I combined the 5E3 Deluxe Bright Hi channel preamp with a 1 watt 12AT7 paralleled single-ended power tube using a $15 Fender Reverb Transformer as the output transformer. The little amp sounds fantastic and very tweedy. Headphone out works like a champ.
I built the prototype using Merlin's (ValveWizard) B9A development boards but we have a successful second build using a turret board. I'm ordering parts for a turret board build too.
I did some more tweaking to the amp design and the little Deluxe Micro sounds fantastic. It's absolutely killer tweed with a 12AY7 in V1 and it gets snarly mean with a 12AX7. I made four design changes during the test and tweak phase. The first was to drop the Master Volume pot from 1M to 500K to attenuate the signal from the driver stage to the power tube. The second change was to increase the power tube grid stopper resistor from 330K to 470K, again to attenuate the signal from the driver stage and reduce power tube blocking distortion. The third change was to add a Master Volume Bright Cap to add some brightness to lower Master Volume levels. This really made the Master Volume more useable. The final tweak was to drop the power tube cathode resistor from 2.2K down to 870 ohms which boosted the clean power output from 135 milliwatts up to 720 and max power with distortion climbed to 1.33 watts. The amp sounds a little more lively too. I also changed my recommended power transformer to the ClassicTone 40-18027. All the diagrams on the Deluxe Micro webpage reflect these changes: http://robrobinette.com/Deluxe_Micro.htm
Tonight I put the Deluxe Micro through its paces with pedals and fx. Hooked up a POD 400HD and tried everything. I also tried a Seymour Duncan tube overdrive, Boss PS-6 Harmonist and boosted EQ.
The amp's two volume controls allow you to use pretty much anything with good effect. The main volume controls how hard the preamp is pushed and the master volume controls how hard the power tube is pushed so you can keep both tubes happy no matter what's plugged in. This little amp makes me smile when I play it.
I know, this thread is useless without sound clips.
For comparison I measured the output of my my Firefly (2 x 12AX7 preamp and 12AU7 self-split push-pull power tube) puts out 154 milliwatts of clean power and 1.12 watts max with distortion.
Did some more comparison playing today. I ran my H&K Tubemeister 5 (single 12BH7 power tube) through my Weber 12A125A alnico 12" and JBL E130 hemp cone 15" speakers along with the Deluxe Micro.
The biggest difference in tone is the Deluxe Micro's low end. It's always there no matter how hard you shred the little amp, while the Tubemeister screams with modern higher pitched accuracy. You could really hear the difference between the two amps through the big JBL but the Deluxe Micro blows away the Little Hoffbrau when playing clean through the 12A125A 12" alnico.
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