5E3 Head Build Power Up

5E3-inspired head chassis with tubes installed.

I fired up my 5E3 head build after my final sanity checks. I connected it to my Suhr Reactive Load into my DAW as my bedtime approached. I was relieved to get a healthy, low noise signal. I used my Monoprice guitar with GFS Mean 90s as my test guitar and the P90 noise was tolerable even with all the EMI and dirty power.

I installed typical modern tubes:

• V1: EH 12AY7
• V2: EH 12AX7
• V3 and V4: JJ 6V6
• V5: JJ 5Y3GT

With a wall voltage of 121VAC, the measured DC voltages off the three 22uF filter caps were 382V, 329V, and 241V. This is perhaps a little bit higher than the desirable range for a 5E3 circuit (350-370V).

I recorded a quick open chord passage using my Monoprice Indio Classic V2 guitar with GFS Mean 90 bridge pickup. The first pass uses a Weber Ceramic Blue Dog SM57 impulse, the second pass a GA10-SC64 SM57 impulse, and the final pass a C10Q M201TG impulse. The tone knob was maxed and the bright volume was set at 12:00. I still have a lot of the nuances of the amp to explore, but the basic sound of the amp is great. I immediately knew that the sound of the 5E3 circuit was more to my liking than the 5F1 circuit.

Outmoded Electronics · 5E3 - Blue Dog - GA10 - SC64 - C10Q

I will mainly be playing this amp loaded down and with IRs applied for now. I like how the amp sounds with the Ownhammer 1012 TWEED and York Audio VLUX 210 P10R libraries. I will have to dig deeper into the older Redwirez and Ownhammer libraries that I have to find IRs that I like. I may look into the CabIR.eu and Tone Junkies Tweed libraries the future.

Edit -12/8/21 - I had read about the interactive controls of the amp, but did not expect some of the more extreme results. I came across the so-called “better than blackface” setting by turning the unused normal channel volume to maximum or almost that value. This dropped the gain of the bright channel significantly: the amp can stay clean up to about 12:00 with bridge PAF-level bridge humbucker guitar on the bright channel when dialing back the tone knob. The amp is otherwise breaking up by about 9:00-10:00 on the volume dial. I would imagine that there would be even more headroom with a single coil guitar, and will try soon.

Edit - 12/21/21 - I had to reflow the solder on the V3 heater pin 2. I noticed that the tube wasn't glowing when playing through the amp the other night. The amp sounded a bit off, and it looked like there was asymmetrical clipping from looking at recorded waveforms.

Difference in positive and negative parts of waveforms. 

I did not get a dropped voltage on V3 pin 3, but rather the full B+ of 378VDC at the time. I believe that this is a recent development, since both power tubes are typically glowing. It must have been a bad solder joint on the tube pin eyelet itself. I perhaps narrowly averted disaster before I blew the output transformer, or burnt out other components.

Once I verified continuity on all filament tube socket pins, I powered up took down all relevant voltages using a cheap Tenma multimeter. I will check the voltages again with a calibrated Fluke 289 meter.

Voltages measured at tubes.

B+ voltages 

My B+ measurement was lower this time around. Perhaps this means that there was a problem further back in time. The wall voltage was lower by 1VAC this time however.