Woo Audio WA3 Impressions and Tube-Rolling

[bpiotrow13]

In any event, you are right about WA3’s musicality. I actually prefer the WA3 to its bigger OTL sibling, WA2.

Same with me, once I had them

 

[erics75]

• What tubes are you using in WA3? I have found that I certainly prefer a variety of ECC81 / 12AT7 tubes, with Pulse Tube Store adapters, over ECC88 / 6922 / 7308.
• In any event, you are right about WA3’s musicality. I actually prefer the WA3 to its bigger OTL sibling, WA2.

i'm not sure the exact vintage of the tubes, this is what the seller put in the ad:

Includes a Raytheon 6080 and National Brand 6922 tubes.

They don't look like new production tubes, but beyond that i'm a novice at reading NOS tubes. they're in the amp and warmed up for the day but i'll snap some pics at lunch when i let the unit cool down.

i'll have to look into those adapters, i have a bunch of 12A_7 tube from previous amps. from your experience would i get more noticeable changes swapping driver or power tubes? with my Stratus and Kenzie I definitely notice more meaningful changes on the power tube side, but with the pendant it was all about the input tube.

 

[jonathan c]

i'm not sure the exact vintage of the tubes, this is what the seller put in the ad:

Includes a Raytheon 6080 and National Brand 6922 tubes.

They don't look like new production tubes, but beyond that i'm a novice at reading NOS tubes. they're in the amp and warmed up for the day but i'll snap some pics at lunch when i let the unit cool down.

i'll have to look into those adapters, i have a bunch of 12A_7 tube from previous amps. from your experience would i get more noticeable changes swapping driver or power tubes? with my Stratus and Kenzie I definitely notice more meaningful changes on the power tube side, but with the pendant it was all about the input tube.

This sounds ‘hedgey’ but with WA3, power tube and driver tubes make differences. The depth & extension of Chatham 5998 are obvious compared to those of, say, Thomson-CSF 6080WC. The same can be said of RFT ECC81 ‘foil getter’ versus Amperex PQ 6922. EDIT: if WA3 used tube rectification, the choice of that tube would be critical to sound quality.

 

[Pharmaboy]

i'm not sure the exact vintage of the tubes, this is what the seller put in the ad:

Includes a Raytheon 6080 and National Brand 6922 tubes.

They don't look like new production tubes, but beyond that i'm a novice at reading NOS tubes. they're in the amp and warmed up for the day but i'll snap some pics at lunch when i let the unit cool down.

i'll have to look into those adapters, i have a bunch of 12A_7 tube from previous amps. from your experience would i get more noticeable changes swapping driver or power tubes? with my Stratus and Kenzie I definitely notice more meaningful changes on the power tube side, but with the pendant it was all about the input tube.

It took me years to get the right NOS tubes to make the WA3 come alive. And then it did come alive, quite noticeably, compared to all other tube sets used:

• My first big step was to get the legendary Tung Sol 4998 to use as the power tube. Big sonic gain there, immediately evident
• As for drivers, I tried a number of pairs of 6DJ8/6922/7308s. But nothing really stood out until (with Jonathan C's extremely knowledgeable help) I tried a pair of 1950s Brimar C455s with adapters. Instant success!

The WA3 always sounded pretty good, no matter what tubes I used. But with that particular combination of input and power tubes, it scaled upwards quite noticeably.

Of course these are not the only NOS options that work well with the WA3, but once I stumbled onto those, I'm done experimenting.

 

[jonathan c]

[Chatham 5998, Brimar CV455 (KB/FB, Footscray), Norne Audio Vykari HPC, ZMF Verite Open (LTD Stabilised Green)]

 

[jonathan c]

.

 

[jonathan c]

Another wonderful Woo WA3 trio: Mullard ‘gold pin’ 6201 pair, RCA 6080 .

Slightly warm, no loss of detail!

 

[Gemini88]

Here's the Cetron 5998A in action with 2 Russian 6N1P-EBs. This 5998A looks like a Tung-Sol 7236 with a few pieces missing but the datasheet says it's electrically the same as the 5998. The sound is similar to both, with deep powerful bass and a wide open soundstage.

 

[jonathan c]

@Gemini88 , nice trio for WA3! It prompted me towards:

[Cetron 7236, Tungsram ECC81 pair, Pulse Tube Store 12Axx—>ECC88 adapters]. ‘Muscular’ sound from top-to-bottom, with the finesse of an Impressionist master!! And all the soundstaging that one could want!!

 

[jonathan c]

On a roll () with WA3 … I haven’t used these for quite some time … very pleasantly reminded of their excellence …

Genalex / Gold Lion 6922 new production (Kevin’s Stash / Cryo Treated: from Upscale Audio). Airy, deep, detailed presentation with ‘heft’. Extremely well balanced. Litmus tests for me - female voices and individual / massed strings - were easily passed.

 

[Gemini88]

Here are some cousins! 6H23N-EB Silver Shields from '88. The sound is something like you described, very detailed and crisp. You said it much more artfully!

On a side note, has anyone here tried (or ever seen?) a 7802? It seems similar to the 6080 family but the amplification factor is 9 and the transconductance is 20,000. I'm not sure it would be compatible, I think I read about it in a Bottlehead Crack thread. I'll attach a data sheet. They seem very rare.

 

[jonathan c]

Another ‘shout-out’ for Woo WA3 with Cetron 7236 + pair Genalex / Gold Lion 6922!!

Atrium LTD Cocobolo is spectacular in its dynamics, musicality, naturalness, spaciousness with this ‘cwoo’ ().

 

[GrindingThud]

On a side note, has anyone here tried (or ever seen?) a 7802? It seems similar to the 6080 family but the amplification factor is 9 and the transconductance is 20,000. I'm not sure it would be compatible, I think I read about it in a Bottlehead Crack thread. I'll attach a data sheet. They seem very rare.

They are definitely hard to find. That’s pretty much all I run in mine these days. Sounds similar to a 5998 or 421A.

 

[Smallpie]

What is the output impedance of this amp?

 

[kkrazik2008]

What is the output impedance of this amp?

Depends on the version, some has a range on them such as the WA3+. Which one only will know by looking inside as it’s labeled on the choke. Typically 30-600 ohms according to the manual.