12AU7 Preamp Vacuum Tube, Single

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 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.

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 bought these tubes after reading another person's review for the BoyuuRange amp. I also got the adapters from Amazon. Very pleased.

I bought this as a replacement for the stock GE tube in the Bottlehead Crack with speedball and stock 6080 power tube. The sound seems thicker, warmer and fuller but does not subtract from the quick accuracy and clarity. Very close in sound to the GE. I’m using Sennhesier HD58X so this combo is the only time I’ve ever heard any of the HD become bass cannons!

Great improvement on my Bravo, sounds warmer and more clarity at the same time.Great buy.

~ Mullard 12AU7 Preamp Vacuum Tube, Single ~My main amplifier is a Carvin Belair 2x12. I love it. But a 50 Watt tube amp does not make for friendly apartment building neighbors. So I use an old 'CRATE V508'. It's a 5W tube combo with an 8 inch speaker. I run it through a Carvin 2x12 angled stack. Being a 5W amp there isn't much head-room before breaking up. I changed the 12AX7 PreAmp tube to the Mullard 12AU7 > SUCCESS. With the 12AX7 the amp started breaking up at 3-4. With the 12au7 it starts breaking up at 6-7 on the gain knob. This is exactly what I was hoping for. More head-room.

Poor quality

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

Buona qualità costruttiva e risposta audio con basso rumore.Produzione russa.