Question about Princeton 112 Plus

mixtape · Post by **mixtape** » Wed Oct 10, 2012 7:02 pm

This post in the "worst gear you've ever owned" thread got me thinking:

Billy3000 wrote: - Fender Princeton 112 plus - this was one of the 90's solid state princeton models and it sounded absolutely horrible. It picked up radio signals more than any other amp I've ever heard, it would randomly have squeeling feedback sounds for no reason while set to clean. The volume knob was also pretty much useless, it was either loud as fuck at barely 1 on the knob, or no sound at all. Those were the options.

That is the one thing I dislike about this amp, which I otherwise like the sound of, perhaps misguidedly. It makes me wonder whether the stock volume pots might have been linear taper rather than audio taper. Can someone verify this, or tell me how I can verify this (will the pots be clearly marked A or B if I open it up just to take a look)? If that's the case, a change of pots would--I think--give me a volume control that actually controlled the volume in some meaningful way.

onedaycloser · Post by **onedaycloser** » Wed Oct 10, 2012 7:20 pm

Princeton 112 Plus Schematic

Seems like it has a 50k pot as the volume, I'm not sure which by that schematic. Seems like it couldn't hurt too much trying another pot but I'm no amp magician.

Billy3000 · Post by **Billy3000** » Wed Oct 10, 2012 7:28 pm

I really don't know anything about whether or not switching them out would do anything, but I'm fairly certain that they should be marked if you open it up and want to see what kind they are.

sholkham · Post by **sholkham** » Wed Oct 10, 2012 8:21 pm

I have a princeton 65 which is another 90's solid state amp, also has the same problem. The clean channel sounds quite nice but sadly I've never really been able to balance the drive channel's gain and volume to get a nice sound without it being too loud for a bedroom

NickS · Post by **NickS** » Thu Oct 11, 2012 9:04 am

onedaycloser wrote:Princeton 112 Plus Schematic

Seems like it has a 50k pot as the volume, I'm not sure which by that schematic. Seems like it couldn't hurt too much trying another pot but I'm no amp magician.

That schematic shows Volume on the clean channel, Gain and Drive Volume on the dirty channel. All of those pots are suffixed "30C" along with the drive channel treble and bass. Clean channel treble and bass pots are suffixed "15A" while Contour and Reverb Depth are suffixed "B". In USA "A" means log/audio taper, "B" usually means linear and "C" usually means reverse log

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(TL; DR) as it seems to be reverse log and you're finding that 90% of your volume appears between 0 and 1, swap it for a 50K linear. I really don't understand why they've specified reverse log for the Drive Volume either.