The full complimentary output stage was near the end of the II series. The main difference between the "series I" and the "series II" is "series I" have a discrete input stage (Q1,2, and 3) and "series II" has an opamp for the input stage. The circuitry from Q4 on is pretty much the same. Another minor difference between the two are the VI limiters, germanium for the "series I" and silicon for the "series II".
Craig
Craig
Yes, I have the service manuals. Just let me know your email address as the size is too large for this forum. Thanks.
...and for European people another BIG difference is Series I had no double primaries transformer so we can't get any of those amps from the USA, especially my love: the rare 700B!!
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PL introduced the full complementary output stage when no more customised XPL909 and FPL909 devices were available. According to the service bulletin, the modification began from s/n 4A31658 for the model 400-II and from s/n 7A10701 for the model 700-II. Therefore very early amps from Series II were produced as quasi complementary.
You have mail...let me know
Concetto
P.S.: there is no full comp. manual. You'll have to read the service bulletin at the end of the manual.
If you are fixing a duff amp I wouldnt just replace all the output transistors.
Just fit a single pair to see if things are going to be OK, just dont drive it very hard.
I would rather blow 2 transistors than 24 !!!
What I usually do is remove all output transistors and feed teh vas output back into the ltp and check for correct dc conditions. This is also good because you are unlikely to blow a fuse with the output transistors out of circuit.
Most probably it won't work - this amp is sensible on any small differences in current sharing (see the applicable test explained in P/L 700 series II service manual).
More info for 700 Series II owners is here: Any Phase Linear Experts out there? - Page 5 - AudioKarma.org Home Audio Stereo Discussion Forums
Regards.
I've actually used the kits from Qua-Co to rebuild a comprehensively blown up 700B. The amp's owner had new carpet installed and staples met speaker wire, with predictable effects. he'd have been OK if he hadn't replaced the blown fuse with a 30A, but after the second turn-on the amp had had enough.
Both boards and all of the outputs had to go. I installed the Qua-Co parts as provided. The only oddity was a temp compensation transistor that had to be re-cased in a clip and had a different pinout. The amp biased up and ran on the first try. I still have some of the original outputs laying around that were not toasted but I doubt they're good for anything after so many years of running.
Both boards and all of the outputs had to go. I installed the Qua-Co parts as provided. The only oddity was a temp compensation transistor that had to be re-cased in a clip and had a different pinout. The amp biased up and ran on the first try. I still have some of the original outputs laying around that were not toasted but I doubt they're good for anything after so many years of running.
700B assistance
I have a 700B and the amp operates fairly well, replaced outputs with MJs, and during usage I noticed output heat sinks get relatively HOT! Is this normal?
I fiquring the outputs might not be sharing current evenly, is there anyway to test and balance...or do i need to move transistors around to get balanced as close as possible?
On the output section how would I test the output currents, refrence to ground and check voltage at emitter? or test voltage across .33ohm resistors of each transistor?
Would never connect to my speakers unless I have inline fuses on speaker cables both red and black..
Normally I wouldnt fuss with transistors but love the look of this amp...love tubes better anyway, they are more natural sounding than transistors and being a tech for tubes very easy to fix and balance...and if tube shorts my speakers dont got POOF!...
I have a 700B and the amp operates fairly well, replaced outputs with MJs, and during usage I noticed output heat sinks get relatively HOT! Is this normal?
I fiquring the outputs might not be sharing current evenly, is there anyway to test and balance...or do i need to move transistors around to get balanced as close as possible?
On the output section how would I test the output currents, refrence to ground and check voltage at emitter? or test voltage across .33ohm resistors of each transistor?
Would never connect to my speakers unless I have inline fuses on speaker cables both red and black..
Normally I wouldnt fuss with transistors but love the look of this amp...love tubes better anyway, they are more natural sounding than transistors and being a tech for tubes very easy to fix and balance...and if tube shorts my speakers dont got POOF!...
Hi...
Flame Linear, Fuzz Linear, .ay Linear...whatever...
But mine works fine and sounds ok to me. I use it in combination with AR10pi...
Where I live we have cold winters and hot summers. It is warm but not too hot.
If you want to drive some 2E loads or use it in PA application it is probably bad idea. It is not designed for such use (which amp from that era was?) and it is 35 years old so....and it has some construction mistakes.....mechanical mainly...
So Idle current can be adjusted by means of measuring voltage across driver emitter resistors. There is service manual for 700 series II but output stage is identical so...
It is funny vintage amp. I like it. But must be properly serviced otherwise it will torch down your speakers....To install dc protection circuit is wise idea.
I've found this text as well. I hope that it will be helpful.
Very best regards, Taj
http://thecarversite.com/shell2.htm
Flame Linear, Fuzz Linear, .ay Linear...whatever...
But mine works fine and sounds ok to me. I use it in combination with AR10pi...
Where I live we have cold winters and hot summers. It is warm but not too hot.
If you want to drive some 2E loads or use it in PA application it is probably bad idea. It is not designed for such use (which amp from that era was?) and it is 35 years old so....and it has some construction mistakes.....mechanical mainly...
So Idle current can be adjusted by means of measuring voltage across driver emitter resistors. There is service manual for 700 series II but output stage is identical so...
It is funny vintage amp. I like it. But must be properly serviced otherwise it will torch down your speakers....To install dc protection circuit is wise idea.
I've found this text as well. I hope that it will be helpful.
Very best regards, Taj
http://thecarversite.com/shell2.htm
"(which amp from that era was?) "
The McIntosh MC2300 can drive a 0.25Ω (0R25) load in mono.
A PL is kind of iffy at 4Ω, depends on how reactive the load is. Cerwin Vega made some special 6Ω coils for PA use (instead of their normal 4Ω coils). I cut holes in the front panels of my PL400s and mounted a fan in them, it really helped.
The McIntosh MC2300 can drive a 0.25Ω (0R25) load in mono.
A PL is kind of iffy at 4Ω, depends on how reactive the load is. Cerwin Vega made some special 6Ω coils for PA use (instead of their normal 4Ω coils). I cut holes in the front panels of my PL400s and mounted a fan in them, it really helped.
I guess what can PL drive if you connect some 100:1 transformer to the output...if only matters how ,,low,, it can go. I agree completely that all PL amps suffer from overheating and poor mechanical construction. Mine has chassis torn apart at corners because metal is ti thin to support bulky transformer......but again for its age for era when it was build ....for materials which were available and experience with solid state which Bob can possibly have.....today everything is much more available. Good materials and experience. Bob already made some mistakes and we can learn ....
And again I don't think it was intended to use PL amps in ,,pro,, applications at first place but there really was't a lot of choice.
What about classic american muscle car? Is it rational to have it? Is it good choice? What about fuel consumption? What about brakes?.....
But if someone like such car( I do)..... it is beautiful piece of history.
And PL amps are just like that. Piece of history. There is no use to debate is it good or bad. It is history. Past....
No hard feelings and very best regards, Taj
And again I don't think it was intended to use PL amps in ,,pro,, applications at first place but there really was't a lot of choice.
What about classic american muscle car? Is it rational to have it? Is it good choice? What about fuel consumption? What about brakes?.....
But if someone like such car( I do)..... it is beautiful piece of history.
And PL amps are just like that. Piece of history. There is no use to debate is it good or bad. It is history. Past....
No hard feelings and very best regards, Taj
phase linear 700B
It really is a shame bob created a great looking amp with a crappy design, I really like the amp but not a SS guy. Tubes forever! I hear all the stories in the years about these amps and would never even consider putting these on my Infinity's or Magnapans only because of the shorting potential of the transistors...fortunatly didnt pay for this amp so its been in the sideline for a few many years and will probably never see a connection to my speakers. Should gut it and build a tube amp from the chassis with those huge VU meters...
It really is a shame bob created a great looking amp with a crappy design, I really like the amp but not a SS guy. Tubes forever! I hear all the stories in the years about these amps and would never even consider putting these on my Infinity's or Magnapans only because of the shorting potential of the transistors...fortunatly didnt pay for this amp so its been in the sideline for a few many years and will probably never see a connection to my speakers. Should gut it and build a tube amp from the chassis with those huge VU meters...
think of it this way, what real audiophile is going to have speakers that are 8ohm rated unless they are single ended tube lovers with horns and super efficient speakers, if the 700B with all that power cant handle a 4 ohm load even 6 ohms it deserves to be a place to put my coffee cup while Im listening to my homemade amps that drive my infinity's with ease...I really havent found a SS amp that I really liked anyway, they are always lacking or overpowered in areas mostly midrange. alot of the amps are massed produced and to cut corners, they cut the component quality anyway, unless you by a McIntosh or Threshold but whos got 8-12k to spend in this Obama Nation...
"think of it this way, what real audiophile is going to have speakers that are 8ohm rated "
When the PL700 was current most hi-fi speakers were 8Ω.
We used them in PA (with fan-cooled racks) for mids and HF driving 4Ω loads, usually four 16Ω drivers in parallel. Bass was a different story.
"unless you by a McIntosh or Threshold but whos got 8-12k to spend in this Obama Nation... "
One can buy used for a reasonable price, or build a clone of same. Both Nelson Pass and McIntosh are quite free with their schematics.
Story:
I loaned a small (120W) McIntosh out to a bar while their PL700B was being fixed, they wanted to keep it when I got their PL done (the Mac sounded better). An agreement was reached that made everyone happy.
When the PL700 was current most hi-fi speakers were 8Ω.
We used them in PA (with fan-cooled racks) for mids and HF driving 4Ω loads, usually four 16Ω drivers in parallel. Bass was a different story.
"unless you by a McIntosh or Threshold but whos got 8-12k to spend in this Obama Nation... "
One can buy used for a reasonable price, or build a clone of same. Both Nelson Pass and McIntosh are quite free with their schematics.
Story:
I loaned a small (120W) McIntosh out to a bar while their PL700B was being fixed, they wanted to keep it when I got their PL done (the Mac sounded better). An agreement was reached that made everyone happy.
When the PL700 was current most hi-fi speakers were 8Ω
Yes,hi-fi speakers were 8ohms, today there called CE, consumer electronics. Hi-fi then were speaker like cerwin vega, bose, kenwood, pioneer, even radio shacks Mach1s.. SPL's were 90 -110s, what I meen by audiophile are speakers like Apogee, Martin logan, Magnaplanar, infinity etc..loads that were 4 ohm and under and SPL's are 80-86. Minimum wattage on some of these are 100 watts.
One can buy used for a reasonable price, or build a clone of same. Both Nelson Pass and McIntosh are quite free with their schematics.
I've looked for Mac's and some amps like thiel and manley's but people know what they have and your lucky to get 20% off what they were new. as for building them, the problem is trying to source the parts and equiptment to align and bring amp to specs. Then you got the aggravation of building a enclosure..
Ive been a audiphile since I was 13, and at 15 bought my first real set of speakers, Infinity RS4.5s from which I worked and saved. I still have them too. Studied in the EE field and now at 46 i'm lucky to get 8 hours at work.
If your intrested I posted couple of my amps in section tubes/valves, sticky's photo gallery, page387 post 3864 and 3867.
So what was the agreement? How was everyone happy?
Yes,hi-fi speakers were 8ohms, today there called CE, consumer electronics. Hi-fi then were speaker like cerwin vega, bose, kenwood, pioneer, even radio shacks Mach1s.. SPL's were 90 -110s, what I meen by audiophile are speakers like Apogee, Martin logan, Magnaplanar, infinity etc..loads that were 4 ohm and under and SPL's are 80-86. Minimum wattage on some of these are 100 watts.
One can buy used for a reasonable price, or build a clone of same. Both Nelson Pass and McIntosh are quite free with their schematics.
I've looked for Mac's and some amps like thiel and manley's but people know what they have and your lucky to get 20% off what they were new. as for building them, the problem is trying to source the parts and equiptment to align and bring amp to specs. Then you got the aggravation of building a enclosure..
Ive been a audiphile since I was 13, and at 15 bought my first real set of speakers, Infinity RS4.5s from which I worked and saved. I still have them too. Studied in the EE field and now at 46 i'm lucky to get 8 hours at work.
If your intrested I posted couple of my amps in section tubes/valves, sticky's photo gallery, page387 post 3864 and 3867.
So what was the agreement? How was everyone happy?
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