Hi,
I've tried a search & also trawled the web....I can find lots of circuits with baxandall bass treble boost/cut circuits....all I seek is a simple treble cut circuit for a TL072 opamp. (or any opamp come to that!)
This is for a guitar with piezo pickups. Unprocessed these piezos sound a little harsh at the upper end, so I'd like to be able to roll this treble off a bit
I have magnetic pickups going through the same signal path (they are summed in TL072 opamp), which sound fine (no need for any treble cut), therefore I'd like the pot at one extremity *not* to affect the treble ...& at the other extremeity the treble to be rolled off (a bit like how a passive treble control rolls off the treble.
Many thanks in anticipation.
I've tried a search & also trawled the web....I can find lots of circuits with baxandall bass treble boost/cut circuits....all I seek is a simple treble cut circuit for a TL072 opamp. (or any opamp come to that!)
This is for a guitar with piezo pickups. Unprocessed these piezos sound a little harsh at the upper end, so I'd like to be able to roll this treble off a bit
I have magnetic pickups going through the same signal path (they are summed in TL072 opamp), which sound fine (no need for any treble cut), therefore I'd like the pot at one extremity *not* to affect the treble ...& at the other extremeity the treble to be rolled off (a bit like how a passive treble control rolls off the treble.
Many thanks in anticipation.
1) see http://sound.westhost.com/projects-3.htm, indeed the entire site, all kinds of circuits, information, and ideas.
2) download a copy of LTspice and start messing about.
2) download a copy of LTspice and start messing about.
Nigel - The thing is about the baxandall it'd need an extra knob (bass), & I don't want to go putting another knob on my guitar!
Also, I don't want to emphasise the treble any more than it is at present (the piezos are *so* cutting already).
Like I say, all I need is a treble rolloff.
Mightydub - Re the linkl you gave. I'm aware of it - but I couldn't find anything that suits (I'm sure there is but I guess what I'm saying I'm not too sure how to hack one to suit my needs!)
Also, I don't want to emphasise the treble any more than it is at present (the piezos are *so* cutting already).
Like I say, all I need is a treble rolloff.
Mightydub - Re the linkl you gave. I'm aware of it - but I couldn't find anything that suits (I'm sure there is but I guess what I'm saying I'm not too sure how to hack one to suit my needs!)
download Rod Elliot's crossover calculator:
http://sound.westhost.com/software/esp-lr13.exe
which has the abstract schematic and calculates values for 12dB or 24dB/octave Linkwitz-Riley filters. A very handy tool, makes it too easy really.
One disadvantage to doing this with an opamp is you need the +/- power supply, OK if the circuit goes in the amp but maybe a problem if it goes in the guitar. I suppose you could use 9V batteries.
http://sound.westhost.com/software/esp-lr13.exe
which has the abstract schematic and calculates values for 12dB or 24dB/octave Linkwitz-Riley filters. A very handy tool, makes it too easy really.
One disadvantage to doing this with an opamp is you need the +/- power supply, OK if the circuit goes in the amp but maybe a problem if it goes in the guitar. I suppose you could use 9V batteries.
Thanks guys.
in the end, (inspired by the simplicity of Mooly's suggestion), I continued searching & found this thread...
http://www.diyaudio.com/forums/showthread.php?s=&threadid=125808&highlight=
Essentially that works for me!
I did try the baxandall, but I was getting faint ringing/static when turning the bass & treble controls (a bit like when tuning through an AM radio). Rather than try to get to the bottom of that (would anyone know what couldn have caused it?), I ripped all the associated extra components out - the simplicity of this solution suits me down to the groun.
many thanks once again.
in the end, (inspired by the simplicity of Mooly's suggestion), I continued searching & found this thread...
http://www.diyaudio.com/forums/showthread.php?s=&threadid=125808&highlight=
Essentially that works for me!
I did try the baxandall, but I was getting faint ringing/static when turning the bass & treble controls (a bit like when tuning through an AM radio). Rather than try to get to the bottom of that (would anyone know what couldn have caused it?), I ripped all the associated extra components out - the simplicity of this solution suits me down to the groun.
many thanks once again.
HankMcSpank said:
But did you read the next message ?
"It forms a low-pass filter (treble cut) in conjunction with the output impedance of the opamp. As that impedance is going to be pretty low you should try adding a resistor in the wire between the opamp and the top of the tone pot."
I would be adding a resistor just before that filter.
I suspect you were getting high frequency noise with the baxandall cct. But if you were just using treble cut then that shouldnt have been a problem.
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