Greer Soma 63 treble barely does anything

[Svenson007]

Hey guys. I’m not posting pics yet. As everything checks out and it sounds great. I’m just wondering if anybody else has ran into this. The eq is stated to work more like a vintage amp. The problem is except for when the bass and presence is cranked, the treble knob barely makes a difference. Turning down the bass adds treble as does presence. But in most settings is seems to do very very little if anything. I really have to listen for it. I’ve tried varying the voltages of the trims. They are all around 4.5. I know with the benson preamp the third trimmer really affects the treble control. I just can’t find any info about this. It’s bothering me, because I don’t know if it’s normal or not. Something tells me no. But I can also see how the vintage amp style controls might have a say in this. It’s almost perfect. Just this one thing bugging me!

Is there any particular area I should be checking in the schematic? I’m not sure how it is co trolling the treble content. All the values I’ve checked out so far are fine. I’ll get back to you if one is off.

 

[spi]

I happen to have this on my board today, so I checked out how mine behaves.

First of all, with moving between treble at min to max, there's always a noticeable change in treble response. However the range where most of the change happens is not even across the rotation.

With the bass and presence at noon, I notice the treble control does most of its thing between 3 and noon, with not much changing happening above noon (although there is slight difference). As I move the bass to different positions, the range where the treble knob makes the most change is also moving around, so these two are interactive.

Hope this helps.

 

[Svenson007]

Thank you. That’s good to know. Cheers