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AX84 ÜberGain Tube Guitar Amplifier Projects

[classic projects] [current version] [testing version] [old versions]


So you wanted more gain, eh?  Well, prepare to be stunned by just how much gain is availble from 3 stages plus a cathode follower.  The preamp design is curtesy of Alex Kenis, the CF is from Merlin, and credit for the powersupply goes to Celeste and Merlin.


  • Gain, gain, GAIN!
  • Bootstrapped cathode follower
  • Bass, Mid and Treble tone controls.
  • Ultralinear output stages.
  • Fixed bias
  • Capacitor multiplier power supply

Skill Level: advanced --- Status: Ready to Prototype.

Before using these materials, please read our terms and conditions.


09.12.24 ÜberSEL Schematic  (Please note that the clips recorded below are from a modified version of this schematic.  Those modifications will be documented on the schematic once the tweaking process is done to the poweramp and tone shaping.
11.11.10 ÜberSEL Preamp Update Schematic  2011.11.10 Update of the preamp schematic.

ÜberSEL Sound Clips

MasonAtom's Notes:
There is actually a lot more high end crunch in the amp that didn't come out in the clips because I have to do some more work with mic placement, but hopefully I'll get that sorted out the next time I record it.
I've made a couple changes to the poweramp so the schematic will need to be updated at some point, but I'll wait until I'm completely done before forwarding those to you. Still have to sort a few minor things.

Recording details:
Ubergain preamp into KT-88 UL PA. Guitar is a 1998 Gibson Les Paul with EMG pickups. Amp is set as follows: Gain 1: 8, Gain 2: 9, Bass:5, Mid:5, Treble: 9, Master Volume: 10. Cabinet is a closed back Marshall 1936 2X12 with Celestian G75T.
Right channel is recorded with a Shure SM57 into a MOTU828mkIII firewire interface. Left channel is a Sennheiser e609 into the same interface.

Dam That River
UberSEL Clip #1
Know Your Enemy
UberSEL Clip #2
UberSEL Clip #3

Please Note:  The following clips were recorded on a prototype amp that has this preamp and a 2W October Studio power amp and are for comparison purposes only.  As such, the clips are not going to sound exactly like what the 20W design does.  These clips are just to give you an idea of what to expect from the preamp.  If there is enough interest in a 2W version of the poweramp we might design one.

MasonAtom's Notes:
Setup was Les Paul Studio with EMGs / Comm IV pre / October Studio PA / gains 9 each, bass 6, mid 3, treble 8, NFB 3, presence 10.  Two mics: SM57 through Onyx 400F preamp, e609 through 12AV7 preamp.

UberGain Preamp + 2W Studio poweramp, courtesy of MasonAtom.
UberGain Preamp + 2W Studio poweramp, courtesy of MasonAtom.
UberGain Preamp + 2W Studio poweramp, courtesy of MasonAtom .
UberGain Preamp + 2W Studio poweramp, courtesy of MasonAtom.
UberGain Preamp + 2W Studio poweramp, courtesy of MasonAtom.

Before using these materials, please read our terms and conditions.

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