Disappointment with a Psvane order....

[kb7215]

I've had problems with my Woo WES headphone amp, which I use to drive my Stax 009 headphones. I ordered the WES originally with a 'matched quad' set of Shuguang Treasure 6CA7 tubes (with a one year warranty). After a few weeks of use, I was startled to hear scratching and crackling noises from my 009 headphones after firing up the WES. The WES has two power switches: the first one warms up the tube filaments and then after a minute the second power switch turns on the rest of the unit. I immediately shut down the WES and pulled the 6CA7 quad, replacing them with a JJ (Czech) EL34 quad set which came with the WES originally. I subsequently tested the 6CA7 quad with my Amplitrex 1000 tester and found one of the tubes had a high GAS reading.

Woo Audio replaced the 6CA7 quad with the EL34PH quad. I used the EL34PH quad for just under one month (28 days) and once again heard the dreaded scratching and crackling noises from my $5K 009 headphones. The JJ EL34 quad went back in and everything is back to normal. The Amplitrex 1000 showed two of the EL34PH tubes had very high gas readings (1000mA). When I first received the EL34PH quad, I tested them and the GAS readings ranged from 1.9mA to 4.8mA.

Woo Audio will exchange the two duff EL34PH tubes and I'll continue to use the JJ EL34 quad until the replacement EL34PH tubes arrive.

It's amazing the relatively inexpensive JJ EL34 quad set gives exemplary service while the fancy Shuguang/Psvane 'matched quads' wind up with one or two bad tubes after a few weeks of use. Note: the WES is only used a few hours/day.

I'm starting to wonder if matched means: "they're glass, they have the same number of pins, they have the same silkscreen words on them - yep - they're matched."

The ironic thing is the EL34PH quad finally makes the WES headphone amp 'sing' (when they work properly). The JJ EL34 quad give a 'meh' impression. I did try KT88s in the WES but found the quads I tried (Gold Lions and the stock McIntosh ones left over from my MC2301 amps), are too harsh and brutal compared to the EL34 sound.

Finally, I've been using two octets of Shuguang 'Treasure' KT88s (the 'black bottles') in my MC2301 amps for almost two years and they continue to give superb sound.

Tube audio is basically a crap shoot ...

Ken