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

Gepetto said:
Voltage gain is identical between the 400 and 700 Mark.

Rather than doing all the swaps, post some good photos of your G1 assembly.
Click to expand...
I’m pretty sure I swapped a resistor somewhere...
Was gonna look at that before the “surgery.”
 
Gepetto said:
Rather than doing all the swaps, post some good photos of your G1 assembly.
Click to expand...
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):
 

Attachments

MarkWComer said:
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):
Click to expand...
Are you in direct mode for the direct/normal switch?
 
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.
 
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...
 
.01 on your 20 M ohm scale likely means you have 10K resistance from input Jack to pin 1
 
Gepetto said:
.01 on your 20 M ohm scale likely means you have 10K resistance from input Jack to pin 1
Click to expand...
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..819624B4-54D3-48A7-8FD0-A4D7E0C907BE.jpeg
 
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
 

Attachments

1618597857760.png

1618597890070.png

These views are in the White Oak PL700 backplane instructions on Pg 26 and 29 Mark.
 
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.
 
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 said:
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!​
Click to expand...

You were also killing all your bass response with that resistor value. You turned your preamp output coupling caps into differentiators.
 
Well, you guys must be laughing yer asses off! What a boneheaded mistake!
I feel so stupid...
 
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