My New Early Model PL400 w/ 4 Fin Heat Sink

[MarkWComer]

Yep, tons of small amp folks out there think we are nuts for clipping a little ole 250 watter.

To each their own.

(Funny how we think of the 400 as a "small" amp...)

 

[punchback]

Would it be wise to get a variac? I already have a DBT. Ebay has 1000W 10 amp variacs for a little over $50. Would that be good enough? I may as well throw another log on the fire!

 

[laatsch55]

Yep, that's plenty. It's not like your running a variac during max out testing...

 

[VSAT88]

I would have burned up a heap o mo shit than I have without one.

 

[VSAT88]

If Jimmy Carter is the first thing you think of when the 70's are mentioned, you might have inhaled...

Purple Haze man, Purple Haze.

 

[punchback]

Please forgive my inability to understand the wiring for the WOA board. Attached are some files regarding identifying the wires I'm left with after cutting off the PL400C. There is a close up photo of both the left and right back wall of the chassis. Right being the side of speaker connections and inputs. Also attached is the wiring color code connections diagram from the Excel file sent by WOA. The bottom table closely matching the colors of my PL400. I have a couple of color discrepancies and they are noted below the bottom table. What are the "Schematic Reference #'s" in that bottom table? Are those numbers referencing PL400 schematics? The PL400C schematic in the service manual doesn't reference any numbers.

Do I use the middle table "White Oak Audio - PL14_20 PCB Wiring" and reference the colors I've identified in the bottom table? The middle table seems to be referencing signal names from the top table. I think I'm in a bit of analysis paralysis right now.

I now have a variac so as soon as I can feel like I'm connecting the correct wire color to the correct WOA terminal I'm ready to "light it up" so to speak. Would the PL400 be plugged into the DBT and it be plugged into the variac?

 

[Gepetto]

Following the narrative instructions is the easiest method.

Also recommend getting rid of the ty raps on your wire bundles, both before and after install to maximize performance.

 

[punchback]

I think what's throwing me is the PL400C schematic has different designators for the back wall transistors. Is the back wall the same no matter version of the PL400 you have? If so I can just use a schematic that matches designatorwise??

 

[Gepetto]

I think what's throwing me is the PL400C schematic has different designators for the back wall transistors. Is the back wall the same no matter version of the PL400 you have? If so I can just use a schematic that matches designatorwise??

To my knowledge and GENERALLY speaking, the backwall wiring was always consistent regardless of control board (there was variability in the wire color used sometimes, as well as wire that faded differently over the years leading to color ambiguity). I say that without having every amp that PL ever built in front of me. The narrative instructions reference the ref designators in the schematic on the third page of those instructions. Mainly for the reason you point out. The designator names changed more than the reality.

 

[punchback]

I'm bumming... I was ready to power up for the first time but... I was making sure my new variac was operational and found that it is not. I checked the fuse and it was OK. I decided to pop off the housing with the meter and outlet, I found the back of the rocker switch is cracked. I thought it felt a little weird like it wasn't right. I'm sure I could fix it but Amazon will take it back and I will get it replaced. I'm glad I decided to go with Amazon instead of ebay. It couldn't have been easier to return it plus no cost to me.

It was a PITA to remove the PL909's and clean up the heat sink grease. Not so much removal but cleaning it up. There were a few that had gobs of grease in the holes for the base and emitters. Toothpicks and Q-tips got them cleaned up pretty good.

Since they're off I'm thinking about the MJ21196's. Do you keep the SJ2741's?

 

[bill7621]

I had my WOPL Claire Bros. 700 Series II Built by Perry and not once have I regretted it. Could I have built one? Maybe, but we'll never know. However I will say this. If you're going to do it, don't skimp on anything. Do it once and do it right. These guys here are great and will help you every step of the way if necessary. All you have to do is ask.

 

[Gepetto]

I'm bumming... I was ready to power up for the first time but... I was making sure my new variac was operational and found that it is not. I checked the fuse and it was OK. I decided to pop off the housing with the meter and outlet, I found the back of the rocker switch is cracked. I thought it felt a little weird like it wasn't right. I'm sure I could fix it but Amazon will take it back and I will get it replaced. I'm glad I decided to go with Amazon instead of ebay. It couldn't have been easier to return it plus no cost to me.

It was a PITA to remove the PL909's and clean up the heat sink grease. Not so much removal but cleaning it up. There were a few that had gobs of grease in the holes for the base and emitters. Toothpicks and Q-tips got them cleaned up pretty good.

Since they're off I'm thinking about the MJ21196's. Do you keep the SJ2741's?

Yes you keep the SJ2741 or RCA410 in the bottom row when you upgrade to the MJ21196 outputs.

 

[punchback]

Here it is, all ready to go but I guess it'll have to wait for the replacement variac.

 

[laatsch55]

Nice job on the wiring bud!!

 

[Gepetto]

Nice work...

What is that which seems to be under R39L? Looks like a piece of wire but could just be the photo (like flash reflection).

 

[punchback]

It's just a reflection of the edge of the trace that runs diagonally under R39L.

 

[Gepetto]

Good, looks like you are ready. Wire colors match narrative so you are good there. Too bad about the damaged variac and the delay you have to put up with.

 

[punchback]

I'm ready to power things up. I've had the face plate removed this whole time. Would it hurt anything to do the power up sequences with it removed? Seems like it would be easier without it attached.

 

[VSAT88]

If I were doing so I would have to do it that way. Far to difficult to set bias any other way.

 

[VSAT88]

Remember I am a sticker, not a WOPL r. So I would wait till Lee or Perry chime in. Lots of other WOPL guys here too.