Woo Audio amps

[harri009]

I have been listening all night. Recently purchased a Esoteric SA-10 from a buddy but since I am in the middle of a complete system swap out I currently have 3 pairs if speakers, 1 set of headphones, 1 woo amp, no stereo amps, no pre amps, and 2 SACD players lol. So I decided might as well replace my Denon 2200 which is in my headphone setup with the SA-10. Mmmm so now I am wanting a second esoteric for when the 2 channel comes back together. The WA-6se really is a great amp!!!

[djwhog]

OK 6 months on the amp + counting

Ok 1st off I want to say I have had this amp for a while now about 6 months, with all upgraded tubes, totally love it!

I also upgraded that power cable with a WW cable from Ivan, and have a dedicated power conditioner too.

I have a question, I have a pair of Sennheiser HD700s and was wondering which is best to use for the connection.

High impedance headphone output or the Low impedance headphone output?

I did read this:
"The output impedance is measured to around 15 ohm for the low headphone output, and the high headphone output right around 48 ohm. If you believe in NWAvGuy’s theory(?), your headphones should have at least 8 times higher impedance than the output to avoid distortion of the audio signal. "

The 700s are rated at a 150 ohm load. I think I have always used the LOW connection. This amp has enough power to drive 2 pairs of I think about anything at the same time. Only diff I hear is on the low connection the loudness is maybe a little lower 5-10% or so perceived. Noise floors seem the same.

I sent a request to Woo to get their reply, but thought someone could chime in with some input too.

thanks!


HD700 specs.
Frequency response 10-42,000 Hz
Ear coupling Around-the-ear
Transducer principle Dynamic, open-aire
Nominal Impedance 150Ωs
Sound Pressure Level 105 dB (1 kHz, 1 V)
Total Harmonic Distortion <0.03 %
Jack plug ¼ inch (6.3mm) straight

WA6SE specs for a stock amp ( Mine has the best in class tube +cable upgrades)

• Technical Specifications :
• Headphones impedance : 8-600 Ohms
• Input impedance: 100 Kilo-Ohms
• Frequency response: 15 Hz - 40 KHz, -3dB
• Power output > 1 watt
• Signal/Noise: 93 dB
• THD: <= 0.3%
• Voltage: AC 110/220 V, 50/60 Hz
• External dimension (each unit): 6"(H), 5½(W), 13"(D)
• Weight: AMP 12 lbs, PSU 10 lbs

• Standard Features:
• Point-to-Point wiring
• One 5AR4 [PDF] rectifier tube. Direct substitute: 5U4G
• Two 6DE7 / 6EW7 [PDF] drive/power tubes
• Pseudo-dual power supply
• All tubes. No semi-conductors in the entire circuitry
• High and low impedance headphones outputs
• 1/4" (6.3mm) headphone jack
• 2 RCA inputs with a input source switch
• Individual filter choke per channel
• 80 watts specially made toroidal power transformer.
• Full aluminum die-cast chassis, anodized finish
• Whole aluminum volume knob and power switch button
• Gold-plate RCA
• Alps potentiometer and power switch
• Silver-plated hook-up wires in Telfon jacket

• Brief Introduction to 6DE7/6EW7:
• 6DE7/6EW7 is a dual triode tube, consisting of one drive triode and one power triode. Its performance is similar to a combination of a 6SN7 and a 2A3.

Rectifier tube upgrade:
Sophia Princess Mesh Plate 274B rectifier


Drive/Power tube option 1:
1 matched pair of 6GL7/6EM7 plus one pair of 6GL7->6DE7 Teflon tube adapters. $150 (2 tubes + 2 adapters)

The 6GL7/6EM7 is the ultimate driver/power tube for the WA6-SE. It has great extension and excellent clarity on all frequency range. You will hear each note with breathing air around it. The sound is smooth and well balanced.

FYI, more info from a independent review.

Output Load Impedance
Rated for 8 ~ 600 Ω loads.
(measured output source impedance is 15 Ω LOW, 50 Ω HIGH.)

HIGH output (600 Ω load)
-91.7 dBV A-weighted.
-83 dBV unweighted.

LOW output (37.5 Ω load)
-98.0 dBV A-weighted.
-91.0 dBV unweighted.



OK here is a link to copy and past for all the results of the amp.
kenrockwell.com/audio/woo/wa6-se.htm#z

[G8YU]

djwhog

You'll probably be fine using which ever setting sounds the best to you. I don't think either setting would cause damage to the amp or headphones. Yes, it is technically better to use the setting that gives the best damping factor (low output impedance setting); but it doesn't necessarily sound the best.

My example of this is that my headphone amp has a high or low gain switch which also changes the output impedance respectively. Many of my headphones are under 100 ohms; but I almost exclusively use the high gain setting. Yes, the bass does tighten up a bit on the low setting (because of the higher damping factor ) but the high frequency extension and sparkle is diminished and overall the music sounds dynamically flat and lifeless. I even live with the slight hiss in the background and the small range of volume adjustability because music just sounds better on the high setting.

[djwhog]

Thank you for the input. I guess it is like do you use the 4 ohm or 8ohm taps on say a McIntosh amp. You kinda want to match them to a point right.

So I did some more searching and posted that in another thread about the 700s with a review of my new cable too.

I will post some more specs on the load in another post.

But I did find this.

Output Load Impedance
Rated for 8 ~ 600 Ω loads.
(measured output source impedance is 15 Ω LOW, 50 Ω HIGH.)

And a rule of thumb is about 8 times the rated can load, so my 700s are rated at 150 so the low impedance seems from that take the best fit.

But you are correct, on either tap they run fine, and since they do tend to be a ta bright maybe the low tap is a + for the 700s vs the high tap.

PS I did install a better cable, make a HUGE diff!

Again thank you much for your help too

http://www.audioaficionado.org/fs-fe...d-rscotth.html

[Toccata]

Originally Posted by HiFiGuy528

I think the WA6 pairs well with HD800 if you like tubey sweetness.

It does and I do! The 800s can be a little cold and sterile when plugged straight into most headphone outputs. (My new Esoteric K-03 doesn't have one, so I can't make a comment about it!) But when plugged into a WA6, they have to my ears the perfect blend of warmth and detail.

[HiFiGuy528]

Originally Posted by djwhog

OK 6 months on the amp + counting

Ok 1st off I want to say I have had this amp for a while now about 6 months, with all upgraded tubes, totally love it!

I also upgraded that power cable with a WW cable from Ivan, and have a dedicated power conditioner too.

I have a question, I have a pair of Sennheiser HD700s and was wondering which is best to use for the connection.

High impedance headphone output or the Low impedance headphone output?

I did read this:
"The output impedance is measured to around 15 ohm for the low headphone output, and the high headphone output right around 48 ohm. If you believe in NWAvGuy’s theory(?), your headphones should have at least 8 times higher impedance than the output to avoid distortion of the audio signal. "

The 700s are rated at a 150 ohm load. I think I have always used the LOW connection. This amp has enough power to drive 2 pairs of I think about anything at the same time. Only diff I hear is on the low connection the loudness is maybe a little lower 5-10% or so perceived. Noise floors seem the same.

I sent a request to Woo to get their reply, but thought someone could chime in with some input too.

thanks!

Which ever setting sounds best to you. I like the high setting with my Sony MDR-Z7 @70 Ohms.