[VanHai]

Interesting. The 12au7 is typical in hi-fi with a µ= 20, while the 12at7 is typical in guitar amps and triple the gain with µ= 60. I'm glad to hear that it works and doesn't distort or throw off frequency response.

I will receive my custom make amp from Australia in 3 weeks that uses many combination of driver tubes including 6v6, 6J5, 6SN7 with adapter to 12XX7s. I was intrigued about 12XX7s to WA22 but could not find any information about and decided give a try with WA22.

Very surprise that it works even better than my Melz 1578 and way less expensive than many 6SN7s. Give it a try and let me know that my ears not deceiving me

 

[LegionofDoom]

I gave the GND Defender a solid dozen a/b tests on my WA22 tonight.

Sad to report no audible difference in background hum versus straight cable without it. Granted my hum problem is what I might call a 3 on a 10 scale on Hi Z and a 1.5 on Low Z. So I don’t really complain. And with any music I don’t notice it. Just wish it were gone.

Tweak search goes on. Defender gets returned.

 

[elig63]

Here !!!

 

[Promee]

Here !!!

Super exciting! Congrats!!

 

[skhan007]

I gave the GND Defender a solid dozen a/b tests on my WA22 tonight.

Sad to report no audible difference in background hum versus straight cable without it. Granted my hum problem is what I might call a 3 on a 10 scale on Hi Z and a 1.5 on Low Z. So I don’t really complain. And with any music I don’t notice it. Just wish it were gone.

Tweak search goes on. Defender gets returned.

Well, that's disappointing. I'm continuing to test the GND Defender, DC Blocker, new IEC cable, and different power supplies. I've also emailed iFi to get their input.

Reply from iFi:

Thank you for contacting us regarding your GND Defender and DC Blocker. We would begin by noting that, based on the information you have provided regarding the hum in your audio setup, the DC Blocker appears unlikely to provide any benefit to your setup. The DC Blocker is intended to remove DC on the mains, which can cause mechanical hum in the transformer of an amplifier. When DC power reaches a transformer such as those found in amplifiers, it causes excessive vibration in the transformer, which presents as a mechanical hum from the transformer itself. You would therefore expect to be able to hear this hum coming from the headphone amplifier unit itself, rather than through the headphones. If you are not hearing a hum from the headphone amplifier unit, then the DC Blocker will not resolve the issue.

With regards to the GND Defender, we would note that this device is intended to break ground loops, which in turn can reduce or eliminate ground loop hum. Please note, however, that if there are still multiple earths within your audio setup, you can still encounter hum until you are left with only one earth connection in your audio setup. Additionally, the GND Defender is unable to remove hum caused by the lack of an earth connection in your audio setup. A quick way to identify that your setup does not to have an earth connection is to touch a metal component within your audio setup and check whether this has reduced or eliminated the hum. If it has, then you will need to add an earth to your audio setup, which can be done using our Groundhog+ kit.

 

[elig63]

 

[elig63]

The device made me cry! The sound is just crazy! It's driving me crazy!
I turned off the lights in the room, looked at the tubs and listened to Julio Iglesias.

 

[ColSaulTigh]

I gave the GND Defender a solid dozen a/b tests on my WA22 tonight.

Sad to report no audible difference in background hum versus straight cable without it. Granted my hum problem is what I might call a 3 on a 10 scale on Hi Z and a 1.5 on Low Z. So I don’t really complain. And with any music I don’t notice it. Just wish it were gone.

Tweak search goes on. Defender gets returned.

If you want to try a little exeriment, get some tin foil and make a loose fitting cover for each tube (roll it into a tube with a paper towel or TP tube) and close off the top. Place one on EVERY tube and see if the hum persists. If I goes away, remove one at a time until the hum returns. You could be picking up RF interference from something like the wifi router or a cell phone.

 

[LegionofDoom]

I rolled in a pair of Foton 6N8S drivers to my WA22. I got these for about $60 each. I can report they are VERY enjoyable on hard rock music. The bass response is very strong with lots of weight and drive. Crunchy guitars have all kinds of presence that again I don't experience otherwise. They are not the last word in clarity or air. That's for sure. I would not call them the most accurate "timbre" driver tube I own either, but they sure do have grunt in the ways my other tubes don't. I kinda call them my Metallica tube. There is something about the way they perform on albums like "Load" and "Garage, Inc." that nothing else I own does.

It's more like being AT the concert. No one would say being at a Metallica concert is an experience in clarity or detail. But it is an experience of being emotionally involved and smacked around by the musical energy. That's what these Fotons do with my ZMF VCs. Lot's of toe tapping and head bobbing without having to break the bank.

Good picture from the web as to what the tube structure looks like close up.

 

[elig63]

I use Apos Ray Vacuum Tube 6SN7 Select drivers. I like their sound.

 

[elig63]

I bought these power tubes:
https://reverb.com/item/55190312-pr...complete&utm_medium=email&utm_source=sendgrid

Has anyone used them? How was it ?

 

[skhan007]

I bought these power tubes:
https://reverb.com/item/55190312-pr-nos-rca-6080wa-triode-power-tubes-1950s-black-plates-boxes-matching-ex-sound-brand-new-1950s?utm_campaign=BundledCheckoutMailer#notify_buyer_purchase_complete&utm_medium=email&utm_source=sendgrid

Has anyone used them? How was it ?

From what I recall, those RCA metal base are a solid middle of the road performer. Maybe as good or slightly better than stock. For 6080's, my favorites have been Bendix and GEC.

 

[elig63]

From what I recall, those RCA metal base are a solid middle of the road performer. Maybe as good or slightly better than stock. For 6080's, my favorites have been Bendix and GEC.

Could you provide a link to a reliable store?

 

[skhan007]

Could you provide a link to a reliable store?

I've bought most of my tubes from other members. In terms of stores, I've had good experiences with Billington in the UK: http://www.tube-and-valve-electronics.co.uk/stocklist.asp and Brent Jesse in the US: https://audiotubes.com/

I will state (and many agree) my favorite overall are Tung-Sol 5998. Equally good are Chatham 6AS7G.

 

[skhan007]

Cleaned the pins with Deoxit and fired up the trusty vintage GEC 6080's (April, 1964, Hammersmith UK). What a fantastic sound. My favorite 6080 tube. Very punchy, great sub-bass, but very smooth in the highs. Not as "crisp" in the high end as my 5998 tubes, but I use EQ, so a couple of minor tweaks and we're all good.