phase linear 400

bad news...with 8 fin...
that pesky hum on power up...
came back to bite me...
rail voltage on left output...
no damage thanks to mr. watts...
plenty of parts ...
will figure it out ..
i installed new watts input jacks...left channel had old mica and compound...cleaned it up...installed sil pads....last it played....at first bias would not adjust...all down hill from there...within an hour...it quit ...gave up...surrendered...
today was 10 steps forward...only 1 backwards!!!!
 
gene french said:
thank you mr. george...how was vacation???
Click to expand...
Spent the first week in a State Park cabin on a lake on the OH/PA border and this week in a beach front house on NCs Outer Banks.
Most of my inside free time this week was spent reading Steven Tyler's autobiography "Does The Noise In My Head Bother You?", and researching AR-XB turntable upgrade mods on AudioKarma.
I was going to leave it pretty much stock, but remembered reading years ago about a Mechanical Engineer and AR turntable guru named Marc Morin and his upgrades. Sadly, he passed in 2020, but he freely passed on his knowledge.
So, I'll be doing most of his upgrades once the parts come in.
 

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Gene, zoom in on the photo and look at the feet that are visible and the gap between the faceplates. Nice gaps on the stacked components and nice gaps under the face plates on the amps. This aids cooling.
 

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first wopl observations:
not in any particular order....just writing as i think of these...
1: once populated with outputs the offset on both channels was plus or minus 1 mv....very accurate....
2: once the bias transistors added....the bias was extremely stable...and was so easy to set....
did not wander or fluxuate back and forth as the original counterparts...very stable....short warmup...
3: the boards were well marked, and easy to decipher when installing the components...
4: the board quality was quite evident....as were the parts....the tolerances were the best available...
5: wire supplied is the finest money buys....looks absolutely gorgeous when completed....
6: plenty of documentation....maybe too much...i got 34 multi page document files upon purchase....i know i did not read thoroughly enough...
is very very difficult for me...after a few minutes i lose concentration and find my mind a million miles away....i end up rereading passage after passage in order to absorb the content....i know many think i needed baby sitting...well, the truth be known....i really appreciated the efforts of so many....
7: built with the watts dcp board in mind and recommended....nice touch...
8: the chassis i got was a quality piece...heavier...welded corners...a bit bigger.....no screw holes....all reinforced threaded holes for the machined and color matching screws....the power socket was a very nice touch....additional holes which george helped me take advantage of...the switch hole was a nice touch too....i used an early 4 fin as a donor amp for the build...the holes on the fins was not an exact match for the holes in the new chassis...was easily remedied....i clamped them together and used a reamer to align perfectly....with georges suggestion....i bought a tap and die set to freshen all of the female threads....a very simple task that made a world of difference installing....i had a buddy here make new fins to convert the chassis to an 8 fin....worth every second of effort....i did leave them unpainted as advised that paint is not your friend for heatsinks....i did color the edges with a marker...from the edge looks nice....
9: very improved mounting for the outputs....no air conditioning duct screws....lol....again...machined....
10: the outputs were a bit difficult to mount because the holes were not tapered...i took a new pencil and glued a small round magnet on the eraser to install the transistors....was tedious but not necessarily frustrating to install....enough of the legs came through the holders that i felt secure about the connections as the back planes are spaced away from the chassis wall....the back planes were extremely accurate....
11: looking forward at the time of construction i felt the build was more complicated than i anticipated....
12: looking back after completion....it is more understandable about the how and why of the process and parts....very well planned out...i feel if'/when i ever built another....i would not be intimidated as much as i was when this one started....
13: i really liked the way the parts were bagged and labeled....you were given multiple tasks involving one part at a time....very organized....
14: all of ones needs for this build....all misc parts were made available through white oak....big parts, small parts....very convenient not having to buy from different sources....
15: white oaks prices were very reasonable....even cheaper than mouser in most instances....at least it was for me....
16: plenty of support from the head knocker at white oak and the kind members of phoenix audio forums....above and beyond the call of duty....i was told that i would not be allowed to build a crappy amp....was guided every step of the way....i know i aggravated many, for which i extend my sincere apologies....however i have an heirloom as well as a durable daily driver...
16: the first song i played was marcus nimbler rendition of the wanderer....i was a bit set back with the power and definition of the sound coming out of my speakers....this amp retained the sound and feel of the original phase linear amps....great designing job....i am sure that was white oaks plan all along....more accuracy, head room, durability, noise free....yet retaining the look/feel of this classic and revolutionary design by bob carver....
17. the power up was very nerve racking for me...but, very uneventful....many eyes were watching my photos...and a few errors were caught and corrected....
18. i bought more equipment and tools for this adventure...and now can accomplish more with less effort and more confidence...
19. i improved my knowledge and understand of electronic behavior as a result of this build...
20. white oak has an honest love of this part of audio history....it shows in the quality of his design and parts....no cut corners...
plenty of mounting and building aids included to ease the pain of assembly....
21. i want to thank sniff too....he helped me improve my soldering capability....i appreciate his advice and experience...
22. laatsch with the first a silent....was so encouraging....and has done a great job of presenting and maintaining the web site....i have made 3 or 4 contributions for maintainance....maybe others can do the same....when they feel as if they got their moneys worth of aid....very cheap investment i think....
23. mr george ... your help is beyond my appreciation....i cant say enough...
24. nicely done joe...
i am sure there is so much i have left out....but, my days listening to my creation have just begun...
i am still waiting on the handles....and the switches that i misordered....
to finish my amps...
i learned so much....and have the pride to know....that i built it myself....i am very happy with the results...
thanks to all....again and again...

now, i must return to the 8 fin to see what gives...i have enough info in this post to go back and reread to help me find the error of my ways....
i appreciate all of the eyes and ears that guided me...
 
you guys should REALLY be proud....
i diagnosed, changed out the transistor, and got the 8 fin back on line....all by myself....
didnt even have a cheerleader....maria went to the big city to see her mom....
it was q3 on a 14a driver board....
waiting on handles....switches....
thanks everybody!!!!
 
gene french said:
you guys should REALLY be proud....
i diagnosed, changed out the transistor, and got the 8 fin back on line....all by myself....
didnt even have a cheerleader....maria went to the big city to see her mom....
it was q3 on a 14a driver board....
waiting on handles....switches....
thanks everybody!!!!
Click to expand...
btw...no more pesky hummmmm.....
all sounds great...
gotta put the extra fins on the original 4 fin 400....
maybe today...maybe not...
good morning phoenix!!!!
hope all of you the very best!!!
is pura vida here!!!
 
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