Deluxe 5e3 build question

[DavidN]

I recently built a 5e3 as my first build. I used a small parts kit from Mojotone for most of the electronics and used Classic tone transformers. Also included several Rob Robinette modifications including a negative feedback switch, a pre-phase inverter master volume and rectifier diodes. I used RCA NOS tubes and an EV12L Classic speaker. The amp sounds great with awesome tone but it is really loud and powerful at almost all volume settings. The master volume has most of its effect from 0 to 2 and then jumps to almost full volume for the rest of its range. The amp is a beast and hard to play inside. I should also mention that it seems to breakup at very high volume settings and there is very little 5e3 breakup or distortion at low volumes.

The negative feedback switch gives the amp three tonal stages and gives some attenuation to the power but the amp still seems overly loud and powerful. I removed the negative feedback loop and it made no change other leave it in the 5e3 beast mode.

I used a 1M log pot for the master volume but am wondering if a linear pot would make a difference in the response. In the 5e3 the pre-phase inverter master volume replaces the 1M resistor with a 1M pot and I noticed that the grid voltages of the V2 phase inverter at pin 7 range from 6.9v at full volume to 46.3v at zero on the master volume. I have measured the all the voltages in the amp and they are pretty close to values on a Weber layout that I found.

I haven't removed the master volume but may give it a try. At this point it is hard to play it in the back bedroom

Interested in thoughts and suggestions.

[dorrisant]

Certainly an audio taper pot will help. Keep in mind this is a very loud circuit to begin with.

Welcome to the forum!!

If you can, post a schematic as built. Or maybe a part of a schem that highlights your implementation.

[DavidN]

Thanks for the reply. Maybe I am just surprised by the power of the amp and a linear pot for the master volume may be a good next step to get better control. I play a Gibson 335 which give a ton of bottom end. I tried a Tele today and it sounded really nice.

The layout and mods are attached. These are from Rob Robinette's site which is full of great information. I also wired it with an impedance switch which runs into the negative feedback.