Larry's Phase Linear 700B

[speakerman1]

I want you to listen before you put the new board in. I think you will be surprised. After you listen to it and tell me. You can do it in a PM. I'll get it ready to ship this week. So you can install the GBs on the old board and burn them in. It took me awhile for it to get to this point. You know what I mean. If it isn't messed up don't fix it. LOL

Larry

 

[laatsch55]

I totally respect that. AND I think you';ll be surprised.

 

[Gibsonian]

I want you to listen before you put the new board in. I think you will be surprised. After you listen to it and tell me. You can do it in a PM. I'll get it ready to ship this week. So you can install the GBs on the old board and burn them in. It took me awhile for it to get to this point. You know what I mean. If it isn't messed up don't fix it. LOL

Larry

Agree with everything here except the "you can do it in a PM". We all will hound you anyway out of curiosity. What all are the mods on this one?

 

[laatsch55]

I think he wanted my opinion in a PM but that ain't gonna just be in a PM. I did this amp before Joe's board came out. DC protects , new caps and LED lights. He supplied some Blackgate caps for the electro's on the PL 14b board. It's coming back for the new board, IF I think it would sound better after talking to Larry about it via a PM. The world will know anyway. I'll listen to it for a week at least, as it was an extremely fine sounding unit when it left.

 

[speakerman1]

Remember the mods that were done before you got it. Did we or you ever figure them out?

Larry

 

[laatsch55]

yep, PL was out of 220K resistors so they used a 100 and a 120K, hence the 2 jopined together.

 

[speakerman1]

I have been reading that sometimes putting resistors in series does something. Can't remember what; but it depends on where they are put.

Larry

 

[laatsch55]

In series totals the resistance as opposed to parallel which does something different.

 

[speakerman1]

In parallel the sum is less than the lowest resistor. That isn't what I meant.

Larry

 

[laatsch55]

Well then say what you mean.

 

[speakerman1]

Well I can't remember. If I recall it is something like a buffer by having them in series. I think if the lowest is 1st. Dude I have been reading so much it isn't funny. LOL

Larry

 

[laatsch55]

Ah, but are you retainng?????

 

[speakerman1]

Some LOL

Larry

 

[mlucitt]

Slight topic change. There was an earlier discussion of AC wiring, here is what I did, the before:
[attachment=0:3a5xbrww]PL 700B Power Before.JPG[/attachment:3a5xbrww]

And the process:
[attachment=3:3a5xbrww]PL 700B Power Gutted.JPG[/attachment:3a5xbrww]

Next:
[attachment=2:3a5xbrww]PL 700B Power Jack.JPG[/attachment:3a5xbrww]

And the result:
[attachment=1:3a5xbrww]PL 700B Power After.JPG[/attachment:3a5xbrww]

Mark

 

[speakerman1]

Mark
Is that IEC filtered? If so where did you get it? The one I got for my pre is filtered. But it cost me a tad more than a regular IEC.

Larry

 

[laatsch55]

Mark-------NICE!!!!

 

[mlucitt]

That 15A filtered IEC jack was Digi-Key P/N CCM1788-ND for $2.30. I also bought a smaller one (the smallest footprint I could find) all plastic, no filter, P/N 708-1338-ND for $1.60; but I didn't need it because the filtered jack fit just fine.
The chassis on the PL is a bit thicker than they use on components today, so after it snapped-in, I used some metal epoxy to keep it in place.
I also was able to adhere to the rule, "The ground wire should be the longest in case the wire is yanked out of the unit and the 'hot' or 'neutral' power wires are severed, the ground wire will be the last to break, keeping the chassis at ground potential to avoid shocking the user." or words to that effect. I'll explain what I did with the ground wire in the next post.

 

[speakerman1]

Thanks buddy. If you ever need any thing just ask.

Larry

 

[mlucitt]

Here is how I terminated the ground wire, I used a loop breaker circuit adapted from Rod Elliott's work here: http://sound.westhost.com/earthing.htm

Here is a top view:
[attachment=1:5nst4224]PL 700B Ground Loop Breaker Closeup.JPG[/attachment:5nst4224]

Here is the final (the yellow wire leads back to the IEC jack):
[attachment=0:5nst4224]PL700B Ground Loop Breaker 1.JPG[/attachment:5nst4224]

This grounds the amplifier chassis with protection. In case of a fault, the diodes in the bridge short and the .1/400V cap and 10 Ohm/5 Watt resistor supply an alternate path. The electronics are grounded from the "star" ground between the caps. I have not tested it yet but the test should be very boring - nothing should happen, maybe a little less hum.

I know you are not supposed to use a "dedicated" grounding point for anything else, but I just had to use the terminal mounting screw. I HATE drilling into the PL chassis.

 

[laatsch55]

Paint the terminal mounting screw "Looksee" green and you'd be official!! Yeah doesn't make sense sometimes does it Mark?