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Woo3 Modified - Page 15

post #211 of 242
Thread Starter 
That is a tough one without measuring the tube. It could be going bad or it just may be a noisy tube. Sometimes it might be gassy, which can cause the hissing or the internal construction could be a little off. Some people never store their tubes on the side but keep the tubes in the upright position. Most of the time I have seen tubes on their side but I try and store my tube upright. The idea is that the internal constuction could sag over time to one side causing problems due to the very close tolerances.

I have some tubes in that I have used in my 27 preamp that are from the late 1920's that will be noisy until they are on a few hours. I would just use the good tube, if it were me. It is part of the tube world. Some are good and some brand new tubes aren't.

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post #212 of 242
thanks John, I'll follow your advice (also about storing tubes upright, never thought about that...)
post #213 of 242
Thread Starter 
Quote:
Originally Posted by pftrvlr View Post
Has anyone tried re-wire the driver tube into SRPP?
This is an old post but for some reason I never saw it. SRPP would be interesting to do. Some people like it and others don't. I would enjoy trying it but often I have also found that having one single tube section or parallel, is more transparent. It would still be interesting though.
post #214 of 242
Hello!

My friend bought recently WA3 for his Senn HD650. He wants to change the stock tubes for something better. The impression is that, with the stock tubes, bass is great, highs are ok (even though they are rolled-off too much to my liking, I can hear the details are lost), the biggest complaint is sparkling mids. They are too emphasized - sibilant consonants are unpleasantly accentuated.

I am looking for any advise which tubes should I buy for my friend, with the following goal in mind:

Highs: Increase detail, reduce roll-off
Mids: Tame their sparklingness, remove the emphasis on sibilants
Bass: Leave untouched (or make it better/deeper, if possible)

The changes in sound we are looking for apply both to headphone output and pre-out, because the amp is also used as a pre-amp for his power amp/floor-standing speakers.

I would especially appreciate if someone could direct me to places where the recommended tubes are sold.

Regards,
Evgeny K.
Russia
post #215 of 242

Review This Thread...

Review this thread... and the other WA3 threads... and... you'll find your answer.

But, as I recall...

... most think the Tung Sol 5998 tube produces the best sound, in conjunction with Amperex 6DJ8 / 6922s, or maybe Siemens, Mullards, or even JJs, or maybe you could find some Telefunken equivalents.

But... you might try some Sylvania 6DJ8 / 6922s, or some Russian Saratov 6H23N-EBs, or possibly the Voskhod 6N1P-EBs.

I'd just do a Google search for these.

But... you might try www.tubeworld.com, Welcome to TubeDepot.com!, Vacuum tubes @ thetubestore. New and NOS electron tubes for any amplifier., or eBay. There are a lot more, though.
post #216 of 242
Quote:
Originally Posted by Gradofan2 View Post

... most think the Tung Sol 5998 tube produces the best sound, in conjunction with Amperex 6DJ8 / 6922s, or maybe Siemens, Mullards, or even JJs, or maybe you could find some Telefunken equivalents.

But... you might try some Sylvania 6DJ8 / 6922s, or some Russian Saratov 6H23N-EBs, or possibly the Voskhod 6N1P-EBs.

But... you might try www.tubeworld.com, Welcome to TubeDepot.com!, Vacuum tubes @ thetubestore. New and NOS electron tubes for any amplifier., or eBay. There are a lot more, though.
Thank you, Gradofan!
post #217 of 242
Oh boy this is a good thread...I lost my HP amp virginity here.

I use Tung Sol 5998 & Amperex 6922. Mine is 100 % stock inside...I was never brave enough to change it.
post #218 of 242
Just read the whole thread this morning(Now twice). This is on my radar. Good read.
post #219 of 242

Can anyone give a ballpark of how much Jack charged for the V-Cap + Black Gate upgrade?

post #220 of 242
Thread Starter 

I don't know if you can get the Black Gates any longer. I have some but they are no longer sold having been last produced a few years ago. On the V caps, I wouldn't put them into the Woo 3 but maybe some nice oil caps. The V caps are a few hundred and I don't think the Woo 3 will resolve enough to warrant the V caps. 

post #221 of 242
Before I embark on my WA3+ mods, I figured I drop in here 1st. As I look at adding a B+ bypass cap, I'm considering placing a .01 poly right on the tube socket for the output tube, between plate pins and ground with shortest leads possible as opposed to on the last cap on the filter choke. Any opinions on location and type for this cap?
post #222 of 242
Ended up going with a .1 WIMA MKP10 on the tube socket between B+ and ground. My impression is that it did add a little resolution to the high end and some air that seemed to be lacking before. Nothing profound, but a noticeable difference. I'm currently using a NOS GE 5998A in the output stage (gm of 15500)...I know some do not like them as they are solid state sounding and can go microphonic, but it does drive the output impedance down and I like the SS like control. Took me a while to get a quiet one. Drivers are Japanese gold pin 6BZ7. I really like this tube combo. When I get some time I may install a modified version of the ever popular Crack Speedball upgrade in appropriate locations in the WA3 to see what happens. Also investigating potential to drop a 6SN7 in the driver section. smily_headphones1.gif
post #223 of 242

I recall that Woo had a cap on the power tube several years back and it was removed to improve the sound. Maybe John can chime in and answer if the cap was on the same pin outs. Mines also a much older version.
 

post #224 of 242
Yes, there is sometimes one there. It's been interesting tracing the evolution of the design through the many photos posted on the web. I've seen early units with simple CRC-RC power supplies both with and without bypass that slowly evolved to a CLC-RC design with and without bypass....typically on the tube where I put this one. The driver circuit has also evolved significantly from a single stage with and without cathode bypass to parallel triodes with and without bypass to what now appears to be a gain stage and cathode follower buffer neither with bypass into the power tube via a coupling cap. My guess is that it was done this way to make it easier to add the preamp output...there are empty lugs in mine that look like it would be easy to just add in. Output seems to have always been a 6AS7 cathode follower coupled through fast electrolytics...sometimes bypassed, sometimes not. I think the modern low ESR caps may not really need bypassing on the output....mine sounds great with Nichicon PW(M) right now although I may try both bypassing and substituting with Silmic II to see what effect that has. Bypassing the gain stage in mine drives the gain way too high, so I pulled those back out. This really is a cool little amp!
Quote:
Originally Posted by Capt. Z View Post

I recall that Woo had a cap on the power tube several years back and it was removed to improve the sound. Maybe John can chime in and answer if the cap was on the same pin outs. Mines also a much older version.

Edited by GrindingThud - 2/5/13 at 2:17pm
post #225 of 242

If I understand you correct the Woo 3 has gone through some major changes, not just some tweaks. Is that correct?  blink.gif
 

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