Adding a passive tone feature to an all active bass.

[Soliloquy]

My Zon has a nice active circuit that as well as having bass, mid and treble cut or boost, it also has a passive tone control.

I've had other basses with the same type of circuit. I generally have the passive tone rolled all of the bass off. I then just boost the highs as required with the active treble control.

I think this gives a less harsh, more natural sound.

My one bass however doesn't have a passive control, just the active cut and boost circuit. The result, at least to my ears is a very harsh over bright sound.

I've had other basses the same over the years, and I've changed the preamps on them. I want to avoid that cost at the moment though.

Is there a simple modification that I can do ?

I was browsing various sites last night, as well as this one and Talkbass. The passive tone control is just a knob and a capacitor. Could I just (seeing how I like the sound with the passive all the way off), just solder a capacitor somewhere along the pickup wire ?

All suggestions are greatly recieved .

[Paul S]

I#ll be keeping an eye on this as I wondered the same....

[voxpop]

I was thinking of doing the same on my Smith...... Can anyone help.

[Soliloquy]

I thought it was just me being picky lol .

My Zon bass has a really nice Audere pre fitted to it. It just seems to sound so much better with the passive treble turned off, and then just use the active treble. I don't really want to go to the trouble and expense of changing the pre though.

And there's a guy here selling some capacitors too [url="http://basschat.co.uk/index.php?showtopic=102699"]http://basschat.co.uk/index.php?showtopic=102699[/url]

I've always preferred the sound of my basses like this.

[voxpop]

[quote name='Soliloquy' post='1205830' date='Apr 20 2011, 01:52 PM']I thought it was just me being picky lol .

My Zon bass has a really nice Audere pre fitted to it. It just seems to sound so much better with the passive treble turned off, and then just use the active treble. I don't really want to go to the trouble and expense of changing the pre though.

And there's a guy here selling some capacitors too [url="http://basschat.co.uk/index.php?showtopic=102699"]http://basschat.co.uk/index.php?showtopic=102699[/url]

I've always preferred the sound of my basses like this.[/quote]


I have the green one and want to add it to my active Smith.

[Soliloquy]

[quote name='voxpop' post='1205852' date='Apr 20 2011, 02:07 PM']I have the green one and want to add it to my active Smith.[/quote]

Yes, I noticed your post last night while I was looking through.

I have found these -

[url="http://www.fender.com/community/forums/viewtopic.php?f=10&t=23438"]http://www.fender.com/community/forums/vie...=10&t=23438[/url]


[url="http://www.guitarnucleus.com/wiring.html"]http://www.guitarnucleus.com/wiring.html[/url]

[chuck_stones]

If I recall correctly when I installed my John East pre-amp which has the passive tone control you're referring to, the pickups wire directly into the passive tone control, which then in turn feeds into the pre-amp (not sure if there is a complication here with balance controls and the order of the pots?).

I would imagine that the same principle applies? So would look something like this (where passive control and balance might have to be switched):

Pickups > passive tone control >< balance > active controls > output?

[voxpop]

[quote name='chuck_stones' post='1206045' date='Apr 20 2011, 04:19 PM']If I recall correctly when I installed my John East pre-amp which has the passive tone control you're referring to, the pickups wire directly into the passive tone control, which then in turn feeds into the pre-amp (not sure if there is a complication here with balance controls and the order of the pots?).

I would imagine that the same principle applies? So would look something like this (where passive control and balance might have to be switched):

Pickups > passive tone control >< balance > active controls > output?[/quote]


Think you are right. I dont want to add another pot to the bass........ just dont know how to add it to the active system.

Think I might just give up and buy another bass...............

[chuck_stones]

[quote name='voxpop' post='1206056' date='Apr 20 2011, 04:25 PM']Think you are right. I dont want to add another pot to the bass........ just dont know how to add it to the active system.

Think I might just give up and buy another bass............... [/quote]

LOL - always worth buying another bass

If you're not adding another pot to the bass, how would you adjust the passive control, or would it be on full the whole time? If so, I guess you can literally just wire the pickups to the capacitor and then into the pre-amp?

[Soliloquy]

I'm thinking you can just wire the capacitor in line with the pickups. Presuming you're happy with not being able to control the passive tone level. I always prefer to have mine off anyway, so I think I may try it.

[LawrenceH]

[quote name='Soliloquy' post='1206133' date='Apr 20 2011, 05:20 PM']I'm thinking you can just wire the capacitor in line with the pickups. Presuming you're happy with not being able to control the passive tone level. I always prefer to have mine off anyway, so I think I may try it.[/quote]

If there's room in the cavity you could always wire in a small pot there along with the cap to act as a trim, allowing you to tweak the sound before closing it up.

[Silent Fly]

The simpler way is probably [url="http://basschat.co.uk/index.php?showtopic=124651"]this[/url].

The problem in adding passive tone control with active circuits is that to get the full effect they should be just after the pickup (i.e. before the active circuit).

Even with active pickups like EMG that are sold with passive tone control, the effect of the tone is not [i]exactly[/i] like a passive tone applied to passive pickups. The main reason is that the active electronics isolates the inductance of the pickup’s coils and it doesn't allow the interaction between the pickup and capacitor. For a simple treble cut-off is usually not a problem but it is not exactly the same thing.

[Soliloquy]

[quote name='Silent Fly' post='1206192' date='Apr 20 2011, 06:03 PM']The simpler way is probably [url="http://basschat.co.uk/index.php?showtopic=124651"]this[/url].

The problem in adding passive tone control with active circuits is that to get the full effect they should be just after the pickup (i.e. before the active circuit).

Even with active pickups like EMG that are sold with passive tone control, the effect of the tone is not [i]exactly[/i] like a passive tone applied to passive pickups. The main reason is that the active electronics isolates the inductance of the pickup’s coils and it doesn't allow the interaction between the pickup and capacitor. For a simple treble cut-off is usually not a problem but it is not exactly the same thing.[/quote]

Thanks for your reply. Excuse my stupidity , what you're got there is 2 capacitors, is that right ? Are they just in line with one wire from the pick up ?

So for my 2 pickup bass I'll need 2 capacitors ?

I don't want it switched, the bass doesn't have a scratchplate.

Edited April 20, 2011 by Soliloquy

[Silent Fly]

[quote name='Soliloquy' post='1206217' date='Apr 20 2011, 06:27 PM'](...) what you're got there is 2 capacitors, is that right ? (...)[/quote]
Yes - it is exacly what it is. The value of the two capacitors depends on the pickup type and model.

[quote name='Soliloquy' post='1206217' date='Apr 20 2011, 06:27 PM']Are they just in line with one wire from the pick up ?[/quote]
I am not sure I get what you mean by "in line with one wire". They are connected in parallel to the pickup. It can be done with just one capacitor and a simple switch or with a potentiomenter and a capacitor like a standard tone control.

[quote name='Soliloquy' post='1206217' date='Apr 20 2011, 06:27 PM']I don't want it switched, the bass doesn't have a scratchplate.[/quote]
It can be implemented in different ways. It can also be done with a push-pull on the volume.

[Soliloquy]

[quote name='Silent Fly' post='1206225' date='Apr 20 2011, 06:34 PM']Yes - it is exacly what it is. The value of the two capacitors depends on the pickup type and model.


I am not sure I get what you mean by "in line with one wire". They are connected in parallel to the pickup. It can be done with just one capacitor and a simple switch or with a potentiomenter and a capacitor like a standard tone control.


It can be implemented in different ways. It can also be done with a push-pull on the volume.[/quote]

This is the inside of my bass. There's a blue and a white wire going to each pickup, where should I put the capacitor ? I'm not really sure what you mean by in parallel .

I'm not really bothered about being able to adjust it. I really just want the effect of a passive tone control all the way off.

Would I need two capacitors, one for each pickup ?

I've sent you an email asking about your builds by the way, they look very cool .

Edited April 20, 2011 by Soliloquy

[Silent Fly]

[quote name='Soliloquy' post='1206277' date='Apr 20 2011, 07:01 PM']This is the inside of my bass. There's a blue and a white wire going to each pickup, where should I put the capacitor ? I'm not really sure what you mean by in parallel .

I'm not really bothered about being able to adjust it. I really just want the effect of a passive tone control all the way off.

Would I need two capacitors, one for each pickup ?

I've sent you an email asking about your builds by the way, they look very cool .[/quote]
It depends on how the electronic operates but to be on the safe side, I would use two capacitors. One for each pickup.

If each pickup has a two wires (blue and white) you need to connect one leg of the capacitor to the blue wire and the other to the blue white. Do not disconnect any wire between pickup and pots/circuit.

[url="http://en.wikipedia.org/wiki/Series_and_parallel_circuits"]Parallel connections[/url] are like the strings of your bass: all the strings are connected on one side to the headstock, on the other side to the bridge. In [i]series[/i] means they are one after the other, like the carriages of a train.

[quote name='Soliloquy' post='1206277' date='Apr 20 2011, 07:01 PM']I've sent you an email asking about your builds by the way, they look very cool .[/quote]
Thanks for the kind words Soliloquy - if I understand who you are I just replied.

[Soliloquy]

[quote name='Silent Fly' post='1206319' date='Apr 20 2011, 07:35 PM']It depends on how the electronic operates but to be on the safe side, I would use two capacitors. One for each pickup.

If each pickup has a two wires (blue and white) you need to connect one leg of the capacitor to the blue wire and the other to the blue white. Do not disconnect any wire between pickup and pots/circuit.

[url="http://en.wikipedia.org/wiki/Series_and_parallel_circuits"]Parallel connections[/url] are like the strings of your bass: all the strings are connected on one side to the headstock, on the other side to the bridge. In [i]series[/i] means they are one after the other, like the carriages of a train.


Thanks for the kind words Soliloquy - if I understand who you are I just replied.[/quote]

Thanks , I shall order me a couple of capacitors and experiment (trying not to burn myself or set fire to anything with the soldering iron)