PL-400 DCP and WO light board

[AngrySailor]

That's pretty dsmn high. Where are you checking that?

Base to emitter right? Speaker lubricant application started in the past hour, it hasn’t burst into flames yet so I’ll probaly keep my hands in my pockets for the rest of the night...

 

[laatsch55]

There is a 10 ohm resistor from base buss bar to emitter. Go on the common tie point of the emitter resistors..

 

[AngrySailor]

Ok, I went directly on the BE of one output each channel

 

[laatsch55]

Needs to include the emitter resistor..

 

[AngrySailor]

Ok. She’s pretty warm after an hour of ~50w output... too warm. I’ll dig tomorrow.

 

[laatsch55]

Bias should be 350-380

 

[AngrySailor]

RIP Sansui tweeters...

 

[laatsch55]

Oh snap...

 

[AngrySailor]

If I’m checking the bias right, base to the common emmiter terminal after the the emitter resistors, I’m getting 14mv right and 570mv left...

 

[FredR]

If I’m checking the bias right, base to the common emmiter terminal after the the emitter resistors, I’m getting 14mv right and 570mv left...

Lee prefers half-bias, but 14mv is low even for him.

 

[FredR]

A little cleaner...

Is the green ground wire that's connected to the chassis go to ground on your 120v power cable?

 

[laatsch55]

There are 4 bias resistors on the back wall. One on each. Column. Make sure it's not in the first row. Rows go left,right, columns up and down. I usually just measure both sides of the 10 ohm bias resistor. The column closest to the transformer is #1. We are concerned with columns 1 and 3.

 

[laatsch55]

Lee prefers half-bias, but 14mv is low even for him.

You a funny guy Fred.....accurate,....but funny...

 

[FredR]

 

[AngrySailor]

Ok, got the PL 4000 hooked to Linda. I can crank the volume up on the pre amp all the way and can’t deive the amp anywhere near full. I am in the process of returning a China pre amp I bought as a fill in as it wouldn’t light Linda up either. Now it had some issues which makes me think it’s knackered, crosses inputs and cross talk... it also had less output than my iPod straight into the amp. The PL 4000 is better, but can’t drive the amp to anywhere near max power. Ideas?

 

[AngrySailor]

I got it figured out... haven’t broke my speaker cables in...

 

[laatsch55]

Input sensitivity is 1.75 volts input for full output. For a 700 anyway, a 400 is close to that.

 

[laatsch55]

How about bias?

 

[Gepetto]

Input sensitivity is 1.75 volts input for full output. For a 700 anyway, a 400 is close to that.

Helpful info from the WO S2 Cylon light board documentation (updated RMS voltages).

 

[FredR]

Helpful info from the WO S2 Cylon light board documentation.

View attachment 40401

Used those numbers and very happy to have a calibrated meter.