fender tmb circuit

kendarmstat · 3rd April 2011, 05:10 PM

I would like to add 25k potentimeters to this circuit and increase the bass bosst. Anyone have any suggestions?

kendarmstat · 3rd April 2011, 06:47 PM

Instead of using the 100k pots i would like to use the 50k pots and increase the bass boost.

cats squirrel · 4th April 2011, 12:21 PM

should the FET op amps be LF442's ?

mickeymoose · 4th April 2011, 05:49 PM

This is basically the same thread you asked elswhere here.
May I suggest you build one of these circuits and see what they sound like before modding them. The 15 db bass boost in this ckt is a lot of gain! You may run out of headroom in the following stages. E

kendarmstat · 10th April 2011, 03:43 AM

I did build the circuit with stock values and the sound was thin. I would like to use 50k poys. Any real answer would be appreciated.

Markus2006 · 07:58 AM

I think that the guys are right; the IC should be LF442 and the circuit has a lot of bass boost (15dB @50Hz) - enough for a bass guitar. It seems to me that you made a mistake while asssembling the circuit. Changing the pot to 25k will actually decrase the bass boost. If you really want to increse the bass boost, you have to increase the value of the pot. Or, the simplest solution is to decrease the resistor in front of the bass pot (e.g. from 11k to 6.8k). But I would first check the components (and connections) on the board. If bass sounds think maybe you e.g. put 4.99k resistor on the output (instead of 49.9k) or, 470n instead of 4.7uF on the output? Or, the input capacitor 4.7n instead of 47n?
Can you post a photo of the board?

Mark

mickeymoose · 10th April 2011, 07:42 PM

Check your work. No one but you can do that. Do some math. Test. If you do not have a scope, you can feed 50Hz through a small transformer and an attenuation network to the input of your circuit. Read the output with a cheap RMS reading multimeter while rotating the pot(s). Use your DIY immagination.
Are these answers "real" enough?
E

kendarmstat · 18th April 2011, 02:37 AM

Markus you have been helpful. i did find an error and corrected it. as for mickey...you are no help...maybe you should stick to not talking unless you have something helpful to say. Thanks again Markus.

10th April 2011, 07:54 AM	#6
Markus2006 diyAudio Member Join Date: Jan 2006 Location: Poland	I think that the guys are right; the IC should be LF442 and the circuit has a lot of bass boost (15dB @50Hz) - enough for a bass guitar. It seems to me that you made a mistake while asssembling the circuit. Changing the pot to 25k will actually decrase the bass boost. If you really want to increse the bass boost, you have to increase the value of the pot. Or, the simplest solution is to decrease the resistor in front of the bass pot (e.g. from 11k to 6.8k). But I would first check the components (and connections) on the board. If bass sounds think maybe you e.g. put 4.99k resistor on the output (instead of 49.9k) or, 470n instead of 4.7uF on the output? Or, the input capacitor 4.7n instead of 47n? Can you post a photo of the board? Mark Last edited by Markus2006; 10th April 2011 at 07:58 AM.

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3rd April 2011, 06:47 PM	#2
kendarmstat diyAudio Member Join Date: Jan 2011	Instead of using the 100k pots i would like to use the 50k pots and increase the bass boost.

4th April 2011, 12:21 PM	#3
cats squirrel diyAudio Member Join Date: Feb 2011 Location: Devon, UK	should the FET op amps be LF442's ?

4th April 2011, 05:49 PM	#4
mickeymoose diyAudio Member Join Date: Nov 2008	This is basically the same thread you asked elswhere here. May I suggest you build one of these circuits and see what they sound like before modding them. The 15 db bass boost in this ckt is a lot of gain! You may run out of headroom in the following stages. E

10th April 2011, 03:43 AM	#5
kendarmstat diyAudio Member Join Date: Jan 2011	I did build the circuit with stock values and the sound was thin. I would like to use 50k poys. Any real answer would be appreciated.

10th April 2011, 07:42 PM	#7
mickeymoose diyAudio Member Join Date: Nov 2008	Check your work. No one but you can do that. Do some math. Test. If you do not have a scope, you can feed 50Hz through a small transformer and an attenuation network to the input of your circuit. Read the output with a cheap RMS reading multimeter while rotating the pot(s). Use your DIY immagination. Are these answers "real" enough? E

18th April 2011, 02:37 AM	#8
kendarmstat diyAudio Member Join Date: Jan 2011	Markus you have been helpful. i did find an error and corrected it. as for mickey...you are no help...maybe you should stick to not talking unless you have something helpful to say. Thanks again Markus.

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