Now you have two speaker outputs; 8 and 2 ohms or 4 ohm. This speaker matches the amp and cabinet size perfectly and you get a classic, scooped fender blackface tone from a little amp. I tried a 12AT7 in the same circuit and sounded weak at the recovery side which is to be expected. An open foot switch off puts the oscillator grid at volts which shuts down the oscillator by stopping all flow through the triode. Order the Deluxe Reverb multi-tap OT with 2, 4 and 8 ohm taps. Some amps are sensitive and difficult to control the reverb on.

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I’ve used 12AX7s as reverb drivers simply because they were what I had lying around. The triode on the left is the Oscillator and its grid is connected to its plate through three oscillator caps that cause the plate voltage to oscillate. Morgan Jones, Valve Amplifiers4th Edition.

Reverb and Driver tube: 12AT7 or 12AX7?

The tremolo circuit uses one triode of a 12AX7. Revfrb know fender typically used 12at7 for reverb send stages. Logical schematics Layout Click the images for full size versions.

Keep the feedback loop and install a. A good starting point is twice the original resistor value. I had one briefly. For example, blackface Fenders at least my Deluxe Reverb Reissue uses both halves of a 12AT7 single-ended, in parallel as the reverb driver.


What’s a good 12AX7 reverb driver tube?

The glued and stapled baffles on the silverface amps is to us one of the bigger 12aax7 between the blackface and silverface amps, or should we say, the cabinets. I was somewhat confused by the high voltage at 12AX7 plate I have around V there but after I did some measurements it turns out that the driver part draws 2mA of current.

Use the ground switch or foot pedal to make the NBF switchable. If your power transformer doesn’t have a 40v bias tap you can use this Hammond D36 36 volt transformer instead and connect its second rverb lead to the Power Supply Board’s ground bus shown at revefb left “40V AC transformer lead.

I would like to improve the reverb. The Tremolo Pedal control shunts shorts the oscillation signal to ground when closed so if no tremolo pedal is plugged in the tremolo is on.

Log in or Sign up. I’m not getting a clear picture, but always trying to learn. Jul 21, 7. When the neon bulb is bright the LDR resistance is low and more signal is bled to ground. But in the classic Fender circuits a 12ax7 is a bad reverb driver tube.

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A 12au7 works there too, drives it a little less hard and they’re cheaper that dirt as organ pulls. If you make the NBF switchable there will be less volume difference if you use a high resistor value. Home Forums Recent Posts.

King FanJul 20, You must first remove all existing wires to the external speaker jack so that it is totally separated from the main speaker jack. Many players are happy with the default 6. This reduces the effect of the feedback loop, making the amp break up more when the NFB is engaged. You must log in or sign up to reply here. How does it sound?

Yes, my password is: The reverb driver is a 12ax7. We think the Oxfords are underestimated. If you have not been trained to work with high voltage then have an amp technician service your amp.

I like the self-split reverb driver too. From my understanding, and others may feel free to chime in on this one.