Woo Audio WA6
- Thread starter PaulyT
- Start date
mazersteven
Well-Known Member
YOU SUCK!!! :music-listening:
FYI, our friend Ken Rockwell says in his review of the WA6SE, similar in topology to my WA6 but more powerful, that the amp sounds better with the selector switch on the back set to low-impedance, even with high-impedance headphones (he seems to be a fan of the Beyerdynamic line). On my WA6, the switch has two positions, one for 8-99ohm, the other for 100-600ohm.
I tried it this morning just for kicks, and in a word: no. He's wrong. At least, not true with my WA6 + T1.
See Flint, I don't believe everything I read. :teasing-neener:
I tried it this morning just for kicks, and in a word: no. He's wrong. At least, not true with my WA6 + T1.
See Flint, I don't believe everything I read. :teasing-neener:
Ok time for some tube rolling. If you remember from my various other threads (again, sorry for the confusion/profusion of threads), I found that the combination of the T1 headphones with the WA6, using 6FD7 tubes, was a little on the bright side. I asked for recommendations for other tubes to try in order to alleviate this, got suggestions from Head-Fi (6EW7) and Jack @ Woo Audio (6DR7). Fortunately, Jack has both of these in stock, and they're among the cheaper of the various tube "upgrades" he offers, so I ordered them both. Yeah I might have been able to find them slightly cheaper by scouring the web and eBay, but from what I gather, Jack tests and matches all the tubes he sells, so I trust what I order - simpler than the crap-shoot that other tube sources can sometimes be, which is the part I hate most about tube rolling.
Anyway, the 6EW7 arrived yesterday, so I plugged them in this morning and gave 'er a listen. I'm pleased with the result, it did indeed lessen the brightness, the slight edge to the highs that I was hearing with the 6FD7. The highs are still there and well-resolved, though. And the soundstage width+depth are still there. Overall, I have nothing to complain about with this combo - which is a first.
From what I can tell in reading the specs on these tubes, the main difference between 6FD7 and 6EW7 is the amplification factor of the second triode. In this particular amp design, the "power tubes" - one tube for each channel - can be considered as two-stage amplifiers, with two single-ended triodes of different gain. The input signal goes through one triode, and then loops back through the same tube to the other triode, to get it to output level. (And then with the WA6, goes through an output transformer before reaching the headphones.) The gain on the second triode in the 6FD7 is significantly higher than in the 6EW7. This is consistent with a couple observations on the end result with my rig: first, there's NO detectable hum with the 6EW7, where there is (very very slightly) with the 6FD7. Second, the volume knob on the amp needs to be higher to achieve the same approximate SPL level. I'm now using ~2/3 of the range of the knob, where before it was more like half. So I guess one effect of changing tubes is basically changing the overall gain of the amp, since tube amps don't otherwise have a gain control like solid state amps do. And that the lower gain works better with the high-impedance T1.
Anyway, the 6EW7 arrived yesterday, so I plugged them in this morning and gave 'er a listen. I'm pleased with the result, it did indeed lessen the brightness, the slight edge to the highs that I was hearing with the 6FD7. The highs are still there and well-resolved, though. And the soundstage width+depth are still there. Overall, I have nothing to complain about with this combo - which is a first.
From what I can tell in reading the specs on these tubes, the main difference between 6FD7 and 6EW7 is the amplification factor of the second triode. In this particular amp design, the "power tubes" - one tube for each channel - can be considered as two-stage amplifiers, with two single-ended triodes of different gain. The input signal goes through one triode, and then loops back through the same tube to the other triode, to get it to output level. (And then with the WA6, goes through an output transformer before reaching the headphones.) The gain on the second triode in the 6FD7 is significantly higher than in the 6EW7. This is consistent with a couple observations on the end result with my rig: first, there's NO detectable hum with the 6EW7, where there is (very very slightly) with the 6FD7. Second, the volume knob on the amp needs to be higher to achieve the same approximate SPL level. I'm now using ~2/3 of the range of the knob, where before it was more like half. So I guess one effect of changing tubes is basically changing the overall gain of the amp, since tube amps don't otherwise have a gain control like solid state amps do. And that the lower gain works better with the high-impedance T1.
Tried the 6DR7 - Jack's recommendation - and... nope. Decently wide soundstage, no detectable hum. But just as bright as the 6FD7, with less depth in the soundstage. Kinda harsh when turned up loud. (It's been said here that a characteristic of good speaker systems is that you can listen at higher loudness without it *feeling* loud... I think the same applies here.) Not an improvement over the 6DR7, and especially not as nice as the 6EW7. To be honest, I didn't even make it through my entire listening test.
So, back to 6EW7 we go.
So, back to 6EW7 we go.
D
Deleted member 133
Guest
I think someone could make a Schitz-load of money, and save you "users" some in the process, if he invented a control for your headphone amps, maybe knob-based, maybe not, that would provide a continuous adjustment of the "brightness." You could do it real-time, without swapping parts like a demolition derby driver. It would allow for instant comparisons - and instant gratification. Yeah, that would be a winner. Just waiting for someone to come along with it. Come to think of it, the same type of control could add or subtract boominess. Heck let's go absolutely apeshit and make one for the vocal range as well. Just not sure what to call them, but otherwise I think this is a peach of an idea. Don't you?PaulyT said:Anyway, the 6EW7 arrived yesterday, so I plugged them in this morning and gave 'er a listen. I'm pleased with the result, it did indeed lessen the brightness, the slight edge to the highs that I was hearing with the 6FD7. The highs are still there and well-resolved, though. And the soundstage width+depth are still there. Overall, I have nothing to complain about with this combo - which is a first.
malsackj
Well-Known Member
Correct Jeff. the mark of a good amp is to amplify without color.
by Siegfried Linkwitz (Audio, December 1971)
http://headwize.com/?page_id=739
by Siegfried Linkwitz (Audio, December 1971)
http://headwize.com/?page_id=739
Yeah yeah you mock as usual. Perhaps what I'm calling "brightness" may not be a frequency response type thing so much as a little distortion on the high end? A little brittleness. I'm not really sure, and again words fail in describing this. Kinda like the difference between a soft dome and a metal dome tweeter or a ribbon or even a horn; they may test the same by RTA, but they have a different sound to our ears.
Note that I'm not claiming one is more accurate than another in any objective sense. Rather that I simply prefer a not-overly-"bright" sound.
Note that I'm not claiming one is more accurate than another in any objective sense. Rather that I simply prefer a not-overly-"bright" sound.
walls
Well-Known Member
I agree about buying from Jack, you know for sure you are getting top notch quality.
No amount of EQ'ing a solide state headphone amp is going to match what my WA2 or even my lowly Crack can do with music presentation. I have had the pleasure of hearing two separate amps that have those magical knobs that were mentioned and they couldn't come close.
I like the warmth and smoothness of a good tube amp, guess I like distortion. Lol.
No amount of EQ'ing a solide state headphone amp is going to match what my WA2 or even my lowly Crack can do with music presentation. I have had the pleasure of hearing two separate amps that have those magical knobs that were mentioned and they couldn't come close.
I like the warmth and smoothness of a good tube amp, guess I like distortion. Lol.
walls
Well-Known Member
Also IMO there is quite the difference between speaker use and headphone use, besides the obvious of course. Higher end headphone rigs offer a much more intimate experience with extreme detail, soundstage and depth.
I have had quite a few friends listen to my setup and comment on how much more they are hearing in songs that they thought they knew.
And changing out tubes can have either a very minimal or a very drastic effect. And when the right tubes, in the right amp with the right headphones come together... It's quite amazing.
I have had quite a few friends listen to my setup and comment on how much more they are hearing in songs that they thought they knew.
And changing out tubes can have either a very minimal or a very drastic effect. And when the right tubes, in the right amp with the right headphones come together... It's quite amazing.