700/1 “Tim” WOPL driver board

[laatsch55]

Go to Don's website. I thought I included some.
Wattsabundant.com

 

[laatsch55]

No meter connections to the board..

 

[AngrySailor]

Go to Don's website. I thought I included some.
Wattsabundant.com

Perfect

 

[laatsch55]

You'll have to drill a new hole on the backwall to locate p strap.

 

[laatsch55]

IIRC, it will have to line up with a heatsink hole. I'm at work or I'd dig out a pic or two .

 

[AngrySailor]

That’s no problem to get them mounted. This input/rca/level pot wiring got me a little messed up here. Not sure this is original... it’s Belden shielded cable... did PL ever use that? St quick glance it comes from the RCA’s, to the pot then to the board, but there’s also a line straight from the RCA’s to the board... gotta look closer at this...

 

[laatsch55]

K...

 

[Gepetto]

No backwall mounted bias transistors on the 0171 board. How they tracked heatsinks temp on the driver board is a long held mystery. So....you are short p-straps?

Not really a long held mystery Lee, it was an F'up on their part which they quickly fixed.

 

[Gepetto]

That’s no problem to get them mounted. This input/rca/level pot wiring got me a little messed up here. Not sure this is original... it’s Belden shielded cable... did PL ever use that? St quick glance it comes from the RCA’s, to the pot then to the board, but there’s also a line straight from the RCA’s to the board... gotta look closer at this...

PL used Belden shielded twisted pair cable with a white and red conductor inside. Really crappy wire as it melts back like a weenie.

The outputs that connected to the original board should just connect to the White Oak board with signal to pin 1 and ground shield to pin 2 on each channel.

 

[laatsch55]

Not really a long held mystery Lee, it was an F'up on their part which they quickly fixed.

Amen, but a mystery as to how it happened in the firstplace..

 

[AngrySailor]

Had a big snooze after turkey leftovers and woke up bored... stripped the old driver board and the power supply caps and rectifier. New goodies for there going in too. Going to strip the xpl909 outputs also, as Linda’s going full comp and has a new set of 2SD555’s in her I’ve got an extra row to replace all Tim’s 909’s with 555’s.

 

[AngrySailor]

Deaoldered the speaker leads, getting ready for the DCP board install. I’m a little confused with the driver board input connections and the DCP somewhat though... the 700/1 seems to have some significant differences from the 700/2 or 700b. I do not have a schematic or service manual for the 700/1, only 700/2/b.

 

[AngrySailor]

Pulled the bias transistor P straps from Linda, lookin at this input wiring but it’s blowing like mad outside and I’m in my PJ’s drinking coffee rn so I’ll wait for sun up and the wind to die down to go get my meter from the shop, but loookin at the 700b schematic I see how it’s supposed to work but this amp has some slight differences... do the 700b’s have 4 RCA jacks? 2 per channel? Also I don’t see C22 physically in the circuit, it’s not internal in the switch is it? I also have connections to all three poles of the switch, which could make sense if the “direct” RCA jack is attached there... also with the DCP, the Zobel network in the third pick is removed from the amp and replaced by the one on the DCP board correct?

Oh and just to check, the correct bias transistors are 2N5088 right?

Thanks

I guess just to clarify a bit here, I’ve never messed with this amp much (700/1), I plugged it into the “normal” RCA jacks I believe and it worked “normally” in that the level pots worked. If I’m reading this right, and make the connections at the board, the one set of RCA jacks will bypass the pots... if that connection was made AT the pot, it would function and I wouldn’t have doubled up input connections to the board. Again, I have to grab my meter and ohm out this switch to see exactly what the signal path is, but it sure looks like any other DPDT switch...

 

[AngrySailor]

Pulled all of Linda’s 2SD555’s (she’s going full comp WOPL), pulled all Tim’s XPL909’s, they’re being replaced with 2SD555’s. What a mess to clean up from the thermal paste...

Looking forward to reassembly/bring up. I’m sure there’s only a couple hours of real work left here for one of you guys but I’m a friggin n00b so...

 

[AngrySailor]

Drivers and heat sinks removed. Too much of a mess of thermal paste to clean in place. Gonna have to drill some holes to mount the bias transistors to the backplane and two mounting holes for the WOPL driver board anyways.

 

[George S.]

700/700B service manual, lots of schematics, hopefully your "variant" is here.
https://www.vintageshifi.com/repert...?pdf=Phase-Linear-700-700B-Service-Manual.pdf

 

[AngrySailor]

Thanks. Looks like C1 is located on the PL0171 board then. I think I’m gonna have to do some custom wiring if I want to keep the capacitor coupling option working then.

 

[George S.]

I think WOPLSniffer dispenses with that option on his 700 builds, while others want to retain it. Me, I have no 700 experience to offer. All I can say is really think this through and get it right the first time. Hopefully others can help. "Bump" the thread as needed!

 

[laatsch55]

Andrew, sorry, I fell asleep on ya last night. Hopefully work won't be so bad today and I can help. Hard to see some things on my phone.

 

[AngrySailor]

THanks guys and no problem Lee! I was in bed real early yesterday myself. I don’t really see the need for that option, but looks like I could retain it without too much misery also. Pull C1’s from the PL0171 and reroute the one set of leads to the pots with C1 in line should do it I think.