phase linear 400
- Thread starter gene french
- Start date
- Joined
- Mar 6, 2022
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- 5,563
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- music...the healer of souls...
well....got a bit done on the new to me 400....
installed the dcprotect board....
checked a few things....did a bit of cleaning....
prepared for led board install....meter switch wired up and in...
noticed something different....of course i have seen just 6 pl400s on the inside of the chassis...
the driver board just says 14...
no a or b...
did not know that existed....
b- fuse blown....
main power fuse blown....
dbt bright...
this machine has rca 66546 drivers....never seen this either...the service manual shows these drivers on one of the revisions....
and the f 909s....
found two 909s bad....honestly the first pull and the last pull....
there are reddish silicone pads under the transistors....very slick...slippery....
and were tightened so hard....some were cut...but evidently not shorted....
absolutely no sign of the heat sink compound on this machine....
did they build these in that fashion???
all of my other 400s were covered with the white compound....
with all of the transistors removed....no more bright dbtester....
but, will change the sil pads under the drivers....i do have spare f 909s....
all of these seem to be original as the batch numbers match on all transistors...
no signs of mods....or work being done....except the above noted sil pads...
after a bit more investigation.....i will order the cap upgrade from mr. joe...
and see what gives....
maybe this will be a nice unit....for now it is my spare...
thanks for reading....
all advice welcomed....
installed the dcprotect board....
checked a few things....did a bit of cleaning....
prepared for led board install....meter switch wired up and in...
noticed something different....of course i have seen just 6 pl400s on the inside of the chassis...
the driver board just says 14...
no a or b...
did not know that existed....
b- fuse blown....
main power fuse blown....
dbt bright...
this machine has rca 66546 drivers....never seen this either...the service manual shows these drivers on one of the revisions....
and the f 909s....
found two 909s bad....honestly the first pull and the last pull....
there are reddish silicone pads under the transistors....very slick...slippery....
and were tightened so hard....some were cut...but evidently not shorted....
absolutely no sign of the heat sink compound on this machine....
did they build these in that fashion???
all of my other 400s were covered with the white compound....
with all of the transistors removed....no more bright dbtester....
but, will change the sil pads under the drivers....i do have spare f 909s....
all of these seem to be original as the batch numbers match on all transistors...
no signs of mods....or work being done....except the above noted sil pads...
after a bit more investigation.....i will order the cap upgrade from mr. joe...
and see what gives....
maybe this will be a nice unit....for now it is my spare...
thanks for reading....
all advice welcomed....
- Joined
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- 74,874
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- Halfbiass...Electron Herder and Backass Woof
- Joined
- Mar 6, 2022
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- 5,563
- Tagline
- music...the healer of souls...
thank you mr. george!!!
i have 4 gold plated ones from watts and a pair from you!!!!
i changed them out...finished the recap...installed the light board...bias set 350mv...9mv offset....
plays beautifully!!!
meters respond!!!
gonna order the ps cap upgrade and call it done for now!!!
gonna write now to mr. joe!!!
i have 4 gold plated ones from watts and a pair from you!!!!
i changed them out...finished the recap...installed the light board...bias set 350mv...9mv offset....
plays beautifully!!!
meters respond!!!
gonna order the ps cap upgrade and call it done for now!!!
gonna write now to mr. joe!!!
- Joined
- May 14, 2014
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- 2,321
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- Tagline
- No such things as bad days, just bad moments
- Joined
- Mar 6, 2022
- Messages
- 5,563
- Tagline
- music...the healer of souls...
- Joined
- Mar 6, 2022
- Messages
- 5,563
- Tagline
- music...the healer of souls...
just heard back from my buddy....
220 is good as it is set up for being able to bridge. you can also bridge the 200. If you are really lucky and can find two P-230 amps, they have the mono/stereo switch already installed. All you have to do is change the 1/4 phono jacks with rca connectors for home use and they have 6 Mosfets a channel instead of 4. I am not on any forums as I am old and too busy but there are some who mention my designs. The Hafler is a more stable design than any Phase Linear amp. Phase may look impressive, but it was never very stable in the Quasi output mode. The late model complementary output amps were better but too late in production.
pretty much what joe and sniff say too...
220 is good as it is set up for being able to bridge. you can also bridge the 200. If you are really lucky and can find two P-230 amps, they have the mono/stereo switch already installed. All you have to do is change the 1/4 phono jacks with rca connectors for home use and they have 6 Mosfets a channel instead of 4. I am not on any forums as I am old and too busy but there are some who mention my designs. The Hafler is a more stable design than any Phase Linear amp. Phase may look impressive, but it was never very stable in the Quasi output mode. The late model complementary output amps were better but too late in production.
pretty much what joe and sniff say too...