Jerry's " ONLY ONE IN THE COUNTRY" Phase Linear 700 Thread

[laatsch55]

Re: Jerry's " ONLY ONE IN THE COUNTRY" Phase Linear 700 Thre

I found the cause of the distortion on channel A. I had a open resistor that I had not seen before. This is R39 and it normally supplies B- bring-up to Q12 and sets the quiescent base voltage for the negative half of the output power transistors. Am I close because that was a stream of conscienceness?

Here is what I found. My PL700B is now happily running in pre-driver mode. I will install the output transistors tomorrow.

Mark

also test point for setting bias, but you knew that.

 

[laatsch55]

Re: Jerry's " ONLY ONE IN THE COUNTRY" Phase Linear 700 Thre

Kerfluffle??????? technical term???? jeez..........engineers do have a sense of humor.

 

[laatsch55]

Re: Jerry's " ONLY ONE IN THE COUNTRY" Phase Linear 700 Thre

Ok Joe, you set out to cure the turn on/off thump and cured the lock up phenom too?? I had this "lock up " on 2 PL 14 A boards and on Jer's when i first fired it up. A couple turn on's and off's and it went away, still bugs me, why the intermittent character of it???

 

[laatsch55]

Re: Jerry's " ONLY ONE IN THE COUNTRY" Phase Linear 700 Thre

Laatsch55,
What do you think you could do to a Phase Lineat 400 Series I, or would it be better to just go all in and get a 700B? I used to own a 400 back in the day, and it and my speakers stayed in the shop. I'd love to talk to you about redoing a 400 Ser I or a 700B. Could you PM me? I want all the same thigs Jer wanted...bulletproof..non-speaker eating, non-smoking, and can do wahtever you think is best. Thanks and yes, I want to full treatment....I can buy the parts and send to you, or you can source them. I just wanted to see if you'd do it for me, and about what the cost estimate would be....

Thanks,

Sutton Rigg (this could be a Rigged Phase nor a Phase Rigg or....)

Or......................................................


The Sutton Linear Phased Rigg.

 

[laatsch55]

Re: Jerry's " ONLY ONE IN THE COUNTRY" Phase Linear 700 Thre

I am experimenting next on how to further improve the low end of the PL400 and 700B which I think is relatively easily done.

Joe...............oh man......................................

 

[laatsch55]

Re: Jerry's " ONLY ONE IN THE COUNTRY" Phase Linear 700 Thre

Time for a review.............

The turn on/off thump is eliminated with 2- 5 cent diodes per channel, disgusting!! joe you're gonna break us!!! nice work!!

I can now power the DC protect boards directly from the regulated + 20 volt feed off the board with no worry about being "kerfluffled" at mach 8, that's very cool.

A Pl that can stand toe to toe with a DC 300 A in the eartquake freq range would be a positive.

The latch up phenom that has cost me many a sleepless night and a slew of hair(see camping pics) is a thing of the past.

I know you're secretly working on the elimination of the 1304, 05 problem.

The improved grounding scheme has now made the distortion specs like a black hole for noise.

AND ---------you've probably got some esoteric, state of the art DC protect scheme that you can't talk about because the patent has not been issued yet,


Shit Joe, whatcha gonna do the rest of the week??

 

[stuwee]

Re: Jerry's " ONLY ONE IN THE COUNTRY" Phase Linear 700 Thre

A Question, it say someone shuts off the preamp first an it has a known turn off thunk, will that still get through the PL?

 

[speakerman1]

Re: Jerry's " ONLY ONE IN THE COUNTRY" Phase Linear 700 Thre

I used my power switch on my filter to turn everything off; but I did turn down my pre. I left the amp alone. I still got the thump; but only in one channel. Since Lee did the mods. No more thump.

Larry

 

[mlucitt]

Re: Jerry's " ONLY ONE IN THE COUNTRY" Phase Linear 700 Thre

I think the thump came from C6L and C6R discharging rapidly through R13 and R15, the far end of R15 is tied to the output on pin 6. As far as the latch-up, that is a mystery to me but clearly the fused +100 VDC was finding a path from pin 7 to the output on pin 6. Maybe through Q10, which was turned on by a positive transient from Q8 and oscillations as C6 was charging. Just a guess.

I used the R38s for the bias measurement, is that the same as the R39???

Also, Lee did you install R70L/R and R71L/R? I installed D3 and I'm not sure it is doing anything.

Mark

 

[Gepetto]

Re: Jerry's " ONLY ONE IN THE COUNTRY" Phase Linear 700 Thre

Guys, I will describe the latch up details but I will type into Word and then cut and paste into the forum later on tonight. It is pretty straightforward and will be obvious to you guys once I describe how it happens.

 

[Gepetto]

Re: Jerry's " ONLY ONE IN THE COUNTRY" Phase Linear 700 Thre

R70L/R and R71L/R should NOT be in (these are listed on the not installed section of the BOM). Just R73L/R and R72L/R. Disaster will happen if you install either R70 or R71 (wipes out the +20V regulator) .
D3R needs to be populated but not D3L although leaving it in does no harm.

R38 is used for the bias adjustment. R39 measurement should be close to the same as R38 measurement however.

 

[mlucitt]

Re: Jerry's " ONLY ONE IN THE COUNTRY" Phase Linear 700 Thre

Oh, and I left the .47/100 input caps out because I could not find a convenient place for them. It would be great if there was a provision to place them right on the board. This means I don't have any caps in the direct signal path, which is the holy grail for some audiophiles. I will have to test the amp down to 20Hz to see what the effect might be. I'm thinking the diode fix will help with any low frequency oscillations too.

Joe, just so you know the only things that are not original on this amp are the addition of an X-type .047/375 VAC capacitor on the primary side of the transformer leads, a small .0047/250 VAC cap across the power switch to reduce arcing, a bump in the storage capacitors from 2X 9,800 to 2X 22,000 with .047/400 VDC bypass capacitors on each cap, a White Oak Audio Light Board, gold-plated, isolated, RCA input jacks, and of course the White Oak Audio PL14A/B PL 20 Rev A Main Board with Phoenix edge connectors.

I plan on replacing the original volume pots with a pair of Blue ALPS RK27 100K pots and an IEC power jack so that I can finally ground the amp the way it should have been. I want to use Rod Elliott's method because I think that is the best design I have seen for grounding power amps. I am also thinking of using his soft-start circuit (P39) and maybe the speaker mute relay driver board (P33 Rev A). I found some real nice 24 VDC relays with 16A/250 VAC contacts from a Thyssen-Krupp elevator board I got from my brother.

Mark

 

[speakerman1]

Re: Jerry's " ONLY ONE IN THE COUNTRY" Phase Linear 700 Thre

Mark
You may some how want to relocate the IEC. When Lee did mine I could get a regular cord in it; but could not use my other cords that I usually run. Don't know what kind of cord you want to use. Lee changed my pots to ALPs also.

Larry

 

[mlucitt]

Re: Jerry's " ONLY ONE IN THE COUNTRY" Phase Linear 700 Thre

Joe, you mentioned "Unpopulated Components" in the BOM and that almost sounds like it is optional. I might suggest some stronger language, such as "Do not install these components for this version" or words to that effect.

 

[laatsch55]

Re: Jerry's " ONLY ONE IN THE COUNTRY" Phase Linear 700 Thre

The p-33 kit of Elliots is worlds class stuff, EW uses it exclusively, now that turn on/off thump is no longer a concern , a simpler DC protect with no on/off muting is possible.

 

[Gepetto]

Re: Jerry's " ONLY ONE IN THE COUNTRY" Phase Linear 700 Thre

I will do that Mark, good suggestion as it would probably not be a good user experience

Sometimes I can't see the forest for the trees...

 

[mlucitt]

Re: Jerry's " ONLY ONE IN THE COUNTRY" Phase Linear 700 Thre

Larry, good call. I found a very low profile metal cased jack that does not include a fuse for my Hafler 220. I wanted to install it in the PL700B where the current 120 VAC fuse is now, and that means I will have to relocate the fuse somewhere. I may move the existing fuse to the side (around the corner) if there is sufficient clearance within the cabinet.

I can order several of them if there is a demand. These input power jacks are rated at 15A and 250 VAC. They have a RFI filter inside and they are about 35mm wide to fit in the back corner of the PL chassis with some room to spare.

Mark

 

[laatsch55]

Re: Jerry's " ONLY ONE IN THE COUNTRY" Phase Linear 700 Thre

Mark if had to do it again, i would locate the IEC jack by the transformer where it belongs. Do away with the "convenience" outlet, and keep all the high current 120 stuff by itself in the tranny corner.

 

[laatsch55]

Re: Jerry's " ONLY ONE IN THE COUNTRY" Phase Linear 700 Thre

So.........Mark..........Jammin yet?????????????????????????

 

[speakerman1]

Re: Jerry's " ONLY ONE IN THE COUNTRY" Phase Linear 700 Thre

Larry, good call. I found a very low profile metal cased jack that does not include a fuse for my Hafler 220. I wanted to install it in the PL700B where the current 120 VAC fuse is now, and that means I will have to relocate the fuse somewhere. I may move the existing fuse to the side (around the corner) if there is sufficient clearance within the cabinet.

I can order several of them if there is a demand. These input power jacks are rated at 15A and 250 VAC. They have a RFI filter inside and they are about 35mm wide to fit in the back corner of the PL chassis with some room to spare.

Mark

How much are they Mark. I can get the regular ones and the fused ones. The fused one I had. I was using silver solder and it got to hot. Had to change it out. Wasn't a happy camper. Wondering what was wrong and it was the IEC. LOL

Larry