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The Worlds First Fully Comp PL 400 Using White Oak Components !!!!!
- Thread starter laatsch55
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Damn nice job Joe - that's a beauty (and I know beauty). Lee - great work there as always. You're both an inspiration to us all.
I must ask though - what sort of mechanical tolerance did you have to deal with regarding the pre-drivers and drivers. In my mind I saw four boards but this makes much more sense with two - nice stuff here. How do you get the heat transfer to the bias transistors? If I saw correctly it was a standoff of some sort?
The test results Lee alluded to show fantastic improvements and it sure sounds like the listening test has gone over the top. I wish I could show my smile here but can only type words. Maybe a special photo of some sort will help. I'll think on that one.
Again - great job guys!!!!!!!!!
I must ask though - what sort of mechanical tolerance did you have to deal with regarding the pre-drivers and drivers. In my mind I saw four boards but this makes much more sense with two - nice stuff here. How do you get the heat transfer to the bias transistors? If I saw correctly it was a standoff of some sort?
The test results Lee alluded to show fantastic improvements and it sure sounds like the listening test has gone over the top. I wish I could show my smile here but can only type words. Maybe a special photo of some sort will help. I'll think on that one.
Again - great job guys!!!!!!!!!
Nice work Joe and Lee. The amount of heat transferred through cooling fins will be the same as original quasi - comps?? i.e. new design run any cooler? Ever consider adding the dc protect to the main amp board? Output power remaining the same for the fully comp?? Am happy that I saved a couple amps back for restore, although one is a 700 (hint). Thanks for the continued development guys.
DAMN !!!!! WOW !!!!! And just last night Lee, Nando, You and I were talking about how sweet the 400 sounded... I bet you was about to bust !!!! While reading all this all I could think about was .... I gotta have one..... I gotta have one ! Then .... Right in the end Joe got all that out of my head ! He said 700 (hint) !!!!
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I was wondering about the alignment of the chassis holes and the printed circuit board holes for the driver and pre-driver transistors. It seemed like that could have been an Achilles heel not knowing the tolerance Phase Linear adheared to when punching the holes. The board looks great and I'm glad this all worked out so well.
This is an awesome advancement - kudos again.
This is an awesome advancement - kudos again.
If you have a 8 finner everything lines up perfectly. All you have to do is check the diameter of the TO-3 holes for the clearance of the nylon inserts and go from there. Some of the chassis were punched with the dies a little dull and you had to ream the holes with a drill bit. Both of the chassis that I have did not need reaming, so mine must have been punched when the dies were sharp.
Hi Dennis
Thermal coupling via a short aluminum standoff gets the bias tranny up on top of the board where you can properly connect it and provide a secured attachment point for the wires. The thermal path is short and all aluminum for good conductivity.
The PL chassis were punched pretty accurately on the X-Y coordinate basis. The only observation that I have is they seemed to have worn punches in 2 locations near the RCA inlets. Those end up slightly undersized but are easily made the right size by a twist of a 0.234" drill bit.
I determined the original locations by caliper measurements first and then confirmed same by comparison to the readout from a CMM machine scan that I had done on the chassis. I converted all that into a SolidWorks model for the back wall.
The board is dual to allow that AC thermal cutout and the standoffs for the board with no practical interference. I did look at one board early on but the size is unwieldy and you end up paying a lot for a 4 layer board that size with a lot of cutouts. I gravitated to the 2 board set to keep costs down to a minimum. 4 layer boards are still expensive but not as much as one big board would have been. The smaller size also makes it easier to assemble each and keeps flexing with the chassis to a minimum.
Thermal coupling via a short aluminum standoff gets the bias tranny up on top of the board where you can properly connect it and provide a secured attachment point for the wires. The thermal path is short and all aluminum for good conductivity.
The PL chassis were punched pretty accurately on the X-Y coordinate basis. The only observation that I have is they seemed to have worn punches in 2 locations near the RCA inlets. Those end up slightly undersized but are easily made the right size by a twist of a 0.234" drill bit.
I determined the original locations by caliper measurements first and then confirmed same by comparison to the readout from a CMM machine scan that I had done on the chassis. I converted all that into a SolidWorks model for the back wall.
The board is dual to allow that AC thermal cutout and the standoffs for the board with no practical interference. I did look at one board early on but the size is unwieldy and you end up paying a lot for a 4 layer board that size with a lot of cutouts. I gravitated to the 2 board set to keep costs down to a minimum. 4 layer boards are still expensive but not as much as one big board would have been. The smaller size also makes it easier to assemble each and keeps flexing with the chassis to a minimum.
Hi Dennis
It sounds like you want to know that the TO-3 transistors are tilted at an angle of 32.59325 degrees
It was a vexing task to extract all the chassis dimensions accurately. The other challenging task was finding enough room on the board for the quasi and full comp strapping while at the same time totally flooding the power/ground planes for minimum signal and voltage loss as well as quiet and stable performance.
Finally, one of the things I personally like most is throwing away the junk sockets and sheet metal screws that were in the original amp and are 99% of all PL problems (the back wall) except for the burned out incandescent lamps.
It sounds like you want to know that the TO-3 transistors are tilted at an angle of 32.59325 degrees
It was a vexing task to extract all the chassis dimensions accurately. The other challenging task was finding enough room on the board for the quasi and full comp strapping while at the same time totally flooding the power/ground planes for minimum signal and voltage loss as well as quiet and stable performance.Finally, one of the things I personally like most is throwing away the junk sockets and sheet metal screws that were in the original amp and are 99% of all PL problems (the back wall) except for the burned out incandescent lamps.
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Doing a pair of 400's with all White Oak parts in them. The Version D driver boards. 16800 uf filter caps, the new backplane boards and light boards. Also Watts abundant DCP. The only thing that is Phase Linear is the transformers and meters. I am doing 1 fully complementry and the other one Quasi complementry. Almost finished with the fully complementry one. Pictures to follow.
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