Author Topic: Phase Linear 700 B restoration complete  (Read 7161 times)

bmwr75

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Phase Linear 700 B restoration complete
« on: February 09, 2014, 07:19:09 PM »
Picked this amp up before Christmas with blown outputs in one channel.  Built and installed a White Oak Audio control board and LED light board in it.  Also installed a Watts Abundant speaker out DC protection board.  Replaced two rows of blown outputs.  Haven't taken beauty shots of it, but here are a few pics.

bearjew

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Re: Phase Linear 700 B restoration complete
« Reply #1 on: February 09, 2014, 07:51:45 PM »
looks good.  now it's time to crank those levels!

bmwr75

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Re: Phase Linear 700 B restoration complete
« Reply #2 on: February 09, 2014, 08:13:00 PM »
350 now safe watts per channel, at least.   :'(

Offline Reverend

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Re: Phase Linear 700 B restoration complete
« Reply #3 on: February 09, 2014, 08:16:39 PM »
Very cool.  Let us know how it sounds once you give it a test drive.

Offline MacGeek

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Re: Phase Linear 700 B restoration complete
« Reply #4 on: February 09, 2014, 08:21:09 PM »
Beautiful.  I wish I could do things like that.
Mac stuff, Sony HDR-F1HD AM/FM/HD tuner, Denon DRS 810 cassette, Denon CDR-W1500 CD recorder, Music Hall MMF-9 w/B&O MMC2, B & O 4002 w/B & O 20 CL, Revox A-77

Anders

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Re: Phase Linear 700 B restoration complete
« Reply #5 on: February 09, 2014, 08:29:09 PM »
yeah me too.

Offline mbskeam

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Re: Phase Linear 700 B restoration complete
« Reply #6 on: February 09, 2014, 10:53:44 PM »
what does the White oak board do?
mbskeam

http://photobucket.com/albums/a96/mbskeam/

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Offline Kingman

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Re: Phase Linear 700 B restoration complete
« Reply #7 on: February 10, 2014, 06:22:59 AM »
IN REALITY IT ONLY MATTERS WHAT IT SOUNDS LIKE TO YOU!!!!!

bmwr75

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Re: Phase Linear 700 B restoration complete
« Reply #8 on: February 10, 2014, 06:29:40 AM »
what does the White oak board do?

It replaces the low quality single sided original board.  When I recapped the original board, circuit traces would lift at the blink of an eye.  The new double-sided White Oak board prevents the latching up to the B+/B- rails too and putting 80+ volts on the speaker outs.  It eliminates on/off thump too.

Offline AdamG

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Re: Phase Linear 700 B restoration complete
« Reply #9 on: February 10, 2014, 01:35:35 PM »
That's a cool piece of gear! Love the looks of it.

bmwr75

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Re: Phase Linear 700 B restoration complete
« Reply #10 on: February 10, 2014, 05:16:05 PM »
I tried to take a better low light shot of the new LED lighting.  But, as you can see I don't know how to make my camera do this very well.

Offline Planarguy

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Re: Phase Linear 700 B restoration complete
« Reply #11 on: April 17, 2014, 12:23:28 PM »
Very nice!  I tinkered with a few of these myself over the years, installed Don's relay board, etc.  I had good input boards and they took the cap. changes, etc without issue - lucky me as I don't recall the White oak boards as being available back then..  IIRC there were several stock board variations, and mine were in the last series for both the 700B's I had.  OH, btw, I have several sets of the original stock handles for   700B's.  If someone needs a set, let me know.

When all the work is completed, bias dialed in, offsets down to near 0, etc., these are a very good sounding amplifier.  Back when these were being built of course, most audio "guru's" would say they were poor sounding, prone to blowing up and taking your speakers, perhaps your home with them(well... ok, a SLIGHT possibility of burning your house down, but we audiophiles thrive on danger,eh?). Bob constantly fought an uphill battle getting his stuff accepted in the MORE PROFIT for all, environment of the time. His stuff just didn't cost enough!
With the updates, and protections you've incorporated, I'm jealous!  You now have a terrific sounding and thoroughly updated piece of real audio gear.

bmwr75

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Re: Phase Linear 700 B restoration complete
« Reply #12 on: April 17, 2014, 01:35:13 PM »
Have some new power supply caps coming in a day or two.  Will install those and be done.

Offline papabearjew

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Re: Phase Linear 700 B restoration complete
« Reply #13 on: April 17, 2014, 04:05:47 PM »
Why can't I see the photos?  I'm using a MacBook Air (one of the original ones).
Any thoughts anybody?
thx