[mmwwhats]

Just wanted to share some info with the woophiles out there in headfi land. I contacted Jack at Woo Audio asking if the pseudo dual power suply mod (that is so highly regarded when performed on the WA6) can be performed on the WA2. Jack's response is below:

"The WA2 already has PDPS. It is a better version because there is more space to work with. It is also worth pointing out that we currently re-designed the power supply for the WA2. Now it is more flexible to match low impedance cans and it offers higher output power."

I like knowing about the design of an amp I'm considering (actually, about to purchase), so I thought I'd share the info in a new thread. If anyone else has some cool info about the design of the WA2 that you think is cool, go ahead and share that here as well.

 

[atbglenn]

I like that it uses a tube rectifier and a choke for each channel. Also looks like the heaters are DC (I noticed a bridge rectifier internally) And since it uses two 6AS7 dual triode output tubes, one for each channel (probably wired in parallel) the output power must be significant. I WANT ONE

 

[xenithon]

atbglenn - it certainly is a phenomenal amp (took delivery of one a couple weeks ago; review in the works). However there is a caveat - you'll likely find yourself hunting for tubes (Jack told me that the power tube rolling has the most significant impact; the EZ80 and 6922/6DJ8 less so). And unlike many amps where tube rolling can be done on the cheap, it's unfortunately the likes of $100 Tungsol 5998's, $200 Bendix 6080's or $350 WE421A's that catch your eye

 

[mmwwhats]

Quote:

Originally Posted by xenithon /img/forum/go_quote.gif took delivery of one a couple weeks ago; review in the works.

xenithon, can you post some pics of the internals. There's a pic on the Woo Audio site, but it's been there for ages and so I think it's of the older design. Since yours uses the EZ80s it's the new design.

 

[atbglenn]

I'd love to see internal pictures of the latest version as well...hint hint

 

[jamato8]

Quote:

Originally Posted by xenithon /img/forum/go_quote.gif atbglenn - it certainly is a phenomenal amp (took delivery of one a couple weeks ago; review in the works). However there is a caveat - you'll likely find yourself hunting for tubes (Jack told me that the power tube rolling has the most significant impact; the EZ80 and 6922/6DJ8 less so). And unlike many amps where tube rolling can be done on the cheap, it's unfortunately the likes of $100 Tungsol 5998's, $200 Bendix 6080's or $350 WE421A's that catch your eye

Those tubes have all gone up too much in price. I have them all in NOS but didn't pay near that for the 421A. I wouldn't buy them, the 421A, as I don't think they sound any better or as good as some other choices.

 

[Golden Monkey]

Yeah, those are some silly prices, if that's what you're expecting to pay. I have a pair of NOS Tung-Sol 5998's, and I paid $80 for the pair. Pretty much the same damn tube as the 421A at a fraction of the cost (although they are going up, as the demand goes). There's a whole boatload of 6080's out there going for much less...in fact, dirt cheap. I picked up a 1960 Tung-Sol 6080WB and a 1956 JAN CRC RCA 6080 (both of which had never even had their boxes opened) for a grand total of $20 shipped. Neither are in the class of the 5998 or 7236, but were inexpensive and do the job. You ought to try finding a Tung-Sol 7236 these days...very hard to find, and when you do, paying less than $75 a tube is even rarer. Still, aside from the 421A, none of these prices even begin to compare to the extortion going on over 6DJ8/6922/7308/Cca's these days, especially matched NOS pairs. Early 1950's pinched waist D getter Philips Holland Cca's for $1,000 a matched pair?!? Get the F out...

 

[xenithon]

Have you guys had any experience with Raytheon 6080/CV2984 tubes? Was considering a pair of these.

Oh, and if anyone has some spare NOS pairs of power tubes which you would consider parting with, along the lines of the Tung Sol 5998, Bendix 6080, or Cetron 7236 please let me know

 

[JayG]

I ordered a Woo 2 about a week ago after fairly extensive email discussions with Jack about headphone matching and my personal audio preferences. He also mentioned the power supply redesign to me, but only in the last few days before I ordered my amp. This leads me to believe that they just finalized it and my amp (and those already in the queue that get built between now and when they build mine) will be the first with the new power supply design, but I don't know that for sure.

I wanted to be sure that the WA2 would perform well with a variety of phones before I ordered one, since I was also considering the WA6 SE. I currently own 650s and GS1000s, and I am considering a new purchase, probably K702, SA5k, or 880s. As you can see, those phones cover basically the entire range of headphone impedances. After asking a couple times, I was able to get Jack to quote the actual output impedance of the WA2 at 60 ohms. Therefore, he said it will match very well with high impedance phones, very well with mid-impedance phones (like the 3 I'm considering), and less well with very low impedance phones like my GS1000s. However, the WA2 has tons of power and so should not have too much of a problem with the Grados even taking into account impedance mismatch. I was willing to sacrifice a perfect impedance match for Grados in return for 1) an OTL design with its many advantages over transformer-coupled designs 2) a lower base price than the SE plus a significantly less expensive capacitor upgrade package 3) a better feature set with preamp capability and four inputs 4) the IMHO much better looking single-chassis design 5) a beefier power supply than the 6SE with individual tube rectification and chokes per channel 6) a sound signature closer to my personal preferences according to Jack 7) the opportunity to spend time with a less well-known and seemingly neglected amp offering, and 8) a tube selection that I prefer.

I realize that point number one above is debatable and that OTL has its own problems, such as the higher output impedance mentioned. But OTL makes more sense to me, especially when supported by enough power to handle losses due to impedance mismatch and at a price point that makes it very difficult to include a truly high-quality output transformer. I don't have any doubt that the 6SE is a great amp, or even that some might prefer it to the WA2. But not being able to hear either of them before purchasing, I went with what made more sense to me after informing myself as much as possible.

My amp should be finished around the second week of January, so I look forward to taking it for a spin and letting you guys know what I think. Maybe some day I will get to hear a 6SE and compare.

 

[Orcin]

Congratulations on your new amp purchases, and I'll be following this thread with great interest!

I agree with atbglenn... let's see the pics!

 

[Gvvt]

There must be quite a run on the WA2; I just ordered one this week after many hours on this site and a few emails back and forth with Jack.

I'm looking forward with as much patience as I can muster to its arrival and to as much tube rolling as I can afford.

 

[JayG]

Wow, a lot of WA2 purchases. As soon as that CNET review came out, I figured there was a pretty good chance that my amp might not be so underrepresented as I expected by the time it gets here.

 

[Drag0n]

I want one with all mods in black!!!

 

[JayG]

Drag0n, you just described my amp.

 

[mmwwhats]

Quote:

Originally Posted by JayG /img/forum/go_quote.gif I ordered a Woo 2 about a week ago after fairly extensive email discussions with Jack about headphone matching and my personal audio preferences. He also mentioned the power supply redesign to me, but only in the last few days before I ordered my amp. This leads me to believe that they just finalized it and my amp (and those already in the queue that get built between now and when they build mine) will be the first with the new power supply design, but I don't know that for sure.

I got the impression that the power supply redesign was attached to the use do the EZ80 rectifiers. If that's true then the amp used for the CNET review was the new version and they state they've been using it for two months prior to writing the article.

Also, I'd love to know why they decided to redesign the power supply and what that redesign constituted. I imagine only Jamato or Takezo would be able to help out on that front if they had pics...