phase linear 400

gene french said:
i have noticed...
on the 8 fin...which has been recapped...
ps cap upgrade...led upgrade...dcp added...
first power on of the day only....produces a noticable hum until the dcp relay engages....has done it since i got it from rob...i kept thinking that each upgrade would eleminate it...it didnt...
it performs as it is supposed to...
ideas???
Click to expand...
You need to be more specific Gene (you are dealing with a bunch of engineers).

The speakers hum? They are (supposed to be) disconnected from the amp and shorted to ground until the relay cuts in

Or the AMP hums? If it is the amp, have you pinned down where in the amp it hums?

If you hum it, maybe I can guess which :-)
 
If it's transformer hum, try snugging the bolts, gently. Expands as it warms up. That's the warmest part of my WOPLs during normal use. Maybe snug it up and see if it does it again tomorrow cold.
 
bunch of engineers, to say the least....
i noticed that....
you would have to drive a railroad spike through their ear so i could beat them at checkers....
sometimes i feel inadequate....
but, i quickly get over it...lol
anyway....
its just an amplified audio hum....at a moderate volume for a couple of seconds until the relay kicks in...then dead silence....and normal operation...
no clicks...no pops...no scratching....just an audio hum....no spikes or anything on the meters...
it never does it twice....only the first power on...i have two amps 8 fin and 4 fin...two preamps...with amp outputs connected to ab switch...as i only have one set of speakers....the 4 fin does not make any noise at all on power up...
the 8 fin has always done it since its arrival....i just kept thinking recap, setting bias, offset, ps cap upgrade would remedy it...it has not...
i will make a short video in the morning when i power up...
i can do mixing and matching when my switches and parts come in...and i open both up again...
i need to add the meter switch, add an iec socket on the 8 fin put the extra cooling fins, move the meter switch to joes position, and experiment with the leds on the 4 fin....wish i had some lighter lenses....that 8 fin looks nice and warm....
and of course new handles for all ....
 
George S. said:
If it's transformer hum, try snugging the bolts, gently. Expands as it warms up. That's the warmest part of my WOPLs during normal use. Maybe snug it up and see if it does it again tomorrow cold.
Click to expand...

yes sir...i too believe something is cold and expands when heated up...
its definitely coming through the speakers...
 
gene french said:
understood...
after 2 or 3 seconds you can hear the relay latch...the hum goes away...it only does it first power up...then no more...
when my switches and bias transistors come in...i can compare...i need to change out input jacks too...i bought 2 pair from watts...the 8 fins jacks are very loose...sometimes cut out and i have to wiggle input cable....
Click to expand...


Fix the loose wiggly shit. That's gonna be a KABOOM
 
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