• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Looking for Harman Kardon Allegro A-10 Schematic or PhotoFact.


2006-05-29 10:00 pm

I have two HK A-10's that are in need of some TLC. I replaced the power supply caps and that got most of the hum out but I would like to replace all of the parts that are out of spec. I have looked every where online and the only schematic I can come up with is very blurry with a side cut off. If anyone has or can point me in the right direction I would be eternally grateful.

I bought the one A-10 in a small junk/antique store on a weekend vacation to Cleveland. They had a sign up that said 50% all electronic items. The A-10 was under some books with a $40.00 sticker on it. I asked the lady if it was included as well and she asked, “ Does it run on electricity? “. Yup, it was mine for a 20. When I got it home I opened it up and found two Bugle Boy 12AX7's and two HK labelled Mullard EL84's. They all test new or better. I had to buy the other one online for $60.00, but to make a pair I figured it was worth it.

I do not know how all of this Harman Kardon stuff keeps finding me. I redid a set of PC-200 Preludes a couple years back as well as a Citation V. I also have a Citation II upstairs right now that I am looking at for a friend.