Looking for a simple Tone Control circuit. (Want to add to a phono amp. Any suggestions?. Thanks, Drew

Did you mean adding a tone control, and a phonograph input to an existing stock radio ? If this is the case, it's easy to do. Need only a few parts. Look at the schematic for like a Silvertone 1017 .. This is about the most simple there is.

:Did you mean adding a tone control, and a phonograph input to an existing stock radio ? If this is the case, it's easy to do. Need only a few parts. Look at the schematic for like a Silvertone 1017 .. This is about the most simple there is.
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Google "Baxandall", they have some more complicated bass and treble controls that, if you waqnt to go to the troble, will give better results.
Lewis

The complicated ones are definitely interesting to use. A modification to a simple tone control that would give both bass and treble control would be to use a 5 meg potentiometer. Connect the center to the audio input. Connect one end to a 100K resistor (approximately--adjust to taste). Connect the other end to a .002 to .01 MFD cap (again, adjust to taste). Connect the other end of the two most recently mentioned components to B-. The resistor will reduce bass, and the capacitor will reduce treble, depending on which way the control is turned. Unfortunately this does not allow the reduction of both, but is adequate for general listening purposes.

Another tone control that I like a lot is my negative feedback circuit. There are many variations on this that you can also try, and may like better. Typically I like mine the best, but there are some other good ones out there.

To build the circuit, assuming a two stage amplifier, be it push-pull or single ended, connect a 50K resistor or potentiometer between the 1st audio's plate resistor and B+. Connect a 100K rheostat between the junction of these two resistors, or to the center terminal of the potentiometer, if used. Connect a .47 MFD capacitor between the other end of this rheostat and the plate of the output tube that is driven by the tube just mentioned (if not push-pull, then there will be only one output tube). Adjust the 100K rheostat for desired effect. Adjust the 50K potentiometer (if a potentiometer is used) to cut in or out the negative feedback as desired. Making the 50K resistor a rheostat instead of a potentiometer will change bass response as the control is adjusted. This may be undesirable.

Other interesting effects can be had with this control. Connect a .001 to .002 MFD cap from the junction of the three resistors to B-. This will brighten the crisp highs, which can be desirable for high fidelity records (be they 78s or LPs). Change the .047 MFD cap to something closer to a .01 MFD cap for a sharper high-end, somewhat like that heard when listening to 1930s NBC music radio shows--a nice sharp 1930s high fidelity sound, but without too much of the lower mid-range that can be so obnoxious. Using the .047 MFD cap will leave you with a flatter, more natural response. Both are pleasant to listen to. Adjustments in this department can also be made to overcome unnatural tonal characteristics in the speaker, pick-up, or various transformers, or even records themselves.

T.

:The complicated ones are definitely interesting to use. A modification to a simple tone control that would give both bass and treble control would be to use a 5 meg potentiometer. Connect the center to the audio input. Connect one end to a 100K resistor (approximately--adjust to taste). Connect the other end to a .002 to .01 MFD cap (again, adjust to taste). Connect the other end of the two most recently mentioned components to B-. The resistor will reduce bass, and the capacitor will reduce treble, depending on which way the control is turned. Unfortunately this does not allow the reduction of both, but is adequate for general listening purposes.
:
:Another tone control that I like a lot is my negative feedback circuit. There are many variations on this that you can also try, and may like better. Typically I like mine the best, but there are some other good ones out there.
:
:To build the circuit, assuming a two stage amplifier, be it push-pull or single ended, connect a 50K resistor or potentiometer between the 1st audio's plate resistor and B+. Connect a 100K rheostat between the junction of these two resistors, or to the center terminal of the potentiometer, if used. Connect a .47 MFD capacitor between the other end of this rheostat and the plate of the output tube that is driven by the tube just mentioned (if not push-pull, then there will be only one output tube). Adjust the 100K rheostat for desired effect. Adjust the 50K potentiometer (if a potentiometer is used) to cut in or out the negative feedback as desired. Making the 50K resistor a rheostat instead of a potentiometer will change bass response as the control is adjusted. This may be undesirable.
:
:Other interesting effects can be had with this control. Connect a .001 to .002 MFD cap from the junction of the three resistors to B-. This will brighten the crisp highs, which can be desirable for high fidelity records (be they 78s or LPs). Change the .047 MFD cap to something closer to a .01 MFD cap for a sharper high-end, somewhat like that heard when listening to 1930s NBC music radio shows--a nice sharp 1930s high fidelity sound, but without too much of the lower mid-range that can be so obnoxious. Using the .047 MFD cap will leave you with a flatter, more natural response. Both are pleasant to listen to. Adjustments in this department can also be made to overcome unnatural tonal characteristics in the speaker, pick-up, or various transformers, or even records themselves.
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:T.Thanks to all for the fdbk. Will give it a try. Just adding a circuit to an old 45 player. Drew
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