Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Quatro on February 27, 2013, 10:55:16 pm
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(http://amps.zugster.net/images/articles/tonestacks/tweed-scheme.gif)
Hey,
I'm using this tone circuit in a build. There are three differences in mine than the schematic. The tone pot is 1meg linear instead of audio. The "bass" cap is .02uf instead of 4.7nf. Also, the tone knob is also the on/off switch.
The problem is when the tone knob is also the on/off switch, the last part of the rotation, the "bass" part, is eliminated by the switch mechanism. To restate: if i use the circuit with a regular pot, the last part of the counter clockwise rotation is where the deepest bass is. If i swap an on/off switch on to the back if the pot (like on an old radio), the detent where the pot clicks off eliminates the last part of the rotation and that deep bass setting.
Can change the value, or taper to get more bass at the end before the click without drastically altering the rest of the rotation performance?
Thanks
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Why not just use a 1MΩ audio pot with an On/Off switch for your Volume pot, like the older tweed Champs and Princetons did?
Hoffman has them for $3.84.
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Not sure if the plan favors Audio or Linear as a general thing. Perhaps the Tone should ape the Volume.
Agree that Linear *with* a switch may be a problem.
Say the switch makes the last 10% useless. 10% of 1Meg Linear is 100K. 100K is not-much effect. 10% of 1Meg Audio is about 10K. 10K is significant effect.
Or sneak a power switch on the back panel. (Not like I just did: ran my internet connection on a switched outlet, then bumped the switch with my elbow....)
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i'll try the swap.