Preamp signal boost?

Noose · #1 02-21-2011, 06:07 PM

I am wanting to find a way to boost the output of my sansamp bddi. I'm using it as a preamp to a PA power amp. It sounds good, but i don't think it quite pushes the power amp very well.

I've heard of the line level shifter that could be used for this. Is there anything else that will make my signal going into the power amp stronger?

I don't have a lot of money to spend, so think cheap. Thanks in advance.

RickenBoogie · #2 02-21-2011, 06:18 PM

Another preamp in front of the Sansamp?

rpsands · #3 02-21-2011, 06:31 PM

I believe there is a way to mod the BDDI to take more voltage, that's pretty standard. Call up a custom pedal guy.

Guttermouth (Ian League) is the guy I deal with for all that kinda stuff, but there are a bunch of them out there.

rumblinbass · #4 02-21-2011, 06:41 PM

Quote:

Originally Posted by Noose

I am wanting to find a way to boost the output of my sansamp bddi. I'm using it as a preamp to a PA power amp. It sounds good, but i don't think it quite pushes the power amp very well.

I've heard of the line level shifter that could be used for this. Is there anything else that will make my signal going into the power amp stronger?

I don't have a lot of money to spend, so think cheap. Thanks in advance.

...do you have a schematic?
it might be as simple as adding a resistor or changing the value of an existing resistor.

Noose · #5 02-21-2011, 09:48 PM

The most common mod that I have found involves removing a resistor, but all that does is bring the xlr output up to the same output level as the 1/4 inch output. The 1/4 out isn't strong enough either. It's functional, but I have to boost the gain on the preamp so much that I lose the tone that I want. I need more clean output.

I called customer support at tech 21 and the guy suggested a line level shifter made by Ebtech. Looks like it will work for what I need, I was just hoping there were some other less expensive options. I was hoping there was some kind of cheap pedal or gadget that was commonly used for this purpose.

rpsands · #6 02-21-2011, 09:56 PM

I am nearly positive there is a simple mod to 18v that most pedal guys can do. I'd suggest getting a hold of Putnam guitars - guy is a big tech21 modder.

tech21nyc · #7 02-22-2011, 10:42 AM

Quote:

Originally Posted by Noose

I am wanting to find a way to boost the output of my sansamp bddi. I'm using it as a preamp to a PA power amp. It sounds good, but i don't think it quite pushes the power amp very well.

I've heard of the line level shifter that could be used for this. Is there anything else that will make my signal going into the power amp stronger?

I don't have a lot of money to spend, so think cheap. Thanks in advance.

Which version of our Bass Driver DI do you have? Also how do you have it set and what power amp are you using it with?

Noose · #8 02-22-2011, 11:03 AM

Quote:

Originally Posted by tech21nyc

Which version of our Bass Driver DI do you have? Also how do you have it set and what power amp are you using it with?

I've got one of the earlier model bddi that doesn't have the switch.

I am running it directly into a peavey 1200 power amp. It has a knob that reduces input sensitivity down to zero.

I should be clear that I am getting a reasonable level of volume when i ise the 1/4" out, but I have to crank the level, treble, and bass up full blast with the drive up just past halfway. If I try to cut bass/treble to bring out more mids, I lose volume. I am trying to avoid excessive distortion.

Also, I just wanted to point out that your tech people have been fantastic on the phone. It is sincerely appreciated.

craig.p · #9 02-22-2011, 11:18 AM

IMO the v1 (earlier variant) is not really suited to the work you're asking it to do.

I'm thinking along the lines of what RB said, except I'd put a mic preamp AFTER the BDDI, and run the mic preamp's output to the Peavey.

Or sell the BDDI v1 and pick up a used BDDI v2. They pop up from time to time in the classifieds here. I'd sell you mine except I like it way too much, LOL.

Noose · #10 02-22-2011, 11:38 AM

Quote:

Originally Posted by craig.p

IMO the v1 (earlier variant) is not really suited to the work you're asking it to do.

I'm thinking along the lines of what RB said, except I'd put a mic preamp AFTER the BDDI, and run the mic preamp's output to the Peavey.

Or sell the BDDI v1 and pick up a used BDDI v2. They pop up from time to time in the classifieds here. I'd sell you mine except I like it way too much, LOL.

You may be right, but according to the person I talked to from tech 21 the only difference between the v1 and v2 is they added the switch so that the xlr level could be brought up to match the 1/4 inch out. He said both have the same output. I have not used the newer version though, so I could very well be talking from my arse.
Either way, the line level shifter should solve the issue if output from the bddi is really the problem.

Noose · #11 02-22-2011, 11:41 AM

I've never used a "mic preamp". Is that like the art tube pre I've heard about? How much are those? What does it do exactly?

tech21nyc · #12 02-22-2011, 11:45 AM

Quote:

Originally Posted by Noose

I've got one of the earlier model bddi that doesn't have the switch.

I am running it directly into a peavey 1200 power amp. It has a knob that reduces input sensitivity down to zero.

I should be clear that I am getting a reasonable level of volume when i ise the 1/4" out, but I have to crank the level, treble, and bass up full blast with the drive up just past halfway. If I try to cut bass/treble to bring out more mids, I lose volume. I am trying to avoid excessive distortion.

Also, I just wanted to point out that your tech people have been fantastic on the phone. It is sincerely appreciated.

Do you have the input attenuator turned full clockwise? Also how are you running the amp? Stereo, mono bridged etc.?The specs I read say it is 600 watts per side into a 4 ohm load.What speaker cab or cabs are you using it with? With no input attenuation the BDDI should be able to drive the amp to full power into the correct load. How do you have the BDDI set? Passive or active bass? Is you bass guitar volume full up? Also if it's the same amp I looked up be sure that you are plugged into the main inputs and not the crossover inputs.

jpTron · #13 02-22-2011, 11:59 AM

Bartolini makes a boost only pre that costs 30 bucks. Gives 12 db of gain. It's supposed to go in your bass. I don't know how, if it's even possible that you could wire it externally into a pedal.

craig.p · #14 02-22-2011, 12:28 PM

Quote:

Originally Posted by Noose

You may be right, but according to the person I talked to from tech 21 the only difference between the v1 and v2 is they added the switch so that the xlr level could be brought up to match the 1/4 inch out. He said both have the same output. I have not used the newer version though, so I could very well be talking from my arse.

No, probably not, because a) Tech21 knows their BDDIs better than I ever will, and b) I haven't tested both the v1 and the v2. I can tell you that the switch on mine does affect the 1/4" output, but what I can't say (and what I guess I wrongly assumed) is that the "line" position boosts the v2's 1/4" output relative to the v1's; it may be that the v2's "inst" position is designed to reduce its 1/4" output relative to the v1's, to reduce the risk of overload when running to a bass amp's instrument input.

Ugh. My brain hurts.

gregoire1 · #15 02-22-2011, 12:50 PM

I'm sure the Art Tube mic-preamp will do exactly what you want (I've used it to drive a bass directly into a power amp, in fact, it'll almost drive earphones!), but I know plenty of people here have used the BDDI v-2 to drive an amp by itself.

Noose · #16 02-22-2011, 01:24 PM

Quote:

Originally Posted by gregoire1

I'm sure the Art Tube mic-preamp will do exactly what you want (I've used it to drive a bass directly into a power amp, in fact, it'll almost drive earphones!), but I know plenty of people here have used the BDDI v-2 to drive an amp by itself.

Yeah. I think my problem is with the power amp and not the preamp. It's a relatively old amp that probably just want a lil hotter signal.

seanm · #17 02-22-2011, 01:34 PM

I have run a passive bass straight into the ART Tube MP to drive a power amp that needed a huge signal to work properly, and it had lots of headroom left. So it shouldn't even break a sweat with the SansAmp.

And the ART Tube MP is just a great tool to have anyway since it is so versatile.

Noose · #18 02-22-2011, 01:59 PM

Quote:

Originally Posted by seanm

I have run a passive bass straight into the ART Tube MP to drive a power amp that needed a huge signal to work properly, and it had lots of headroom left. So it shouldn't even break a sweat with the SansAmp.

And the ART Tube MP is just a great tool to have anyway since it is so versatile.

Well, crap. Those things seem to go pretty cheap too. Unfortunately I already ordered a line level shifter. Oh well. If it doesn't work ill just sell the LLS and give the ART Tube a shot.

Noose · #19 02-22-2011, 02:18 PM

Quote:

Originally Posted by tech21nyc

Do you have the input attenuator turned full clockwise? Also how are you running the amp? Stereo, mono bridged etc.?The specs I read say it is 600 watts per side into a 4 ohm load.What speaker cab or cabs are you using it with? With no input attenuation the BDDI should be able to drive the amp to full power into the correct load. How do you have the BDDI set? Passive or active bass? Is you bass guitar volume full up? Also if it's the same amp I looked up be sure that you are plugged into the main inputs and not the crossover inputs.

I've tried it several ways

The input attenuator is all the way clockwise, the volume on the bass is all the way up, The only knob not all the way blasted on the pedal is the drive but even it is past halfway. These settings are not what I want to use tone wise. I've got it like this to wring out as much volume as possible. With these settings I get to practice type volume and that's it. Im plugged into the input, running into a 8 ohm GK 410 cab. I have used the power amp to drive other speakers without issue, so I don't think anything is malfunctioning. Is it likely that the input sensitivity on that amp doesn't go as low as it's specs suggest?

Bob Lee (QSC) · #20 02-22-2011, 03:13 PM

If you have a decent signal level from your bass (and this is important!), I'd think that the BDDI should be able to produce a good enough signal level for the vast majority of pro power amps. Of course, you'd have to set the gain control on the amp (I haven't seen an input attenuator on a power amp since maybe the 70s) to work with the signal level from the pre and the sound level you want.