New Mullard tubes

[davoux]

The new Mullard tubes are supposed to be made to the same specs as the old ones. Any comments? I've got to get new tubes for both a Hiwatt DR103 and a Sound City 120L. I'm sure both have fixed bias and essentially the same circuits. The bias voltage is relatively low so they will burn out tubes that allow relatively high plate voltage. I believe both were designed to run the old Mullards.

Any suggestions on other tubes that may work well? My Son is looking for tubes that don't get overly crunchy when overdriven. Thanks for your help. John

[soundmasterg]

None of the modern manufacture tubes are as good as the old ones because the economic incentive isn't there. The vacuum inside each tube is less than old production was because the modern companies don't spend the time to evacuate all the gases to the level the old stuff was, and the metallurgy by and large is not as good either. Some of the new tubes sound just fine and in some examples, sound better than old production, but none of them will last as long in use as NOS stuff will.

For new brands, the new Mullards are fine, but nothing special. You would probably have better luck with the Winged C EL34's, the JJ E34L's, or the JJ KT77's.

A better approach than trying to hunt down tubes that will handle a low bias voltage in those amps would be to modify both amps so a proper bias voltage can be obtained. It is a common mod on both amps and isn't very hard to do, and both amps will work much better. All you need to do is to add a voltage doubler circuit to the bias supply for each amp. If you have no idea what I'm talking about, then you should take your amps to a tech so those mods can be performed. After the bias voltage mod, you can use just about any EL34/KT77 type in the amps without fear.

Greg

[tubeswell]

Hmmm... , I've heard some people have bought and the 'new Mullard' 12AX7s to find that they appear to be nearly identical in construction (and not too different in sound) to Sovtek's 12AX7 LPS. Of course this could be pure coincidence..., but seeing as how they retail in NZ for anything up to $70, I've got to be suspicious.

I try and obtain the finest NOS pre-amp tubes I can afford these days. I just can't get no satisfaction from new pre-amp tubes.

[soundmasterg]

It wouldn't surprise me if the new Mullard 12AX7 and the Sovtek 12AX7LPS were the same thing, as the same company makes them, but there are also a lot of inaccurate rumors floating around on the internet too. The only way to know for sure is to get one of each and compare.

I like NOS European 12AX7 types like Amperex, Mullard, Telefunken, etc., but for most use these days, I've been using the new Tung-Sol 12AX7's and they are fabulous. They're a mid-plate size tube, so aren't a copy of the LPS or EH, and have great tone and gain levels, and have been quite reliable too. A good replacement for the now defunct EI 12AX7's for modern stuff. These new Tung-Sols sound better to my ears then all but the best of the Euro 12AX7's of yesteryear, and certainly a lot better than NOS American 12AX7 types which were often microphonic and often didn't sound very good.

Greg

[Manic]

I was doing a lil VJ research and noticed that the Dr. Z Mini-Z ships with a GT12ax7M.
FWIW

[Amp Kat]

I think Tubeswell and Soundmaster are right on the numbers with this one. I had a customer bring some in yesterday and I matched it up with an LPS and it is identical making me belive that's what it is and it's what I suspected it was when I first saw it. BTW the spiral filaments are quite dim if you know what I mean. Out of 5, two were Microphonic and 1 was a hummer. Not only are they LPS's but they aren't preselected or tested out of the lots so it's basically IMO a quick relabeling job and hopefully not the rejects of a large lot. Haven't seen the Power tubes much except for a couple of Sovtek WXT EL-34's that were not good either.

[Manic]

The plates are similar. If You look just below the getter where the plates hook on, they look different.

Just an observation.

[Dr. Jimmy]

I've been using the new Tung-Sol 12AX7's and they are fabulous. They're a mid-plate size tube, so aren't a copy of the LPS or EH, and have great tone and gain levels, and have been quite reliable too.
Greg

I've tried them, and have tried to like them but for some reason to my ears they seem to become rather lifeless after a few hours use. I do like EH, when I can find ones that aren't microphonic (they have gotten better of late).

[soundmasterg]

Well as with any other tbe, it depends on the amp and guitar combination. I've used the new Tung-Sols in lots of vintage type stuff and they work great there. I don't like them much in more modern amps.

Greg