Quiz

[FractalAudio]

I was working on an amp model today. The amp can be considered moderately "high gain". I couldn't get the treble knob to respond the same as the amp. The model had more treble with the control on 10 than the amp. Finally I opened the amp and poked around and discovered that the amp deviated from the schematic in one small way: the treble pot had a resistor in series with it. So instead of a 250K treble pot it had a 220K pot with a 27K series resistor.

"Why would they do that?", I asked myself. "Why limit the range of the treble control when you can simply not turn the pot all they way up and get the same result?"

Then it dawned on me.

Can you figure out why they did this? Hint: it has to do with tech support.

 

[paranoid]

seems like most want to tweak with there eyes, so maybe?

 

[bammbamm]

To limit the range to what they assume to be usable tones?

 

[FractalAudio]

Keep guessing.

 

[Andrew Male]

To stop them breaking off the treble knob? lol.

 

[bammbamm]

To prevent damage to the speakers?

 

[MrGuitarabuse]

To prevent damage to the speakers?

Was thinking that too... but then shouldn't most amps have it... or...?

 

[Brownmatthall]

The amp designer didn't do it?

 

[Wolfenstein98k]

They want it to be harder to service, or to keep a sneaky in-house "tweak" at the ready?

 

[ChrisCG]

Maybe they want there to be a part that will fail after x number of hours of use so you have to have that part replaced?

 

[FractalAudio]

Hint: it's aimed at reducing tech support calls.

 

[paranoid]

why does my amp squeal when turned up?

 

[FractalAudio]

why does my amp squeal when turned up?

We have a winner!

 

[TubeAmpNut]

The circuit or layout is unstable and too much treble leads to oscillation.

 

[FractalAudio]

The circuit or layout is unstable and too much treble leads to oscillation.

Exactly.

 

[TubeAmpNut]

This amp probably has no plate snubbers. Or the grid stoppers are insufficient.

 

[FractalAudio]

This amp probably has no plate snubbers.

The amp has large snubbers.

 

[h.c.e.]

The amp has large snubbers.

Gentlemen, let's not go comparing the size of each others snubbers here... 'sides, everyone knows it's not the size of your snubbers, but how you use 'em.

 

[TubeAmpNut]

Hmm, is it a PTP amp on a turret board?

 

[FractalAudio]

Hmm, is it a PTP amp on a turret board?

Nope, it's a PCB amp.