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active/ passive for newbs

F

fourmations

Jun 6, 2009
26
0
#1
hi all

i have tried searching but not done well

is there a way to have a passive bass
with an active option via a switch or push pull etc

or is it a totally different pickup/setup type

i.e. can i just take my current passive bass
and make it active without gutting the whole thing out
(but still have the passive option)

regard

4
 
#6
To answer your quesiton... Yes, active basses can have switches that activate or de-activate the PreAmps. Many stock basses already do. These setups usually have passive pickups and active PreAmps.

Active Pickups like EMG's require batteries to run and cannot be deActivated to the best of my knowledge.

Personally, I prefer Passive pickups and Active EQ's with an Active/Passive switch or push/pull knob, along with an always on Passive Tone Roll Off pot that works with the bass is in passive mode and also when in Active mode. Just one more level of tone control.
 
#7
thanks guys

i am primarily a guitarist
but really enjoying my first bass

it is a sx ash pj and i must say i am really pleased with it
(i officially sign up for the sx value hype!)

its likely to be my only bass
and im not afriad of a drill and a soldering iron
i did jimmy page wiring on an lp as my baptism of fire!

i am happy enough with the bass
but i am a compulsive modder!
i didnt think i was... but i now confess, I am!

i definately want to have the option of it playing as it is,
but would have no problem rewiring and
adding a battery snap, switchs, push pulls etc
as an experiment and a learning experience

is there any good links for what im talking about?
i assume i am re-hashing old topics here

regards

4
 
#8
What exactly do you want the push/pulls and switches and such to do? Are you just trying to mess around and add things for kicks, or do you understand the need for various features?

For a PJ bass, you can do series/parallel switching for the pickups, and you can also do a series/parallel switch for the two coils of the P pickup.
There is the option to add a phase switch on one pickup for out-of-phase sounds.
I'm a huge fan of bypassable tone controls. You can do that as well.
Selectable capacitor values maybe?

There are a million things you can do, but the question is how useful they will be...


I am not sure of any websites.
I post my schematics to my Flickr page incase that interests you: http://www.flickr.com/photos/jrkdesimone/sets/72157616015420655/
 
#9
line6man said:
What exactly do you want the push/pulls and switches and such to do? Are you just trying to mess around and add things for kicks, or do you understand the need for various features?

For a PJ bass, you can do series/parallel switching for the pickups, and you can also do a series/parallel switch for the two coils of the P pickup.
There is the option to add a phase switch on one pickup for out-of-phase sounds.
I'm a huge fan of bypassable tone controls. You can do that as well.
Selectable capacitor values maybe?

There are a million things you can do, but the question is how useful they will be...


I am not sure of any websites.
I post my schematics to my Flickr page incase that interests you: http://www.flickr.com/photos/jrkdesimone/sets/72157616015420655/
Click to expand...

Nice schematics looks like you put a lot of work into that.

I was just wondering the same thing however mine is already active. I have an SR500 that I was just wanting to put in a passive/active switch. What material would be needed and can you point us to any directions on how to do it?
 
#10
mkrtu9 said:
Nice schematics looks like you put a lot of work into that.

I was just wondering the same thing however mine is already active. I have an SR500 that I was just wanting to put in a passive/active switch. What material would be needed and can you point us to any directions on how to do it?
Click to expand...

[Invalid or Expired Link Removed]

A simple DPDT mini toggle will do ya.
I have seen some diagrams where the preamp's output was shorted to ground in passive mode. I don't feel this is necessary, because the output should be isolated from the input. SD seems to feel the same way, as they drew their diagram without that feature.

There is one thing to take into account though...
What kind of volume controls do you have in the circuit?
You want 250K/500K pots running before the preamp in order for things to work properly in passive mode. If your bass has a 25K/50K volume control after the preamp, you are going to need to work in passive volumes, and things probably won't work out favorably.
 
#11
line6man said:
[Invalid or Expired Link Removed]

A simple DPDT mini toggle will do ya.
I have seen some diagrams where the preamp's output was shorted to ground in passive mode. I don't feel this is necessary, because the output should be isolated from the input. SD seems to feel the same way, as they drew their diagram without that feature.

There is one thing to take into account though...
What kind of volume controls do you have in the circuit?
You want 250K/500K pots running before the preamp in order for things to work properly in passive mode. If your bass has a 25K/50K volume control after the preamp, you are going to need to work in passive volumes, and things probably won't work out favorably.
Click to expand...

Thanks

I found the toggle just at radio shack and the diagram looks pretty self explanatory. Will this only work on one pickup? Or would I run it off of my balance knob?

thanks again, I'm absolutely ignorant when it comes to this. I can do it when it is painted black and white though :hmm:
 
#12
Here is a schematic of an sr500 which looks like it has a 500K balance pot.

ibanezSR500.gif
 
#13
mkrtu9 said:
Thanks

I found the toggle just at radio shack and the diagram looks pretty self explanatory. Will this only work on one pickup? Or would I run it off of my balance knob?

thanks again, I'm absolutely ignorant when it comes to this. I can do it when it is painted black and white though :hmm:
Click to expand...

Based on the diagram you posted, the blend pot is passive, and therefore will continue to function normally regardless of whether you are in active or passive mode.

Can you check the value of the volume pot?
Since it's PCB mounted, i can't tell whether it's pre or post preamp.
 
#14
ok the diagram was for a 94 sr500... I am home now and have everything in my hand and it looks like all the pots are 50k none of them are PCB mounted. So I guess this is out. Shucks I just wanted something that if my battery went out in mid song I could flip a switch and atleast have something to finish the song with. Had this happen a few weeks ago..... oops

Thanks though I appreciated it.
 
#15
mkrtu9 said:
ok the diagram was for a 94 sr500... I am home now and have everything in my hand and it looks like all the pots are 50k none of them are PCB mounted. So I guess this is out. Shucks I just wanted something that if my battery went out in mid song I could flip a switch and atleast have something to finish the song with. Had this happen a few weeks ago..... oops

Thanks though I appreciated it.
Click to expand...

Are you willing to add a seperate passive volume control?
Since there is only one volume control, you can work in a passive volume that will bypass in active mode if you use a 3PDT toggle for the active/passive switch...
 
#19
mkrtu9 said:
Now that is a very good idea. Where would I run the volume in accordance with your toggle schematic?
Click to expand...

FWIW, that was Seymour Duncan's schematic that i linked, not mine.

Anywho, here is a diagram of how to incorperate the volume control.
3641654631_d84cd08000.jpg

In active mode, your bass should function normally.
In passive mode, the preamp will be bypassed, and the passive volume will be engaged in the circuit.
 

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