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Phase Linear???

ChopperChas said:
Is there someone in or around North Carolina that can work on Phase Linear gear? I have a Series II Model 700 amplifier and it works great, but it has a few very minor issues.....
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This amp has an opamp on the input as opposed to the discreet front end in the 700B. It's possible the opamp has become noisey. For long term reliability it's probably best to do the White Oak driver board upgrade. Also there are a couple caps on the bargraph that fail.

If properly packed the amp can survive shipping.
 
I got the White Oak Phase Linear, but what does that MEAN? What is actually done to my amp? Is it DIY-able for someone who can solder, but otherwise knows nothing about circuitry? What does it get me?

Charles.
 
A new driver board with new components with an improved topology. There is also a new product that replaces the sockets and associated wiring on the backwall for the outputs. These baccplane boards are configured for a fully comp output stage...in essence you get an amp that is BRAND NEW on the inside with better sound, frequency response, world class signal-to-noise ratio and an amp that will last another 30-40 years with none of the bad habits from before. No turn on/off thump, no latching up, no oscillations.....not much I guess..
And the DIY doable depends ON YOUR experience. To do the backplanes, the amp is stripped down to just the transformer and bare chassis and all wirng done from the ground up. Depends on if you can follow directions and ask questions.. Joe fields a lot of questions on DIY builds on Phoenix, and there are now over 50 build threads documented there on various White Oak conversions. The driver board and backplanes can be bought bare with no components, bare with all components to complete, or assembled ready to install.
Driver boards assembled by Joe himself are 175.00 tested and ready, backplanes are 125.00 a set unassembled with components, or 175.00 a set assembled and ready to install.
 
SolderIron said:
Any link to a schematic?
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Essentially the basic design is retained, but optimized for ultimate operation. Regulated power supplies were added. Parts quality is vastly improved. Phase Linear had to mass produce and trade off parts quality to keep cost down.

All said the original design is not bad or they wouldn't have lasted this long. However it's no longer cost effective to try to maintain or repair the original driver board when the White Oak is available at reasonable cost.
 
The bleeding off of the PS caps through the front end is also treated differently to eliminate on/off thump, traces rerouted and beefed up for lower noise...speaking of noise, Don, on the 700 just finished, the residual noise was at 203 microvlts --unweighted and 83 IEC "A" weighted...the protection circuit threshold was raised to accomodate the newer outputs, and all ceramics eliminated on the board and only MF-1% resistors used. An oustanding amp now by anybody's measure....Bob had most things right.....
 
Thanks, I like hints :).

>All said the original design is not bad

It was great to put that much power together back then. Today you can get that kind of power with half the output transistors for example.
 
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