My New (old) PL400 --how to upgrade?

rinman77 said:
Have you completed the upgrade successfully?
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I thought I had it, but had to order some Pico fuses that go on the Backplane boards, I think I shorted out with my
Digital Multi Meter. I will replace once they come in, so I can put it all back together, and try once again. This would
be my first WOPL build.
 
Gepetto said:
Easiest to most difficult
Output transistors...
Cap upgrade
Light board upgrade
Control board upgrade
Backplanes

Not going full comp with the backplanes will limit the improvements received however.
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Can the backplane upgrade work without upgrading the control board--eventually I will do the whole thing, but I want to parse it into manageable projects so I can at least finish something sooner. So could it work as follows:
Project 1: Backplane + output transistors (is it 6 of each?)
Project 2: Capacitor upgrade
Project 3: Control board
Will I have a working amp (assuming I do it correctly) after each of those projects?
Thanks in advance.
 
You certainly will. Haven't seen just the back planes first, but yeah it'll work.
 
rinman77 said:
Can the backplane upgrade work without upgrading the control board--eventually I will do the whole thing, but I want to parse it into manageable projects so I can at least finish something sooner. So could it work as follows:
Project 1: Backplane + output transistors (is it 6 of each?)
Project 2: Capacitor upgrade
Project 3: Control board
Will I have a working amp (assuming I do it correctly) after each of those projects?
Thanks in advance.
Click to expand...

You can, but be aware that you'll have a bit of work to do if you do decide to go to full comp when you get to replacing the control board. You'll need to pop them back out to rearrange the jumpers for full versus quasi, not to mention transitioning half the outputs from NPN to PNP.
 
jbeckva said:
You can, but be aware that you'll have a bit of work to do if you do decide to go to full comp when you get to replacing the control board. You'll need to pop them back out to rearrange the jumpers for full versus quasi, not to mention transitioning half the outputs from NPN to PNP.
Click to expand...
Well I was assuming the back plane project was already going full complementary. So can all the upgrades be done without going full complementary? I.e. is going full a separate project in itself, but more easily done as part of the upgrades?
Related question--is the new control board usable in quasi or full complentary configuration?
Sorry for all the question, I just want to know mostly what I'm doing before I jump in.
 
Since you were planning on the backplanes first, that implies Quasi since the stock driver board will not work with backplanes configured for FC.

The WOPL PL14 can do either, and if you order the kit comes with components to do either/or. Also tho.. in ANY case and whichever way you decide to go, I would strongly suggest the main caps first. Being that the old ones can be over 30 or so years old, they most certainly are "ticking time bombs" to borrow a phrase from WoplSniffer.. They could just blow the line fuse when they do finally go, but they also could do a lot worse.

If it were me..

Caps+DCP (the DCP you really REALLY need in there, especially if running stock without any mods preventing latchup i.e. the back to back diodes for C6)
Driver Board (set initially for Quasi)
Backplanes to FC as well as recoverting the PL14 for FC operation.

Outputs? Hmmm.. well you would need to initially populate with NPN's across the board so you'd have to eat that somewhere along the line. I would say sure at stage 2 with the WOPL board in place is where they should come in. Or before if you want to chance it.
 
jbeckva said:
You can, but be aware that you'll have a bit of work to do if you do decide to go to full comp when you get to replacing the control board. You'll need to pop them back out to rearrange the jumpers for full versus quasi, not to mention transitioning half the outputs from NPN to PNP.
Click to expand...

There are no jumpers on the backplane for quasi or full. Backplanes are only full comp.

The first version of the 400 was convertible but there was zero uptake on that feature so it was eliminated in favor of better performance by making them full comp only.

If you start with the backplanes, you will be without your amp until you complete the control board project. If you are OK with that, it is a fine order.

For first time upgraders, I recommend only doing one change at a time.
 
Gepetto said:
There are no jumpers on the backplane for quasi or full. Backplanes are only full comp.

The first version of the 400 was convertible but there was zero uptake on that feature so it was eliminated in favor of better performance by making them full comp only.

If you start with the backplanes, you will be without your amp until you complete the control board project. If you are OK with that, it is a fine order.

For first time upgraders, I recommend only doing one change at a time.
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So best order if I don't want to buy anything that I later don't need is:
  • DCP
  • Cap upgrade
  • Control board
    • control board in quasi mode and listen for awhile
      • OR
    • control board in full mode, and commence the backplane upgrade upon completion (I assume there are plenty of tests to confirm the control board upgrade is successful even if I cannot yet listen to the amplifier due to incompatible output configuration--correct?)
  • Backplane upgrade
Have I got it right?
 
Yes, except do not upgrade the wopl PL14 to full until the backplanes are there - do both at the same time. The PL14 can go to full, but your current point to point wiring is still for quasi.
 
jbeckva said:
Yes, except do not upgrade the wopl PL14 to full until the backplanes are there - do both at the same time. The PL14 can go to full, but your current point to point wiring is still for quasi.
Click to expand...
Understood--that was my first double-indented bullet point, ("control board in quasi mode and listen for awhile").
 
How much difference is there between a fully modded PL400 series 2 vs. PL400 ?
 
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