Sutton's Phase Linear, White Oak 500

[laatsch55]

What section is that to??

 

[laatsch55]

Now this is an OLD SCHOOL RECTIFIER!!!! I Love it!!!!

 

[speakerman1]

Full wave with 4 diodes. I have built those and put them on a scope. It wasn't pure rectification. You would get a bump every so often. With what I had I tried to get full rect. Could never do it.

Larry

 

[laatsch55]

You were just missing 20,000uf of filter cap is all.

 

[laatsch55]

Running the little PL/WO 550 hard enough to use the fans. The Crystal Method-----"Vegas"
Sutton, this 2nd 400 is tagged by "Anita" so........I guess..... "Anita" it is.

 

[laatsch55]

the first 400----with the PS cap issues sounds pretty damn good!@!

 

[laatsch55]

Anita awaiting the complete parts package. the White Oak Driver PCB, the White Oak LED board, wattsabundant's(Don Imlay's) DC protect boards, and On-Semis MJ 15024's and MJ 21194's, and Cornell-Dubilier 18,000/80 volt PS caps.

 

[ksrigg]

Taking something that'a already good and making it great.......



Where was the Anita tag? Inside the little jewel?

Did Anita have the old school rectifier?

 

[ksrigg]

Maybe it meant....anita new bridge rectifier.............

 

[laatsch55]

Nope. It was assembled by "Anita" . I wonder if she was seated next to " Cathy?" Yep she had the old school rectifier.

 

[laatsch55]

Getting a little done. Had to stay at home today. A bit of infection in a tooth. Didn't stop me from doing some work on "Anita"

I also added the extra wires to run separate power supplies to the WO board.

 

[Gepetto]

Lee
One step I take on my PL amps is to unlace the white ground wires that PL originally bundled in with the AC wires on the thermal disconnect and separate them spatially. No point adding any AC induced currents in the ground path if one can avoid it.

 

[laatsch55]

Yep, makes sense. So you're saying that those white ground wires that are grounded on that particular run can induce hum from the AC main in? Granted there is ground current running all the time. At what threshold of signal level on the AC to DC can we expect problems?? I knmow that was a loaded question, but you would think that even in 1974 this grounding/ground loop thing would have been figured out, or was iot the bean counters having sway again??
Also, some 400's and 700's I've done have a heavy , black sheath over those partiocular wires besides the normal insulation, was that an attempt to address this??

 

[laatsch55]

DUH!!! And if it's in the ground path it's EVERYWHERE!!

 

[laatsch55]

I blew you off once about the caps, not again. Ground has been re-routed up top.

 

[laatsch55]

Speaker posts unsoldered , cleaned up and DC protect board mounted.

 

[ksrigg]

Was Bob Carver's Phase Linear design revolutionary, or were others using the same topology? Is anyone using it today? How does it stack up with other schemes? Just interested in what Bob was doing and how it stood out, and whether it effected later designs..Beautiful work Lee, and thanks Joe for all your hard work to bring these beauties back to life..

 

[laatsch55]

It was revolutionary in that it used the newly developed " hi power silicon " transistors. His topology in the protection circuit was patented, so that was I guess. It took awhile for PL to go fully comp in the outputs, but aftert seing and hearing what Joe has done with the NPN only output stage I don't know if fully comp would have any more audible differences.
It's a classic AB amp design, and is still used today, albeit with different input and V/A stages they pretty much follow the same principles.

 

[laatsch55]

Sutton, can you see how the small bypass caps are on the BR??

 

[ksrigg]

Yes, I can. I was just looking at those. NICE...Now I must repeat the same..