[lawshredpower]

Hi guys: I just received my new WA22. I bought it as an alternative to the PassLabs HPA-1.

The sound is great: full, sweet and very involving. The problem I am having is... the hum!

I hate the hum, it adds another layer of bother to my already bad tinnitus. I have tried all the usual recommendations like isolating the power supply, upgrading tubes (I bought the most expensive tubes Wooaudio has in stock). The hum is still there, loud and vivid. The only bearable headphones are the HE1000V2, all others are a no go.

After fifteen days trying I gave up. Now the WA22 is silent on the shelf and the HPA-1 is again in business.

There are a lot of posts here on the thread regarding hum. It seems that either the amp design is flawed or some hum is expected or both.

Some people actually managed to achieve pitch black background here afaik, it all came down to tube combo.

I am in that journey myself right now. Instead of being frustrated I‘m enjoying this part of the adventure. I get immensely annoyed by hum as well and a completely silent background is my goal. I am enjoying the sound of the amp too much to give up. Also, I’m stubborn.

Here’s my personal experience so far:

1. It wasn’t ground loop for me (I’ve created a ground loop on purpose and then there was ground hum on top the amp hum just to test lol).

2. Power? I’ve tested the amp with different cables in different outlets in different parts of homes in literally two different continents (no joking, it was a pain to take the amp as my carry-on luggage). Nothing changed (props to Woo for making an amp with a 110-240v switch though. WHY CAN’T MORE PEOPLE DO THAT?)

3. All about the tubes. The stock ones were garbage. Not only they had hum but some also had RF interference.

4. You can sometimes pinpoint which tube is the cause of the hum. The hum is stronger on one side? Switch power tubes sides and see if the stronger hum migrates to the other channel. Do the same with the driver tubes. I can tell even in matched pair some tubes are noisier than others. But then again, I’m still refusing to buy the overpriced tubes from the Woo website and I’m getting mine from eBay, the classifieds here and such. I’ve read here that really strong tubes with good matching may impact on the hum. I’m too much of a fan of cold, analytical solid state amps to let myself spend that much on NOS tubes.

5. Some tubes may sound noisy from the box but will get quieter as they settle down after some hours of use. Do not buy, test for a few minutes, conclude it’s noisy AF and then flip them on head-fi. Give them a week or two. My U52 rectifier got considerably quieter.


I’ve just put a pair of GE 6AS7GA in the place of my matched quad GE 6BL7GTA yesterday. Sounds like a Mr. Coffee machine, but I’ll keep the amp running with headphones plugged in for a couple hours every day and then check it out just to be sure.

I’m also tired of going this vintage NOS tube way and I’m trying brand new psvane tubes next. Just out of curiosity and because I’m enjoying this quest. Before an audio gear enthusiast I was a guitar player so I can tell ya: every tube amp has its own cross to carry. Not a defect, a feature lol can be super frustrating if you don’t enjoy the ride. Godspeed and keep sharing your experiences!

 

[Onik]

Hi guys: I just received my new WA22. I bought it as an alternative to the PassLabs HPA-1.

The sound is great: full, sweet and very involving. The problem I am having is... the hum!

I hate the hum, it adds another layer of bother to my already bad tinnitus. I have tried all the usual recommendations like isolating the power supply, upgrading tubes (I bought the most expensive tubes Wooaudio has in stock). The hum is still there, loud and vivid. The only bearable headphones are the HE1000V2, all others are a no go.

After fifteen days trying I gave up. Now the WA22 is silent on the shelf and the HPA-1 is again in business.

Did you try upgrading the coupling caps to a better quality ones? If not try some Jupiter or Jensen Capacitors they might be good choice for amps like wa2/ wa22, imo some caps are not good enough to block DC at output so if I were you I would try it.

 

[jonathan c]

Did you try upgrading the coupling caps to a better quality ones? If not try some Jupiter or Jensen Capacitors they might be good choice for amps like wa2/ wa22, imo some caps are not good enough to block DC at output so if I were you I would try it.

How would DC (at 0 hertz) create hum if it were not blocked? Would the DC not just “fry” the headphone drivers?

 

[Eduardo C]

Thanks for your answers. I guess there are some things to try before giving up.

Is there is a particular type of tube (driver, power, rectifier) were I should start making changes?

 

[Onik]

How would DC (at 0 hertz) create hum if it were not blocked? Would the DC not just “fry” the headphone drivers?

There's always some DC at output which can't be measured sometimes with testing equipments, the coupling caps job is to get rid of any DC at the output stage of an amplifier, the hum might or might not be caused by a bad cap or low quality cap its just a step to reduce/eliminate the hum, I don't think a very tiny amount of DC can fry any headphones.

 

[lawshredpower]

Thanks for your answers. I guess there are some things to try before giving up.

Is there is a particular type of tube (driver, power, rectifier) were I should start making changes?

Really depends on what’s happening over there. The worst noise on mine came from the driver tubes. If you can just upgrade everything

 

[maro65]

Hi guys: I just received my new WA22. I bought it as an alternative to the PassLabs HPA-1.

The sound is great: full, sweet and very involving. The problem I am having is... the hum!

I hate the hum, it adds another layer of bother to my already bad tinnitus. I have tried all the usual recommendations like isolating the power supply, upgrading tubes (I bought the most expensive tubes Wooaudio has in stock). The hum is still there, loud and vivid. The only bearable headphones are the HE1000V2, all others are a no go.

After fifteen days trying I gave up. Now the WA22 is silent on the shelf and the HPA-1 is again in business.

In my experience, the Wa22 does not match very well with very efficient headphones (over 95 db) I found the ideal match with the Abyss Diana, zero hum

 

[Eduardo C]

In my experience, the Wa22 does not match very well with very efficient headphones (over 95 db) I found the ideal match with the Abyss Diana, zero hum

I think you nailed it. With the help of some friends I have tried different headphones. There is little to zero hum with HE1000V2, Abyss Diana or AEON 2C.

Any experience with WA22 (5998 power tubes) driving Susvara?

thanks.

 

[maro65]

I think you nailed it. With the help of some friends I have tried different headphones. There is little to zero hum with HE1000V2, Abyss Diana or AEON 2C.

Any experience with WA22 (5998 power tubes) driving Susvara?

thanks.

You should ask Woo Audio

 

[Melting735]

I had a Feliks Elise. I like the balance option on wa22. How does this compare to Elise in terms of sound?

 

[HiFiGuy528]

In my experience, the Wa22 does not match very well with very efficient headphones (over 95 db) I found the ideal match with the Abyss Diana, zero hum

Agreed! WA22 is a high power and high gain amplifier. It should be paired with headphones that can utilize the power.

When paired with highly efficient headphones, it is expected to hear some noise because the headphone doesn't need all that power. This would be like a car engine for a bicycle, too much power.

 

[davehg]

Odd, I use Focal Clears and Audeze LCD 3 with a WA22 which are both very efficient and I don’t have issues. Both do better with a WA5, but they sound great on the WA22.

I do think the HD650 is a special pair however. And that headphone is very efficient even though it is also high impedance

 

[maro65]

Odd, I use Focal Clears and Audeze LCD 3 with a WA22 which are both very efficient and I don’t have issues. Both do better with a WA5, but they sound great on the WA22.

I do think the HD650 is a special pair however. And that headphone is very efficient even though it is also high impedance

Do you have the Wa22 first or second generation?

 

[davehg]

First Gen, with Jupiter Copper caps

 

[maro65]

I'm talking about the second generation ,they're not the same