work!!
I have been enjoying the amp and preamp for one day now. I have to say the hard work has paid off the hk870 seems to have a lot of power, it’s driving the infinity iiib speakers much better than the Kenwood KA-9100 did. In spite of having 2 12” drivers The infinity’s are weak on bass. The infinity’s emit tweeters have a very detailed high end, sometimes more than I want. On the other hand I am hearing instruments in familiar recording that I have never noticed. It’s like wow what was that? Almost startling sometimes. I am now using a small sub to fill in the bottom end. Hopefully once I get the EQ I will see better bass from the infinity’s. Next week I will hook up the Polk sda’s and have a listen.
Having replaced a mountain of caps in the 870 and 825, I have noticed the larger caps measured pretty close to spec but some of the smaller caps were way off with the meter reporting esr of 30 ohms or more.
Having replaced a mountain of caps in the 870 and 825, I have noticed the larger caps measured pretty close to spec but some of the smaller caps were way off with the meter reporting esr of 30 ohms or more.
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Tonight I starting the hk tu615 tuner. Seems to work with the exception of the preset buttons.
Looks like the plastic tabs holding the buttons in place are busted,3 on the left.
Fortunately I just happen to have a spare 615 that is a little cosmetically challenged, it’s buttons are fine, but it’s got lots of krusty glue on the main board, so it’s time to make one good one out of two.
Looks like the plastic tabs holding the buttons in place are busted,3 on the left.
Fortunately I just happen to have a spare 615 that is a little cosmetically challenged, it’s buttons are fine, but it’s got lots of krusty glue on the main board, so it’s time to make one good one out of two.
Hi
Most of the larger caps were glued on, the glue needs to be removed from the board. Some areas they used way too much glue and covered other components, resistors, diodes,etc they need to be replaced as well
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A little late to the party but for future projects, I've used a small paint brush and some lacquer thinner to soften up the glue. Then use the blade side of a tool like this to scrap off the glue. Seems to work without scratching up the board.
Thanks
I tried isopropyl alcohol, but will try lacquer thinner next time, for some reason the glue on this board seemed much harder than the preamp
The EQ 8 arrived yesterday, unit was missing one of the plastic feet, luckily my parts tuner tu615 has the same feet.
More glue to remove
I used the plastic spudger and it came up pretty easy without scratching the board
I had enough caps on hand so I went ahead and recapped it. Again all the small electrolytic caps were way out of spec. Used Wima film caps for the 2.2 uf and smaller. Cleaned all sliders with deoxit fader-lube. Everything seems to be working normal.
A little cleaning and it’s looking pretty good
Finally I am able to get the bass out of the infinity’s speakers, and the hk870 doesn’t seem to mind the extra load
More glue to remove
I used the plastic spudger and it came up pretty easy without scratching the board
I had enough caps on hand so I went ahead and recapped it. Again all the small electrolytic caps were way out of spec. Used Wima film caps for the 2.2 uf and smaller. Cleaned all sliders with deoxit fader-lube. Everything seems to be working normal.
A little cleaning and it’s looking pretty good
Finally I am able to get the bass out of the infinity’s speakers, and the hk870 doesn’t seem to mind the extra load
Champco
Super Member
Any idea how much gain the EQ has?
Hi
I haven’t measured it but it claims +- 12db
Finished up the EQ 8 cleaning the top case with dish soap and water, the case felt sticky, maybe it spent some time in a smokers house ?? I had some de-Solv-it sitting on the bench from another project and decided to give it a try, it quickly removed the sticky substance. I wouldn’t recommend it on anything with lettering but it worked fine here and gave it a nice lemon sent
I still have the tuner and preamp to refurbish but decided to stack it up for a photo shoot
Sounds even better!!
I still have the tuner and preamp to refurbish but decided to stack it up for a photo shoot
Sounds even better!!
Hi
That’s the cd491 on top and cd401 below, 491 was hk tol 83-88 , the cd401 was hk tol in 82.
I also have the cd291 and cd191.
The hk cassette decks were some of best made, many folks claim they are compatible to the Nakamichi line. With the exception of the cd491 all of them work. I did complete rebuild of the cd491 and am having some tape wrinkling problems, could be tape tension problem, it’s a dual capstan deck so that may complicate things.
superdog
AK Member
A really nice stack as I am a big fan of 80s stacks.Im sure there was a matching cd player.Did you ever try to aquire one?
