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.
• The 30 — 600 ohms range refers to the nominal impedance of the headphones that can be used with WA3. No amplifier nominal (stated) output impedance is disclosed. My guess, comparing it to other OTL tube h/p/a, is 100 — 120 ohms.
• The 30 — 600 ohms range refers to the nominal impedance of the headphones that can be used with WA3. No amplifier nominal (stated) output impedance is disclosed. My guess, comparing it to other OTL tube h/p/a, is 100 — 120 ohms.
• The 30 — 600 ohms range refers to the nominal impedance of the headphones that can be used with WA3. No amplifier nominal (stated) output impedance is disclosed. My guess, comparing it to other OTL tube h/p/a, is 100 — 120 ohms.
Woo is not the only one, lots don’t either. Or they will confuse with an ohm rating in the tap which does not indicate output impedance but rather the headphone impedance in order to plug say a 100 ohm headphone into the 100 ohm tap.
Or they will confuse with an ohm rating in the tap which does not indicate output impedance but rather the headphone impedance in order to plug say a 100 ohm headphone into the 100 ohm tap.
That’s interesting you brought this up! I’ve thought a lot about this topic and was planning on posting in a thread here.
I remember hearing someone casually talk about this and if an 8 ohm tap is outputting 8 ohms exactly.
The WA3 continues to surprise me. I abandoned the stock tubes on day-1 (bought it new). Right now the input tubes are vintage NOS Mullard CV4033s and the power tube is the NOS Tung Sol 5998. And amazing to say, this little amp really has balls. If it's wooly, warm, fuzzy, "tubey," any of that stuff people say about OTLs, I'm certainly not hearing it.
On the contrary, I'm rocking out on the Verite w/some exciting R&B & funk tunes. The bass is the best I've ever heard from this amp.
This is the second Woo amp I owned; the other was the WA22, a big, heavy transformer-coupled balanced design. I sold that one, but kept the WA3. For a long time I kind of resented the idea that Woo amps don't really come close to their sonic potential until the owner spends real $$ on the best NOS tubes available. That struck me as unfair. Well, I don't feel that way any more. It's almost like a mini-super power: if I get the right NOS tubes, I can turn this polite, compact little amp into an OTL firebreather.
I got through hot and cold periods with the WA3. Right now it's definitely hot...
The WA3 continues to surprise me. I abandoned the stock tubes on day-1 (bought it new). Right now the input tubes are vintage NOS Mullard CV4033s and the power tube is the NOS Tung Sol 5998. And amazing to say, this little amp really has balls. If it's wooly, warm, fuzzy, "tubey," any of that stuff people say about OTLs, I'm certainly not hearing it.
On the contrary, I'm rocking out on the Verite w/some exciting R&B & funk tunes. The bass is the best I've ever heard from this amp.
This is the second Woo amp I owned; the other was the WA22, a big, heavy transformer-coupled balanced design. I sold that one, but kept the WA3. For a long time I kind of resented the idea that Woo amps don't really come close to their sonic potential until the owner spends real $$ on the best NOS tubes available. That struck me as unfair. Well, I don't feel that way any more. It's almost like a mini-super power: if I get the right NOS tubes, I can turn this polite, compact little amp into an OTL firebreather.
I got through hot and cold periods with the WA3. Right now it's definitely hot...
The WA3 continues to surprise me. I abandoned the stock tubes on day-1 (bought it new). Right now the input tubes are vintage NOS Mullard CV4033s and the power tube is the NOS Tung Sol 5998. And amazing to say, this little amp really has balls. If it's wooly, warm, fuzzy, "tubey," any of that stuff people say about OTLs, I'm certainly not hearing it.
On the contrary, I'm rocking out on the Verite w/some exciting R&B & funk tunes. The bass is the best I've ever heard from this amp.
This is the second Woo amp I owned; the other was the WA22, a big, heavy transformer-coupled balanced design. I sold that one, but kept the WA3. For a long time I kind of resented the idea that Woo amps don't really come close to their sonic potential until the owner spends real $$ on the best NOS tubes available. That struck me as unfair. Well, I don't feel that way any more. It's almost like a mini-super power: if I get the right NOS tubes, I can turn this polite, compact little amp into an OTL firebreather.
I got through hot and cold periods with the WA3. Right now it's definitely hot...
That’s a great combo, my main roll aslso included the 5998, with a double dose of Amperex PQ from the 60’s. Did a bunch of you do a group by for this special CV4033 Millard’s? Got any left
The WA3 continues to surprise me. I abandoned the stock tubes on day-1 (bought it new). Right now the input tubes are vintage NOS Mullard CV4033s and the power tube is the NOS Tung Sol 5998. And amazing to say, this little amp really has balls. If it's wooly, warm, fuzzy, "tubey," any of that stuff people say about OTLs, I'm certainly not hearing it.
On the contrary, I'm rocking out on the Verite w/some exciting R&B & funk tunes. The bass is the best I've ever heard from this amp.
This is the second Woo amp I owned; the other was the WA22, a big, heavy transformer-coupled balanced design. I sold that one, but kept the WA3. For a long time I kind of resented the idea that Woo amps don't really come close to their sonic potential until the owner spends real $$ on the best NOS tubes available. That struck me as unfair. Well, I don't feel that way any more. It's almost like a mini-super power: if I get the right NOS tubes, I can turn this polite, compact little amp into an OTL firebreather.
I got through hot and cold periods with the WA3. Right now it's definitely hot...
For 6080/6AS7G OTL cathode follower amps, like the WA3, output impedance is roughly 1/transconductance for a cathode follower. That puts the 6AS7 with transconductance of 7000micromhos at about 142ohms. Changing the tube to a 5998 with transconductance around 14000 gets you down to 72 ohms. Even better is the 421A at 20000 which gets you close to 50 ohms. For OTLs with two output tubes (like WA2), cut those in half.
When buying rectifier tubes I find it's not uncommon to get a tube that produces no sound or it produces a loud hum, especially with tubes from Ebay. Could this be a sign of problems in the amplifier or just bad tubes?
Is there any way to attempt to fix these? Or any risk? I'm considering putting one in and leaving it on for several hours.
When buying rectifier tubes I find it's not uncommon to get a tube that produces no sound or it produces a loud hum, especially with tubes from Ebay. Could this be a sign of problems in the amplifier or just bad tubes?
Is there any way to attempt to fix these? Or any risk? I'm considering putting one in and leaving it on for several hours.
For which headphone amplifier are you buying rectifier tubes? WA3 does not use rectifier tubes. WA3 uses 1 x 6080 (or equivalent) and 2 x 6922 (or equivalent) or 2 x 12A#7 (on adapters).
@Gemini88 , these cost a little more; I recommend them, I use (rotate) them in a Woo WA3, in a Liquid Platinum. What are they? Genalex / Gold Lion 6922s. These are excellent in balance, detail, soundstage. Mine (several pairs) have all been quiet, non-microphonic. They are ‘new production’ made in Russia; they are sold by The Tube Store, Tube Depot, Upscale Audio, Viva Tubes and other vendors.
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). PS - fuse upgrade works a charm, too, in WA3 
.
