Mark goes at it again... just bought a PL700/II!

[MarkWComer]

Voltage gain is identical between the 400 and 700 Mark.

Rather than doing all the swaps, post some good photos of your G1 assembly.

I’m pretty sure I swapped a resistor somewhere...
Was gonna look at that before the “surgery.”

 

[MarkWComer]

Rather than doing all the swaps, post some good photos of your G1 assembly.

I'm a picky little twit, pretty exacting, and more than a tiny bit OCD. Not exactly sure what I did wrong, but will check the assembly instructions against the circuit. Whatever I did wrong was done symmetrically, the problem is with both channels.
Assembly photos (rather LARGE and high resolution):

 

[Gepetto]

I'm a picky little twit, pretty exacting, and more than a tiny bit OCD. Not exactly sure what I did wrong, but will check the assembly instructions against the circuit. Whatever I did wrong was done symmetrically, the problem is with both channels.
Assembly photos (rather LARGE and high resolution):

Are you in direct mode for the direct/normal switch?

 

[Gepetto]

What are the differences between your 400 and this 700?

Direct/Normal switch
Attenuation pots on the front panel
Anything else?
Those should be the initial focus areas to check.

 

[MarkWComer]

Switch in normal mode
Pots at full input

 

[MarkWComer]

Resistance from input jack to pad 2 of driver reads .01 (20MΩ scale) so no resistance from jack through pot to driver.

Pad 1... oops...

 

[Gepetto]

Resistance from input jack to pad 2 of driver reads .01 (20MΩ scale) so no resistance from jack through pot to driver.

Pad 1... oops...

Then you must be in direct switch mode

 

[Gepetto]

Resistance from input jack to pad 2 of driver reads .01 (20MΩ scale) so no resistance from jack through pot to driver.

Pad 1... oops...

Why are you on a 20M ohm scale? Go to a 200 ohm scale

 

[Gepetto]

.01 on your 20 M ohm scale likely means you have 10K resistance from input Jack to pin 1

 

[MarkWComer]

.01 on your 20 M ohm scale likely means you have 10K resistance from input Jack to pin 1

I was checking for continuity, not resistance. At the time, the value of the resistance was irrelevant.

Bingo- it’s the input jacks! I cannibalized a cable and connected directly to the driver pads, getting full volume now. I have resistors on them because they were there originally- I should have questioned their importance. None of the WOA documentation covers that area- the “direct/normal” switch and the jacks, I just followed the PL schematic for that. Nod to Perry here- “Captain Dunsel” strikes!

So, the thing to do is snip those suckers off..

 

[Gepetto]

You have the wrong resistor value there Mark. You have 220 ohm resistors, the White Oak Audio schematic calls for 220K. That is why I had you chasing this path. See attached

 

[Gepetto]

These views are in the White Oak PL700 backplane instructions on Pg 26 and 29 Mark.

 

[Gepetto]

Those resistors are there as 220K to bleed of charge from the 1uF NORMAL caps that are in the circuit. So you don't get an unintended snap if you connect a cable while powered up.

 

[MarkWComer]

Dang... read the colors wrong, grabbed the wrong ones, whatever. Regardless, I’m thankful it’s a simple fix! Got halfway through checking the driver board even though I wasn’t convinced that was the problem.

Thank you!​

 

[MarkWComer]

View attachment 50061

View attachment 50062

These views are in the White Oak PL700 backplane instructions on Pg 26 and 29 Mark.

I have a black- only laser printer, wouldn’t have seen that...

 

[Gepetto]

Dang... read the colors wrong, grabbed the wrong ones, whatever. Regardless, I’m thankful it’s a simple fix! Got halfway through checking the driver board even though I wasn’t convinced that was the problem.

Thank you!​

You were also killing all your bass response with that resistor value. You turned your preamp output coupling caps into differentiators.

 

[MarkWComer]

Well, you guys must be laughing yer asses off! What a boneheaded mistake!
I feel so stupid...

 

[Gepetto]

Well, you guys must be laughing yer asses off! What a boneheaded mistake!
I feel so stupid...

We were on it and found it quickly...what's not to like?

 

[FredR]

Well, you guys must be laughing yer asses off! What a boneheaded mistake!
I feel so stupid...

I've seen worse. Lee?

 

[Steve K]

At least there were no Ka Booms!