[Puzzles]

So I got a pair of RCA 6as7g from a huge tube seller on eBay. (Over 9k feedback). Start warming them up in the woo. I get that same horrible noise as I did with the Ei ez80's. Power amp kicked into protect mode immediately. Pulled them out. Replaced with tung sol 7236. Wa2 warms up just fine. What is going?!

Did I actually damage the wa2 with those ez80's. Something that can't charge up on first power up maybe? I just doubt that I got another pair of bad tubes. Or am I really that unlucky? Is the wa2 sensitive to brand new tubes? Each of the sets was sold as NOS. I don't want to keep troubleshooting if I'm going to do damage.

Any help would be appreciated. Thanks

 
I had the same thing (see a few posts above), also with RCA tubes from the 50s. Turn out the lights and you will occasionally see a tiny flash around the lower radiator. I trashed them because they kept doing it. 

 

[Franatic]

Behemoth
 
You definitely need to contact Woo Audio customer service on this one. Where did you purchase this? Is it still under warranty?
 
Here is the contact of the person who helped me when one of my tubes was bad when I received my WA2:  mike@wooaudio.com
 
Good Luck

 

[Behemoth27]

Behemoth

You definitely need to contact Woo Audio customer service on this one. Where did you purchase this? Is it still under warranty?

Here is the contact of the person who helped me when one of my tubes was bad when I received my WA2:  [COLOR=555555]mike@wooaudio.com[/COLOR]

[COLOR=555555]Good Luck[/COLOR]

Yeah, I probably will end up contacting them. I purchased it directly from woo website. Should still be under warranty. But right now I'm thinking it should just be bad tubes. Why would it work fine with 7236's and not the 6as7g. I'm going to try and find somewhere to test tubes near me. As of right now, I'll refrain from rolling. But if I experience any more noise I'll be sending it directly to woo.

 

[mikoss]

Fwiw I have a couple pairs of RCA 6as7g's purchased cheap off eBay as tested nos and used/testing good. Both work fine, no flashes. The seller is cjt13b.

Hopefully there is no damage to your WA2. I've spoken with a local audio store owner who told me OTL amps are less prone to being damaged by faulty tubes, but I have no idea if that is true. There are no transformer windings to worry about, but there are chokes (inductors/reactors) which I imagine could still overheat or burn up on a short circuit.

I'm not a tube or amp technician, just what I've heard. Hope you have better luck. I like the sound of the RCA tubes, I think they're a great deal for the price.

 

[StanT]

 Why would it work fine with 7236's and not the 6as7g. I'm going to try and find somewhere to test tubes near me. As of right now, I'll refrain from rolling. But if I experience any more noise I'll be sending it directly to woo.

In my experience, 7236s are as stable and reliable as tubes get, 5998s less so (even though I prefer them). 6as7gs try my patience.
 
Tube sellers test tubes on a machine, rather than listen to them. It's very possible for tubes to test fine and still have an audio issue.
 
I'd start with a set of tubes that you know to be good and swap one pair at a time. Give it a day or two before deciding that a pair is good.

 

[Puzzles]

Fwiw I have a couple pairs of RCA 6as7g's purchased cheap off eBay as tested nos and used/testing good. Both work fine, no flashes. The seller is cjt13b.

 
My experience is that even the most reputable dealers have a few noisy or bad tubes. The only thing that most dealers can do is checking for gas and shorts but they can't check for noise.
I had two pairs of TS 6AS7G from cjt13b on eBay oh which two tubes were grossly rattling, a flashing RCA 6AS7G and dysfunctional Sylvania 6CA4 from Tube World, a flashing Mullard 6080 from Electols, a noisy Mullard 6080 from Langrex and the a rattling GEC 6AS7G from Valvetubes.
Since I've purchased many other tubes from all of them and most tubes did work, so I'm not overly suspicious of any dealer. Most of them sent replacements anyway. 

 

[mikoss]

   
My experience is that even the most reputable dealers have a few noisy or bad tubes. The only thing that most dealers can do is checking for gas and shorts but they can't check for noise.
I had two pairs of TS 6AS7G from cjt13b on eBay oh which two tubes were grossly rattling, a flashing RCA 6AS7G and dysfunctional Sylvania 6CA4 from Tube World, a flashing Mullard 6080 from Electols, a noisy Mullard 6080 from Langrex and the a rattling GEC 6AS7G from Valvetubes.
Since I've purchased many other tubes from all of them and most tubes did work, so I'm not overly suspicious of any dealer. Most of them sent replacements anyway. 

 I must have much better luck from "fleaBay" - just had the pair of TS 5998's where one gave me issues.

 

[billerb1]

Speaking of Tung Sol 5998's, I've decided to sell my last remaining pair.  They were bought NOS and matched... have about 250 or so hours on them now.  No tube noise, microphonics or any BS.  Dead quiet.  $199 + $12 USPS Priority shipping (CONUS only).  I'll eat the Paypal fee.  PM me.


************** S O L D *************

 

[Behemoth27]

Anyone using a 7DJ8 / PCC88 instead? My understanding is they're essentially compatible with any device that uses 6DJD.
 
They seem to be cheaper and I was hoping to grab some for mainly back up purposes. And of course to give them a listen

 

[mikoss]

Yes, put some pinched waist PCC88's in yesterday... they sound amazing.
 
I think 7DJ8's are completely compatible... just have 7V rated heater filaments instead of 6.3V

 

[Puzzles]

  Anyone using a 7DJ8 / PCC88 instead? My understanding is they're essentially compatible with any device that uses 6DJD.
 
They seem to be cheaper and I was hoping to grab some for mainly back up purposes. And of course to give them a listen

 
 
It works fine and it's listed in the manual as compatible with the WA2. There are some nice gems among them, e.g. Philips (dimpled disk) or Siemens Halske. The Telefunken PCC88 got quite expensive but are still cheaper than their E88CC counterpart. My current favorite is the Matsu****a PCC88 (which I use more often than the Siemens-Halske CCa and Telefunken E88CC). More interesting pearls are the Mullard PCC88 with pinched waist and Lorenz Stuttgart PCC88, but they're hard to find and the prices are nuts. 

 

[walls]

Hey Walls

You will love those tubes with your T1s! They will improve the details, imaging and soundstage nicely. What driver tubes are you using? Upgrading the driver tubes has almost as much impact as the power tubes on your SQ.

Well I had to send these back to the seller as one tube was making my amp buzz horribly. I end d up buying a matched pair of TS 5998's and they are stellar! A serious improvement over the stock tubes.

Now to start rolling the other tubes.....

 

[Franatic]

Well I had to send these back to the seller as one tube was making my amp buzz horribly. I end d up buying a matched pair of TS 5998's and they are stellar! A serious improvement over the stock tubes.

Now to start rolling the other tubes.....

Walls
 
Unfortunately tubes can get damaged in shipping, which is most likely what happened. I've had 2 bad tubes, an RCA 6080 power tube when I received my amp and an EI EZ80 tube from Ebay Yugoslavia. Both times I had the tube replaced. Glad you got a nice pair of 5998s. I'm listening to 421As right now....ooh la la!
 
Hopefully you'll have better luck with your driver tubes....never got a bad one of those.......yet :/

 

[walls]

Kind of worked out for me as the Pair of TS were a tad cheaper.

I've had quite a few pairs of tubes delivered for my other amps and have only had one bad one with those, it's a gamble. Lol

 

[mikoss]

So, got those Brimar EZ81 tubes in the WA2... I've had them in for a couple of days now and probably approaching the 40 hour mark. 
 
At first, I didn't hear much of a difference compared with the Ei EZ80's, but listening with the HD-650s, I'm really feeling a nice spaciousness, with the Sylvania 7236 tubes. I've always felt the soundstage/separation of the 7236 tubes was great, but I'm pretty sure it's stretched even further out now. I was telling @billerb1 how they sound about the same as the Ei rectifiers, so I haven't really heard a big change in tonality, or impact of bass per se. What is sticking with me is everything I love about the WA2... refinement, and a smooth easiness in presentation. Very nice.
 
These ones I'm pretty sure are made in France... can't really find much for etching/coding on the tubes, but the box says "Valve Electronic 10CV 5960-99-000 5072 EZ81 CV5072 Foreign"
 
Tubes just say Brimar Valve EZ81 / CV5072 Foreign