PL 700 Pro Build

[J!m]

I didn’t know they existed!

Need to get the 0.1% tolerance variety- aka tin plated copper wire.

 

[J!m]

I think we need a derail here, no?

@Gepetto : can you make up a speaker protect board for a balanced (XLR input) amplifier? Does it even need to be any different than what you have? I know you have a solid, proven design, and if I make me a JSA 100 or pair of monoblocks, I’d like to protect my speakers from whatever mischief I get into in an amplifier… don’t want to blow them up and a fire would not go over well either.

 

[laatsch55]

DC protect is not dependent on input configuration. It is responsive to output conditions only. It monitors the output signal for DC, a hard clip can also trip it depending on frequency and duration. If Don's board is not what you need, there are quite a few out there. Visit westhost.com to take a generic design and adapt it to your situation...

 

[laatsch55]

Westhost sound.com.

 

[George S.]

This point in populating the board is a good time to stop and clean the flux. Lee's tip about shortening the acid brushes bristles is spot on. A heat gun aids drying. It took 3 cleanings to get it as shown and there's still a little here and there. We'll get that later.
Joe's documentation gives a build order. Smallest components like diodes first, then resistors. Smallest components first, tallest last. Time to break from this, family time.

 

[Gepetto]

Your right(of course!), 0.2 ohms on the Fluke. Guess you needed a small amount of resistance there as they replace a trace. Looking at how you use them on the double sided board confuses me. I'll look at the schematic this evening.

And most of that 0.2 ohms is your meter leads. They are used as wire jumpers, to tie two ground systems together. Zero ohm resistors are a convenient substitute for jumper wires.

 

[mlucitt]

Zero ohm resistors are a convenient substitute for jumper wires.

Just don't put them in backwards, always observe proper polarity.

 

[laatsch55]

Just don't put them in backwards, always observe proper polarity.

LOL!!!!!!!!!!!!!!!!!!!!!!!!!!

 

[George S.]

Has anyone seen stepped nylon washers on 700 transformer bolts? Is this common?

 

[mlucitt]

Has anyone seen stepped nylon washers on 700 transformer bolts? Is this common?

Never seen that kind of transformer bolt jewelry.

 

[laatsch55]

Someone added those, to complete that process, cut a plastic straw to cover the bolt in between the nylon washers...

 

[laatsch55]

It's a hum reducer...

 

[George S.]

Yes, I added heat shrink to smaller diameter bolts on my two 400 builds to isolate the transformer. As far as I can tell, these are original to the 700 Pro. Was somewhat surprised.

 

[laatsch55]

Me too..

 

[grapplesaw]

Has anyone seen stepped nylon washers on 700 transformer bolts? Is this common?

These are used on the later dual 500 and all D-500 transformers. The pro was kind of the last kick at the cats as it was before phase linear 700’s met their demise. I found in earlier dual 500‘s they used full length drinking straws. I found these on serial number 1002 and had red stripes. I put shrink wrap on all transformer bolts now even if they have this bushing set up you have remarked about George

 

[George S.]

Glenn, thanks, that explains it all. Was wondering where using the drinking straws originated from.

 

[George S.]

Control board is finished. Meter boards are next.

 

[Gepetto]

Glenn, thanks, that explains it all. Was wondering where using the drinking straws originated from.

It is an age old transformer practice...not Phase Linears...

 

[George S.]

I recently pu'd a set of stepped washers that should fit the 400s. Just need to find time to check the fit. Personally, I'd rather have the bolts insulated with step washers than heat shrink. That's how HP did it on the old test equipment. "Ya gotta keep'em separated".

 

[grapplesaw]

I recently pu'd a set of stepped washers that should fit the 400s. Just need to find time to check the fit. Personally, I'd rather have the bolts insulated with step washers than heat shrink. That's how HP did it on the old test equipment. "Ya gotta keep'em separated".

Do both. Washers plus heat shrink between. Can’t hurt