finally got around to doing the mod on my wa-6...
i used all the same black gate caps as jack recommended, except
for the four cathode bypass caps... i used the black gate N-series
470uF/16v instead of the standard series...
changed all the resistors, except the arcol power resistor used for
filtering...mills 5 watt series and riken 1 watt series mixed in there...
purchased the .1uF v-cap as chris of vh-audio recommended this
as his personal favourite for balance and clarity for class-a tube amps.
had a hell of a time soldering the ground forks. had to clean and sand
it slightly to get it to adhere to the solder, but no cold-joints measured!
used only silicon rubber to hold the v-caps in place but it should hold
considering how solid and stiff those lead wires are!
here's a pic of my sloppy but efficient result:
initial listening resulted in less than mind-blowing impressions...but, i can already
sense the difference in the extension of the lower and upper frequencies.
everythings sound less burdened as if the bottle neck has widened vastly.
the bass is not as tight and focused, as expected of a new part...
the black gates will take some time to stabilize i'm afraid...the soundstage,
width and depth is smaller than what the stock caps provided with burn in...
(only about 30 min. burn in so far...) i'll give another listen at 100 hrs. of burn
one thing i did noticed, to my delight, was the salient superior clarity of
the mid region...at less than an hour burn in, the clarity of the mid region is already
superior to the stock caps...i can hear texture and nuances that i didn't detect earlier
with the stock version...one of my wife's favourite song is "in a manner of
speaking" by nouvelle vague but it's plagued by less than stellar record engineering.
that particular song sounded flat and not very dynamic nor
involving...but with the upgrades it sounds like a different version...i can now
hear the vocalists taking a breath between lines and the upper freq. is so
much more energetic and alive now...impressive...my wife, who's a musician,
but not an audiophile, could tell the difference too! "so, that's what you've
been doing..." was her comment to me...that's a compliment in my book...
my reference track to judge equipment is keith jarrett's "no lonely nights"
recorded by ecm, the 6'21" version. initial impressions with this track
is promising...the bass is somewhat less focused at this stage, but the
instrument separation, texture and clarity is already an improvement on the
already very good stock wa-6...the soundstage can open up with some
significant burn-in, i'm hopefully optimistic...was this upgrade worth the time
and money? an overwhelming yes, at this initial stage...i'll do another
comment at hour 400...btw, i'm using a 5r4ga tube with 6de7s and listening
with 701...transport is yamaha s-657 with vda-2 dac with vac-1 power
supply. using diy vampire silver stranded and jena labs cryo copper interconnects...