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Did harmon Kardon make integrated tube amps

68.39.154.27
Posted on July 30, 2013 at 12:14:04
airtime
Audiophile

Posts: 11287
Location: Arizona
Joined: February 4, 2003
 I was looking for the more traditional opened top type of integrated tubed amps.

Yes I have gone completely modern (to the dark side). But my ultimate goal in retirement is to have one tubed stereo. Either vintage or new - but at least one tubed integrated stereo.

charles

 

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Yes, several great integrated vacuum tube amps......, posted on July 30, 2013 at 12:25:12
Mossback
Audiophile

Posts: 1871
Location: Washington, the State
Joined: November 17, 2001
 a simple search here would bring up much useful information.

 

Not only did they make tube integrated amps and even tube receivers,they made some of the finest of all time., posted on July 30, 2013 at 13:19:47
Michael Samra
Dealer

Posts: 36118
Location: saginaw michigan
Joined: January 30, 2005
The A500 and the A700 are a sight of art and workmanship to behold.The electrical architecture and chassis layout of Harman Kardon is one of the best in the business when it came to integrated amps and the other would be Eico IMHO.
This is an A700 with 7591s but they also made an A500 that used 7355s as well as a TA260 receiver that is the best layout for a receiver I have ever seen.The controls are even on a separate chassis and it's very easy to modify and recap these units.







This is the TA260 receiver
\
"For every complex problem there is an answer that is clear, simple, and wrong" H. L. Mencken

 

RE: Did harmon Kardon make integrated tube amps, posted on July 30, 2013 at 17:39:32
dls123
Dealer

Posts: 1214
Location: Beautiful B.C.
Joined: April 15, 2003
 I would also add the A300 to the list. I have rebuilt a few and when run with a 6V6 and the bias properly set they are a glorious 13 watts or so per channel that sounds like 50 watts.... Great little amp.

 

I wanted to ask you about the TA 260..., posted on July 31, 2013 at 23:02:30
Bung
Audiophile

Posts: 9378
Location: NYC
Joined: October 20, 2002
 I now have one that I play every day. I remember reading about you replacing electrolytics (I ran mine up with a variac and replaced most of the resistors, now I'm moving on to the caps)and doing a few mods to improve performance and reliability. Could you give me a breakdown of what you did?

 

RE: Did harmon Kardon make integrated tube amps, posted on August 1, 2013 at 05:49:44
Uncle Mike
 They also renamed some of their models for other companies that put them in consoles. A chance to get something that would fly under the radar.

 

RE: Did harmon Kardon make integrated tube amps, posted on August 1, 2013 at 09:24:58
Jim McShane
Dealer

Posts: 5910
Location: Chicago
Joined: January 13, 2003
 Charles,

As was posted below, there are a few models that are more desirable than others. But do plan on some rework, as not only did some use the now unobtainium 7355 tubes (you can sub a 6L6GC with some rewiring), they used the "cheap Charlie" bias circuits that were also used to provide DC to the phono tubes. Plan on adding a real DC (regulated?) supply for the front end, and putting a proper bias circuit together for the power tubes.

The somewhat rare A700 uses 7199s, and will require a rework for that tube is about gone.

If it was me I'd probably look for a nice A300, sub a 12BH7 for the 12AU7, add a proper bias and DC supply, and stick a good tube set in there. It'll do a nice job if you don't need too much power.

 

RE: I wanted to ask you about the TA 260..., posted on August 2, 2013 at 13:01:17
Michael Samra
Dealer

Posts: 36118
Location: saginaw michigan
Joined: January 30, 2005
 yes.
I used a pair of 470uf nichicons in the doubler and down the stream I used the dual 100uf@500v JJS..For the three and four section caps,you will have to glue some singles underneath.
The last TA260 I did three years ago,I used the 820uf panasonics in the doubler.These caps are perfect there because I even put them in my Mac MA230 seven years ago and the Mac has a solid state preamp and no tuner.The TA-260 is powering a tuner,preamp,and an amp.The transformer is well made and I would use the 820ufs in the doubler.The 470ufz are great caps also however,with all those tubes you are powering,the 820uf panasonics are ideal.You want to also put a buss bar ground in the unit.The diodes I would use are the GI that Jim sells..You can also use Cree,which are HV Schotkeys but no necessary.

The output couplers should be K40y paper in oil..I would also use a paper on oil on the driver/phase splitter..The other caps I would the Nichicon Q or some 716p orange drops on the preamp out.You can use paper in oil caps in any part but keep in mind that if there is little or no B+ on the dielectric,they will take a long time to break in.
Put in the Mills or Huntington power resistors for the square Albino Monkey coffins.Use Nichicon muse KZ for the bypass caps..Change the ceramic discs to silver micas. If the cap is used for parasitics,those aren't as critical to change but I do it out of general practice.Any stock silver micas in the unit,let those be.They are fine.


"For every complex problem there is an answer that is clear, simple, and wrong" H. L. Mencken

 

Cool, thanks!, posted on August 5, 2013 at 17:55:45
Bung
Audiophile

Posts: 9378
Location: NYC
Joined: October 20, 2002
 It looks like a very carefully thought out plan. I'll probably buy a bunch of parts from Jim McShane and warm up my soldering iron.

 

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