Son of Ben (Benson Preamp)


Well-known member
This is my first build with smd components on it. When I first fired it up, there was no signal. So I took my audio probe and it was silent on the source leg of Q3. I added a quick little dab of solder and it fired right up.

I’ve had mixed feelings about the whole amp in box with jfets replacing tubes, but I couldn’t quite put my finger on it. The distortion never quite sounded right.

Here’s what I thought comparing pickups and the amount of drive on the pedal.

Single coillow gainGood
Humbuckerlow gainGood
Humbuckerhigh gainGood
Single coilhigh gainGross and squishy

This thing really shined when I plugged it directly into my fx loop return, using it in place of the amp’s preamp.

Over all I really like it, but just not with single coils and high gain.

Last edited:
Is that your herb garden? It's very green!

Funny you should that about Jfets. I have friends who swear that Jfet ODs are the best. I've heard some good ones but agree with you about the squishiness sometimes. Some people like that, some don't. I have some great ODs which use the distortion of BJTs and they have a chewy, tactile feel which is cool. But I find that I like the results I get with the regular IC and clipping diodes most of the time.
I tried with a dmm but it didn’t seem like I was doing it right. So I did it by ear until I got the sound I liked the best.

I read through this thread (assume you did too):

I tried two methods from the first page. Both sounded fine. One was dirtier, one was cleaner, both were usable given the amount of gain I would normally dial in. Thusly, I'm sure doing it by ear would work well too.

I gigged with it for the first time a week ago (and with no band practices or much testing). Worked great. I wound up boosting it with a klone set as a boost most of the time, but that likely reflected my inability to set the amp suitably rather than anything wrong with the Son of Ben.