need a preamp to drive power amp

runmikeyrun · #1 01-24-2009, 04:22 PM

I already have the distortion and eq covered (15 band), i just need something to drive the power amp. I'm trying to keep things around $100, give or take a few bucks. I'm thinking of basic instrument preamps like an ART or this Studio Projects one:

http://pro-audio.musiciansfriend.com...amp?sku=180360

I know if i go to GC or Sam Ash and ask to demo preamps on their power amps with a bass they're going to be like "yeah right". I hate buying stuff and taking it home then having to return it; so here i am asking those of you using something like this to help me out.

Last thing i picked up was an M-80 which doesn't have the guts to drive my amp the way i'd like it to. I'm trying to avoid that again... don't want to buy a preamp to have it not perform.

bongomania · #2 01-24-2009, 06:35 PM

Nearly all "mic pre" type units can do the job. You need to read the specs for each unit. Look for a balanced output with a nominal +4dBu level, which is approx 1.25 V. Lots of devices that are sold as "preamps" are not set up with that kind of output, but for devices that can do it, the output specs are usually published.

Note that I'm not naming any specific units- that's because there are literally hundreds, if not thousands, of choices.

Nyarlathotep · #3 01-24-2009, 08:17 PM

Quote:

Originally Posted by bongomania

Look for a balanced output with a nominal +4dBu level, which is approx 1.25 V.

Glad I stumbled into this one know. Good info to know.

bongomania · #4 01-24-2009, 08:21 PM

FWIW that spec is not necessarily ideal for all power amps, but it is the most common and also the most likely to work with a wider range of power amps.

Nyarlathotep · #5 01-24-2009, 08:23 PM

Quote:

Originally Posted by bongomania

FWIW that spec is not necessarily ideal for all power amps, but it is the most common and also the most likely to work with a wider range of power amps.

Even

er

seanm · #6 01-24-2009, 08:33 PM

I have used the ART mic pre successfully into a terrible power amp.

newbold · #7 01-24-2009, 09:26 PM

those ART units usually work really well and if you get the Tube Mic preamp/DI then you'll get a balanced out for FOH.

runmikeyrun · #8 01-25-2009, 03:10 PM

maybe i'll go demo a couple, see what i think. some of the outputs were listed in dB, others in the amount of gain, it got confusing which was which. I'll check some out, thanks for the help!

bongomania · #9 01-25-2009, 06:40 PM

"Gain" means "how much the input is increased". So the output level is dependent on the input level. Gain is a very useful spec to know, but it doesn't actually tell you the level you'll get at the output.

FWIW if the only spec they give you is dB gain, look for 50dB or higher, as that's roughly what you need to bring an average bass signal up to line level.

"dB" is a relative measure but "dBu" and "dBv" are actual levels corresponding to a certain signal voltage. "+4dBu" corresponds to about 1.25V, which is line level.

runmikeyrun · #10 01-26-2009, 11:22 AM

i suppose i'm still confused on what value to look for- line level, is that considered what your output is at the bass's output jack? That's probably what my M-80 puts out but it obviously isn't enough. I am running a distortion pedal and effects chain into the input so i can control the input gain some but don't want it to clip (unless it clips nicely).

seanm · #11 01-26-2009, 11:55 AM

Quote:

Originally Posted by runmikeyrun

i suppose i'm still confused on what value to look for- line level, is that considered what your output is at the bass's output jack? That's probably what my M-80 puts out but it obviously isn't enough. I am running a distortion pedal and effects chain into the input so i can control the input gain some but don't want it to clip (unless it clips nicely).

No, the m-80 is a pedal that is meant to plug into an preamp. It puts out instrument level, not line level.

bassman1185 · #12 01-26-2009, 12:51 PM

I've got an ART Tube PAC that I just started running directly into the effects loop return on my amp. It sounds fantastic clean and pushed a bit, and it will tear your head off when I run my VT Bass into it. See if you can find one used. I got mine from a TBer for $40, and I threw a couple of JJ Tesla tubes in.

runmikeyrun · #13 01-26-2009, 08:06 PM

sounds like a plan- I plan on putting a JJ 12AX7 in whatever i get because they have awesome response for a distortion player like me. I have them in all the spots on my Peavey Windsor.

I am salty about the M-80 because it's advertised as a preamp and it really isn't. Spent $100 for nothing. That and everyone raged about how much distortion it had and it really doesn't have that much. It'll go on the chopping block for another preamp.

seanm · #14 01-26-2009, 09:33 PM

Quote:

Originally Posted by runmikeyrun

I am salty about the M-80 because it's advertised as a preamp and it really isn't. Spent $100 for nothing. That and everyone raged about how much distortion it had and it really doesn't have that much. It'll go on the chopping block for another preamp.

The word preamp is used to mean a preamp that goes before a power amp, the preamp section of a head, or a pedal that has gain, or a pedal that has eq or.... well, you get the picture

roflol · #15 01-27-2009, 06:08 AM

keep an eye out for a zoom power driver and don't let the zoom name put you off, it was part of there very good analog line.

John Wentzien · #16 01-27-2009, 06:31 AM

The Seymour Duncan "pickup-booster" is pretty darn good too.
Just pure clean class-A Gain.

bongomania · #17 01-27-2009, 08:06 PM

So you two can both confirm that the pedals you recommended can drive a power amp well?