ambient Posted April 16, 2016 Share Posted April 16, 2016 My Roscoe 6 string fretless has a Bartolini 3 band active preamp installed in it. I like to roll off the passive tone completely, and just use the high frequency tone control on the preamp. The Bartolini doesn't have a passive tone control though, so I want to add one. I don't want to drill another hole on the bass though, I was thinking of just adding the capacitor thing inside the bass, it doesn't matter that it will be totally off all the time. Where would the capacitor thing be soldered, and what sort of capacitor should I use ? My brother will be doing the soldering for me. Quote Link to comment Share on other sites More sharing options...
Dad3353 Posted April 16, 2016 Share Posted April 16, 2016 Not the best worded request, but if I understand correctly, you're wanting to cut the bass with a fixed, passive, high-pass circuit. Here's one, very simple, taken from a fuzz-box schema... You may have to play about with the values to get the exact degree of tone adjustment that you require; on the other hand it's about as 'cheap and cheerful' as one could wish. Your brother will know where to solder this in (undo the o/p jack and insert this circuit...). Have fun; hope this helps. Subject to correction, completion and/or contradiction from others. Quote Link to comment Share on other sites More sharing options...
ambient Posted April 17, 2016 Author Share Posted April 17, 2016 [quote name='Dad3353' timestamp='1460850578' post='3029363'] Not the best worded request, but if I understand correctly, you're wanting to cut the bass with a fixed, passive, high-pass circuit. Here's one, very simple, taken from a fuzz-box schema... You may have to play about with the values to get the exact degree of tone adjustment that you require; on the other hand it's about as 'cheap and cheerful' as one could wish. Your brother will know where to solder this in (undo the o/p jack and insert this circuit...). Have fun; hope this helps. Subject to correction, completion and/or contradiction from others. [/quote] I basically want to add a passive tone control to the bass, but keep it inside the cavity, keeping it rolled off. Thanks for your reply. Quote Link to comment Share on other sites More sharing options...
Dad3353 Posted April 17, 2016 Share Posted April 17, 2016 [sharedmedia=core:attachments:167485] Quote Link to comment Share on other sites More sharing options...
SubsonicSimpleton Posted April 17, 2016 Share Posted April 17, 2016 You could just get a simple enclosure and make a passive pedal - easy to experiment with component values, instantly reversible, and no chance of damaging your instruments electronics. The advantage with this aproach is that you can play with options such as rotary switches to give you the choice of multiple capacitor values (like the tonestyler), different tone pot values etc. Quote Link to comment Share on other sites More sharing options...
3below Posted April 17, 2016 Share Posted April 17, 2016 (edited) [quote name='ambient' timestamp='1460845958' post='3029333'] .....I like to roll off the passive tone completely, and just use the high frequency tone control on the preamp. [/quote] A key part of what you want hinges on the phrase "roll off the passive tone completely". This can be construed in one of two ways. Are you describing: a) turning the passive tone control fully anticlockwise (high frequencies removed, you have a bassier (muddier) tone)? or turning the passive tone control fully clockwise (high frequencies pass through, you have treble (clearer) tone)? As Dad3353 has described the solution is straightforward, With the answer a) or some component values can be calculated. SubsonicSimpleton's prototype box suggestion is also good until you have settled on final component values. Edited April 17, 2016 by 3below Quote Link to comment Share on other sites More sharing options...
ambient Posted April 17, 2016 Author Share Posted April 17, 2016 [quote name='3below' timestamp='1460906473' post='3029670'] A key part of what you want hinges on the phrase "roll off the passive tone completely". This can be construed in one of two ways. Are you describing: a) turning the passive tone control fully anticlockwise (high frequencies removed, you have a bassier (muddier) tone)? or turning the passive tone control fully clockwise (high frequencies pass through, you have treble (clearer) tone)? As Dad3353 has described the solution is straightforward, With the answer a) or some component values can be calculated. SubsonicSimpleton's prototype box suggestion is also good until you have settled on final component values. [/quote] A standard passive tone control that you find on most basses. I like the sound of it turned fully off, and I use the treble control on the active circuit to add or decrease treble. My old Modulus had a John East circuit that was brilliant. It had a passive tone control, I had it set fully off all the time. Sadly I can't afford to change the Bartolini circuit, so I want to add the passive control to it. I have absolutely no knowledge of electronics, and burned myself last time I attempted to use a soldering thing. My brother is good with a soldering iron, and will do the necessary soldering once I can show him what to do. Quote Link to comment Share on other sites More sharing options...
ikay Posted April 17, 2016 Share Posted April 17, 2016 The last page of this Aguilar wiring diagram shows how to add a passive tone control in front of the preamp - http://aguilaramp.com/pdf/support_wiring_obp1.pdf It's just a standard tone control (typically a 250k pot and .47 cap) wired in front of the preamp. You should be able to do the same with a Bartolini preamp. Actual wiring needed will depend on how many pickups and how the existing volume/blend pots are wired. Instead of a full size tone pot just use a small preset pot inside the cavity. Quote Link to comment Share on other sites More sharing options...
3below Posted April 17, 2016 Share Posted April 17, 2016 +1 to ikay Quote Link to comment Share on other sites More sharing options...
MoonBassAlpha Posted April 17, 2016 Share Posted April 17, 2016 Dad's diagram is a high pass filter, the OP wants a low pass filter. The cap across the signal and ground would do it. No need for a pot or resistor. Quote Link to comment Share on other sites More sharing options...
Dad3353 Posted April 17, 2016 Share Posted April 17, 2016 [quote name='MoonBassAlpha' timestamp='1460920571' post='3029827']... the OP wants a low pass filter. ... [/quote] I understand the opposite; he wants a more trebly sound. I could be wrong, but it's still a bit ambiguous. Well, Ian..? More treble, or more bass..? Quote Link to comment Share on other sites More sharing options...
ambient Posted April 17, 2016 Author Share Posted April 17, 2016 [quote name='Dad3353' timestamp='1460922794' post='3029865'] I understand the opposite; he wants a more trebly sound. I could be wrong, but it's still a bit ambiguous. Well, Ian..? More treble, or more bass..? [/quote] Less trebly 😊. I find it too trebly with the passive control up, and the active control up. It's kind of too brittle sounding. Quote Link to comment Share on other sites More sharing options...
Dad3353 Posted April 17, 2016 Share Posted April 17, 2016 (edited) [quote name='ambient' timestamp='1460923431' post='3029874'] Less trebly ��. I find it too trebly with the passive control up, and the active control up. It's kind of too brittle sounding. [/quote] Ah, OK; thanks for clarifying. Isn't the English language splendid, enabling us to communicate so well..? I'll drum up the opposite schema, for a low-pass filter, then. Back in a tick... Here we go, a low pass filter... As before, try different values to optimise, but that'll kill the treble. Edited April 17, 2016 by Dad3353 Quote Link to comment Share on other sites More sharing options...
ambient Posted April 17, 2016 Author Share Posted April 17, 2016 [quote name='Dad3353' timestamp='1460923992' post='3029880'] Ah, OK; thanks for clarifying. Isn't the English language splendid, enabling us to communicate so well..? I'll drum up the opposite schema, for a low-pass filter, then. Back in a tick... [/quote] Thanks Quote Link to comment Share on other sites More sharing options...
Dad3353 Posted April 17, 2016 Share Posted April 17, 2016 [sharedmedia=core:attachments:167485] Quote Link to comment Share on other sites More sharing options...
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