power supply question

yngwiewho1 · #1 10-06-2009, 12:43 AM

well guys, i have to say, when it comes to a bass with 2 active pickups and a passive eq, i totally dig 18v's for the headroom.

so, im putting in 2 active pups in my spector along with an audere 4 band eq. my q is, will i still get that same headroom with the active eq? or should i add a third battery for the eq and use the other 2 for the pups? practicality is not a concern. i want what i want you know?

ive also been toying with the idea of getting an active redeemer. anyone ever used one of these?

bongomania · #2 10-06-2009, 12:52 AM

Yeah, we've had some threads on the Redeemer. I was a big skeptic, but I have one now and it's great. Important to know what it will and won't do, however. It's great for taking your dry signal and just increasing the clarity, which does not change perceptibly no matter what amps or cords you use. It won't sound "fat" or particularly interesting though.

About the headroom of the preamp, it's not so simple. For one thing, unless you are clever with the wiring, you will have to use a third battery for the preamp. Although I guess you could get the 18V version of the Audere and then daisy-chain the batteries to it with the pickups... might work, but of course the batteries would drain faster then. The only reason I say "might" is because the Audere is finicky about the ground connections, and it may have a problem sharing ground with those active pups.

The next issue is that voltage does not always equal headroom. Depends on how the specific preamp was designed.

yngwiewho1 · #3 10-13-2009, 07:43 PM

interesting. so i should wire one 9v to each pickup and one or 2 to the audere?

**line6man** · #4 10-13-2009, 08:10 PM

Quote:

Originally Posted by yngwiewho1

so, im putting in 2 active pups in my spector along with an audere 4 band eq. my q is, will i still get that same headroom with the active eq? or should i add a third battery for the eq and use the other 2 for the pups? practicality is not a concern. i want what i want you know?

I'm not sure what you are asking.

Why can't you run both the pickups and the preamp on the same 18V system?

Eric Moesle · #5 10-13-2009, 11:05 PM

Quote:

Originally Posted by yngwiewho1

so, im putting in 2 active pups in my spector along with an audere 4 band eq.

If you read the info on the Audere web site, you'll see where he says that you must have PASSIVE pickups to work with his systems. Active pickups won't work with the Audere.

**line6man** · #6 10-13-2009, 11:08 PM

Quote:

Originally Posted by Eric Moesle

If you read the info on the Audere web site, you'll see where he says that you must have PASSIVE pickups to work with his systems. Active pickups won't work with the Audere.

Good point.

IIRC, Audere preamps have some sort of impedance selector switch right?

bongomania · #7 10-13-2009, 11:10 PM

Yes, and that is a big part of why it needs passive pups. I had forgotten about that when I posted before.

yngwiewho1 · #8 10-21-2009, 12:10 PM

no no no guys, I got the classic 4 band, and it DOES work with active if you order 330 nF metal film caps with it. you can use the 3z as well but the z mode thing doesnt work right on one of the settings if you have active. trust me, I'm the type of guy that does all the research and thensome before I do something, because I usually want to do something kind of crazy. as for why I want more batts, I have always felt that my emg on my guitar gain monster headroom when I put a 2nd emg on it. now that I'm running 2 emgs on my bass + an active eq, the voltage going to the pickups will be significantly less. It may sound stupid, or it may not even effect the sound on bass pickups, idk but im just picky like that.

yngwiewho1 · #9 10-27-2009, 01:54 PM

anyone?

yngwiewho1 · #10 10-27-2009, 01:56 PM

can someone at least tell me if i'm just crazy, or do you indeed get more headroom out of emgs with more voltage? 18v is 18v, so when you divide it amongst the pickups AND the preamp, you get voltage drop, dropping the power to 6v at the pickup

bongomania · #11 10-27-2009, 02:16 PM

When you divide the circuit in parallel, the voltage stays the same and the current gets divided. So it will depend on how the wiring is done that divvies up the power, but it seems to me that parallel is most likely. So then it becomes a question of whether the parts are getting enough current. Because you're using batteries, the current is not as restricted as if it was running from a regulated supply, so the current will not drop by much to each piece, but the batteries won't last as long.

I could be muddled there about current draw from a battery, so maybe another electrohead will come in and confirm or correct that.

**line6man** · #12 10-27-2009, 02:22 PM

Quote:

Originally Posted by yngwiewho1

can someone at least tell me if i'm just crazy, or do you indeed get more headroom out of emgs with more voltage? 18v is 18v, so when you divide it amongst the pickups AND the preamp, you get voltage drop, dropping the power to 6v at the pickup

What?

You are dealing with only a couple of milliamps of current.
What you are saying about only getting 6V to each component from an 18V supply is not logical. It doesn't work that way.

Right now my Aguilar OBP-1 preamp is out of my bass while my luthier is doing some work on the body for me again...
I just hooked it up at 9V (9V would equal the maximum current draw versus 18V or 27V) and pulled out my meter to check how much current it draws.
The preamp drew 1.10mA of current. That is like one tenth of the current that an LED draws.

If you figure that each of your components draws three full times more current than my preamp did at 9V, you are talking about drawing as much current as an LED then.
Stop worrying about it.

JackANSI · #13 10-27-2009, 02:30 PM

Quote:

Originally Posted by yngwiewho1

can someone at least tell me if i'm just crazy, or do you indeed get more headroom out of emgs with more voltage? 18v is 18v, so when you divide it amongst the pickups AND the preamp, you get voltage drop, dropping the power to 6v at the pickup

I think you are confusing things a bit. Just because you have 2 9v's to get 18v doesn't mean its divided at the two pickups to 9v each. They both get 18v as would your preamp. I prefer 18v with EMGs, just make sure your preamp can stand 18v. Adding a third 9v for 27v is pointless from my experience. I've never tried to run pickups at 18v with 2 batteries and the preamp with a seperate 9v, but I see no reason it won't work. I would recommend against using 2 9v's to supply 18v to the pickups and 9v to the preamp (by splitting between the 9v's and using one for 9v to the preamp)

And no, your batteries don't drain faster at 18v vs 9v. Don't worry there.

**line6man** · #14 10-27-2009, 03:47 PM

Quote:

Originally Posted by line6man

What?

You are dealing with only a couple of milliamps of current.
What you are saying about only getting 6V to each component from an 18V supply is not logical. It doesn't work that way.

Right now my Aguilar OBP-1 preamp is out of my bass while my luthier is doing some work on the body for me again...
I just hooked it up at 9V (9V would equal the maximum current draw versus 18V or 27V) and pulled out my meter to check how much current it draws.
The preamp drew 1.10mA of current. That is like one tenth of the current that an LED draws.

If you figure that each of your components draws three full times more current than my preamp did at 9V, you are talking about drawing as much current as an LED then.
Stop worrying about it.

Hmm, odd, it looks like my preamp is drawing 1.6mA at 18V and 2.14mA at 27V.
As the voltage goes up, the current should go down.

Am I missing something somewhere? Maybe Aguilar configured the preamp to run a different way when more voltage is available?

Everything else I said is still valid. A couple of mA maximum from each active component.

slyjoe · #15 10-27-2009, 07:31 PM

Quote:

Originally Posted by line6man

Hmm, odd, it looks like my preamp is drawing 1.6mA at 18V and 2.14mA at 27V.
As the voltage goes up, the current should go down.

Am I missing something somewhere? Maybe Aguilar configured the preamp to run a different way when more voltage is available?

Everything else I said is still valid. A couple of mA maximum from each active component.

Only for passive components. Try this calculator with the emitter R2=0 and R1 at say 10000.

http://www.csgnetwork.com/transistorcalc.html#at

The preamp may or may not be configured this way, but it shows you what can happen. The voltage across the transistor is fixed, as are the resistances, so when you have to drop more voltage across the the collector resistor the current goes up.

yngwiewho1 · #16 11-16-2009, 10:23 PM

awesome thanks guys!!