Phase Linear prototype TS200 AMP??

JustMike

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laatsch55 said:
Ed said he usually has to talk to Dean about these kinda things..
Click to expand...
I cleaned the amp up. It looks a whole lot better now that the Pc boards are cleaned, I can see that they
are printed Phase Linear 200. A proto-type build probably would not have had any I.D. screened on the boards to start with so
these PL200 boards were borrowed to build this amp maybe. But the screen print (TS 200 Phase) on the rear is a mystery.
If i can dig up a service manual for the PL 200 series 1, this may help I.D> the circuit boards and give me the Info I need
to where to hook-up to check Bias. Does Bias adjustment also affect DC offset?

JM
 
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laatsch55

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Yes, generally the input differential pair, but it can come from mant nplaces depending on the amount of offset. Yours being slightly over 130mv is probably the input pair. Need some closeups of the component side of the boards...
 
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gadget73

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Could also be a resistor drifted off value and messing it up. Worth a try anyway, resistors are cheaper and easier to source.


Isn't the 200 board normally designed more like a combination backplane / driver with the output transistors right on the board vs bolted to a heatsink? Could be another sign of pre-production. All the ones I find pictures of look like this inside:



Thats actually pretty neat construction with a modular amplifier like that. Probably not too bad to service either, just pop the module out, do what needs doing, pop it back in.


The series 2 service manual seems easy enough to find. No idea how different it is from the S1.

http://akdatabase.org/AKview/thumbnails.php?album=94

schematic for a series 1:

http://www.schematicsunlimited.com/p/phase-linear/phase-linear-200-power-amplifier-schematic
 
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JustMike

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Sorry for the delay guys, had to go pic-up a family member at the airport unexpected. I'll get those pics of the
boards today Lee.
Gadget, thanks for the reference on the 200 stuff. I couldn't find a service manual either on line for the series 1.
later,
jm
 
JustMike

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laatsch55 said:
Yes, generally the input differential pair, but it can come from mant nplaces depending on the amount of offset. Yours being slightly over 130mv is probably the input pair. Need some closeups of the component side of the boards...
Click to expand...
For what its worth ,(good song by the way by Buffallo Springfield)

here is about the best pic I can get of the left board. (Right board component side is not pic-able without pulling but should
be same as left.

The IC's in the square heat sink cages are : RCA ic13 7708 grey and the lower one is: RCA ic12 7627 green.
OUTPUTS are : Left bank: RCA/BO4-CN7741 , Right Bank: RCA 401- 7940

After Cleaning, I verified that line voltage from Variac was right at 117vac.
And now the DC offset is:
Left ch: 22.6mv
Right ch: 24.0mv

Since I'm not sure on where to take the reading for the Bias, think I'll go ahead and hook it up and have a listen.
Sound ok to you all??
JM.
 
JustMike

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Asap I'll give it a listen Lee, Thanks for the input buddy. What was the Gentleman's name that owned the stack?
And Ken? is the one that also worked at PL and was helping with the shipping?
Wifes Brother arrived late last night so we will probably do a little smokin and jokin so be back shortly,
jm
 
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bias *might* be read across the two 10 ohm 2 watt resistors on the circuit board. Just a guess though.
 
laatsch55

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I don't know exactly who owned the stack. It was a friend of Ken's and ken had sold some of the pieces to that guy. I'll ask Ken about the 200.


Mike, could you see what the bolt size is that holds the rack handles on your Ser II 700 are. Joe asked yesterday and from memorey on Przems I told him 1/4-20. Could you conmfirm that please?
 
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laatsch55 said:
I don't know exactly who owned the stack. It was a friend of Ken's and ken had sold some of the pieces to that guy. I'll ask Ken about the 200.


Mike, could you see what the bolt size is that holds the rack handles on your Ser II 700 are. Joe asked yesterday and from memorey on Przems I told him 1/4-20. Could you conmfirm that please?
Click to expand...
Thanks Lee and Mike...the 700B only uses 10-32. Usually Phase Linear left plenty of slop in their screw holes in the sheet metal.
 
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I believe mine is 1/4-20 but it might be a #12 or #14 machine screw. The 700-II is a pan head screw, the Pro is a flathead with a countersink in the back side of the faceplate.
 
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Well after messing around with this little unknown ts200 phase amp for a few days now, I found that is has one dead
channel and the other doesn't sound too bad but in orde to repair this its going to take alot on un-soldering just to
get to the parts. I'm not that interested in doing any of that now, so into the broken pile it goes for the time being.
I was mainly just curious if it could have been a proto type. maybe the answer will surface later.
So I decided to move on and test the first of the two big amps. This PL700 SERIES II is the one Ed rebuilt and converted it
to full comp. Its a beauty. I check the DC (- 1.75mv left & 5mv right), brought it up on the variac slowly and all good.
Hooked it up to a known good preamp and a couple of small bookshelf speakers for a listen via cd player with a little
Diana Krall.
The common turn on current rush blew the speaker fuses (2amp) instantly! So left it as it was, replaced the fuses and
brought up the gain and the preamp volume.
THIS AMP SOUNDS AMAZING ! And quiet as a mouse.
What do you think I should do next? If anything. Joe? Lee? Add the WO board to rid the turn on rush? And is the board compatable
with Ed's full comp conversion?
I don't want to hook it up to the Dahlquists until I'm sure it won't start taking out fuses at start up. Mine are mounted
8 ft high on the walls like studio monitors at the moment. Pain to change fuses.
Man its nice to hear a Phase again. And I have two more waiting for the final system when the man cave room is done!
Jm
 
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