Larry's Phase Linear 700B

[peachdog]

No need being concerned with a non-=worker as that is preferred.Less stuff to take out, and send to Ed. The tricky part, (and even moreso as the world awakens to what the PL 400's and 700's sound like after this), is getting a cherry cosmetically and trashed electronically. it's a rare occurance when one event is responsible for both conditions. Anticipating a shortage of said "rare occurances" this member has been on a mission to encourage the creative process of members past , present and future to overcome these pesky little details and find a way to get new faceplates and meters.

Someone asking $200 for a PL 400 he describes as "works very well but needs a new light in the right meter." His pics aren't so great and show just a portion of the face which looks somewhat scuffed up. What do you guys think, worth it?

 

[laatsch55]

Yep, we have access to better plates than that. Skratch ran off 20 last run I believe. A lot of what you think are scratches in those pics could be that mysterious "camera stuff".

 

[Skratch]

I have some 400 front panels, but they have to be silkscreened

 

[laatsch55]

Did you decide on the font yet?? And as we were talking about Mark, I don't know if it has to be exact. On another note, can you whip up a couple for my mono-blocs? Don'y know the exact size yet but can let ya know.

 

[laatsch55]

Ok, one of life's embarrasing moments. In all the work done on Larrt's and now Dougs bad ass 700b(WOPL 1000) now, I never instituted Joe's improved grounding scheme, and I have some HUM. So, due to the gracious and patient nature of Doug, I will cure said here-to-fore- overlooked grounding scheme and make it so. Thanks Doug for understanding.

It seems to like it on it's back on my bench.

 

[laatsch55]

New ground wires run and cable ties back on.Not long now.

 

[laatsch55]

Just as well run some noise, crosstalk and THD & N figures, this shouild have changed them.

 

[mlucitt]

Lee,
Did your last post indicate that you still have some hum? If you do try pulling the B+ and B- fuses, that will kill one or two paths for hum onto the WOA board. If you still have hum you can look at the DC protect wiring or the thermal switches to see if they have some hum bleeding into the DC. Let us know.

Mark

 

[laatsch55]

Not so much hum as I'm losing voltage from 1500hz to 10 hz I start with 7.25 on the output down to .87 at 10hz.

 

[laatsch55]

Get ya up to speed here Mark. I was walking the amp up on a level test after doing the improved grounding scheme. There are 2 ways to do this on the AP, rotary pot or pushbuttons labeled X10, inc, dec, and divided by 10. At 650MV I hit the X10 button by mistake. Blew the rail fuse, put it back in and now we are chasing lost gain from 1500hz on down. Right channel only.

 

[Gepetto]

Check your MPSA92 or 93 in the bad channel Lee. In an overdrive situation, this guy takes a lot of abuse due to the diode clamp on the base of Q5

 

[Gepetto]

Q4 by the way...

 

[laatsch55]

OK, was running through the voltages posted on the schematic.

 

[laatsch55]

I have +100 volts on the collector of Q4.

 

[jbeckva]

I have +100 volts on the collector of Q4.

Oh noo Mr Bill.. nooooooooooo!

(sorry.. couldn't help myself... carry on... )

 

[laatsch55]

DUDE!!! You are too much man!

 

[laatsch55]

Good test on the DC protect relay. Shut that channel right down.

 

[laatsch55]

Doug, we don't have time fort a long de-bug. You're getting a new board. Tonight.

 

[fitz43]

Doug, we don't have time fort a long de-bug. You're getting a new board. Tonight.

Well thanks. Like I said before, ship it after your happy with it. Doug

 

[laatsch55]

Depending on how it goes it might go out Tuesday instead of tomorrow morning. bad things happen when I hurry. Doing good so far though. Got all the resistors mounted.