PL 700 Pro Build

[laatsch55]

Film caps are what I use on the 400's and 700's. I wrap the leads around the tabs instead of drilling...turns out pretty nice..

 

[George S.]

Film caps are what I use on the 400's and 700's. I wrap the leads around the tabs instead of drilling...turns out pretty nice..

Cool, yup, already got the extra holes drilled. Now measuring and cutting backplane wire after cleaning the leaves out of the gutters. Might even cut the grass this afternoon for the final time. Gotta wait for the sun to melt the frost first. That last system that blew thru stripped every last leaf off the trees. I'll mulch what's on the ground.

 

[FredR]

Yeah, a guy should build at least one...

Nobody can build just one. They are like potato chips.

 

[George S.]

Fred I hear you!

 

[George S.]

Making progress. Ready to tack solder the bias transistors to the backplane, then pull the boards and do final soldering on the backside. This is the one component in the build that really requires extra precision and care.
Putting on some Black Sabbath so I find my groove and don't blow this.

 

[laatsch55]

I solder to Shpongle....never tried Black Sabbath!!

 

[George S.]

When I built the 400s I bent the bias transistor leads to a 90 and soldered them in. Mark L. posted he solders them in straight, then bends the transistor over. That's what I did this time and it's far easier. Used a short pointy needle tip and turned up the heat to 750 because their is so much copper in that area. Done and looks good.

 

[Gepetto]

When I built the 400s I bent the bias transistor leads to a 90 and soldered them in. Mark L. posted he solders them in straight, then bends the transistor over. That's what I did this time and it's far easier. Used a short pointy needle tip and turned up the heat to 750 because their is so much copper in that area. Done and looks good.

Hi George
Actually there is very little copper in the bias transistor area. If you hold the board up to the light, you will see that all the planes have been voided in that area to minimize stray capacitance which would upset the amplifier performance.

 

[George S.]

Hi George
Actually there is very little copper in the bias transistor area. If you hold the board up to the light, you will see that all the planes have been voided in that area to minimize stray capacitance which would upset the amplifier performance.

Thanks Joe, guess the fine tip and double sided board tricked me on the 400s.
Was just looking at the wiring photos you included with "Assembly Notes for PL700 Backplane RevC PCB". Just excellent. Wiring this is going to be easy with the photos.
That's all for today. Tomorrow I'll wire the bridge rectifier and transformer leads. There's plenty of extra wire left over from the wire kit plus I have extra so I'm set.

 

[laatsch55]

I like the capstrap George....fuckin excellent...

 

[George S.]

Got a little bit done today. Spent more time thinking about how I'm going to wire this than working on it.
Does anyone know what that woven protective wire cover like they used on the power cord runs inside the amps is called or have a part#?
Also, Joe, a while back you posted a killer power distribution schematic for a 700. I've looked and can't find it, can you post it or a link please.
So, that terminal strip mounted on the end wall is very handy to have. Makes wiring the dual primary transformer easy. If I ever go back into my 400s they'll be getting one of those.

 

[J!m]

This stuff on my power cord?

My local (gold mine) has it in eleventeen colors and sizes

 

[George S.]

View attachment 58523
This stuff on my power cord?

My local (gold mine) has it in eleventeen colors and sizes

Hmm, was looking for something similar, but old style, pre-plastic. Phase Linear used a woven flexible tube to protect the power cord on a long run inside the 400s. Looks almost like fabric, probably flame retardant.
Been looking for it on eBay, Mouser, and Digikey for a good while with no luck. Chances are it is woven Asbestos so that's why I can't find it
We have a big Microcenter store up in Cleveland that sells all the braided plastics. Wonder if someone braids Teflon or Nomex. Going to look. Thanks Jim. Nice looking cord!

 

[J!m]

Fabric? I’ve not seen it. There is a “denim” color that has a bit more texture to it.

Probably faux carbon fiber too…

 

[Skratch]

Its woven glass that is used in high temp applications. Used in the plastic industry on molding and extrusion lines

 

[George S.]

Ah, cool, woven glass, like fiberglass cloth. Your right on the money I believe, it looks very similar to woven fiberglass cloth used for auto body repair. That helps a bunch. Thanks!

 

[Skratch]

Ah, cool, woven glass, like fiberglass cloth. Your right on the money I believe, it looks very similar to woven fiberglass cloth used for auto body repair. That helps a bunch. Thanks!

McMaster Carr. High temp expandable sheathing

 

[J!m]

We use it with orange silicone rubber over the glass.

But we’re running 40kW+ all day long

 

[George S.]

Will check that out. Also several listings on eBay, some with silicone over the fiberglass.

 

[George S.]

Will check that out. Also several listings on eBay, some with silicone over the fiberglass. Now that you all helped me I'll do some research. Pretty sure I don't need silicone. Just simple fiberglass fabric tubing