post #241 of 508
12/21/08 at 11:51pm
hi guys, i have a woo 6 with Sophia and western house 6de7 run with hd650. What tubes should i change to have a better sound? I found 2 Sylvania 6de7 for pretty cheap ($10). Should i give them a try?
the following rectifiers (input) and dual triodes (output) are compatible and safe to use with
the woo audio wa6 and wa6SE headphone amps. please feel free to add any other tube types
that are confirmed compatible, and are not listed below.
i was concerned about the high "mu" or amplification factor on some of the output tube types but
fortunately i've yet to encounter any distortion in SQ nor increase in floor noise. the increase in
"mu" definitely gives an increase in dynamics and soundstage. it should help those of you who
have a relatively low output power source DAC. likewise, if your DAC or CDplayer source has a
very high power output, you may encounter some noise or distortion with the high "mu" output tubes.
i use the vda2/vac1 DAC which puts out 2.25 vrms and did not encounter any humming.
i've been trying out the output tubes for the past 2 months and would've posted them earlier but
delayed it till i had a chance to receive all of those listed and gave it a good listen. i find them
more than acceptable and preferable to the 6DE7.
RECTIFIERS ( INPUT ):
5U4G/ 5U4GA/ 5U4GB/ 5U4WG ( U52, VT-244, 5931 )
5AR4 ( GZ34 )
5R4/ GA/ GB/ GY/ GYA/ GYB/ WGA/ WGB ( CV717 )
5V4G ( GZ32, CV593 )
5Z3 ( with adapter; 4-pin version of 5u4g )
5Z4G/ T ( GZ30, 52KU, CV1863, CV2748 )
U50, U54, U88
GZ37 ( CV378 )
274A ( with adapter )
DUAL TRIODES ( OUTPUT ):
(#) = AMPLIFICATION "MU" FACTOR
In which amp did you try these the WA6, or WA6 SE?
I would have thought the MU would produce too much gain in the SE, which already has a lot of gain / power output. I can barely stand the volume levels above 11 O'clock with the 6DE7s and the standard 2.2 volt source. I would think that would drop to <9 O'clock with these high MUs... and... would be very sensitive to adjustment. No???
So... all these output tubes are identical, except for the MU... and... are interchangeable???
i've tried them on both.
it will reduce the volume pot range if your source is high but it's a trade off
for the ability to try tubes other than the 6de7/6ew7. my source is 2.25vrms,
and using the 6de7 comfortable listening volume is at 11 o'clock... with a
6fd7 it's around 9 o'clock.
and best is that most of these are very cheap ~ $1 to $5 ... except the 6DA7/A
which go for about $10. and yes, these are safely interchangeable.
i'd say the 6fd7 is preferable to the 6ew7...
people hear things differently and have personal preferences, so
i don't want to say "better" like it's written in stone... i like all of
the output tubes... maybe the 6fd7 the best... followed closely by