Mullard 12AU7 Preamp Vacuum Tube, Single

I bought this pre-amp tube as an experiment for my 5 watt Vox amp which had very little headroom before going into distortion. I wanted a cleaner native tone and to get FX such as distortion with pedals. Upon some questioning in a guitar amp group I learned changing out the 12ax7 would have dramatic effect on that which it did. Unfortunately I think I went a bit too extreme as this tube literally requires my amp to be almost at full volume just for bedroom jamming which is all I do these days after retiring from the music biz. But with that I will say the amp sounds better overall with this tube replacing the no-name 12ax7 it originally came with, and not just the headroom but it also seemed to help with the "fizzy" tone the amp had. Although I going to do some more experimenting with different tubes this tube will still come in handy as I have some other single pre-amp tube gear I believe would benefit from the restriction this tube creates so it's a win win.

I bought this 12au7 a 12AT7 and two new 12AX7's to replace the stock tubes on my Marshall DSL1H. Going purely off of reviews i wanted to try to make the gain more usable and and reduce the compression a bit. 1- the 12AT7 turned out to be to much of a power loss i dont recommend. 2- I put the stock 12AU7 back in with the mullard 12AX7's and it still had decent compression and some of the fizzy gain the stock marshall tubes produce. 3- I put in the mullard 12au7 wich removed the compression almost complestely and reduced the gain by about 20% making it more usable across the range. That said i think i liked the marshall 12au7 along with the mullard 12ax7 combination the best it has a nice compression cranked and a nice distortion to my ear it is a very nice inbetween compromise. I highly recommend trying the stock 12au7 for the power amp and the mullard 12ax7s in the pre amp for a nice balanced tone that still rips when you want. Hope this helps.

The Mullard tubes were a definite step up from the stock core tubes on the Gremlin amp. And I liked the stock core tubes. But the Mullards are step up in every way. They have that tube warmth and very full deep base. The sound stage is better as well. The highs are good and dynamic when need be.

I play bass for Worship Teams at my church. I installed this Mullard 12AU7 in a Behringer Ultragain MIC200 which I use as a DI. This tube is GREAT! It is exactly what I hoped for. The 12AX7 that came with the Ultragain was not only quite noisy it had almost no gain adjustment before it was over-driving the input to the board. It went from almost no output to overdiven and very noisy when moving the output less than one mark. The gain had to also be set very low which didn't work the original tube hard enough to warm it much. Now with this Mullard 12AU7 I set the gain to about the 1 oclock position and set the gain at the3rd or 4th mark and my bass has a very nice warm sound with a really nice low growl when I want it with almost no induced noise. If you have a Behringer Ultragain MIC200 you want this tube in it.

I used these Mullard 12AX7 and the 12AU7 tubes along with the current production Tung-Sol 7581A (replaces 6L6) in my High Fidelity system. Simply put, I'm blown away! I would not use this combination in a guitar amplifier as they contribute absolutely no discernable distortion at all. But in High Fidelity service, that is what you want, crystal clear reproduction. That is what I got. I put these in a pair of Heathkit A-9B mono blocks which I have driving a pair of Boston A-360 speakers. The room is filed with delightful music. Brass and woodwind instruments sound as if they are alive and bass response is powerful with crystal clear faithfulness to the details of even the most resonant of stringed instruments. My wife and I listened to Chicago IX as if we had never heard it before. This pair of amplifiers from 1954 sound brilliantly new!

Tube was shipped without the package carton shown in the description. There was no bubble wrap, cardboard enclosed in a slightly padded Amazon envelope. I have ordered and received other such vacuum tubes and they were packaged appropriately in a box with bubble wrap, cardboard package, and styrofoam peanuts. This is a relatively expensive tube and care was not taken into packaging it safely. The tube tested out slightly good so no idea if this is a brand new tube (unused).

I have an older Vox Valvetronix guitar amp with an Electro Harmonix 12AX7 tube in it that I was experimenting with different tubes (valves) to see how the modeling circuits would change in tone. This amplifier uses a single dual triode tube in the power section instead of the input, and then sends the output of the tube to a solid state power amp. The stock tube is fizzy sounding in this configuration and doesn't give a smooth break up at lower volumes when you push it lightly into overdrive, so the 12AU7 mellowed the fizzies right out - but the amp now is unable to get metal-like tones with this tube, its really weak amplification. This was the result I expected, and it made the cleaner amp models sparkle in the process, so I got what I was looking for. I will try the 12AT7 next to see if I can get the best of both clean and dirty. I bought a new 12AX7 too, just in case I was wrong, will be testing it later and reviewing them all eventually. As I understand the 12A-7 (7025) series of tubes, the 12AX7 is the hottest with 100% amplification, 12AT7 comes next with 70%, then the 12AU7 is around 19% gain. The AU's were used a lot in the preamp circuits of vinyl stereo consoles noted for very clean and warm sounds.

Very nice, it helps to balance the output of a Fender Hotrod amp

schlechter Klang, Röhren überaltert und eigentlich für den Restmüll

Low volume gain. I bought a pair earlier this year. Poorly matched gains. One tube was much louder than the other.

Better then the original chinese tube. Using on the modded Bravo V2.

Parfait pour mon vox lil night train.

Non sono un tecnico ma la valvola in questione è a mio giudizio migliore dell'altra che ho sostituito nel preamplificatore valvolare per voce, la uso per cantare, tono più caldo e deciso la voce è migliorata