Double Bass Pre-amp with my Underwood pickup?

[hublocker]

I've had an Underwood pickup for my bass for about 20 years. I back up folk singers, and also play in a western swing group. I just simply plug it into my Roland cube 60 for small gigs but for bigger halls and clubs I use the Roland for a stage monitor and go DI into the board.

There's the problem. it is hit and miss. Some sound men can get a good bass sound and some can't and I end up sounding like a quacking duck instead of an upright bass.

Is there a pre-amp I could use to insure that the signal I send into the DI box provides a more bassy sound for the sound guy to work with?

 

[Michael Glynn]

I've had good success with the Tech21 SansAmp Bass Driver DI making the Underwood sound better. I usually put the drive knob at about 12 o'clock, as this warms up the sound and gets rid of some of the honkiness. If I turn it up higher I start hearing distortion in the low end. I've had good success running straight from this into PA systems.

One thing in general is to keep an eye on is the input impedance. Piezo pickups need a high input impedance or you can end up with an electric banjo kind of sound. The Bass Driver is 1MΩ, which could still be considered a little low, but it has worked fine for me. Many passive DIs have impedances in the kΩ range, which can result in bad sound.

 

[Ric Vice]

I've had an Underwood pickup for my bass for about 20 years............

......There's the problem. it is hit and miss. Some sound men can get a good bass sound and some can't and I end up sounding like a quacking duck instead of an upright bass.

Is there a pre-amp I could use to insure that the signal I send into the DI box provides a more bassy sound for the sound guy to work with?

I owned and used an Underwood for several years. Running any piezo into a house system without some kind of buffer/pre amp will cause he "quacking duck".

FDeck (Francis Deck) builds the HPF/Buffer Pre Amp. It has a 10 meg ohm input impediance, a adjustable high pass filter to cut the boomy lows, a phase reverse switch, and a volume control (on Version II).
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The Headway EDB-1 is also a great box with all the bells and whistles.

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Ric

 

[tornadobass]

Some sound guys use passive direct boxes, which will not sound good with a piezo pickup. Either carry a pedal preamp or active DI box to be sure you'll get good sound.

 

[Richard Simon]

When I was auditioning amps, I tried out a Genz-Benz. The fellow at the store took note of my Underwood pickup, mumbled something about impedance and plugged in a Fishman Platinum Pro EQ device. (I have one of those lying around, but it gets lots of sleep because of my plug-and-play proclivities.)

The sound was instantly warmer and fuller.
In fact, that was the sound that sold me on the amp.

TB'ers have weighed in about the Fishman here, usually on the down side because it is "noisy." I haven't had that problem with it.

Will I damage the amp by not addressing the piezo/impedance issue? And if I do take the bait and use the Fishman, where does one adjust for tone - on the amp or on the EQ box?

Thank you.

 

[Ric Vice]

When I was auditioning amps, I tried out a Genz-Benz. The sound was instantly warmer and fuller. In fact, that was the sound that sold me on the amp.

If I read the specs for Genz Benz amps they have a 500 kohm input impedance. That's a little low for a piezo pickup, especially the Underwood. You need at least 1 meg ohm to be in the impedance matching ball park.

TB'ers have weighed in about the Fishman here, usually on the down side because it is "noisy." I haven't had that problem with it.

Well, since it isn't bothering you then it probably isn't a problem with your pickup and amp. Most battery powered devices will put out high end hiss though.

Will I damage the amp by not addressing the piezo/impedance issue? And if I do take the bait and use the Fishman, where does one adjust for tone - on the amp or on the EQ box?

It will not damage your amp. It just won't sound as good. You can use both pre amps together or just plug the Pro Platinum into the effects loop return and by pass the Genz Benz's pre amp.

 

[Richard Simon]

If I read the specs for Genz Benz amps they have a 500 kohm input impedance. That's a little low for a piezo pickup, especially the Underwood. You need at least 1 meg ohm to be in the impedance matching ball park.



So...How do I reconcile the impedance discrepancy between the Underwood and the GB?

What type or brand of pickup would this amp find most hospitable?

(Please don't say Gage Realist: it hates my basses.)

Thanks for all your "input."

 

[agedhorse]

My first suggestion... there's a whole lot of rule of thumb guesses about optimum input impedances for piezo-ceramic pickups. After say 30 years of woring with such devices (including a few of my own commercial designs), there is a whole range of impedances that are suitable, as well as the associated trade-offs between noise, RFI, underdamped response (ringing) and impedance.

The output impedance of a piezo is inversely proportional to total crystal area, and each crystal geometry has a particular impedance profile.

With the vey small crystals, the kind that you might find on a flute pickup, or a violin bridge pick-up, somewhere between 1M and 5M might be a good choice. For bass guitar, acoustic guitar, harp, etc, the crystals are larger (in part to more accurately pick up the longer wavelength and associated harmonics and in part the physical/mechanical needs). These larger crystals operate more accurately with a lower impedance, from about 300k - 1M and with much less noise and less ringing.

With 95% of the piezo's used for bass pick-ups, we have found the sweet spot to be in the 500k-1M range and tested this out with a pretty large sample of pro players. The Shuttles are a little bit >500k, the Streamliner is ~1M, both are well within the range of most bass pickups. The benefit of staying away from the really high input impedances is mostly reduced noise, reduced tendency for RFI pick-up, lower tribo-electric noise from interconnect cable, and a more controlled (electronic) damping of the pick-up which reduces ringing (much like lowering the Q of an electronic filter).

When comparing to a passive DI which typically has an input impedance that falls with frequency, typically around 20-50k, this is indeed way too low for accurate reproduction. So, let's be sure we understand what the real problem is and the more accurate numbers involved.
Hope this helps.

 

[Ric Vice]

So...How do I reconcile the impedance discrepancy between the Underwood and the GB?

What type or brand of pickup would this amp find most hospitable?

(Please don't say Gage Realist: it hates my basses.)

Thanks for all your "input."

Richard,
I'm not certian that you have to reconcile anything if you're pleased with the sound you currently get from the Underwood, Genz Benz combination. If it sounds good to your ears then go with it. In my mind the issue isn't with the pickup or the amp. You might wish to experiment with the Pro Platinum and see if that is more pleasing to your ears.

Ric

 

[agedhorse]

Richard,
I'm not certian that you have to reconcile anything if you're pleased with the sound you currently get from the Underwood, Genz Benz combination. If it sounds good to your ears then go with it. In my mind the issue isn't with the pickup or the amp. You might wish to experiment with the Pro Platinum and see if that is more pleasing to your ears.

Ric

Absolutely, try it and see if you even have a problem before assuming you will. There are a lot of these out there doing exactly what the OP wants to do, and with Underwoods too.

 

[Federighi]

Most definitely. I use the Fishman Platinum Pro-EQ with my underwood. Very functional, predictable & a relatively inexpensive investment.

 

[reverendrally]

On a similar note...

After years of unhappiness with my 'cheap' setup (DOD fet preamp + Moen amp sim/DI), I've bought a LR Baggs Para acoustic DI. This was on the recommendation of some TBers and a bunch of product reviews on line. Well there are some great features on it. The phase switch is EPIC. The EQ is nice. I can get a better sound than the old setup, however...

I'm still getting the scrapy/shuffly sound of my fingers sliding round on the strings and to be honest, it really sticking in my craw... to put it politely. Even with the treble wound all the way down, it's still scratchy as.

Is it the preamp or is it the pickup? I suspect it's the pickup. If so, how do I fix it? It seems to be wedged in tight enough, but am I missing something?

P.s. The arco sound is sublime, it's just pizz that is sounds scratchy...

 

[Jake deVilliers]

On a similar note...

After years of unhappiness with my 'cheap' setup (DOD fet preamp + Moen amp sim/DI), I've bought a LR Baggs Para acoustic DI. This was on the recommendation of some TBers and a bunch of product reviews on line. Well there are some great features on it. The phase switch is EPIC. The EQ is nice. I can get a better sound than the old setup, however...

I'm still getting the scrapy/shuffly sound of my fingers sliding round on the strings and to be honest, it really sticking in my craw... to put it politely. Even with the treble wound all the way down, it's still scratchy as.

Is it the preamp or is it the pickup? I suspect it's the pickup. If so, how do I fix it? It seems to be wedged in tight enough, but am I missing something?

P.s. The arco sound is sublime, it's just pizz that is sounds scratchy...

What pickup are you using?

 

[reverendrally]

as per post, underwood.

I played with it last night after reading the Underwood site and lessened the tightness of the pickup in the bridge a little. This reduced some of the the scratchy noise, but there is still a lot of finger noise.

 

[Jake deVilliers]

as per post, underwood.

I played with it last night after reading the Underwood site and lessened the tightness of the pickup in the bridge a little. This reduced some of the the scratchy noise, but there is still a lot of finger noise.

Gotcha Rev. I hate to say it but they all do that - Underwood, K&K Bassmax, Revolution. The Realist to a lesser extent but all the bridge/wing pickups do pick up that finger contact noise.

I find that the Underwood/FDeck Pre combination minimizes the artifacts on both my wife's Kay and my Hybrid Roma...maybe because the lower frequencies are more present/fuller, the higher aren't as prominent? Its my favourite combination as far as pickups go, anyway.

 

[reverendrally]

I guess I'll just wind the presence and treble down on the preamp and live with it, but it is pretty annoying. It's much worse with a 10" speaker than a 15" too. Have to keep that in mind. I guess the balance of things is that those sorts of noises dissappear in a band situation with other instruments too.

I've sent Don Underwood an email with a question about it too, so I'll see what his insight on the subject is.

 

[Roger Davis]

Its my favourite combination as far as pickups go, anyway.

Yes, mine too. After I've recently gone through the pickup merry go round following a resonant open D jumping out at me on a new bass I've gone back to the Underwood and the D is no longer there. It must be a slightly better fit that did it. Anyway, I didn't really like the other pups. I'm sure our ears get attuned to our preferred pickup after so many years playing through it. So that's four basses and four Underwoods.

I use either an FDeck or a Fishman Pro eq, the budget version of the Plat and never have finger noise, even with the treble flat.

By the way, and re 10" speakers, I've belatedly come to try an Epifani UL110 and it's very very good. No mids to eq out and a solid bass. With Clarus, as usual.

 

[reverendrally]

No finger noise? really? I find that kinda hard to believe given that even my bass guitars with electromagnetic pickups transmit finger noise. So does my acoustic guitar with a piezo. It's not a matter of whether you have finger noise, but whether it sounds organic. With my guitar through the LR Baggs, it sounds organic. Not so for the upright.

 

[Roger Davis]

No finger noise? really? I find that kinda hard to believe given that even my bass guitars with electromagnetic pickups transmit finger noise. So does my acoustic guitar with a piezo. It's not a matter of whether you have finger noise, but whether it sounds organic. With my guitar through the LR Baggs, it sounds organic. Not so for the upright.

Oh, alright then. I've got a gig tonight and I'll have a good listen and let you know tomorrow. Probably my point is that the finger noise is not loud enough for me to notice.

 

[KUNGfuSHERIFF]

I've sent Don Underwood an email with a question about it too, so I'll see what his insight on the subject is.

Not to derail the thread, but I was under the impression that Don had retired from the company and his daughters were running it in his stead. They do business on eBay under the username "underloe" so there's a second avenue of contact.

Back on topic, I've had Underwoods on a DB and an EUB. Both quacked mightily, and as Jake said, that's life with piezo pickups. With the Underwood in particular, proper fit is critical to minimize quack and maximize tone. Using just one contact minimizes phase cancellation but then you have to deal with a live contact flopping around making noise. It's a pain in the butt.

In my experience a DI with 10 meg input impedence, such as the Countryman, will tame but not end the Underwood quack. A preamp/buffer such as the Fishman (which I own) or the fdeck (which I'd like to try) will further minimize quack but I've never heard a unit that will banish the quack entirely.

My solution was to ditch the Underwoods for a Rev Solo on the EUB and a Bass Max on the DBs. The RS is almost as touchy fit-wise as the Underwood but not quite, and has a fairly natural sound considering it's amplifying a fence post with strings. The Bass Max is not natural-sounding but is very sturdy and easy to use, and the sound is adequate for the music I play.

Personally, I don't see the point in going crazy over pickups when the sound tech, in most cases, is going to EQ you like he would an electric bass. Bass Max --> Countryman --> house system. Done. Time to get a beer.