700 Series 1 Build

[mr_rye89]

A butterface?……..or um Unconventionally attractive?

Either way I can’t wait to see what a full WOPL 700 Series I looks like

 

[Hexis22]

Had to make minor modifications to the housing to properly mount the faceplate.

 

[Hexis22]

Faceplate all wired up.

Added a terminal strip to mount resistors and diodes for meter signals, instead of the factory method of dangling off the meter terminal.

Went with LED's for meter lighting, given I do not know history of current incandescent bulbs. The LED's are slightly brighter, although the dark meter cases could use brighter illumination.

All wiring for meter lighting installed with wire ties and loops to strain relief solder joints.

 

[gene french]

very nice!!!!

 

[Hexis22]

All buttoned up and playing music on the bench.

Rubber feed added to keep the faceplate off shelving.

Next is power testing and listening room testing, my favorite parts of the build.

 

[Hexis22]

A few pictures of the ass end of this beauty, in all it's 2500W of Max Power In glory...

I call this a Series 1 “back half” build.

 

[mr_rye89]

Mmmmm not a butterface at all. I wouldn’t kick that outta bed

 

[Gibsonian]

She sure does have a purty face.....

I'm smitten! Is it illusion or is one meter alot brighter than the other?

 

[Hexis22]

She sure does have a purty face.....

I'm smitten! Is it illusion or is one meter alot brighter than the other?

Yes, the right meter has a much darker lens.

All internal LED lamps are the same between left and right.

 

[Bob Boyer]

Beautiful work, Eric! Love the sleeper look... all hotrod under that daily driver veneer.

 

[mlucitt]

Eric, how was the "Hi Temp" light wiring accomplished?

 

[Hexis22]

Eric, how was the "Hi Temp" light wiring accomplished?

That's a great question and one that I needed to draw a schematic to figure out, given I didn't have the original amp wiring configuration (I was only sent the transformer and faceplate).

Essentially, one side of the lamp is wired to the AC Neutral side of the first thermal switch (Purple wire in pictures, Here) and the other side of the lamp is tied to the front panel power switch AC Line through resistors. When the power switch is on and either of the thermal switches open, the only thing powered is the power and over temp lamps.

 

[Hexis22]

Sorry, that description was not very clear.

The Over Temp lamp is wired across the thermal switches as shown below.

 

[laatsch55]

If the thermoswitches are normally closed, and open.on temp rising, how can they be in series?

 

[Vynuladikt]

If the thermoswitches are normally closed, and open.on temp rising, how can they be in series?

Just like an Emergency Stop circuit, any one in the circuit that opens will shut it down.

 

[laatsch55]

Understand that , but how does the light come on..

 

[Hexis22]

Understand that , but how does the light come on..

 

[mlucitt]

Interestingly, a PL700 over temp condition does not remove all power from the amplifier as it does in the PL700B and PL700II.
This is because there is still a path for a small current to flow in the circuit of R72 (4.7K or 3.6K in Eric's amp) and the NE-2 lamp, which are parallel to the over temp switches.

Eric, your drawing is awesome. I will be restoring an original PL700 amp soon. I wanted to keep it as original as possible, so I may only use a new WOA Capacitor Kit/Bridge Rectifier/Bypass Board, Rev G1 Control Board, and new Output Transistors.

 

[Gepetto]

Lee it may be easier to understand if you look at this modification to the drawing...

 

[laatsch55]

Thanks Joe...