Woo Audio Amp Owner Unite
Nov 5, 2010 at 5:14 PM Post #6,556 of 42,298
I guess people call them different way. I think the true "smoke glass" have a gray translucent glass like these.

 
Mine are the "solid grey glass with the vertical stripes". They are similar to these but the lettering on mine is almost gone.

 
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Nov 5, 2010 at 5:14 PM Post #6,557 of 42,298
Quote:
Originally Posted by sillysally /img/forum/go_quote.gif
 
Actually its the RCA fat bottle chrome top 6EW7. 1963 would be the best but any 60's built RCA chrome top will work just fine. Good match for the EML 5U4G.
 
ss

Quote:
The prices are on the high side but TubeWorld stocks them from time to time.  He seems to be under the impression that Woo owners want the thin bottle 6EW7 because that is what is always listed there where as the fat bottles tend to be sold out.  I found my favorite 6FD7 fat bottle tube there though so it is worth keeping an eye out.  Otherwise check eBay once a week or so, sometimes things pop up but it is harder to find matched pairs there.
 
The easiest way is to use vacuumtubes.net but because they deal in such bulk the quality/vintage can be a crapshoot with cheap tubes like these.  They have the largest inventory though so that is probably the best bet.


As I posted earlier, I was able to get a pair of Raytheon big bottle 6EW7s from Woo Audio; $18.00 for the pair including shipping.
 
One of the sites that came up during a Google search for the RCA tubes was www.electrontube.com.  Hodgjy had posted earlier about them. I contacted several places mentioned here earlier, and this was the only place that replied saying they had them in stock; they are RCA big bottle 6EW7 chrome tops, for $8.50 each, and they will test them to find a closely matched pair for an additional $3.00 per tube.  I also have a pair of these on the way.
 
If either of these pairs can improve upon the Sylvania 6EW7 / EML 5U4G combo by adding a bit more bottom end, I'll be extremely happy, especially at these prices.  
 
Nov 5, 2010 at 8:07 PM Post #6,558 of 42,298

This has been very helpful.  Thank you.
 
Quote:
I guess people call them different way. I think the true "smoke glass" have a gray translucent glass like these.

 
Mine are the "solid grey glass with the vertical stripes". They are similar to these but the lettering on mine is almost gone.



 
Nov 5, 2010 at 10:21 PM Post #6,559 of 42,298
Mike, if you go after a pair you want the ones on the bottom.  Try to find a pair from 1944 or 1945 (anything before that is super rare for this tube), if you take your time it isn't that hard to find this vintage.  The greyglass types where you can partially see through the coating don't sound as good.  I have both and the difference isn't subtle.  The ones with the solid grey RF coating are the best of the RCA 6SN7 tubes.  Very nice midrange timbre and well resolved with satisfying drive, but I find the top end to be their weak point.  They aren't open enough at the top for my tastes.  Definitely a worthy tube to have in your collection though.
 
The ones with the translucent grey coating don't sound bad per se, but if you are after clarity and resolution they are not it.  They really lack drive too, just soft everywhere, but they are incredibly smooth and warm without sounding cottony.  If you can live without some of the micro detail and texture they make an awesome jazz tube, but the ones with the solid grey glass are better all around tube and work better for most genres of music.
 
Nov 5, 2010 at 10:38 PM Post #6,560 of 42,298

 
Quote:
If either of these pairs can improve upon the Sylvania 6EW7 / EML 5U4G combo by adding a bit more bottom end, I'll be extremely happy, especially at these prices.  


Yes the RCA chrome top (there is a tip at the top of the tube also) should give you more lower end and a more realistic sound stage.
I think I got a lot of 10 nos RCA for $24 on E-Bay.
imo the RCA 6EW7 and EML 5U4G are about as good as it gets for the WA6SE.
 
Nov 6, 2010 at 12:04 AM Post #6,561 of 42,298


Quote:
Yes the RCA chrome top (there is a tip at the top of the tube also) should give you more lower end and a more realistic sound stage.
I think I got a lot of 10 nos RCA for $24 on E-Bay.
imo the RCA 6EW7 and EML 5U4G are about as good as it gets for the WA6SE.

 
That's good to hear; I'm anxious to get these and try them out.
 
I just spent a couple of hours listening with the EML and Sylvania 6EW7s (Mark Knopfler, Bruce Hornsby) and it seems to me that the bass and the midrange warmth and detail improve a bit after the amp has been on for an hour.  
 
I guess it's also possible that some of the improvement is from the EML 5U4G settling in, too; it has only 20-25 hours on it so far.  I have not put the Sophia Princess back in since I got the EML.
 
 
Nov 6, 2010 at 12:11 AM Post #6,562 of 42,298

Is this for a WA22?  I'm having problems keeping all these tubes straight.
 
Quote:
 
That's good to hear; I'm anxious to get these and try them out.
 
I just spent a couple of hours listening with the EML and Sylvania 6EW7s (Mark Knopfler, Bruce Hornsby) and it seems to me that the bass and the midrange warmth and detail improve a bit after the amp has been on for an hour.  
 
I guess it's also possible that some of the improvement is from the EML 5U4G settling in, too; it has only 20-25 hours on it so far.  I have not put the Sophia Princess back in since I got the EML.
 



 
Nov 6, 2010 at 12:17 AM Post #6,563 of 42,298


Quote:
Mike, if you go after a pair you want the ones on the bottom.  Try to find a pair from 1944 or 1945 (anything before that is super rare for this tube), if you take your time it isn't that hard to find this vintage.  The greyglass types where you can partially see through the coating don't sound as good.  I have both and the difference isn't subtle.  The ones with the solid grey RF coating are the best of the RCA 6SN7 tubes.  Very nice midrange timbre and well resolved with satisfying drive, but I find the top end to be their weak point.  They aren't open enough at the top for my tastes.  Definitely a worthy tube to have in your collection though.
 
The ones with the translucent grey coating don't sound bad per se, but if you are after clarity and resolution they are not it.  They really lack drive too, just soft everywhere, but they are incredibly smooth and warm without sounding cottony.  If you can live without some of the micro detail and texture they make an awesome jazz tube, but the ones with the solid grey glass are better all around tube and work better for most genres of music.



This is very helpful.  Jack says he has some of the RCA's, what he calls the smoke glass drivers and I am thinking they are the bottom pair.  However he is quoting me a price of $280 a pair.  What do you think of that price?  I'm thinking of bidding on a pair on ebay that look like the ones on the bottom photograph, and I don't think they will be nearly as expensive as with Jack (although you never know on an ebay bid.).
 
I am a jazz guy, and am sensitive to too much on the high end.  I just got an EML which replaced a Sophia and I found the Sophia leans to harsh.  So something that is not as open as say the Treasures would fit my tastes (especially with an HD800).
 
Back to price.  Since I don't actually know what I am doing yet, maybe it would be better to spend more with Jack and be safe.  So do you think Jack's pricing is a good deal?  Also where did you get your RCAs?
 
Thanks.
 
Nov 6, 2010 at 12:43 AM Post #6,564 of 42,298
Wow.  That is really high.  I got my pair off eBay for just over $50 bucks.  The trick to these is to watch auctions carefully.  Sometimes if they word the description strangely or cannot prove the tubes are NOS the auction will be largely ignored.  When I was watching this tube most auctions for the good tubes were ending around the hundred dollar mark, but sometimes you get lucky and they end lower like mine did.  What other tubes are selling at the time also matters a LOT.  If you are bidding in a greyglass pair and they are the only ones listed at the time it will be bid on by every person on eBay who is looking for that kind of tube.  But if there are several auctions for greyglass going on at the same time it spreads the interest around and everybody ends up bidding less aggressively as a result.
 
Either way the max I would ever pay for a pair of these is $100, unless they were pre-1944 and in absolutely pristine condition.  Don't be afraid to compromise a bit.  For example if they test a bit below NOS they'll go really cheap and so long as the tube was tested properly it likely will have nearly all of its usable life left still.  They generally last for several thousand hours, and in the Woo amps even longer so they will give years of service even if they aren't true NOS tubes.  I think of it has not having to deal with breaking them in personally. 
smily_headphones1.gif

 
Nov 6, 2010 at 12:49 AM Post #6,565 of 42,298
Yeah I am all about <slightly> used tubes, and seconds when available as long as they test good and are well matched. This NOS stuff gets a little ridiculous, and it will only get worse IMO.
 
Nov 6, 2010 at 12:59 AM Post #6,566 of 42,298


Quote:
Wow.  That is really high.  I got my pair off eBay for just over $50 bucks.  The trick to these is to watch auctions carefully.  Sometimes if they word the description strangely or cannot prove the tubes are NOS the auction will be largely ignored.  When I was watching this tube most auctions for the good tubes were ending around the hundred dollar mark, but sometimes you get lucky and they end lower like mine did.  What other tubes are selling at the time also matters a LOT.  If you are bidding in a greyglass pair and they are the only ones listed at the time it will be bid on by every person on eBay who is looking for that kind of tube.  But if there are several auctions for greyglass going on at the same time it spreads the interest around and everybody ends up bidding less aggressively as a result.
 
Either way the max I would ever pay for a pair of these is $100, unless they were pre-1944 and in absolutely pristine condition.  Don't be afraid to compromise a bit.  For example if they test a bit below NOS they'll go really cheap and so long as the tube was tested properly it likely will have nearly all of its usable life left still.  They generally last for several thousand hours, and in the Woo amps even longer so they will give years of service even if they aren't true NOS tubes.  I think of it has not having to deal with breaking them in personally. 
smily_headphones1.gif


Where are you with regard to how these guys sound in relation to the Tung-sol's?
 
 
Nov 6, 2010 at 1:40 AM Post #6,567 of 42,298


Quote:
I've tried this route before, and it was unsuccessful.  I emailed Roy and asked him if he had JAN CRC 6AS7G RCA black plate tubes.  I was told they did.  I ordered online and used the "no substitutes allowed" to order three of them.  All I can say is that I did not get the requested tubes.  Heck, they weren't even black plates.
 

 


Based on this Cat's feedback in this space, I think I'll walk! While he was pleasant during my conversation with him (Roy), I wasn't looking for tubes either. Just asking a general question... but now, why would I?
 
Nov 6, 2010 at 1:52 AM Post #6,568 of 42,298

 
Quote:
Where are you with regard to how these guys sound in relation to the Tung-sol's?
 


The round plates I assume, right?  I'm actually kind of hesitant to compare because I was listening to the greyglass when my EML tube was still new.  I intend to pair that combo again here shortly and listen some more.  The round plate tung sol is in a league of its own though.  I had to recalibrate a bit to enjoy my other tubes again after taking them out.
 
The presentation is quite different between the two.  The RCA exhibits a weight and thickness that contrasts sharply with the tung sol which comes off as sounding light and delicate.  The fascinating part is how the TS does this without sounding slow or feeling like it is lacking in drive.  There is a sense of finesse present that no other tube I've heard matches.  The detail comes in layers where you only hear a flat plane of sound with other tubes.  Tonally the greyglass RCA is more forward in the lower midrange, and has much less air from the upper midrange through the treble region.  High notes don't project like they do on the TS.  I think the TS midrange is more accurate, but the RCA suits some vocals well by lending added weight.  Both have nice detail and speed.  I think the RCA wins on PRAT by a little bit, but the TS has superior resolution and microdetail.  More than that it is all in how things are presented where the TS really excels.
 
Truthfully its really hard to put into words what I want to say for comparison.  They sound very different, but explaining that in words is hard for some reason.  The tung sol is better, no question, but it is also way more expensive so it ought to be.  I want to mention again my impressions of the greyglass are not fresh either so take this with a grain of salt.  That, and I actually thought the greyglass RCA didn't have great synergy with my EML 274B.  The detail got better, and everything gained control but they suffered tonally.  The midrange loses much of the warmth this tube is known for, but again I think I need to break them in more and try again now that the EML has more hours on it.  I've found that rectifier synergy really matters a lot in general.  Some rectifiers I have which I wrote off as bad sounding have turned out to be pretty nice with different driver tubes paired up.  It's all about identifying the characteristics in a tube you like and trying to pair those up with a tube whose characteristics will be complementary.  Or you could just randomly try stuff and be surprised when a combo sounds good, like I've been doing for the most part. 
smily_headphones1.gif

 
I also have some t-plate tung sols which are more in the same league with the greyglass.  These are basically tung sol mouse ear tubes only they don't actually have the mouse ears.  If I had to pick one or the other I would take this tung-sol too, but again this really reminds me how much the rectifier can change things.  Without the EML my answer would be the opposite.  I really like how the greyglass RCA sounds on my 5R4GY (my previous regular use rectifier before the 274B) and thought the tung sol t-plates sounded detailed but dry and off sounding somehow.  The EML literally fixed everything I didn't like about those tung sol tubes, and took something away from the greyglass in terms of portraying emotion in the music in exchange.
 
Something I would say in general is that I find myself just preferring the Tung Sol sound regardless of which particular tube it is.  They have a sense of balance and neutrality that I've come to prefer more and more over time.  Of course my EML is not losing its place in the rectifier slot on any long term basis, but I've been really surprised at how much I like the all Tung Sol combo I was running for the last few days (TS 5V4G and TS 6SN7GT T-Plate).
 
In the end all you can do is try things out and see what you prefer.  What I like might not be what you like, and what headphones we're listening on is a huge x-factor too.
 

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