Vintage HK-700 series questions

[Mr Marco]

Newbie question here.
I currently run a HK-750. Really great integrated unit that has served me well. However, the previous owner must have been a Volume Knob Dancer (Holds volume adjustment knob while dancing in place). The volume control has a slight loose feel and the right channel has audio loss at low listening levels.

Here is my dilemma, I recently came into ownership of a pair of HK-725 pre-amps and an HK-770 amp. One of the pre-amps is in sad shape. I'm wondering if I should use it for spare parts and salvage the volume control and make the HK-750 perfect? A recent check of eBay shows an HK-750 in prime condition sold for $120. Mine would be on par with that unit if I spent the time to replace the 1/2 working volume control (I only paid $40 for it in 2009).

-Or-should I just put up the HK-750 "as is" on eBay and shoehorn in the HK-725 & 770 inside my electronic toys cabinet?

I have the HK-725 service manual, but can't find the HK-750 manual to confirm if the two units use the same control for volume.

Totally torn here. Really don't need all this HK, and certainly don't have room for it as I've already packed a HK-EQ8 Graphic Equalizer in the cabinet too.

Any advice would be appreciated.

 

[theophile]

Welcome to AK. :thmbsp:

I used to own a HK 750. I bought it when they were brand new.

Great integrated, isn't it? :yes:

Have you listened to the 725/770 combination? If you prefer the sound of them to the 750, then you might wish to substitute them for the 750. Before scavenging the knob from the 725, check whether there is a means to fix the 750 volume control by tightening a nut or bolt (for example).

Tell us what you find.

 

[Mr Marco]

Thanks theophile. Initially I thought that the problem was corrosion or oxidation. I cleaned the entire unit and sprayed the volume control with deoxIT. It wasn't until later that I realized pulling back on the knob brought the level back up.

Could be worse. In college I had a Marantz 1090 in which the little plastic piece that joins the left and right channels together in the volume control snapped. Instant mono amp.

 

[Mr Marco]

Sold the HK 750 and got the new set-up 725&770 running. Wonderfullll sound from the pre-amp after cleaning a scratchy balance control. I added a cooling fan to the back of the enclosure because watching a movie on the playstation with the sound coming from the old 750 created WAY too much heat inside. Much to my surprise this system is much cooler, so my fan was overkill. LOve iT!!!

HK-725, HK-770, HK EQ-8, Nak BX-300, Moto Cable box, PS3, Marantz ST-7001, & Note the VHS unit...Yes I still have VHS tapes too.

 

[theophile]

Another very good integrated from HK of around that era, is the HK 505.

See this thread:

http://www.audiokarma.org/forums/showthread.php?t=393093

http://www.hifi-pictures.net/amplifiers-home/Harman kardon hk505/Harman kardon hk505.jpg

Truth be told; I t was really the fantastic reception that the HK 505 got in some quarters back in the day, that inspired me to purchase the HK 750 brand new when it was released. The publicised involvement of Matti Ottala at the design level also influenced my buying of the 750.

All in all, those amps were very worthy releases by Harman Kardon.

 

[Mr Marco]

^Funny because I was looking at Vintage Marantz, saw the HK-750 at such a good price I couldn't turn down the bid. I just got lucky.



For some reason the pic is not working for me.

http://www.audiokarma.org/forums/picture.php?albumid=2590&pictureid=17341