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Review: Woo Audio WA6 vs. WA6SE (stock units) - Page 21

post #301 of 508
Quote:
Originally Posted by atbglenn View Post
I don't think it matters if they're matched or not. As long as they are the same brand, from the same vintage. I bought 4 RCA 6DE7's from tubedepot.com awhile back and I highly doubt if they are matched. I cant detect any imbalance whatsoever.
the pair doesn't have to be matched very closely, but i have found some
volume discrepancy between pairs with more than 20% difference in
transconductance using the tv7 d/u. for example 75/48 and 56/36 for a 6de7.
(using a bias probe and multimeter is much more exact since you'd be getting
reading at the amp's operating voltage...) the volume difference wasn't very
great but it is noticeable and can be somewhat annoying.
post #302 of 508
Quote:
Originally Posted by takezo View Post
the pair doesn't have to be matched very closely, but i have found some
volume discrepancy between pairs with more than 20% difference in
transconductance using the tv7 d/u. for example 75/48 and 56/36 for a 6de7.
(using a bias probe and multimeter is much more exact since you'd be getting
reading at the amp's operating voltage...) the volume difference wasn't very
great but it is noticeable and can be somewhat annoying.
I haven't noticed any imbalance the pairs that I own. I guess I got lucky, or my hearing is not as sensitive as yours in that respect.
post #303 of 508
This has been a very informative thread. Thanks to everyone for educating me about the two Woo6 amps and all of the possibilities.

A couple of questions if I may. How long is the umbilical cable from the PS rectifier unit to the 6EW7 unit? And does it help to physically separate the two sections, or can they sit side by side without any difference in noise/hum from the large power supply unit?

Thanks again for such an inspiring thread. Maybe if I get a tax refund this year . . . . . .
post #304 of 508
The umbilical is about 8 or 9 inches long so the units have to sit side by side.
post #305 of 508
Thank you sclamb!
post #306 of 508
Some quick, dusty snaps. Not used my camera for a while so I decided to test to see if still working.

Rear shot shows second inputs and switch removed from mine for cleaner signal path (by Jack Wu on my request).

The serial number is : S1108025. I assume this is numbered after its order or completion date 25/11/08??





post #307 of 508
Very nice AntiGeek.

This thread is killing me . . . . must . . . . . refrain . . . . . . from spending . . . . . .
post #308 of 508
My initial impressions with the RCA fat bottle 6FD7 are:

- Better soundstage.
- Much better instrument separation and air.

I like!!
post #309 of 508
Quote:
Originally Posted by tin man View Post
Very nice AntiGeek.

This thread is killing me . . . . must . . . . . refrain . . . . . . from spending . . . . . .
Resistance is futile!!

Sounds even better than it looks..
post #310 of 508
Quote:
Originally Posted by Torero View Post
My initial impressions with the RCA fat bottle 6FD7 are:

- Better soundstage.
- Much better instrument separation and air.

I like!!
What tubes were you using before the RCA 6FD7s?

I Also have some of these RCA fat bottle 6FD7 tubes.

Not yet tried them, though the thin RCA version does sound very good. Too much gain with the k701s through the 6se though. Perhaps the power output is slightly higher through the SE.
post #311 of 508
Quote:
Originally Posted by AntiGeek View Post
What tubes were you using before the RCA 6FD7s?
Before the 6fd7 i had used these tubes:

RCA 6DE7
RCA fat bottle 6EW7
SYLVANIA fat bottle 6EW7
GE clear-top 6EW7
RCA thin bottle 6EW7

IMHO, the best are GE and RCA thin bottle 6EW7's.

Now, the RCA 6fd7 are still burning. But my first impresions are very positive.

Coming soon: the GE clear-top 6FD7
post #312 of 508
Yeah, the GE 6EW7's are excellent tubes and seem to match the K701s perfectly. What I like most is the excellent treble / mids. On the start of almost any track of any CD recording, I can hear the background recording hiss (any anything else going on!!) prior to music starting. Really noticeble in recordings such as Nirvana "Unplugged in New York", one of my favourate "reference" recordings.

Another positive of these tubes is the deep 3d headstage. Makes excellently produced / engineered albums like Roger Waters "Amused to death" sound almost scary..
post #313 of 508
A very well written and thoughtful review and an interesting thread. Thanks everyone for the great info.
post #314 of 508
Thread Starter 
Thank you, Raylinds! A lot of people have contributed information to this thread, and it has become a great resource about these amps.

I am still very happy with my amp. I am thinking a lot lately about how nicely it could drive a pair of high-end phones. Say maybe... HD800's for example.
post #315 of 508
I have mine since last May, and I'm still in love with it. Great Amp!
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