Machine Gun Amps
Tube Descriptions
All tubes listed here are either new production or New Old Stock ("NOS means New Old Stock which are old tubes that have never been used. If a tube is used, it is not "NOS", it is used! Don't be fooled...)

Notice: I am not selling any tubes anymore.

I will attempt to describe the sound that they give and the application they are for. For tone considerations and what you should think about before you buy new tubes, go here. I also have experience with other tubes. Look at the page. What tubes does my amp use?

Power Tubes (not for sale)
Svetlana 6L6GC Ruby 6L6GC STR JAN Philips 6L6WGB
JAN Philips 7581A/6L6GC Svetlana EL34 JAN Philips 6V6GT

Preamp Tubes
JAN GE 12AX7WA Ruby/Tesla 12AX7/ECC83 Ruby/Ei 12AX7/ECC83
JAN Philips 12AT7WC GE 12AT7 JAN GE 12AY7WA
JAN GE 5751 JAN Philips 12AU7WA

Rectifier Tubes
GZ34/5AR4 Mullard GZ37

Power tubes (not for sale)

Svetlana 6L6GC
This is a great new tube. It's only been in production for a few years, but it's been very reliable and good sounding. It appears to be very sturdily constructed, like the old American and European tubes. The sound is like a classic 6L6GC, more in RCA and GE territory than Sylvania STR. They have the nice balanced sound and nice high end of the classics. They don't quite have the punch and headroom of the Philips 7581A, but what does? These are definitely worth consideration if you like classic 6L6GC tone. I've been using them almost exclusively in 6L6 amps because it's my opinion that you really don't need to spend the extra cash on the NOS tubes as far as quality is concerned. But the NOS tubes I  carry do have a different tone so they still warrant consideration. I use these in some of my own amps.

Ruby 6L6GC STR
I have started carrying this tube as an economical alternative to the other 6L6's. This is a nice sounding tube and the quality seems to be getting better and better. Ruby's guarantee is the best there is, so that should be enough reason to check them out. The sound is similar to the Svetlanas, but maybe not as "refined". These are supposed to be knockoffs of the classic Sylvania 6L6GC STR tube that came in 70's Fenders and Boogies, which is generally considered the best of the high power 6L6GC's ever made. That tube is still available as the 7581A down below. To compare these Rubys to the Sylvanias is a bit optimistic, but they are good nonetheless. If you don't want to spend the extra money on the other 6L6's, there's absolutely no shame in buying these! I use these in some of my amps.

JAN Philips 6L6WGB (5881)
This is a newer version of the famous 5881 from the late '50's early '60's. 5881's are the tubes that came stock in many of the late 50's Fender tweeds. These have the small bottle like the old Tung Sol, in between the size of the 6V6 and 6L6GC. These have a bit of a harder and stiffer tone than the Tung Sol 5881, but try finding a Tung Sol! These tubes emphasize midrange and break up earlier than the other 6L6GC types. They sound better to my ear in tweed amps, but still do fine in blackface and silverface amps. They give earlier breakup in blackface and silverface amps when compared to the 6L6GC. I find that they work well in the 6V6 to 6L6 Deluxe mod. They are very well suited to this job! They also work well in Fender Blues Deluxe/Devilles. These are nice tubes! This tube comes in a white box with military stock numbers on it.

Here's an explanation of what the letters mean on the tube: G means it's a glass tube (instead of the older metal ones). The first 6L6 was metal, then they went to 6L6G which was a glass bottle version. That could be considered the 6L6GA. There were other variants from there. Then came the 6L6GB. B is the version. It was more of an evolution than anything else. The military version of this tube is the 5881. It is rated a little higher than the regular GB. In the later years, companies sometimes attached a W into the tube number rather than using the military designation, hence the 6L6WGB. It's basically a 5881. The JAN means Joint Army Navy. I'm not sure exactly what that means, but it does mean that these are tubes that were made specifically for the US military.

JAN Philips 7581A (6L6GC)
This is the mil spec version of the Philips 6L6GC. These are world class tubes, bottom line. It has double mica spacers but otherwise looks and sounds identical to the famous Sylvania 6L6GC STR. The Sylvania 6L6GC STR is the tube that Fender requested to be made specifically for hanging upside down in guitar amps. These are also the tubes that came in original Boogies. The tone is very up front and clean. They do distort nice though. Think SRV type tone when they do distort. They retain the high end bite. This tube sounds very nice in blackface and silverface amps, particularly Twin Reverbs. It's considered among the best 6L6 type ever made. This tube comes in a white box with military stock numbers on it.

Svetlana EL34
This is a very nice tube, with quality in construction you'd expect from Svetlana. The tone is a little more bottom endy compared to the Siemens EL34 and the Sovtek EL34WXT. These work particularly nice in combos where you need the extra bass and not quite as much high end. But pumped through a 4x12 of Celestions, they are very, very nice. These are the only EL34's I'm stocking right now, although I can get others. You owe it to yourself to try these before you search out some really expensive NOS ones! Here's my take on EL34's: They belong in Marshalls! Some people like the way that they sound in Fenders and I'll give them that. But the reason why Fenders sound like Fenders has a  lot to do with the 6L6's. Besides, installing EL34's in your Fender (which requires mods by the way) will put extra strain on your power transformer due to increased filament draw. There's no guarantee that your power transformer will survive!

JAN Philips 6V6GT
NOS 6V6's? You bet! These sound great and appear to be made really well. They should be, they are US military tubes! They have pretty, shiny black plates. They have a bit more clarity and high end than my beloved GE's. I may even like these better than the GE's now that I have a bit of experience with them. Highly recommended for up front 6V6 sound. Sure they are expensive, but your Deluxe Reverb or other Fender 6V6 amp deserves nothing less than good ol' military stocks! This is my new standard for 6V6's in my own amps! This tube comes in a white box with military stock numbers on it.

Ruby 6V6GTBC
Finally! A new manufacture tube that will survive in your Deluxe Reverb! These tubes are much more rugged than the Sovtek. They sound nice, but not as strong as the JAN Philips. More in RCA territory than JAN Philips. I've been using them in my project and they have survived some extremely merciless pounding by me. Definitely worth a try if you are searching for a 6V6 you like. These are likely the cheapest matched new 6V6 you will find. For the money, they can't be beat! Since it's Ruby labeled, you know they stand behind it too. Comes in a Ruby box with matching specs.

Get these while they last. I'm not sure if I'll be able to hold the price this low, but all the ones I have left will be sold at this price. This is the tube you need in your original or reissue Fender Reverb Unit! It really does make a difference folks. It takes part of the splashy, bitey sound off the RI and makes it sound more like an old one. I usually have a few RCAs and other brands too. Email me for details.

Preamp Tubes

These are the military spec 12AX7. They are a direct replacement for the 7025 as well. This is a nice sounding tube. Very evenly balanced to my ear. Nothing fancy, they get the job done. These are practically identical to the Fender labeled GE 12AX7/7025 that came in late '70's Fender amps. Rumor has it that Eric Johnson uses these! These don't emphasize highs or lows, they just reproduce the sound like it should be reproduced. I like them a lot. The main reason I like them is because they are very tough. I haven't had any experience with newly constructed tubes that last anywhere near as long. These should last AT LEAST twice as long as run of the mill Chinese and Russian garbage. And they don't go rattly or microphonic like the cheapies! Why bother spending more on a Groove Tube that is really foreign when you can have good ol' American Military stock? All of these are tested by me in my amps at high volume. I also tap on the tube to try to drive it into microphonics. This tube comes in a white box with military stock numbers on it.

Tesla ECC83/12AX7
This is my new lowest noise tube. Yes, even a TAD lower than the JAN GE. Since the Ruby 7025STR has been out of production, this is the now the best of the new manufacture 12AX7's I carry. This tube tends to accentuate the high end a little. They make individual notes cut through a little better than the JAN GE and Ei. This is nice for livening up a semi dark amp. These would be good for getting that high end crunch and harmonics in high gain amps.  The tone of the Ei seems to be a bit more complex in the mids. But this tube is definitely interesting. The ones I have now are remarkably free of noise and microphonics. The plate structure is different looking, not like a normal tube. But they seem to be good and if they last, I will continue to carry them! I'm going to experiment with them in my project amps and do some more tone testing. Tesla is making some of the best stuff quality wise these days. They come in either the standard JJ/Tesla box, or a Ruby box.

Ruby/Ei 12AX7/ECC83
Guess what folks? The factory that made these tubes was bombed in the NATO joint bombing thing. These were tubes made in the former Yugoslavia. I used to carry them as a cheaper option to the JAN GE's, and also because they have a different tone. To my ear, the Ei's have more high end and more gain. Kind of sounds like the presence got turned up. They work nice when the amp is going to be pushed to distortion. A lot of people like the tone of these as well as some NOS tubes! As a matter of fact, these are causing a bit of a stir in the hi fi circles. I've found that a few of them go rattly after some time has gone by. For this reason, I'm going to offer the Tesla as an upgrade. Hey, these are not US military tubes! But they are much better than the standard Russian and Chinese stuff in my experience. Don't feel like a cheapskate buying these! They have a different tone compared to NOS. And they do sound nice! I'm using these more and more in my own amps. I weed out the bad ones by testing them in my Marshall.

JAN Philips 12AT7WC
NOS are the only 12AT7's I use at the moment. I haven't found any current made ones that are worthwhile. I started carrying these due to a few problems with the JAN GE's. It seemed that I would get one or two bad JAN GE's in each order I would make (I found the bad ones in testing). Then I started to get more and more bad ones. The price I pay on these is too high for bad ones! I'll probably order the Philips from now on since their success rate seems to be much better. Tone doesn't seem to be much different, if at all, compared to the JAN GE. The main consideration of this tube should be reliability anyway. This is why I like to use NOS 12AT7's! I test all of them in whatever Fender reverb amp I have in front of me at the time, usually the Deluxe Reverb. They get tested in the reverb driver. Whenever you change power tubes, you should change the phase inverter as well. The phase inverter is the closest small tube to the power tubes in Fenders. Blackface and silverface Fenders use 12AT7's as the phase inverter in most amps. This tube comes in a white box with military stock numbers on it.

GE 12AT7
I scored a few of these and they are cool. One more tube to choose from! These tubes are identical in construction to the tubes Fender used in their amps in the late '70's with the Fender label. These are actually the 12AT7's that I use in my own amps. They are packed in generic white boxes. The tubes themselves have no white GE ink like is typical of tubes made in this period, but they do have the grey sandblasted on printing that immediately gives them away as GE's. As far as I can hear, the tone is identical to the JAN GE 12AT7WC. These are not built as stout though. They share the same plate structure as the JAN tube (or it looks like it does), but it doesn't have the double or triple mica spacers and general robust construction. The JAN tube also has extra support to hold the whole assembly together inside. It may be worth the extra money if you are on the road or hauling your amp everywhere all the time. These have been working fine for me. However, if you want the ultimate in 12AT7 tubes, the JAN Philips are still the ones. Go with these if you want NOS tubes but don't need the absolute ultimate in longevity and toughness.

JAN GE 6072A/12AY7WA
This is the tube that came stock in many tweed Fender preamps. The gain of this tube is lower than the 12AX7, 12AT7, and 5751. A lot of people would replace this tube in their tweed amps with a higher gain tube to get more crunch. However, some people like the amps to sound the way that they were supposed to sound when they left the factory. To get the original tone, you need this tube! These are US military tubes made by GE, so you know they are good. This seems to be the only one I can get in any kind of regular quantities too. These have pretty shiny black plates that remind me of my GE 5 star 5751's. I test them all in my Marshall for noise and microphonics. Make your tweed Bassman, Pro, Deluxe, Super etc... sound like it's supposed to sound! This tube comes in a white box with military stock numbers on it.

JAN GE 5751
This is the "option" tube (a little lingo lifted from CART racing from last year...). These can successfully be used to replace any tube in the preamp of a blackface or silverface Fender in a pinch, but are not really suited to the reverb driver position. I'd really recommend using it in the first or second position only (looking at the back from the right) depending on what channel you use. They have less gain and possibly less high end than a 12AX7. The gain factor of a 12AX7 is 100, the 5751 is 70, and the 12AT7 is 60. I like the 5751 if clean is the order of the day. I have a buddy that I run these in the preamp for, because he plays country and wants the amp to stay extra clean. It also helps because he uses high output G&L ASAT's. These things can also smooth out an amp with too much gain for your tastes. Use the 5751 as something different to try. These do work nice in a slot originally designated for a 12AY7. If the 12AX7 is too much for you, these are halfway in between the 12AY7 and 12AX7 on gain. They sound nice in the first position of a tweed Bassman! These tubes are rated to draw a bit more filament current than a 12AX7 or 12AT7. This shouldn't be a problem in an amp, but I'd be a bit leery of using this tube in a tube pedal or otherwise non stout preamp or something. I test these for microphonics and rattle in my Marshall. This tube comes in a white box with military stock numbers on it.

JAN Philips 6189/12AU7WA
This is a mil spec 12AU7A. This tube was never used normally by Fender as I recall. However, I have seen this tube specified on the tube chart of a tweed Super. The "Y" in 12AY7 was crossed out with a pen and replaced with a "U". This crossing out of letters on Fender tube charts is something that is widely accepted that Fender did in lieu of printing new tube charts. Since I've seen this tube specified in a Fender amp, I'm going to stock it! Some Ampeg, Vox and Gibson amps came stock with this tube. This tube would make a good reverb driver in a Fender if you like the tone, it's able to handle the plate wattage fine. I've finally done some testing on this tube, and it does sound nice in the reverb driver slot. It seems to give a bit more depth than the 12AT7. It also seems to run very hot, but this is probably due to the bigger plates absorbing more heat. This tube is probably not something that you'd want to use in the signal path very often due to it's low gain (about half of what the 12AY7 is), but it makes a really nice reverb driver where gain is not important. The 5814A is also a mil spec 12AU7, but my handy GE tube manual shows that these draw a touch more filament current and can handle a very slight bit less plate wattage, so I'll probably stick with the 6189 while they are available. This tube comes in a white box with military stock numbers on it.

Rectifier Tubes
(I also carry other rectifier tubes on my rectifier tube page.)

Chinese GZ34 (5AR4)
This is the only new replacement GZ34/5AR4 tube that is available. You can still get NOS, but at $60 a pop or so, I'll keep away. Since this tube has nothing to do with tone intrinsically, longevity and reliability should be the only concern for this tube (more on that below). You are not going to be able to tell tone differences between the Chinese and Mullard GZ34/5AR4 provided that they are giving you similar B+. I've found that the reliability on the Chinese GZ34/5AR4 is good so far, and they seem to give decent life span. I use these in all my own amps. The only problem I've had lately is that they tend to rattle. It's not a problem at high volume, but if you record at low levels in the studio, it may be a problem.

Now, onto the tone thing. There is no tone inherent to the rectifier tube. You read that correct. A Chinese GZ34/5AR4 will sound exactly the same in your amp as a $60 Mullard. The function of the rectifier tube is to help turn that AC voltage coming out of the wall into DC. There is no signal going through the rectifier tube. This tube does affect tone in an indirect way, it sags. Since the electrons in the tube have to cross a gap, this acts like a resistor. The harder you play the amp the more it will sag. The GZ34/5AR4 has a spec on the amount of gap between the cathode and the plate (which is what determines how much sag you get), and theoretically this gap is the same in the Chinese and Mullards. The only benefit you will get from the big dollar NOS is increased tube life or bragging rights. Is this worth it to you? Maybe. Also, other rectifier tubes will sag more, like the 5U4 or 5Y3. These have a larger gap than the GZ34/5AR4 which causes more sag. However, these are NOT direct plug in replacements contrary to what you may have heard. These different tubes will change voltages throughout the amp and will usually need a bias check/adjust to make sure your amp is working properly. Also, sometimes the voltage change is not a good thing. If you have a Princeton Reverb or silverface Deluxe Reverb that uses a 5U4, I'd recommend against using a GZ34/5AR4. Go here to read about subbing different rectifier tubes before you go ahead and do it.

Mullard GZ37
I have decided to start carrying a few of these. They are NOS British military stocks. They make a wonderful alternative to a 5U4GB and are nice in place of a GZ34/5AR4 if you want less voltage. Watch out, these do draw 3 amps on the filament like a 5U4GB though. An amp originally designed for a GZ34/5AR4 might not like this tube. They are indirectly heated which will ramp up slower and help extend tube life if your amp doesn't have a standby switch. These things sould last years and years, long enough to forget about chaging it for a long time. They sure are pretty too. They are in a really tall bottle with a shoulder on top and a brown base. They come in a British military box. 5U4GB users, this could be your new tube.

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Last updated 11/17/00