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Lee, With amplifiers that have blown, I have found the "Octopus Tester" (a.k.a. "component tester") to be a handy device to find/locate leaky semiconductors quickly. It is particularly useful when 1 channel is good and the other is bad. Simply going back and forth between channels and looking...

Amar Bose died in 2013

Lee Is this a Rev D board? If so, is R78 a 44.2 ohm 1/4 watt resistor? Ed

Ouch! I wouldn't expect that into 8 ohms both channels driven. I might expect it into a 4 ohm load. Particularly if the Zobel network resistors are to low a wattage. If the amp is a 400 series 1 with 5 amp B+ and B- fuses you might consider going from 5 amps to 8 amps like they did on the 400...

Lee, The frequency response of most Phase Linear amplifiers was rated at 1 watt into 8 ohms (or 2.83V output) +0 / -1dB Ed

I would love to see the numbers at rated output (either 200 or 210 watts per channel) (approx 40 volts output) into 8 ohms both channels driven at the same time from 20Hz to 20KHz. Ed

Marco, I have 4 versions of the owner's manuals. Two from when they were in Edmonds, WA and two from when they were in Lynnwood, Washington. I only have 2 of the 3 service manuals I am aware of. I have the 6/76 and 6/81 versions. I do not have a copy of the "fast field service manual" which...

I've already give away much of what knowledge I have of Phase Linear for free. How many people would really be interested in a book on Phase Linear? I think there would be a larger market at the moment for something else that I have experience with. Ed

Marco, I just went to take a look at the 3000 and 3500 owner's and service manuals: The 3000 series two owner's manual: page 9; "LOUDNESS SWITCH" Push in to activate loudness contour circuitry; used to compensate for apparent low frequency loss at low volume listening levels. page 12...

Marco, I revised my previous post and am elaborating further here...... If my memory (after approx. 20 years) serves me correct, the explanation provided to me by Dean about the units built after S/N 2500 which had a boost at 20KHz of 2 to 4dB (and a increase at 20Hz of 7 to 10dB?) may also...

I had to grin a little when I saw your post. It amazes me how many times I see someone selling a 4000 on ebay stating that it works perfectly. When if in fact they tried to use the "test procedures" in the service manual they would run into what you did. Either they would choose to ignore it or...

What you need is the later 6/81 version of the Phase Linear 4000 series 1 service manual. Not the earlier 6/76 version. Ed

The Dual 500/D-500's indeed used .39 ohm 2 watt resistors. They were TRW BWH series now replaced by SPH series. The text below is copied from an earlier post of mine...... Here is a link with some history on TRW BWH series resistors and its replacement SPH series after IRC bought out TRW/TT...

Here are some scans taken from the 6/81 revision of the Phase Linear 400 and 2/81 revision of the 700/700B service manuals: "connect four .01/1000V ceramic or mylar capacitors across each terminal of the bridge rectifier..." The purpose of these capacitors was to eliminate Radio Frequency...

After all the issues I noted in my previous post are dealt with on the 3000's they are a decent pre-amp. If my memory serves me correct, this was Dennis Bohn's first product after coming over to Phase Linear from National Semiconductor. I did give him a little ribbing about it when I met him...

The original relays in the Phase Linear 3000 II had a clear see-through top. Phase Linear had numerous problems with these. Earlier 3000's had 13 relays. Later 3000's added an additional (14th) relay in order to prevent problems when using 3-head tape decks. During the production of the 3000's...

I just received a reply this morning to a message I sent to Mr. Stravitz 2 years ago. Mr. Stravitz is a friend of Ed Hart's. He stated that Mr. Hart is currently in hospice care. Ed would be approximately 88 or 89 years old now. I only wish I had been contacted sooner so that I could have...

For future reference..... OnSemi "Product Change Notifications" including "Product Discontinuation Notifications" can be checked here: https://onsemi.secure.force.com/PCN/ Also you may find this article interesting: "Managing Semiconductor End Of Life" by George Karalias (Rochester Electronics)...

Peter, The cam operated power switch was originally designed for a 700B. I am not sure that it will work for a original 700 because of the clearance. I am also vacationing at the moment. So I don’t have the ability to double-check this. Ed

Here is a copy of the Carver C-1 service manual; 6.15 "Noise Tests" along with 6.1 "Pre-Sets".