Modify your Woo 6. . Sophia and EML 274B . Images pages 32, 33, 34 of int. and ext. and discussion of the SE . . .

Is the EML 274B worth upgrade from Sophia tube? Are there better tubes than the 6DE7 that could improve my woo6? Kevin

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For me it is worth it , definitely , with GS 1000 !

Is it worth upgrading from Sophia ? I do not know , it is a very intimate issue considering price , own rig and taste .

At my level I would say it is more precise , more natural with fantastic soundstage but the Sophia has something special that makes it great .

Sorry for not being abble to help more for the moment .

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I've got the Sylvania and Raytheon 6EW7s as an alternative to my various 6DE7s. They both seem to offer more detail, resolution and air/space. But... a bit less prominent bass. A nice change of pace from my driving, dynamic, punchy Tung Sol 6DE7s. Though by Sylvania 6DE7s seem to be a blend of the 6EW7s and my 6DE7s.

Can't tell you about the EML rectifier. Though, its hard to imagine that it could be much better, if at all, than the Sophia Princess. And... at its price, I would think it would need to be somewhat better... unless... you don't mind investing in two expensive tubes.

I still prefer the Sophia, which sometimes makes me wonder if it is preference or something else. Maybe the interaction of my amp, since the power supply in mine is different from most others.

Ok, after not really using the 6 for about a week I turned it on and let it warm up real good. I then listened with my 5U4GB Philco. Not bad and then I plugged in the mesh plate EML 274B. Wow. Sometimes you need to take a break. The sound, silky but open and dynamic.

It's all good, just some is a little more gooder.

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I think mine is opening up more and more. I guess after the Denon mods I got even bigger sound stage

I truly like my WA6 with my custom Denons. What headphones do you use the most?

Pics:

Right now I am using the GS1000s the most, but I am after the Denon AH-D7000 when they are available in the UK. Just need some good people to buy my K701s and Shanling PH1000

I just added 3 teflon caps to the 6. One each for a bypass on the Mundorf silver/gold oil caps and one on the first power supply cap. I will have to let it all burn in but I have always liked teflon caps. From Russia with love 1989 vintage.

As an update to the teflon caps I have noticed that as they finally break in that the sound has become even more open and fluid. So my first cap in the power supply is bypassed with teflon and my coupling caps, the Mundorf Silver/Gold Oil is bypassed with .022 teflon. I also notice that the highs are even better. There is a more noticeable difference now between the 6 and anything else I have in amps.

On well recorded music the soundscape lays down before you that is open and airy with good placement of instruments and voices.

I have also noticed that the bass has taken on a quality that is nothing short of stunning. It is very tight, like a stretched rubber band but deep and dimensional. I have never heard the Ed. 9 sound so controlled.

With this I have been using the EML 274B mesh and older RCA 6DE7 tubes.

Wow, the sound continues to change and refine. Very, very transparent with the teflon caps. What is odd is that these are .022, which would be best for the high frequencies and can improve speed but the bass has improved as well as dynamics. the bass is very tight and real.

*******Caution: jack of wooaudio has let it be known that recents units of the wa6SE
have differing parts, and may need a change of the cathode caps to make use of alternative
tubes like the 6FD7 and 6GF7A. make sure your amp has the cathode caps rated at 200v or higher.
some earlier wa6SE units may have cathode caps rated at 100v only. (change to 200v or higher
if you want to make use of the 6FD7 and 6GF7A)


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.

after about a half a year of using the 6sn7 on the wa6 and the wa6SE i've come to the conclusion
that the 6sn7 is a superb drive tube with an efficient power section too, at least with class A SET with
a output transformer. it's quite different than the 6de7 which is a fine dissimilar triode in itself. the
6sn7 is an equivalent dual triode that seems to present a larger sound-scape or arena without any
hint of compression nor edginess. the 6sn7 presentation is more refined and has an elegant sound
that will offend the least whereas the 6de7 is very dynamic with a U-shaped freq. characterisics.
for 70's/80's rock the 6de7 is great but with classical and small ensemble jazz the 6sn7's refined
sound hits the spot dead on.

RECTIFIERS ( RECTIFIER ):
*these must be at or below 3.0A

5U4G/ 5U4GA/ 5U4GB/ 5U4WG ( U52, VT-244, 5931 )
5AR4 ( GZ34 )
5AS4
5R4/ GA/ GB/ GY/ GYA/ GYB/ WGA/ WGB ( CV717 )
5V4G ( GZ32, CV593 )
5AQ4
5Y3G/ T
5Z3 ( with adapter; 4-pin version of 5u4g )
5Z4G/ T ( GZ30, 52KU, CV1863, CV2748 )
U50, U54, U88
53KU
GZ33
GZ37 ( CV378 )
422A
274A ( with adapter )
274B *don't use chinese variance with 4.0A



DUAL TRIODES ( INPUT/OUTPUT ):
(#) = AMPLIFICATION "MU" FACTOR
no adapters are needed and these are
safe for use in wa6 and wa6SE:


6DE7 (17.5) - Fast transients, good for rock, pop
6EW7 (17.5) - Softer sound but slightly larger soundstage, good for some jazz, classical

*******Caution: jack of wooaudio has let it be known that recents units of the wa6SE
have differing parts, and may need a change of the cathode caps to make use of alternative
tubes like the 6FD7 and 6GF7A. make sure your amp has the cathode caps rated at 200v or higher.
some earlier wa6SE units may have cathode caps rated at 100v only. (change to 200v or higher
if you want to make use of the 6FD7 and 6GF7A)

6CY7 (68) - between 6de7 and 6ew7
6DR7 (68) - similar to 6de7 but higher gain
6FD7 (64) - punchy bass, large soundstage, fast transients

*update: with homemade adapters one can make use of the following
dual triodes in the output section. for use in the wa6 and wa6SE.

*******Caution: jack of wooaudio has let it be known that recents units of the wa6SE
have differing parts, and may need a change of the cathode caps to make use of alternative
tubes like the 6FD7 and 6GF7A. make sure your amp has the cathode caps rated at 200v or higher.
some earlier wa6SE units may have cathode caps rated at 100v only. (change to 200v or higher
if you want to make use of the 6FD7 and 6GF7A)


6DA7/A - similar to 6ew7 but hard to find
6cg7 **** - similar to 6sn7 but sounds bit more faster with less noise, smaller soundstage
6fq7 **** - same as above
6gu7 **** - similar to above
6gf7/A - higher gain with very fast transients
6cs7 - similar to 6ew7, good for string instruments
6sn7 **** - very little distortion, large soundstage, solid bass, refined mids and highs
7n7 (loktal version of 6sn7) - same as 6sn7
ecc31 - higher gain, clear sound, less euphonic
ecc32 - similar to ecc31
6dn7/6em7/6ea7 - similar to 6sn7 but less refined highs and slightly higher gain
6bz7 - similar to 6ew7
6385/2c51/5670 ** - large soundstage, clear highs, slightly higher gain
6900/5687/7119/7044 - punchy bass, fast transients
7308/e188cc - very musical with refined mids and highs, slightly soft transients
6922 /e88cc *** - same as 7308
6DJ8 /ecc88 *** - same as above with different specs.
7DJ8/PCC88 *** - same as above with differing heater req. but works with softer transients.
6N6P *** very natural, open presentation, with slight warmth. equals or betters the 6922.
............. slight mid-bass hump present compared to 6dj8 and it's variants. great for bass lovers
6H30 *** very open presentation and slightly more dynamic than 6N6P


**this is only for wa6, with or without the pdps
(but not a direct substitute for the wa6SE. one way to use them on the wa6SE is to lower the voltage
to 150v at the anode plates and to raise the resistance to grid at pin 2 to at least 50 ohms to avoid clipping due
to the high gain nature of the amp and the tube itself. this is an amazing sounding tube that's comparable to
the 6dj8 family imo. this can be internally in the amp section or in the adapter with use of resistor at pin 1 (anode
of the power section) and pin 2 (grid of power section).)

***(must lower the voltage being supplied to the anode plate to 90v for 6dj8 and 100-130v for 6922/7308
in both wa6 and wa6SE. cathode resistance must be raised to 5.2k from 3.3k for the wa6SE only, to avoid clipping
due to high gain.) the 7dj8 has a 7v heater requirement but the 6.3 seems to sufficient as the sound is great.
the 6N6P and 6H30 can be used directly, with the adapter, without any resistors in the wa6.
low and high voltages to the anode section works equally well with the 6N6P/6H30 type.
applied 22 to 24 mA seems to work well.

**** the 6SN7 works fine on the wa6 but not so good with the 6SE. However, if you raise the cathode
resistance from 3.3K to approx. 4.7k,to avoid clipping, it sounds very very fine. i love this tube. you can
work with the resistance value to voice the amp to your headphone. playing with the cathode capacitance
will further refine the sound to your liking. the 6cg7/6fq7 and 6gu7 is almost as good as some NOS 6sn7.
it seems to be quieter than the 6sn7 in that there are zero mechanical or microphonic noise.
if you use black gate capacitors after the rectifier, make sure it's rated at above 200v. ideally it
should be at 350v.

*******Caution: jack of wooaudio has let it be known that recents units of the wa6SE
have differing parts, and may need a change of the cathode caps to make use of alternative
tubes like the 6FD7 and 6GF7A. make sure your amp has the cathode caps rated at 200v or higher.
some earlier wa6SE units may have cathode caps rated at 100v only. (change to 200v or higher
if you want to make use of the 6FD7 and 6GF7A)

I thought the 6DE7 and 6EW7 were the only compatible driver/output tubes for the 6 and 6se. Are the others Woo approved? I don't want to shorten the life of my amp if they put more stress on the circuitry.

They shouldn't stress the circuit. There is little reason they would.

I wonder about any high frequency roll off. ?

no i didn't notice any high frequency roll off... which is a good thing.
i was afraid the high mu would cause distortion at top or bottom
but i didn't experience any.

it shouldn't put any extra stress on the amp/power transformer...
the output tubes have smaller heater current draw than the 6de7/6ew7
and both my amps have been fine during the past 7-8 weeks as i've
been using only the new output types on them.

As I continue to listen to the 6 after installing the .01 teflon bypasses for the first cap in the power supply and for the coupling cap, I have noticed positive changes as in fine detail retrieval and a since of air.

The sound is just cleaner with a black background. It has taken a few hundred hours for the teflon to settle and form but it was well worth it for the extra refinement of the sound.

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I'm wondering, everytime you change things it gets more detailed, at what point is it too much? "It's so transparent I can see God!"