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Double Bass LF Help about "low impedance" preamp problem

S

Snorisson

Apr 3, 2024
4
0
#1
Hi everyone ! :D

Straight to point first :
Is it bad if I use any cheaper "acoustic guitar" 10Mohm preamp on the bass ? (or could a D.I be enough? )
What's the cheapest option to resolve the weak "low impedance" sound ?

Some Context :

I'm starting to play again professionnaly after some years of pause, and I feel quite some pressure to find a fast but not ideal solution for amplification... until next year when I will be able to afford good, serious gear. For now I just have a bad bass with a Full circle on it.
--> I've been on gollihur and many other sites for a month, looking for a preamp with very high Impedance (Full circle = 10MOhm Impedance ideally)
Of course I could buy a fishman preamp and/or an amp that's adapted for Dbass, but right now i'm quite low on money :(
I don't care too much about EQ or greater control of sound for now, just that my signal is weak and thin (classic low impedance problem)
I noticed that the greater impedance preamp for bass are more expensive (unlike the K&K ones for ex). But many cheaper acoustic guitar preamp offer 5 to 10 MOhms ....

Sorry, i'm quite bad and uninformed about technical stuff. But I love to learn !
I need some help though, so I don't sound too poopy and can keep my jo

thank you so much for reading :)
 
#2
I’ve been using my Full Circle with amps and preamps with 1 Mohm impedance, works fine.

Are you using an amplifier or going direct into a PA system?

Doesn’t matter if the preamp is meant for bass or not as long as it has 1 Mohm or higher input impedance. Here’s one that’s only brand new, 4.7 Mohm input impedance.

Screen Shot 2024-04-03 at 12.03.27 PM.png
 
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#3
Damn ! So there's no difference ? that's exactly what I was wondering.
Thanks a lot for the advice, i'll buy this one second handed, it's not rare to find one of those. There's also the Schatten micro preamp that looks quite good and cheap (less than 40$), but I have no idea how to mount it, and I guess it's a lot of diy electronics.

For the rest: I can either go direct into PA or in a Fender Bassman 100, haven't decided, but both are possible.
 
#4
Some guitar preamps may have a built in HPF that is set a bit high for DB. I have the Behringer Acoustic ADI-21, though, and it is fine for bass--quite good actually. The output signal is pretty weak with the blend all the way counter-clockwise (which is where you'll want it).
 
#6
There is not single best impedance to load a piezo. 1 Meg is generally considered the minimum and 10 Meg is often touted as the gold standard. However, the optimum load depends on how the piezo is made, which impacts how much capacitance it has. In practice the optimum load often falls somewhere between about 2 and 5 Meg. But the sonic differences can be subtle.

If you insist o 10 Meg, consider buying an HPF pre from @fdeck.

Most DIs do not have a buffered Thru...so if you plug the Thru into your amp, the input impedance of the DI is placed in parallel with the input impedance of the amp. The CoutryMan Type 85 is an example. It has 10Meg input, but the Thru is not buffered.

Radial makes some DIs that are intended for us with piezos. The more expensive option is the PZDI. The PZDI has switchable input impedance 220K, 1Meg, and 10Meg. The Thru can be switched from parallel to buffered. The lower cost option is the StageBug SB-4. The input impedance is 5Meg and the Thru is always buffered. Keep in mind, active DIs generally require phantom power.

You can also consider pedal Preamp/DIs. The Tech 21 Q/Strip has 4.7Meg input impedance and a nice set of controls.

These are just a few options...there are many. For example: Fishman, Grace Design, and Headway Music Audio are three companies that make acoustic focused preamp/DIs that are suitable for piezo pickups. Consider the features you want and how much you are willing to spend.
 
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#7
Hello ! Thanks everyone for the replies :)

Wasnex:
yeah I know there's a lot of options but all I found at 10Mohms is way too expensive for me now. I can't spend 300$ on it
It would perfect if it was around 80 euros
I know about the HPF from Fdeck, and I could almost afford it but the shipping is US only (i'm europe)
Stage bug could be good but it's all over 115$, just like all the preamp from Gollihur.
That's why I'm wondering about roundabout solutions, like items sold as "guitar" preamps with 5 to 10megOhm
 
#8
Snorisson said:
Hello ! Thanks everyone for the replies :)

Wasnex:
yeah I know there's a lot of options but all I found at 10Mohms is way too expensive for me now. I can't spend 300$ on it
It would perfect if it was around 80 euros
I know about the HPF from Fdeck, and I could almost afford it but the shipping is US only (i'm europe)
Stage bug could be good but it's all over 115$, just like all the preamp from Gollihur.
That's why I'm wondering about roundabout solutions, like items sold as "guitar" preamps with 5 to 10megOhm
Click to expand...
I have an fdeck that I've been thinking about selling. Not sure if shipping a used item to Europe would be an issue. You might want to consider the Headway EDM-1 H.E., which is made in Europe and sells for 180 GBP. I am not sure about the impedance, but I assume it's the same as the EDB-2 HE, which is 6.8 Meg Ohm. Or, there is the old version, the EDM-1 (non-HE), which has an adjustable input impedance. You might be able to find it used for cheap.
 
#9
Snorisson said:
Hello ! Thanks everyone for the replies :)

Wasnex:
yeah I know there's a lot of options but all I found at 10Mohms is way too expensive for me now. I can't spend 300$ on it
It would perfect if it was around 80 euros
I know about the HPF from Fdeck, and I could almost afford it but the shipping is US only (i'm europe)
Stage bug could be good but it's all over 115$, just like all the preamp from Gollihur.
That's why I'm wondering about roundabout solutions, like items sold as "guitar" preamps with 5 to 10megOhm
Click to expand...

I would look more for acoustic preamps than guitar preamps. AFAIK acoustic preamps are generally all-purpose and often designed to work with piezos.

Broughton ships international.

From the product page:
The stock input impedance is 1MΩ. If you have an acoustic pickup that requires a specialized input impedance, write it in the notes during check-out, and we will accommodate the request at no extra cost.​

High Pass Filter | Broughton Audio




The old Fishman Pro EQ Platinum has 10Meg input and should sell on the used market in your price range
upload_2024-4-3_14-18-41.png
 
#10
Oh I never heard about Broughton before ! that's very nice. Yeah Headway EDB is too expensive, but it's true that sometimes old Fishman Plat' goes under 100$.

But look at the Fishman G2, mostly used by guitar player
FISHMAN GII Acoustic Instrument Preamp - acousticvilla
Or the Fishman "aura"
Both way cheaper than Platinum (between 30 and 60$ used)
Both has 10MeOhms. Do you think it's a good idea ? There's also the super cheap behringer ADI21
 
Last edited:
#11
Snorisson said:
Oh I never heard about Broughton before ! that's very nice. Yeah Headway EDB is too expensive, but it's true that sometimes old Fishman Plat' goes under 100$.

But look at the Fishman G2, mostly used by guitar player
FISHMAN GII Acoustic Instrument Preamp - acousticvilla
Or the Fishman "aura"
Both way cheaper than Platinum (between 30 and 60$ used)
Both has 10MeOhms. Do you think it's a good idea ? There's also the super cheap behringer ADI21
Click to expand...


Best if you can try before you buy, but in my experience a lot gear designed for acoustic seems to work okay with bass.
 
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#12
If it is just a buffer with no EQ and no filter, any buffer will do.
If it has EQ, the center frequencies might not fit to a bass if it is made for higher pitched instruments.
Also a fixed high pass filter (read: low frequency blocking filter) designed for a higher pitched instrument may interfere with low bass frequencies.

A simple buffer consists of four to seven parts, but the J-FET is hard to get as a hole-through part now and you need to get one of the few that work well for our application.
I made one myself for about 10€ including case and jacks several years ago when it was still possible to get the J-FET. Even without a PCB …
 
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#13
bassically_eli said:
I have an fdeck that I've been thinking about selling. Not sure if shipping a used item to Europe would be an issue. You might want to consider the Headway EDM-1 H.E., which is made in Europe and sells for 180 GBP. I am not sure about the impedance, but I assume it's the same as the EDB-2 HE, which is 6.8 Meg Ohm. Or, there is the old version, the EDM-1 (non-HE), which has an adjustable input impedance. You might be able to find it used for cheap.
Click to expand...
The EDM1 is a great little preamp! It has 1, 5 and 20M impedance options, variable HPF, decent EQ and is battery powered. You can find them used for around $100.
 
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#14
Rick Turner once wrote: "Don't suffer it - buffer it!"
Wise words I still heed some 30 years later.
He didn't specify exactly which unit you have to use, though.
IME it's all about the trial & error. I find what seems best on paper doesn't always work the best on the gig.
I think I am partial to 10M but, but also open to ignoring that spec & rolling with whatever sounds good. That includes plugging straight in to the amp, but my bass usually sounds tangibly better with a buffer.
For a while I used an Ibanez Tube Screamer - in bypass mode of course. If a guitar pre is all that's available in your region & budget, by all means try it! (Acoustic preamps are more universal than the marketing department might have one believe; I use my HPF-Pre for mandolin sometimes.)
 
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#16
Snorisson said:
Hi everyone ! :D

Straight to point first :
Is it bad if I use any cheaper "acoustic guitar" 10Mohm preamp on the bass ? (or could a D.I be enough? )
What's the cheapest option to resolve the weak "low impedance" sound ?

Some Context :

I'm starting to play again professionnaly after some years of pause, and I feel quite some pressure to find a fast but not ideal solution for amplification... until next year when I will be able to afford good, serious gear. For now I just have a bad bass with a Full circle on it.
--> I've been on gollihur and many other sites for a month, looking for a preamp with very high Impedance (Full circle = 10MOhm Impedance ideally)
Of course I could buy a fishman preamp and/or an amp that's adapted for Dbass, but right now i'm quite low on money :(
I don't care too much about EQ or greater control of sound for now, just that my signal is weak and thin (classic low impedance problem)
I noticed that the greater impedance preamp for bass are more expensive (unlike the K&K ones for ex). But many cheaper acoustic guitar preamp offer 5 to 10 MOhms ....

Sorry, i'm quite bad and uninformed about technical stuff. But I love to learn !
I need some help though, so I don't sound too poopy and can keep my jo

thank you so much for reading :)
Click to expand...
Grace Design Felix isn't built (only) for uprights, but also for acoustic guitars and other acoustic instruments...



And works really impressive with Uprights.. so go on and check it out...and an 10 MOhm input shouldn't be "the worst" for high impedance PU's like most piezos...
 

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