700B Customer Build

George S.

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Feb 18, 2020
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The very right bottom transistor bolt holes are very slightly "off" on most chassis and matching heat sink. I've built 3 WOPLs, two 400's, and a 700. In each case the bottom right output bolt holes were slightly off and easily fixed with a drill bit or tapered reamer. These chassis holes receive a stepped nylon washer and must be aligned to the WOAD backplane. A minor issue to make right, but success is in the details. The instructions with the kit point this issue out, and specifies the bit size.
 

WOPL Sniffer

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Screw it
I dunno Perry. You lost half your title there

But I learned to NOT be a cheap ass and replace all the ill fitting half assed PL crap. Now when I turn out an amp, it's got a PL transformer and as little else cheesed out junk as possible. They may have LOOKED cool, but they were cobbled junk. Long live White Oak Audio Design, the only savior of a Pile-O-Shit.
 

mr_rye89

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Lost in the Ozone Again
Yep. I'm doing the new chassis if I ever get around to the 700B build. My 700 chassis doesn't hold screws, someone goofed up holes for the binding posts/rca jacks, and I want that IEC plug too.

I had to drill a hole somewhere in my 4 fin to get something to line up, but I forget. There's a build thread here somewhere......
 

WOPL Sniffer

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Screw it
Yep. I'm doing the new chassis if I ever get around to the 700B build. My 700 chassis doesn't hold screws, someone goofed up holes for the binding posts/rca jacks, and I want that IEC plug too.

I had to drill a hole somewhere in my 4 fin to get something to line up, but I forget. There's a build thread here somewhere......
That's the way that PL wanted it. Screwing sheet metal screws into the chassis and watch the metal shavings rain down on your new electronics..... Nice huh???
 

George S.

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I enjoy working on the old chassis and face plate for reuse. Even if they're beat up and bent, as they usually are. Stripped screw holes are easily rethreaded and deburred. IEC sockets installed. Metal straightened.
But then, I rebuild for myself, and I accept the "patina" these old amps have.
To me, it's worthwhile to invest a couple hours on the old chassis and faceplate.
As for the electronics, jacks, wiring, etc, hell no! WOAD and Wattsabundant products and silver plated Teflon wire are a requirement.
Wait till you all see the PL2000 Series One preamps face plate that came out of San Francisco. Pretty damn rough, but I'm going to use it on the next preamp build. It'll look good (to me) sitting on top of the Pro 700, square corners and all.:)
 
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George S.

Veteran and General Yakker
Joined
Feb 18, 2020
Messages
5,033
Yep. I'm doing the new chassis if I ever get around to the 700B build. My 700 chassis doesn't hold screws, someone goofed up holes for the binding posts/rca jacks, and I want that IEC plug too.

I had to drill a hole somewhere in my 4 fin to get something to line up, but I forget. There's a build thread here somewhere......
Joe's chassis have more clearance above and below the backplane boards.
My 700 Pro with the heavy steel chassis has a business cards thickness clearance there, after some massaging the bent chassis to gain clearance.
This was a issue I read about on the old threads, and experienced first hand, but solved.
A good reason in itself to get the upgraded chassis for reduced issues.
In one post, a member reported sanding the board edges to gain clearance. Nothing wrong with the boards, just bent and wavy chassis, especially on the 700's.
 

spitfun

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Jul 6, 2023
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Allen Park,Michigan
I can't thank Eric enough for building me this fine piece of equipment-exemplary work and I love the way this thing sounds... I threw in my mostly stock 400 (except larger ps caps,fully recapped and speaker protection) just for comparison,it sounds goods- but it ain't no WOPL...
 

Hexis22

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Dec 28, 2022
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Wisconsin
I can't thank Eric enough for building me this fine piece of equipment-exemplary work and I love the way this thing sounds... I threw in my mostly stock 400 (except larger ps caps,fully recapped and speaker protection) just for comparison,it sounds goods- but it ain't no WOPL...
Glad to hear it's working well and thank you for the opportunity in building your project.

Your amp turned out so well, I'll be building it's twin for my own system in the near future...
 
Joined
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Finland via the deep south
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Details, details
All outputs installed and RG-316 coax connected between RCA's and control board inputs.

Initial Bias set at 350mV after 5 min warmup.

Output offsets measured 0.1mV Left and -0.2mV Right.

Eric, question for you regarding the input line. Typically you see a 220K resistor between input and ground and a .47 or so cap in series with the input signal. I notice that you are running "direct coupled" mode and doesn't look like you have the shunt...thoughts/reasoning? I am at that stage of the build and am curious as to why you did it this way.

Thanks
 

Hexis22

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Eric, question for you regarding the input line. Typically you see a 220K resistor between input and ground and a .47 or so cap in series with the input signal. I notice that you are running "direct coupled" mode and doesn't look like you have the shunt...thoughts/reasoning? I am at that stage of the build and am curious as to why you did it this way.

Thanks
The original 700B amps have a switch that allows the user to select direct or capacitive coupling on the inputs.

The resistors are used to bleed off the capacitors.

I chose to wire directly from the RCA jacks to the control board for reduced complexity and most robust low signal level connection to control board inputs.

Most people have no use for input coupling caps when using quality preamps with little to no DC offsets.
 
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