This was sort of an impulse buy. I’ve been getting a great jazz tone from solid state amps, using a pedal so sometimes add a little saturation. I was in a local store and there was this pro junior on sale... So these are well known, this is just a generic black vinyl “version iii.” It has a really good basic good tone without the fender mid scoop and it works really well for my style. The relationship of the volume knob to guitar volume is interesting. Despite the fact that I thought it sounded great out of the box I could not resist some mods. New speaker. I had a homemade cab with a Weber Alnico 10a100 in it. I put the Weber in the pro junior after removing the bell cover. Better? Maybe. Different. I’m liking it. Wire twist. This amp isn’t overly noisy, but it did have some hiss. Unbundled the green leads from the transformer, twisted them together, and shunted them along the chassis wall. Hum is gone! Or at least it’s no louder than any other tube amp Negative feedback switch. I installed a simple sp/st switch to cut the negative feedback in and out. Without negative feedback it’s a little more raw, but in a good way. A bit less polite. So far no additional money spent Wondering about maybe doing a rebias, or installing a bias pot. It does seem to run hot! But I like the way it sounds Also thinking about shock mounting the board with the tube sockets. I have heard a few sympathetic rattles. I have a bunch of tubes around I can swap in. Years ago I gigged on upright bass with a guy who used a pro junior with an arch top, got a great jazz sound. I feel like this is a great amp for a single coil jazz sound.