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Old 12th February 2009, 06:59 PM   #1
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Default Once I had a A-40...

For 20 years ago I had a A-40. I can not forget that sound!

What spesific amp of these is the nearest i sound: Threshold, Pass labs and Nakamichi.

Please give som advice! The amp will have Klipsch RF-7 to handle.

Best regards
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Old 12th February 2009, 07:08 PM   #2
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Maybe you should just build an A40. The outputs are no longer
available, but you can get some Motorola Darlingtons. The rest
of the parts were generic. Replace the Tantalum cap with the Elna
silk.

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Old 12th February 2009, 07:51 PM   #3
mjf is offline mjf  Austria
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hello.
if you like it perhaps you can build it - schematic,layout and so on are still available..............
i used tip 141/ tip 146 for output transistors (offset about 22mv) and i reduced the biascurrent a little bit ........
greetings.............
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Old 12th February 2009, 07:57 PM   #4
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Thanx for answer! I have the schematics for A-40, but not the time to build it! I loved the sweet holographic sound
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Old 12th February 2009, 11:50 PM   #5
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These have worked well for me as output devices over the last few years. You will have to adjust the bias, but they are still available at a reasonable price.

http://www.onsemi.com/pub_link/Collateral/MJ11012-D.PDF

MJ11015 & 16

It's a great amp!
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Old 15th February 2009, 01:22 AM   #6
llwhtt is offline llwhtt  United States
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Location: SoCal
I am in the process of building an A40 now. I tracked down all of the original parts including the output xsistors and the Signal 88-8 pwr xfmr. They will still make one for you on special order.
It's going into an old Sumo Andromeda II chassis, the heatsinks are just about the perfect size according to the equations in an old Audio Amateur article, the same issue the A40 came out in I think. Standard Radio in NY has the Lambda xsistors, .68 Ohm 1 Watt 1% WW Dales, the MPLSxxs too. Going to try and use a 1N530x in place of the FET. Can't wait to hear it, this project is way overdue.

Craig
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Old 25th November 2009, 02:15 PM   #7
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I have got my hands on an A40 from mid '80. The amp is constructed as a tank! Everything is original from that time. And the price? Half of component cost!

I will bring You pics and sound descriptions.

Lucky me.....:-)
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Old 3rd December 2009, 09:35 AM   #8
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THE AMP is here! I love this sound! My tubeamp is packed away...

In this amp there is fuses not only in the negative rail, but also in the positive rail. Is that any problems?

The construction of this DIY amp is outstanding, magnifik! Better than many fabric-amps.
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Old 3rd December 2009, 11:48 PM   #9
llwhtt is offline llwhtt  United States
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I too have noticed that Mr. Pass uses a fuse in the negative rail only on many of the amps I've seen, why is that Mr. Pass?

Craig
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Old 4th December 2009, 12:18 AM   #10
HKC is offline HKC  Hong Kong
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Location: Hong Kong
I built my A40 in 2007 and still using it. A40 is a very good sounding class A power amp. It replaced my classic Pioneer M22 in my stereo system
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