700b #2 Clean Slate

[D-500 Flogger]

Had a very productive day today, if it could go right....it did! I got all of the transistors installed, Backplanes and Main board tested, initial adjustments made on the new 700b, and will hopefully finish up the front panel, input wiring, and DC Protect board tomorrow. Wires are all run and tested for the front panel light board, and I have removed the Zobel Network from the relay board. That wiring for the relay board is all run and checked out as well. I am sharing a few pictures. The quality of Joe's boards honestly sets the standard! It is such a pleasure building these amps.......and then that WOPL'd sound....speaks for itself! So today was more or less the birthday of another WOPL'd 700b.
I set the bias at .360/.360, DC Offset is 0.000 L and 0.001 on the R. My line AC was 126v today. I use one mulltimeter on my Variac and another for testing. In the one picture you can see the "dim: bulb, 126v in and .360 bias. DBT is an antique I rebuilt over 40 years ago! It was old then.
Fun Stuff! View attachment 61511 View attachment 61512 View attachment 61513 View attachment 61514 View attachment 61515 View attachment 61516 View attachment 61518

Vintage 700b,

First off, *nice* workmanship on the inside of your 'better than new' 700B restoration. You guys in here have definitely raised the bar...I will definitely push my soldering/wiring skills to emulate what you have on display.

****

Speaking of which, when you read the following, please keep this in mind: "Imitation is the sincerest form of flattery." :0)

I had the same reaction to your Vac-U-Tronic that George S, Gepetto, & Laatsch55 had. Although I have a growing collection of test gear, I have yet to actually brew up a DBT. I just needed basic functionality, so my original mindset was to go to Lowe's & brew up something quick & dirty.

...But now that I'm actually putting together my personal analog electronics workspace (and I'm going to be taking pictures to share here) I've decided to indulge in some discreet steampunk-ish lab accessories -- especially if the additional cost isn't outrageous.

Without further ado, instead of a homebrew solution, right after I saw your photo I jumped onto ebay, found the following (including documentation) ...and bought the lab a little bit of DBT eye candy for the sum total of $25 + shipping:





Sincere thanks for letting me know that this even existed. FWIW I've come to realize that vintage electronic test gear that's fully functional is a beautiful thing & something to preserve for the future...and hopefully will help to set the stage when I get to start putting my own PL amps through the restoration process.

Cheers --

 

[Vintage 700b]

Very Cool! You'll want to change the socket out on it but that is a heck of a deal for 25.00 and a Manual! Sweet.
I use an old Hitachi V522 and a Rigol DG4062. Nothing fancy. With the Vac-U-Tronic you can moonlight testing Electroluxes, and Kirby's.
Looking forward to your D500 Build.

 

[Vintage 700b]

A new WOPL 700B is born !!!!!...............and it sounds amazing!
Thank You to everyone who helped with the Potentiometer issue. (They are getting harder to find.)
I got new Bourns Pots yesterday and finished everything up......listening to it right now as I type this.
Amazing, simply amazing!

 

[J!m]

Congrats on saving another one! Looks fantastic!

 

[Vintage 700b]

Thank You Jim,
Sounds even better! I do love these upgrades that Joe has pioneered. Full Comp and Dual Mono
and all that headroom really makes for an incredible amplifier. Got my first 700B in 1978, and I am in
awe every time I hear the WOPL version. I said out loud last night when I hooked it up.... WOW.

 

[J!m]

I'm waiting on the White Oak "White Whale"- 1000 watts (4000 into 2 ohms) monoblocks.

Should be any day now...

 

[WOPL Sniffer]

I'm waiting on the White Oak "White Whale"- 1000 watts (4000 into 2 ohms) monoblocks.

Should be any day now...

HUH?