Before and After WO driver board mod

Michael F

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#1
Lets see if I got things right: My understanding is that the noise floor is lowered, frequency response extended and further flattened, more stability i.e. less likely to "latch up" along with yet more power which are all good things but I would be most interested in owners before and after comments on the sonic differences brought on by this mod.
TIA
 

laatsch55

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#2
To put it mildly, the sonic differences are astounding. I have two tricked out Spec 2's. Since the first day the WOPL 1000 debuted here, the Spec's are pulling back up duty and they were the alpha dogs around here for 35 years....having 250 watts of additional headroom is hard to describe...... but once you have it and as clean as it is to it's limit, you'll never go back.

It is not just "less likely to latch up to the positive rail" it will NOT LATCH UP....PERIOD. No turn on/off thump...nothing. It has to be heard to be believed. Check Suttons rebuild threads, heck, check any comments on the conversions I've done, they all have one thing in common......the conversions EXCEEDED THEIR EXPECTATIONS in all cases.......
 

laatsch55

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#3
I have yet to see a White Oaked PL exhibit any of the bad habits of the originals, and the one I ALMOST got to oscillate I had to work real hard to get it to do that....
 

Michael F

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#4
Thanks for the reply Lee.
Can those differences be attributed to the re worked circuit design or to the quality of modern components?
A cursory listening session on secondary speakers was all that was required following the acquisition of my bone stock 700B to see that it holds promise.
I`ve owned many great vintage amps over the years and found them to respond favourably to cap replacements in every case however, never were the original circuits or component values altered, as would be the case here.

In it`s original form, I must say that I was pleasantly surprised at how well it sounds considering its vintage and blown away at how much torque is available. Its overall presentation is quite different though from the bi polar, fully complementary amps I`m accustomed to listening to. It does seem to lack the sparkle and finesse of say the Yamaha PC2002M I have on hand, having more in common with my BGW 750B which are very nice themselves.

It sounds like the driver board would indeed maximize the amps potential,I wish I was able to audition a WOPL, any Montreal area users out there? :grin:
 

laatsch55

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#5
Agreed on the difference of sound. Imagine the bass response vastly improved, the shussh removed from the mids, and the highs so clear they'll part your hair. That's a WO 700.
 

ksrigg

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#6
Simply the finest amplifier available to human beings

I owned a Phase Linear back in my college days, and had one of the better systems on campus. Back in the mid 70's. stereos were a competition, and I was a player. I absolutely loved the amp, having come from a Fisher 35 watt per channel receiver. I was competing with other guys who owned McIntosh amps. both tube and solid state. The only problem I had was my amp was constantly "blowing up", complete with smoke, etc. usually taking my speakers along with the amp, so I spent many weekends returning to the Tri-Cities (TN) and leaving the amp with Mr. Toad (Mr. Toad's Sound Concept) in Johnson City, TN and my speakers with Watkins Stereo in Kingsport, TN. I returned these so many times it began to get really stupid. I finally was convinced by Mr. Toad's to trade my PL 400 for a Luxman M-4000 and matching preamp (I did own the PL 4000), and I bought a pair of Bose 901's during this period also as I thought there was an impedance mismatch or problem inherent with the Watkins speakers (the original dual coil woofer patented by Mr. Watkins and later sold to Polk or some other large speaker maker). I was still happy, and had the cool looking and really great sounding Lux, and had no problems blowing the 901's. But I missed the Phase Linear. I don't know what it was, but I just wanted to get back into a Phas Linear amp, and one day while web surfing, I found this wonderful community of folks who were the first folks I ever met who loved audio as much as I do. As with everything I do, I went overboard, and now have two 700b amps and four 400 amps in my working main system, with two unfinished 700b amps and a 400 completely reworked and one that has not been touched yet. All I have to say, is the Joe at White Oak is a genius, and Lee Laatsch and Dr. Mark are also both genius as well. The work that has been done by these gentlemen and others is simply unreal. These guys have turned a really wonderful sounding amplifier and transformed it into the finest sounding amplifier you could ever find. PERIOD. I have not heard the latest iteration, and can only imagine. I don't know how the amp could have been improved, but if they say they have done so, then it is true. I simply must have my amps all upgraded now....but this time I probably will only do one of each...That really is all I need ..............well maybe two of each....or maybe three 400's............and the amps sound better than the specs or any test result would have you believe. I have heard many a speaker which looked great on paper, but sounded really not so good, and other speakers which didn't look so fine on paper, but sounded wonderful...but with the Phase Linear, you get both. simply the best sounding amplifier you can own.....or does the amp own you....Someone reserve a little bench time for me, and I'll send an amp to you. If the 700b sounds as good as the 400 now, I don't know if I can stand it. They may commit me.
 

laatsch55

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#9
Replacing the CD ignition system TO-3 with a dedicated audio rated part doesn't hurt. The biggest improvement is Joe's re-engineering of the driver board. He has made over a hundred changes to the board. No ceramics on the board---PERIOD. His treatment of what caps go where is simply genius. He knows this stuff so well, his trouble shooting skills are second to none. His improvements are measureable and effective. He is very deliberate in his changes and we are now approaching a 100 MICRO volt noise floor and the last test of UNWEIGHTED SNR on the 400 was 107.2 DB. Ya don't do that just being lucky, you have to be GOOD!! That unweighted figure would be world class for an A weighted spec. A weighted I'm guessing close to 120 DB. That's world class in ANYBODY's book, don't care who ya are.
 

kevin

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#10
Hell.... I gotta jump in here.... Ive not owned alot of big amps in my day but ive sure been around ALOT of em !!!! When I got my first 400 I put two Haflers in the closet !!! When I got my 700 I put the Hafler P-500's IN THE CLOSET !!! I was using four HAFLER'S !!! lol... I've never heard an amp put so much ........ SLAP YOU IN THE FACE..... In a pair of speakers !
 

jbeckva

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#11
I have a big pile of amps, receivers, integrateds , and other pieces of the genus "ampus maximumus" sitting around this room, and one day off to ebay they all go. I had NADS and Yammys with nads... sleepers and creepers... and now that I am WOPL'd I can't go back to 'em..
 
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