Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: audiosalvage on April 05, 2024, 11:17:16 pm

Title: Plexi treble pot does nothing
Post by: audiosalvage on April 05, 2024, 11:17:16 pm

I have a 1987 20watt clone that I built last year.  I put in a Merlin tube effects loop and a lar mar master volume that stays full all the time.  I get a nice mid heavy, brown tone, which I like, but the treble pot seems to have no effect at all.  Presence and bright caps help but no treble bite from the control.  Any ideas?

Title: Re: Plexi treble pot does nothing
Post by: passaloutre on April 06, 2024, 09:32:07 am

How do you have it wired?

Title: Re: Plexi treble pot does nothing
Post by: audiosalvage on April 06, 2024, 10:20:59 am

Right after the treble wiper

Title: Re: Plexi treble pot does nothing
Post by: audiosalvage on April 06, 2024, 09:34:30 pm

Fixed it, thank you

Title: Re: Plexi treble pot does nothing
Post by: dwinstonwood on April 07, 2024, 07:22:09 am

Glad it's fixed!
So, it was the slope resistor? A 3.3K instead of a 33K? (saw your post at TAG  :icon_biggrin:)

Title: Re: Plexi treble pot does nothing
Post by: audiosalvage on April 07, 2024, 12:16:48 pm

Yes, it was one color band off, but still I am shocked at what little these tone controls actually do.

Title: Re: Plexi treble pot does nothing
Post by: Esquirefreak on April 07, 2024, 12:27:04 pm

I have used variable slope resistance on a couple of builds to widen the EQ range. Works really well. Especially when switching between single coils and humbuckers.

/Max