Jump to content
Why become a member? ×

Adding a passive tone control to an active bass ?


ambient
 Share

Recommended Posts

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.

:)

Link to comment
Share on other sites

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.

Link to comment
Share on other sites

[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.

Link to comment
Share on other sites

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.

Link to comment
Share on other sites

[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

B) 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 B) some component values can be calculated. SubsonicSimpleton's prototype box suggestion is also good until you have settled on final component values.

Edited by 3below
Link to comment
Share on other sites

[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

B) 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 B) 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.

Link to comment
Share on other sites

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.

Link to comment
Share on other sites

[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..?

Link to comment
Share on other sites

[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.

Link to comment
Share on other sites

[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 by Dad3353
Link to comment
Share on other sites

[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 :)

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...