Thanks, I will keep Eurotubes in mind, I've just Emailed Hotrox (UK company)...they don't do Ruby tubes, but they said they could match them for me if I send one in, from what I can gather you have to do it that way because different vendors using different matching/testing methods.

Update from Eurotubes:

"I received the package late yesterday afternoon.

This morning I was able to do a little testing. The plate current draw is actually higher on the OEM EL84’s. Not by much but about 7-8mA on average. The quad as a whole was not very well matched. The furthest spread from tube to tube was about 7mA. The transconductance was comparable between the two sets.

There’s a couple of other things I’m going to look at when I have time (this afternoon or tomorrow). At this point though my plan is to send the OEM EL84’s back to you on Wednesday along with a set of the JJ EL84’s that have a comparable amount of plate current draw. I can’t imagine this is going to make the difference but at this point it’s the only measurable difference between the two sets.

I did notice another player with a similar issue on the Vox forum. Definitely a frustrating scenario. It may come down to us just needing to pick one of these amps up to tear into. However, I’m still totally puzzled because I have several other customers without this problem…"

and stranger still that three of us on this thread have the SAME issue. There are others out there I am sure. I am really excited you have someone at Vox looking into it as I have found no good contact. Keep me in the loop on that one! Actually if you have a contact already, send the info and I'll be happy to forward along my amps serial number and description of issue. So would J I am sure.

Eurotubes is FANTASTIC to work with. They have put in a lot of time communicating with me on this, testing the stock tubes for me, shipping it back quickly, and that's all on their dime- they actually love what they do, you can tell.

Well, I am on my second amp so....between my two yours and J's that's at least four we know of right here. Update: The new JJ's matched to the originals I sent in by Eurotubes, same issue. They asked me to do a quick test of running them at 8ohm for a few seconds which I did. I didn't hear the same sound but there was so much more general distortion it was harder to tell. Back in normal mode it makes the sound when loud even while still clean.

So.....I don't know. I don;t know what the 8ohm test was for but will let you know what Eurotubes says about that. J mentioned having Mullards that work in the amp. I will try to verify that once I have more cash for this project. So far there has been no success with what I have tried.

For what it's worth, the Ruby Tubes pre and power tubes that came OEM in my AC30HW2 were manufactured at the "Sino" plant in China. There is some discussion if that plant is still making tubes due to fierce cometition from the New Sensor Corp in Russia. These are the same tubes that came OEM in my AC15C1.

Also, FWIW, I am not currently using any of the Chinese tubes in my amps. I use NOS Philips Miniwatt pre amp tubes and New Sensor Mullards power tubes in my AC15C1 and NOS Amperex across the board in my AC30HW2 with no issues at all. That leads me to believe that the issues we are seeing with this amp in a few cases may be tube related. (Un-scientific opinion, of course, but apparent from the collection of post here)

I agree that is is unacceptable to buy a new higher end amp and have issues out of the box. It may be that Vox needs to send replacement tubes sets out to all the owners having problems.

"mcalldp: when you say your new JJ's were 'matched to the originals' were they matched for transconductance as well as plate current ?.."

Yes the new set of JJ's I just got in from Eurotubes were matched for both against the original tubes that came in the Vox. I actually sent them in and had Eurotubes bench them next to each other.

I've used JJ EL84's from both manufactures in other amps with NO problems. I'm with Jmczaja here: "I dont want a new set of tubes from Vox. I want to know why the JJ's i bought don't work in my amplifier when there's no problem putting them in another amp"

Now I have to wait until I can save up more money and see if maybe the Mullards will work. and I have to totally agree again, "I wish Vox would chime in already.. "

We've got multiple new amps, that are not exactly cheap, all with the same problem, using different sets from different manufacturers. This really isn't acceptable and it's a big worry when I HAVE to change tubes at some point and have to take a crap shoot at trying different sets and hope they work....I can't afford to do that, I'm already out $100 on this stuff and that could go a lot higher just randomly trying tubes.

Without Vox chiming in there isn't a lot more to be done at this point. I guess my only option is to save up for the Mullards and Hope they work. Of course, they are more expensive and sound different so that's still not the most pleasing option.

Just tried both sets of my current JJ's in a Top Hat Club Deluxe (think that's the model) NO PROBLEM WITH THE TUBES AT ALL IN THAT AMP.

Anyone want to trade two new QUAD sets of matched JJ EL84 with less than 30 minutes on each set for one Quad of Mullards?

FWIW, I didnt have to adjust the springs to use the TAD EL84-STR's. I popped them in without any problems and they were a nice tight fit. They seem to have a little bit more headroom than the stock tubes.

But back to the situation at hand.. These aren't cheap amps and wish Vox would 'chime' in already. There's obviously a problem somewhere..

Well, I do have the sound-clip up and we have not only three people with original amps, but I returned mine for a second and we've had the tubes sent into a reputable dealer and bench tested for matching. We've also used the JJ's in other amps where they are working fine. We've also used at least three different dealers. So, I think we've taken some good steps and provided a lot of information here. A video would be fantastic as well, but I am a bit surprised we haven't already heard from Vox.

Even the TADS are more expensive than the JJ's and the description at the Tube Store, if accurate, sounds a bit off from what I was after in tone. I don't know....why should we even have to think about it? The damn JJ's work in every other amp, they should work fine in these new Vox amps.

We've done plenty of investigating on our own. I think it's time for Vox to drop by- calling Vox... Vox?

1) Could turn into a lot of wasted cash long term unless we find a specific tube that seems to always work but then we're also limited in choice.

2) I sent my amp back, got a new one, same issue.

3) Repair is money we shouldn't have to spend but perhaps the most cost effective long term but then we would also have to know what exactly is going on to fix it.

It would be great if Vox got in on this and perhaps, along with all of our info and their own testing, came up with an answer for us.

I want to try to order a few different sets to try but jeez at $100 a quad for some of the other brands that could turn into a lot of money real quick with no guarantee they work either. Right now, I'm flying in a band with no extra tubes which is kinda scary. Arg.
--------------------------------------------
"I can only think of three ways this can be fixed:
1) Finding a set of tubes the amp works with (PITA)
2) Sending the amp back and getting one that doesn't have this problem (PITA)
2) Having the amp modded/repaired to work with any tubes (PITA but probably the best solution)"

In case this helps troubleshoot, I have the AC15HW1 and run it on JJ's at full throttle without issue.