F30 - is this normal?

F30 combo, Vintage 30, not sure about mods (just bought it used from Elderly).

Lead channel Treble control does almost nothing along its travel. I actually thought it was totally not working, but you can hear a bit of a shift if you listen close. Certainly you can't attenute highs to any extent and it's pretty bright.

Is this normal? We're opening it up to see if there are issues (and have a schematic), but I'm curious. Any help?

Thanks - Greg

If you turn the mids and bass all the way down does the treble control do more (making the amp silent if it's turned all the way down)?

My F50's mid pot didn't work at all. Turns out it was broken. $6 part.

I don't know Don, I'll check.

scandoslav said:

My F50's mid pot didn't work at all. Turns out it was broken. $6 part.

Click to expand...

My Express' channel 2 mid pot didn't work at all either. Turned out it wasn't even connected! They missed a solder joint! It sounded fine when the amp was new but after a while the channel lost all of it's punch. One day I noticed the pot didn't do anything at all. I turned down the treble and bass with the mids cranked and the amp was silent.

That's why I asked the op how their amp's treble pot reacts with the mids and bass turned down.

I'm hoping it's that simple. I should know later today.

We did that test - it is apparently working correctly. Zero the mids and bass, and you can silence the amp with the treble knob. We also discovered that its behavior changes a lot with gain - lower the gain and you can get a lot more effect from the treble knob. Apparently that is how it is designed.

So we're going to look at other ways to tame the highs a bit. Either a new speaker (leaning toward an Eminence Patriot Cannabis Rex unless someone steers me elsewhere) and/or an electronic mod yet to be determined.

I disagree that it's by design. My treble control works regardless of gain, and based on the schematic it should be quite unaffected by the gain control.

The tech found two bad solder joints. Treble control now works normally.

Glad to hear it was that simple. It was a relief to me to find out something similar with mine.