Here Is A Guy Doing PL400 Mods

[mlucitt]

I stumbled on the World Pro Audio website today. Has anyone else seen this? He has an extensive mod to the PL400 (one originally assembled by our friend "Linda" at Phase Linear) Control Board and adding the White Oak Audio Bulk Capacitor Kit. I don't know if he realizes there is a new Control Board that would save him a lot of work. He charges $250 for this mod.
Thoughts?
https://www.worldproaudio.com/WPA-Phase-Linear-400-mod1

 

[WOPL Sniffer]

Looks like some Kludged junk

 

[WOPL Sniffer]

OMG

He's not even cleaning up the 40 year old flux or or or........ Hack

 

[mr_rye89]

Oooof.....Looks like I fixed it lol. I'm guessing the new board has holes for those capacitors....And are those scorch marks from resistors on a fiberglass board?!

 

[WOPL Sniffer]

yeah, and ho-made power and ground busses

 

[Phase Linear Phanatic]

Ehhhhhhh. My God. I hope Joe doesn’t see this.

On second thought.......I hope he DOES. Would anyone here like to point that gentleman to the RIGHT forum?

 

[WOPL Sniffer]

This is why I tell everybody that a partial WO upgrade is crazy and a House Fire waiting to happen. All that original crappy work that Phase Linear did, is still waiting to haunt you. If you think "Original" is cool, think again. Most every amp I strip (and that has been many), looked similar to this. Get rid of the PL abortion and fire hazard.

 

[WOPL Sniffer]

If he spent as much on the amps as he did on his website.......

 

[mlucitt]

Thanks for the picture grab Sniff. The most interesting thing to me is that I don't see the latch-up solution that Joe engineered. This means that after all this, the board could still cause the amplifier to send DC rail voltage to the speakers.
I don't know if the PL400 was as prone to latch-up as the PL700, but really?

 

[wattsabundant]

Thanks for the picture grab Sniff. The most interesting thing to me is that I don't see the latch-up solution that Joe engineered. This means that after all this, the board could still cause the amplifier to send DC rail voltage to the speakers.
I don't know if the PL400 was as prone to latch-up as the PL700, but really?

400, 700 doesn't matter. They all use the same circuit. I've never seen one latch but it could happen. Joe's solution works.

Only in recent years have I seen transistor socket failures. Those were due to people who over tightened the screws. All things considered I don't think the construction of the amps are that bad. They are approaching 50 years old.

I can't get over that power switch on the World Pro Amp. He certainly didn't go to Perry's wiring school.