Build active bass preamp into pedal?

[Malta]

I don't know much about electronics, so maybe this is a stupid question, but is there any reason I couldn't (or shouldn't) build an active preamp like the OBP-3 into a pedal rather than built into one of my basses? I was looking at the Aguilar ToneHammer pedal and it says it's based on the OBP-3 pre... Any thoughts?

thanks!

 

[dNA]

while i don't know for sure - i imagine the low level signal from the pickups would degrade terribly before it ever reached the preamp over any significant distance.
I wish i remembered more of the electronics stuff I learned in school. I'm pretty sure it's a matter of impedance on the cable and all that jazz. an instrument cable is meant to carry instrument-level signal and i would guess that active pickups actually produce a signal much lower than a passive before they reach teh preamp. but i'm not sure.

 

[Malta]

This would be used with passive pickups. I believe the only difference between on onboard active preamp and one built into a pedal would be the addition of an instrument cable, a couple jacks, and the passive circuit in the bass. But maybe I'm missing something?

passive bass>--cable-->active preamp built into pedal>--cable-->amp

 

[baskruit]

Sure, it can be done. An onboard preamp is in essence the same as the preamp you'll find in a stomp box or bass top/combo.
I can see that you'd want to go that route if you want to use that preamp on more than one bass.

Recently I built an OBP-3 into a Jazz bass. Great fun, Added some balls to the bass.

 

[dNA]

well in that case i don't know if i'd really call it a pre-amp. I mean essentially what you'd be building would be no different from an active EQ pedal, except customized to your specifications.

 

[baskruit]

Well if you'd use an OBP-3 (or something similar), it will still be a preamp, no matter what you build it into.
Sure, it's also a nice EQ but IME the OBP-3 boosts the signal enough to be able to plug your bass into a line-level input which you definitely can't with solely passive circuitry. Boosting instrument level to line level = preamp.

But in the end, that's all semantics. Whatever you'd call it, it does what it does.

 

[dNA]

Well if you'd use an OBP-3 (or something similar), it will still be a preamp, no matter what you build it into.
Sure, it's also a nice EQ but IME the OBP-3 boosts the signal enough to be able to plug your bass into a line-level input which you definitely can't with solely passive circuitry. Boosting instrument level to line level = preamp.

But in the end, that's all semantics. Whatever you'd call it, it does what it does.

:icon_thumright:

 

[Malta]

Well the idea I was toying around with was to build both my Delano Sonar 3 and my soon to arrive Nordstrand 3 band pres each into their own box, pick up a rapidfire with master bypass kit from Road Rage and be able to utilize either the Delano or Nordy pres with all of my passive basses. Any thoughts? Tips? Comments? Concerns? I don't know much about electronics, but I can follow a basic wiring diagram and can solder fairly well.

 

[Patrick from Davis]

Should work fine.  If you need pedal parts, Small Bear Electronics has all kinds of stuff for them, and Aron Nelson sells 3pdt switches for the best price I have found.  Google their pages for more info.
Patrick

 

[Malta]

Yeah, I'm getting ready to place an order from small bear for some 50k pots, jacks, switches and other miscellaneous parts. I grabbed a couple project boxes at my local frys  electronics too. I'm going to start with the Nordstrand later tonight. They just came in. The Delano is currently installed in my Spector and it looks like my band may be coming of f a 12 mo hiatus, so I can't pull that just yet. Delano is installed with 50k pots, I'm guessing the Nordstrand has the same? If not should I rewire with the same value pots?

 

[Patrick from Davis]

I would go to Best Bass Gear and look up the wiring/layouts for the different preamps.  They seem to have the layouts for them all, and you can get the manufacturers pot values.

Another really helpful tool to have is the step drill bit.  If you are just drilling aluminum boxes, a cheap-o from harbor freight will do fine.

Another good thing from small bear is the 9 volt DC power jacks.  They have an odd wiring, I look it up from BYOC everytime because they have a nice diagram of which lead does what, but you can plug the pedal into a wall wart if you put one on the box.  Very handy.

The whole thing sounds pretty fun.
Patrick

 

[Malta]

Good call on the 9v power jacks. I have a good step drill/varibit that's I'll use for punching through the aluminum pedal box. Ive printed out every wiring variation from bestbassgear as well as Delano and Nordstrand websites and I think I've nearly got it sorted out.

 

[Steve_Karl]

The OBP-3 looks very interesting ... but what does one do for a volume control when using it installed in a bass or a guitar?

Thanks,

 

[Steve_Karl]

Bump!

.... anybody ???

thanks

 

[baskruit]

Bump!

.... anybody ???

thanks

Usually you can either re-use the volume pot that came with your bass or buy one separately. For my jazz bass + OBP-3, I bought a concentric 2x 500k pot (like $5,- @ ebay) for separate volume control for both pickups.

 

[Steve_Karl]

So I'd just kinda slap a passive volume pot in there on the circuit and it'll work?

 

[baskruit]

So I'd just kinda slap a passive volume pot in there on the circuit and it'll work?

Pretty much so.
The wiring diagram explains it all:
http://www.aguilaramp.com/pdf/support_wiring_obp3.pdf

You'd be looking at different values when using active pickups but only a few pickups are.

 

[Steve_Karl]

Beginning to understand. Thank you.

Now here's my plan. I have 1 active Alembic strat pickup from an STR/AE-3 system that is a left over,
and I have 2 Gibson Burstbucker pros.
What do you think the chances are of me getting them all 3 working in the same guitar with this preamp?

 

[baskruit]

Not sure but I suppose you could get it to work if you use a low value vol pot (like 50k) for the active pickup and a separate high value pot for the passive pickups.

 

[Steve_Karl]

Understood.

Thanks!