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Help with a AR amp please


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I just picked up a ar amp, model au.

I gave 20 bucks for it but he said that it had weak output and that it needed caps then he was pocking around and it smoked. so to start with I need a service man and diagram for it. I cant down load the stuff on the amp from the forum. any help would be great I would like to drive my AR3s that now have solon caps and silver wire with this. And a AR turntable.

the face is near perfict with all knobs and the logo looks great I have opened it and found a burnt diode 200 sumething cant tell

Thank you


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I just picked up an AR receiver as well. Works, just needs a little cleaning. The back says it is Model W (serial W00270).It looks just like the one here http://rummageads.com/xstereo/ARreceiver/. But for the fact that someone painted the face black (probably back in the 80's). Luckily, they masked off the control labels, but not the AR emblem. (I can see it underneath)Fortunately as well, the paint is cheap and aged, and comes off with a littl elbow grease and alcohol, so hopefully I can restore it to original. Good luck with yours--


I think this is what you were trying to open on the AR electronics page: Here's what it says about the AR amp:

Some specifications on the AR amplifier! (From AR Literature)

Thanks to Larry Jenkins (OldestLJ@aol.com) for these!

"The AR Amplifier is an integrated stereo preamplifier/control and power

amplifier, all silicon solid-state."

Power Output - each channel, both channels driven - 60 watts RMS 4 ohms

50 watts RMS 8 ohms

30 watts RMS 16 ohms

Distortion - any power output level up to an including full rated power

IM (60 and 7,000hz, 4:1) less than .25%, harmonic distortion,

less than .5% from 20hz to 20khz.

Freq Response - +/- 1db 20hz to 20khz at flat settings

Suggested Retail - $250 w/ black aluminum cover, $15 extra for oiled

walnut wood cover


Thanks to Tom Tyson for these comments on the AR amplifier!

The AR integrated amp was designed in the late 60's by Acoustic

Research's engineers with primary design work being done by a fellow by

the name of Brodzinsky (sp), who has a couple patents relative to this

amp. One was the "standby power supply," in which the amp's power

supply idles when the unit is plugged in, and bias voltage/circuit

voltage is applied when the switch is turned "on." The other patent

related to the actual biasing circuit itself. The amp was followed

about a year later with an FM tuner, and in 1970 AR introduced the AR

Receiver which incorporated both the integrated amp and the tuner into

one enclosure. Oiled walnut cases were available for each unit.

The amplifier, which cost $250, was rated for use with 4-ohm, 8-ohm and

16-ohm speakers, common for the day (e.g., the KLH-4 was 16-ohm, as were

many of the horn speakers and some electrostatic speakers such as the

model 9, etc.). Into 4 ohms, the amp was rated at 60 watts/channel,

rms, both channels driven, 20-20,000 Hz., with harmonic distortion less

than 0.5% and intermodulation distortion less than 0.25%; into 8-ohms it

produced 50 watts; into 16 ohms it produced 30 watts.

When *Audio,* *Stereo Review* and other magazines tested the AR amp,

they were amazed to find that the amp could put out over 100

watts/rms/channel into mid frequencies, and that it could produce over

90 watts into 4-ohms, from 20-20,000 Hz. It was especially stable with

capacitive-reactive, low-impedance loads such as certain AR speakers

(AR-LST, AR-LST-II, and AR-10Pi) and electrostatic speakers.

:) :)

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This was my first solid state amplifier and it still works although there is a DC offset of 0.5 volts on one channel output and 4 volts on the other. This has been an outstanding unit and a great value. In 1968 I paid about $190 at Newmark and Lewis (now defunct) for use driving KLH model 6. I presume it was intended to power AR3a and anything less demanding which was just about everything else on the market. As a low cost reilable alternative to Dynaco PAT4/Stereo 120, it seemed in keeping with AR's philosophy of providing no compromise equipment that was practical and affordable by people of average means. I think it was featured in a popular science article called the Audio System I wish I owned. Also in the system were the Empire 999VE cartridge and the Rectilinear III speakers. I don't recall the turntable.

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  • 3 weeks later...

>Where might find a schematic for this AR receiver (1972--I




Among the many items that I own, I have a schematic of the AR receiver. I will be providing a copy for the archives after I un-pack from moving. All the literature I have was provided to me at no cost and I feel like a librarian that wishes to pass on these to others. At no charge only. Scanning or photocopies will be sent to the webmaster Mark as soon as I possibly can and he can decide the best way of presenting them to you, not withstanding any copyright infringement. Every so often, I browse through my binders and I am sure there is lot's of other interested parties. When I have un-packed I will post a list of the literature that I have. AR is just one of the brands that I have saved. Have a great day.

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