Thinking I should WOPL my 400 and looking for a 700

AngrySailor

AngrySailor

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Have a 400 series one, thinking about hot rodding it. I'm wondering what's involved. I've read some of the threads here and checked out white oak's site. The caps have been changed out already but it's otherwise original. The original caps were shorted, I can remember the value, but 9800uf rings a bell for the new ones, could be wrong though. I'm going to assume you'll want to know what outputs are in it and want pics, I'll work on that. If you could give me a brief overview of what's changed out and rearranged would be great. Also wondering how much more performance I could expect. Is the original power transformer capable of supplying the new unit? I've heard they are a weak link in the original 400's?

Also, would like to buy a 700 (or two:toothy5:) in the near future but they are hard to find out here in bumblefuck Canada (that's the big state on top, the great white north eh!) so if anyone has a line on one, that would be great!

Thanks guys

Andrew
 
laatsch55

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Original 400 caps were 5600, uf@80 volts. A 700 had 9800uf@ 100 volts. The transformers in both are not the weak link but are the limiting factor as with all AB class amps. Joe's rework of the driver board and backplanes accomplish lower noise, better frequency response, Better sound, and complementary output stage. You also get improved Soundstage and a reliable enough amp I guarantee my conversions for life.
 
AngrySailor

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Is the installation something I could handle with decent soldering skills and a multimeter, or would I need to send it out? Electronics is something I've only dabbled with, but I need to up my skills and understanding as I'm getting more involved in the subject at work. I'd like to do it myself, but don't want to toast anything either!

Also, any help finding a 700 would be great!

Thanks!
 
laatsch55

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Peruse the build threads and judge for yourself. You are the one who can make that call.
 
AngrySailor

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laatsch55 said:
Peruse the build threads and judge for yourself. You are the one who can make that call.
Click to expand...
I've been doing a fair bit of reading, and please correct me if in
wrong... Boards are available from WO in various stages of completion, comes with detailed instructions. Once installed you are staring the amp with a dim
Bulb tester to limit current flow then setting the bias. Is this about right? Some threads are dealing with some very technical I problems that I don't have the knowledge or equipment to diagnose. Is this normally a procedure that requires this final finesse to get right? If that's the case, it is beyond my skill and equipment!
 
laatsch55

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You can buy the boards populated. They then just require wiring in. When doing the backplanes the chassis are almost stripped bare. There is no special troubleshooting skills required unless something was done wrong. THAT can get pretty complicated.
 
AngrySailor

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This may be a dumb question, but I've been trying to get my head around these conversions... Guys are talking about full comp outputs (vs quasi?)??? Were these amps built both ways? How do you change between the two? Does this not require changing outputs (as in pnp/npn)? I'm sorry, I have a basic grasp of these concepts, but some reading material seems contradictory, or I'm "special". I will gladly take any "lessons" anyone has to offer so that I may understand things more clearly!
 
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Yes, the PL's were built both Quasi ansd full comp. So can the White Oak versions...yes they eqire PNP outputs,....Gotta go,...
 
ksrigg

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You should send the amp to Lee for a rebuild and FULL upgrade. It is one of the best things you will ever do.

Lee converted SEVERAL 700b's and 400's for me but I HAD TO rebuild one myself....and I did, but it is not an easy task, and by the time you buy all the things you will need to properly build one of these amps, you will spend WAY MORE than the cost of a refurb.....so my advice would be to send it to Lee......as he is a MASTER WOPL maker....and he does guarantee his work for life...can't beat that...





plus, he knows all the tricks of having built probably over 100 of these amps....
 
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If you want the schematics for quasi and full comp to compare them, I think I have copies somewhere. But yeah, they were made both ways. I rebuilt a 700 series II for a friend that was quasi. My own amp is a Pro 700 that is full comp.

If you're converting one, I expect the easy way to do it now would be one of the White Oak backplane boards. If you've had your eyes inside the stock PL 700, you can imagine why re-wiring those sockets might be something of a pain in the neck. I've not converted one, but after seeing what the backplane boards look like, I'd go that route if I were to do it.
 
AngrySailor

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Thanks guys, I would not be against having Lee do it, I'm just trying to figure if it's something I could do myself, as a project to learn more about electronics. I also don't want to send Lee a box of parts that I dickered rather than a working amp! What I was getting at earlier was that if the amp is quasi, you have to change out transistors no? Not just rewire as full comp, it doesn't work that way, I don't think...

If you had the schematics for a 400 or 700 that would be interesting, but don't go out of your way.

Again, I'd be interested in buying a 700. I've seen a few series I's on the interweb, but no 700b's. I believe Lee said these are the desirable models to WOPL. I wonder if Lee only does refurb's, or if he would source and WOPL a unit...

Thanks guys
 
laatsch55

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I bought a bunch of 700B's from Handley sound in Boston but they are trashed. That's why Joe is starting to build chassis'. Every Chassis is F&^%$# on that buy. Faceplates are trashed also but we're working on that. Makes me no nevermind if it comes in pieces cause it gets stripped to the bare chassis anyway.

A stock PL Quasi comp amp can be converted to full comp by changing one row each of out puts to PNP's and rewiring the backwall transistor sockets. I haven't done that because there is a better way now. Ed has done a LOT.

The White Oak approach is really the only way to go IMHO. If sound quality and reliability are high on your priority list , it should be your's too. White Oaking ( or WOPL'd--White Oaked Phase Linear) eliminates soooooo many problem areas of the design it's worth every penny.

You don't buy 480-520 clean 8 ohm WPC cheaply any more and a WOPL represents an excellent value there too.
 
laatsch55

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And with the new chassis' if you like the Ser I look , the faceplates can be used off a Ser I , and the heatsinks off a B and the White Oak boards now make that possible...
 
AngrySailor

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laatsch55 said:
And with the new chassis' if you like the Ser I look , the faceplates can be used off a Ser I , and the heatsinks off a B and the White Oak boards now make that possible...
Click to expand...
Thanks, that sounds interesting... I do like the styling of the series I, vintage looking! Ultimately what I would like to do is put together a bi-amped system with a 700 and my 400. I'm using the 400 as the sub amp right now but I'm lacking power and pushing the 400 to it's limits regularly :/ I bought a QSC cheap ($100) and I'm going to try it for now as the sub amp and move the 400 to the three ways, but I have a funny feeling I'm not going to be happy with it.
 
Northwinds

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laatsch55 said:
I bought a bunch of 700B's from Handley sound in Boston but they are trashed. That's why Joe is starting to build chassis'. Every Chassis is F&^%$# on that buy. Faceplates are trashed also but we're working on that. Makes me no nevermind if it comes in pieces cause it gets stripped to the bare chassis anyway.

A stock PL Quasi comp amp can be converted to full comp by changing one row each of out puts to PNP's and rewiring the backwall transistor sockets. I haven't done that because there is a better way now. Ed has done a LOT.

The White Oak approach is really the only way to go IMHO. If sound quality and reliability are high on your priority list , it should be your's too. White Oaking ( or WOPL'd--White Oaked Phase Linear) eliminates soooooo many problem areas of the design it's worth every penny.

You don't buy 480-520 clean 8 ohm WPC cheaply any more and a WOPL represents an excellent value there too.
Click to expand...
The next two have decent chassis Lee, faceplates are not too bad but have fuseholders drilled into them. Everything is stacked up so whatever is next is what gets packed. Had to move a few regular 700s to get at these. I'll work on getting them boxed up when I am not preoccupied. I see you are backlogged with work so figured you were in no rush and I have been busy at the Homestead. Starting to wind down now with the Farmer's Market and Corn maze over but the house/museum stays open and there is always repair work being done. NHH also just lost a massive 300+ year old oak in front of the house with the last windstorm. That was a beautiful tree but I noticed a major crack up the trunk starting last year. I mentioned it should be chained up but like with all committee's, it was not a priority for funding. I thought that was pretty stupid considering it was almost as old as the house and is a fixture in most images of the Homestead seen online

Yeah, it's was the massive tree shown at right



and seen behind the house

 
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gadget73

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Northwinds said:
... but like with all committee's, it was not a priority for funding.
Click to expand...

Thats the way of it. Spending $50 today to prevent a problem is not a priority, but spending $1000 tomorrow when you've ignored the problem until its too late seems to be no issue.
 
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