12ax7 Tube Geeks

[The Golden Boy]

What would be the most "sterile," "transparent," "not warm," "hi-fi," sounding 12ax7s around? I'm not concerned about NOS or anything- I'm thinking about getting a very "immediate," Solid State sort of sound.

I've got a Mesa Boogie Bass 400+ that needs tubes. I really like the SS bass amp sound, and a cross between the SS and tube sound is appealing.

[sickboy79]

I responded to you in the LPF as well. Here's my post there:

Hmmm - so you're looking for a neautral sounding current production tube? I'd give the following recommendations:

Sovtek 12AX7LPS
EH 12AX7
Tung Sol 12AX7
JJ ECC83/12AX7 (a bit dark - but a flat curve, IMO).

If you got the bucks - the most Hi-Fi sounding 12AX7 I know of is the Telefunken.

Hope that helps.

[The Golden Boy]

You're one busy dude!

Thanks again!

[rockon1]

Telefunken smooth plate. Most Hi Fi tube ever made bar none! Bob

[Timbre Wolf]

What would be the most "sterile," "transparent," "not warm," "hi-fi," sounding 12ax7s around?
To me, that describes the late-production Ei, as long as it is not squealing with microphonics. It is bright (not warm), fairly transparent, and sterile.

Interesting that Telefunken's mentioned a couple of times. I really can't say what you all mean by "hi-fi" in relation to a guitar amp, but I definitely do not consider Telefunkens to be the highest-fidelity 12AX7. Many others color the natural timbre of my guitars less, with greater clarity. The sterile description fits it though, in my opinion.

Weird question, really. But then again, I'm a "12AX7 Geek" so who am I to judge? :messedup :crazy

- Thom

[Blue Strat]

Another vote for the Telefunken smooth plate.

[michael patrick]

To me, that describes the late-production Ei, as long as it is not squealing with microphonics. It is bright (not warm), fairly transparent, and sterile.

Golden Boy,

I've got some spare Ei tubes with low mileage I could sell you for cheap, if you are interested. Shoot me a PM.

[John Phillips]

If you seriously want sterile and not-warm sounding, I would maybe consider trying some 12AT7s instead. Start with the PI position (the only one I really like a 12AT7 in normally, for a guitar amp) and work backwards towards V1. 12AT7s usually do sound cold and too hi-fi in a guitar amp gain position, to me. You could buy a whole set of 12AT7s for less than the price of a single Telefunken 12AX7.

You also may want to use the clearest, highest-headroom power tubes you can get. For 6L6s that would be JAN/Philips 7581As... if you can find any. I'm not certain if this amp will support 6550s (the filament draw is higher, and there are a LOT of them) - but if so that would give you even more clarity and harder tone... I would call Mesa and ask before trying it though. If you do, ask whether they may even still have some of their old STR415 Sylvanias in stock - these are very similar or identical to the 7581As.

[Blue Strat]

If you seriously want sterile and not-warm sounding, I would maybe consider trying some 12AT7s instead. .

True of many 12AT7s but not Mullard CV4024s (haven't tried one of these yet John? They're super cheap). These sound awesome in virtually all applications and much less "thin" than other 12AT7s even in 12AX7 applications.

[rockon1]

To me, that describes the late-production Ei, as long as it is not squealing with microphonics. It is bright (not warm), fairly transparent, and sterile.

Interesting that Telefunken's mentioned a couple of times. I really can't say what you all mean by "hi-fi" in relation to a guitar amp, but I definitely do not consider Telefunkens to be the highest-fidelity 12AX7. Many others color the natural timbre of my guitars less, with greater clarity. The sterile description fits it though, in my opinion.

Weird question, really. But then again, I'm a "12AX7 Geek" so who am I to judge? :messedup :crazy

- Thom

A flat ,uncoloring,tube. It seemed that the Tele SP almost never bought anything to the party -so to speak- whenever I tried it in my amps.I havent heard any coloring of the sound when trying the TSP. Thats probably why all mine are sitting in the closet. Might be good in one of my amps yet if I find thats what Im looking for. Bob

[TheAmpNerd]

What would be the most "sterile," "transparent," "not warm," "hi-fi," sounding 12ax7s around? I'm not concerned about NOS or anything- I'm thinking about getting a very "immediate," Solid State sort of sound.

I've got a Mesa Boogie Bass 400+ that needs tubes. I really like the SS bass amp sound, and a cross between the SS and tube sound is appealing.

I've got some of the NOS China 12AX7s that will last your lifetime.

[rockon1]

If you seriously want sterile and not-warm sounding, I would maybe consider trying some 12AT7s instead. Start with the PI position (the only one I really like a 12AT7 in normally, for a guitar amp) and work backwards towards V1. 12AT7s usually do sound cold and too hi-fi in a guitar amp gain position, to me. You could buy a whole set of 12AT7s for less than the price of a single Telefunken 12AX7.



Good point! Most 12AT7's in place of an 12AX7 do. My exception so far is an RCA black plate 12AT7.

[Blue Strat]

Regarding 12AT7s being thin: Sometimes this is just what's needed to clean up a muddy, overly distorted overdrive channel (Mesas and others come to mind).

Don't dismiss anything until you've heard it for yourself in YOUR OWN application.

[rockon1]

Regarding 12AT7s being thin: Sometimes this is just what's needed to clean up a muddy, overly distorted overdrive channel (Mesas and others come to mind).


Another good point. Ive actually used them in this capacity myself. Worked great in the V2 of my Rivera Chubster to "clean things up "in the midrange a bit. Unfortunately the gain was reduced a bit and I removed it later because of it. Bob

[Blue Strat]

Another good point. Ive actually used them in this capacity myself. Worked great in the V2 of my Rivera Chubster to "clean things up "in the midrange a bit. Unfortunately the gain was reduced a bit and I removed it later because of it. Bob

Yep, if you're used to running your gain control at 3'oclock or higher then using a lower gain tube may not be for you. If you're looking for more of a bluesy thang and run the gain at 9'oclock or lower, the picture changes radically.

[John Phillips]

True of many 12AT7s but not Mullard CV4024s (haven't tried one of these yet John? They're super cheap). These sound awesome in virtually all applications and much less "thin" than other 12AT7s even in 12AX7 applications.I've got a couple of them :). I... er, haven't got around to trying them yet! ;). I'll take your word for the tone until I do :).

I'm actually happy with the sound of my amps at the moment, and not looking for anything different. Give me time, I'll pick up something else that does need experimenting with :p. I actually should have tried them in my Mesa Maverick's dirty channel, exactly for the reasons you mention. I definitely find a 12AT7 PI a big improvement in Mesas. In fact in the Trem-o-verb the tube layout is very odd - V5 is split between reverb drive and the common gain recovery stage after the reverb mix (not the reverb recovery itself, which is V1B!), so in fact I do already have half a 12AT7 (GE) in a gain application in this amp... and it sounds great :eek: ;). But that should maybe be a candidate for the Mullard CV4024s.

All I have to do is lift the thing onto my bench... :( :)

[Timbre Wolf]

True of many 12AT7s but not Mullard CV4024s (haven't tried one of these yet John? They're super cheap). These sound awesome in virtually all applications and much less "thin" than other 12AT7s even in 12AX7 applications.

I agree with Mike on the late-production Mullard CV4024 - they're not thin like most other 12AT7. Early-'60s production Mullard are more akin to other 12AT7.

I also agree with John about the 12AT7 angle, and almost answered that myself in my original reply (except that'd make me a "12AT7 geek" as well :eek:). Definitely worth a try.

- Thom

[silverface63]

I'm running a '69 Twin Reverb preamp out to a McIntosh MC2105 solid state power amp. I've been working on perfecting this for years. I love the super tight bass, try a Sylvania yellow label AT7.

[Blue Strat]

I'm running a '69 Twin Reverb preamp out to a McIntosh MC2105 solid state power amp. I've been working on perfecting this for years. I love the super tight bass, try a Sylvania yellow label AT7.

Jerry? Is that you? :eek: