Double Bass Why Use a Preamp?

[bassmanchu]

So, I've played for a long time using a few different pickups (Realist, Bass Max, Fishman BP-100, never live-mic though) and I see a lot of talk on here about preamps. I've never used one except when I went straight into the board at a musical gig, and I borrowed a Fishman preamp for that. I plug directly into an AI Series II Contra on most jazz gigs. So...

Why use a preamp?

Isn't the EQ on your amp enough?

When is a preamp appropriate?

How do you balance EQ on the amp and the preamp together?

Is there a boosted signal benefit?

Doesn't it only serve to further water down your bass' natural sound?

I don't really have an opinion either way, but I'll be trying out one of those Radio Shack tie clip mics and I've heard a preamp helps the sound immensely (for increased volume output). Thanks for your help.

Alex

 

[KUNGfuSHERIFF]

Impedence matching. Most piezo pickups put out a signal with higher impedence than the majority of amplifiers are prepared to accept. The result is often thin, scratchy sound.

 

[Pat Harris]

I'll be trying out one of those Radio Shack tie clip mics

Save your time, and do not do this with your bass.

Bassists have different needs for preamps depending on their bass, pickup, amp and playing style.

Isn't the EQ on your amp enough?
Not always. Many preamps have parametric/sweepable EQ sections to finely adjust desired frequencies. Most amps do not have a high pass filter built in.

When is a preamp appropriate?
To match impedence with the input of your amp, if you need more control over your sound, to raise the output of your bass before it hits the amp. If you are playing through powered speakers, a preamp is a necessity.

How do you balance EQ on the amp and the preamp together?
Most bassists will set their EQ flat on the amp and use the preamp as an EQ.

Is there a boosted signal benefit?
There can be. Boosting the signal before the amp can help with a signal to noise ratio.


Doesn't it only serve to further water down your bass' natural sound?
If that was the result, why would preamps exist? They are used to further refine amplified tone.

 

[bassmanchu]

Save your time, and do not do this with your bass.

Bassists have different needs for preamps depending on their bass, pickup, amp and playing style.

Isn't the EQ on your amp enough?
Not always. Many preamps have parametric/sweepable EQ sections to finely adjust desired frequencies. Most amps do not have a high pass filter built in.

When is a preamp appropriate?
To match impedence with the input of your amp, if you need more control over your sound, to raise the output of your bass before it hits the amp. If you are playing through powered speakers, a preamp is a necessity.

How do you balance EQ on the amp and the preamp together?
Most bassists will set their EQ flat on the amp and use the preamp as an EQ.

Is there a boosted signal benefit?
There can be. Boosting the signal before the amp can help with a signal to noise ratio.


Doesn't it only serve to further water down your bass' natural sound?
If that was the result, why would preamps exist? They are used to further refine amplified tone.

Thanks for the detailed reply! For a whopping $12 on Amazon I took the plunge on the clic mic. Worst case scenario I have a crappy emergency backup option. I'm looking for a better solution than modifying my bridge to fit a piezo, or dropping $600 on a DPA 4099 (yet).

Doesn't it only serve to further water down your bass' natural sound?
If that was the result, why would preamps exist? They are used to further refine amplified tone.

I think some people do prefer an "electrified" sound, but I am not one of them. Running through two EQs could certainly be used to "distort" the sound, rather than find a natural one. I guess more options for adjustments are a good thing either way, right?

 

[bassmanchu]

The impedance issue is an interesting one - My amp has separate high and low impedance inputs (since it was designed with bass piezos in mind, I'm sure), but I never really understood what that meant, and never bothered to look it up.

Time for some wikiing.

 

[Ric Vice]

+1 to everything above. Your Acoustic Image Amp has a 1 meg ohm input impedance and it also has a high pass filter. So for the most part you're set, except you're Fishman BP-100 really needs a 10 meg ohm load, so in that case the Fishman Pre Amp improves the tone quality of the BP-100, as Fishman sets the load on their boxes at 10 meg ohm. My take is if you really want to try a mic then get a decent one.

Ric

 

[bassmanchu]

+1 to everything above. Your Acoustic Image Amp has a 1 meg ohm input impedance and it also has a high pass filter. So for the most part you're set, except you're Fishman BP-100 really needs a 10 meg ohm load, so in that case the Fishman Pre Amp improves the tone quality of the BP-100, as Fishman sets the load on their boxes at 10 meg ohm. My take is if you really want to try a mic then get a decent one.

Ric

That's really helpful, Ric. Thanks! I no longer use the Fishman pickup (don't even have it anymore) because the sound was so horrid on my 2nd bass (which was my only bass for years) - probably because I didn't use the preamp!

I do find that my AI amp has pretty much everything I could want, though the EQ is a little bit limited on the Series II.

This is my first step into live micing (I've used several for recording), so I didn't want to drop a bundle just yet. This mic has had good reviews, but I get the feeling they're mostly from rockabilly or country players. I'd be using it for jazz, chamber ensembles or musicals, mostly. We'll see what happens! Either way, didn't spend a lot, so it'll be fun to experiment. Undoubtedly an easily mountable mic like the 4099 will be next, if I'm not crazy about this one.

Anyone have recommendations on good preamps?

 

[drurb]

Impedence matching. Most piezo pickups put out a signal with higher impedence than the majority of amplifiers are prepared to accept. The result is often thin, scratchy sound.

When is a preamp appropriate?
To match impedence with the input of your amp, if you need more control over your sound, to raise the output of your bass before it hits the amp. If you are playing through powered speakers, a preamp is a necessity.

Absolutely not impedance matching. Please, please look HERE. I'm afraid Kungfu and Pat Harris have this wrong. It's not at all a matter of what most amps accept. It's a matter of loading (not matching) the pickup to achieve a desired response.

The impedance issue is an interesting one - My amp has separate high and low impedance inputs (since it was designed with bass piezos in mind, I'm sure), but I never really understood what that meant, and never bothered to look it up.

Time for some wikiing.

Follow the second link within the post to which I linked immediately above.

 

[Ric Vice]

That's really helpful, Ric. Thanks! I no longer use the Fishman pickup (don't even have it anymore) because the sound was so horrid on my 2nd bass (which was my only bass for years) - probably because I didn't use the preamp!

Bass Manchu,
Trust me even with the Fishman Model B Transducer Interface (there's a mouthful) the BP-100 was pretty nasty sounding, things have improved quite a bit since that pickup came on the scene.

I do find that my AI amp has pretty much everything I could want, though the EQ is a little bit limited on the Series II.

Here's the scoop, AI is getting ready to release the Flex Preamp and Powered Cabinet. The new pre amp has all the features of your Series II, with additional Low and High Midrange Controls, 48 volts to the Phantom Power, and a host of other new features. You will be able to by the pre amp separately or as part of the two piece system. There's also the Headway EDB-1 Pre Amp, that's less expensive than the Flex.

This is my first step into live micing (I've used several for recording), so I didn't want to drop a bundle just yet. This mic has had good reviews, but I get the feeling they're mostly from rockabilly or country players. I'd be using it for jazz, chamber ensembles or musicals, mostly. We'll see what happens! Either way, didn't spend a lot, so it'll be fun to experiment. Undoubtedly an easily mountable mic like the 4099 will be next, if I'm not crazy about this one.

Well, after working with the DPA 4099B for several years, my take is that it works very well FOH, but into an amplifier you will get feedback in fairly short order. A pickup is still more desirable into you amp.



Anyone have recommendations on good preamps?[/QUOTE]

 

[Mandobassman]

I'll be trying out one of those Radio Shack tie clip mics and I've heard a preamp helps the sound immensely (for increased volume output).

Don't let "KUNGfuSHERIFF" sway your decision to try the Radio Shack mic. If I had taken that advice, I wouldn't have the wonderful bass sound I enjoy now. As I have stated in my previous thread on this, it may not work on every bass, but there are plenty of players who it has worked great for, including me. I use nothing but the RS mic and a GK amp. No preamp. And the sound is great. Better than any pickup I have used. For very little cost, it's a easy way to find out if a mic sound works for you. If it doesn't work, you haven't lost much. However, that little mic might just surprise you!

 

[Ric Vice]

Don't let "KUNGfuSHERIFF" sway your decision to try the Radio Shack mic. If I had taken that advice, I wouldn't have the wonderful bass sound I enjoy now. As I have stated in my previous thread on this, it may not work on every bass, but there are plenty of players who it has worked great for, including me. I use nothing but the RS mic and a GK amp. No preamp. And the sound is great. Better than any pickup I have used. For very little cost, it's a easy way to find out if a mic sound works for you. If it doesn't work, you haven't lost much. However, that little mic might just surprise you!

Mandobassman,

Reading through this thread, looks like he already bought one.

Thanks for the detailed reply! For a whopping $12 on Amazon I took the plunge on the clip mic. Worst case scenario I have a crappy emergency backup option.

Ric

 

[drurb]

...and it wasn't Kungfu who discouraged use of the RS mic.

 

[Pat Harris]

My apologies, by "matching" I definitely meant "loading." Sorry for any confusion.

 

[martinc]

Bassmanchu:

No....you don't have to use a preamp.
Check this little item out....it eliminates the need for a pre-amp with a piezo pickup:

[Invalid or Expired Link Removed]

I normally would never use piezo pickup without a pre-amp but the Stagebug looks like a great substitute.
I have no connection to Radial..and don't own anything they make.

 

[DoubleMIDI]

You don't need a preamp at all, BUT the first input from the piezo should have a rahter high impedance (1 to 10 MegOhms) to avoid loading the piezo too much and getting a distorted waveform (not as much distorted as a fuzz, but enough to sound less good).

Piezos cannot deliver a high current without voltage breakdown, so the load needs to be small to avoid that. For each passive piezo there seems to be an ideal load (too less seems to be bad in one or another way too), but these loads are usually in between 1 and 10 MegOhms.

If you need an EQ like in many "preamps", it depends on taste and (the linearity of) your main amp EQ. Usually each EQ adds noise, so if you don't need it, try to avoid it. If you often need to play on other peoples amps that you don't know, a preamp with EQ helps with a useful input impedance and more possibilities to get a good sound.

Also long cables connected to a high input impedance tend to be microphonic. If you step on the cable or any movement of the cable might get amped, so better use the high input impedance (buffer or preamp) close to the bass and run a longer cable to a lower input impedance input to your amp. But with good cables of medium length (~3m) the effect is not noticable, so decide for yourself how to handle that.

 

[bassmanchu]

Bassmanchu:

No....you don't have to use a preamp.
Check this little item out....it eliminates the need for a pre-amp with a piezo pickup:

[Invalid or Expired Link Removed]

I normally would never use piezo pickup without a pre-amp but the Stagebug looks like a great substitute.
I have no connection to Radial..and don't own anything they make.

Martin, isn't this basically just a DI box?

 

[bassmanchu]

Martin, isn't this basically just a DI box?

Oh, I see. It's specifically designed for piezo pickups. I wonder how they differentiate this from their other DI boxes.

 

[martinc]

It also has a high pass filter and an line out for an onstage amp.
Goes right into the Mic preamp input of the PA. XLR out and phase reversal too:
[Invalid or Expired Link Removed]

I am thinking about trying one.
I would give up being able to control the bass, mids and treble but the sound check ahead of time should solve that.
I am long past carrying any more gear than absolutely necessary......I don't even bother lugging my 50 watt Traynor amp anymore. This little gadget will fit in my pocket.
I would be interested to hear how clean the pickup sounds with that 5 Meg input impedance.
I have been using the Baggs Paracoustic DI or the UltraSound DI Max for may years. I also have the ART tube Pre (Project Series version). Sounds nice with a Mullard tube in it. But I think the Stagebug might be a workable alternative.
I'll report on it if I end up buying one.
Also its made in Canada! No import duties.

 

[Mandobassman]

Mandobassman, Reading through this thread, looks like he already bought one.Ric

" ...and it wasn't Kungfu who discouraged use of the RS mic. "

Right on both counts. My apologies, I stand corrected.

 

[bassmanchu]

Thanks for this, DoubleMIDI.

Now I know which input to use on my Acoustic Image! I probably won't go for the pre-amp just yet. I'm not doing enough amped gigs these days...

and when I do, there's rarely a front-of-house. Mostly just bar jazz.

You don't need a preamp at all, BUT the first input from the piezo should have a rahter high impedance (1 to 10 MegOhms) to avoid loading the piezo too much and getting a distorted waveform (not as much distorted as a fuzz, but enough to sound less good).

Piezos cannot deliver a high current without voltage breakdown, so the load needs to be small to avoid that. For each passive piezo there seems to be an ideal load (too less seems to be bad in one or another way too), but these loads are usually in between 1 and 10 MegOhms.

If you need an EQ like in many "preamps", it depends on taste and (the linearity of) your main amp EQ. Usually each EQ adds noise, so if you don't need it, try to avoid it. If you often need to play on other peoples amps that you don't know, a preamp with EQ helps with a useful input impedance and more possibilities to get a good sound.

Also long cables connected to a high input impedance tend to be microphonic. If you step on the cable or any movement of the cable might get amped, so better use the high input impedance (buffer or preamp) close to the bass and run a longer cable to a lower input impedance input to your amp. But with good cables of medium length (~3m) the effect is not noticable, so decide for yourself how to handle that.