Can ShuttleMAX12 or Shuttle 3 accept ultra-high impedance piezo inputs?

**Ukiah Bass** · #1 07-13-2010, 05:57 PM

Does anyone know if a Genz Benz ShuttleMAX12 or a Shuttle 3.0 preamp will adequately handle a straight passive connection from a K&K Pure piezo-based pickup?

http://www.gollihurmusic.com/product...SS_GUITAR.html

I just bought the dual-pickup model for a Tacoma Thunderchief ABG and plan to use these instead of the stock saddle-based piezo pickup/Fishman Prefix Plus preamp. The K&K Pure can run as a passive connection, but has ultra-high impedance inputs (about 1 - 2 million+ ohms) that are typical for piezo transducers. Can those go straight to either Shuttle preamp without having to buy yet another specialized preamp or wire the pickups into the Fishman? The Shuttle manual mentions input impedance @ >500k ohms, but does not address ultra-high impedance inputs. (looking to get away from an onboard battery and getting better amplified sound.)

Thanks for any input!

KJung · #2 07-13-2010, 08:05 PM

You will need some sort of buffer like the Fishman, regardless of amp. I don't think there is any bass amp with an input impedance high enough to really deal with that and sound decent.

**Ukiah Bass** · #3 07-13-2010, 08:13 PM

One of the users who bought the pickup form Golihur posted on the page above that he successfully used the pickup passively with three different bass amps. Golihur claims that Acoustic Image Contra, Coda and Clarus, SWR California and Strawberry blonde, and some acoustic amps by Epiphone and Trace Elliot can handle the job directly.

Since I own them, I'm wondering if the ShuttleMAX12 and Shuttle 3.0 can handle piezos as passive input.

svtb15 · #4 07-13-2010, 08:22 PM

i dont know the input impedance of the shuttle... Piezios like to see high impedance so of at least a few meg ohm.. used my acoustic into a Demeter tube DI then into amp with XLR to 1/4 adapter and it was fine.. but the input if the Demeter is 10M nice and high.. I dont think the shuttle is that high. but agedhorse would know.

agedhorse · #5 07-13-2010, 08:24 PM

Yes, both amps can handle most passive piezo pickups depending on the specific characteristics of the pickup element in question. The impedance term is thrown around way too casually, it's not a single number but on preamp designs that address piezo pickups specifically, it is common for a compensatory term to be included which causes a slightly falling impedance as frequency increases to better match the pickup's characteristic impedance curve. So a nominal 1 meg input may in fact be >1meg at low frequencies and <1meg at higher frequencies smoothing the response spmewhat.

Try it, see how you like it. Generally, I would recommend piezo's with the LF extend engaged as there is a natural HPF with a piezo element already.

The 10meg number that is often batted about in marketing is somewhat misleading since the wire capacitance and RFI filtering alone will result in considerably less than 10meg at higher frequencies. It APPEARS to be 10meg until the external variables are factored in.

basss · #6 07-13-2010, 08:28 PM

My fishman FC equipped URB sounds fine straight into the shuttle 3.0. Occasionally I'll use a BII preamp (10 Mohm) but the difference is subtle enough that I often don't bother. From what I gather an amp's input impedance is only one part of the equation when dealing with piezos. Often it isn't as huge a factor as people make it out to be - although sometimes it does play an important role - depends on the amp.

svtb15 · #7 07-13-2010, 08:28 PM

Thank you for giving that info...
ya learn something new every day

Quote:

Originally Posted by agedhorse

Yes, both amps can handle most passive piezo pickups depending on the specific characteristics of the pickup element in question. The impedance term is thrown around way too casually, it's not a single number but on preamp designs that address piezo pickups specifically, it is common for a compensatory term to be included which causes a slightly falling impedance as frequency increases to better match the pickup's characteristic impedance curve. So a nominal 1 meg input may in fact be >1meg at low frequencies and <1meg at higher frequencies smoothing the response spmewhat.

Try it, see how you like it. Generally, I would recommend piezo's with the LF extend engaged as there is a natural HPF with a piezo element already.

The 10meg number that is often batted about in marketing is somewhat misleading since the wire capacitance and RFI filtering alone will result in considerably less than 10meg at higher frequencies. It APPEARS to be 10meg until the external variables are factored in.

KJung · #8 07-14-2010, 04:37 AM

Quote:

Originally Posted by Ukiah Bass

One of the users who bought the pickup form Golihur posted on the page above that he successfully used the pickup passively with three different bass amps. Golihur claims that Acoustic Image Contra, Coda and Clarus, SWR California and Strawberry blonde, and some acoustic amps by Epiphone and Trace Elliot can handle the job directly.

Since I own them, I'm wondering if the ShuttleMAX12 and Shuttle 3.0 can handle piezos as passive input.

A lot has to do with the specific pickup. However, even with a high impedance input (like on my old Walter Woods), I was never happy with the sound of a raw piezo. Yes, you can crank a lot of bass in the amp and cut a bunch of treble to make it work, but I never really found that pleasing. A simple little buffer device (like the Rob Allens use internally... the little Fishman pre with the treble cut) makes everything beautiful with any amp you want to use IMO.

I guess the good news for you is your 12/6 and 15/6 cabs don't extend high enough to really get into trouble with the super boosted top end of many piezo pickups, so if you can dial in enough low end, it might work.

**Ukiah Bass** · #9 07-14-2010, 08:10 AM

Quote:

Originally Posted by KJung

I guess the good news for you is your 12/6 and 15/6 cabs don't extend high enough to really get into trouble with the super boosted top end of many piezo pickups, so if you can dial in enough low end, it might work.

Ironically, I just picked up a Shuttle 3.0-8T to try out in small coffee shop type low-volume gigs. Will be interesting to see how the 8 inch driver/tweeter compares to the bigger cabs.

KJung · #10 07-14-2010, 08:40 AM

Quote:

Originally Posted by Ukiah Bass

Ironically, I just picked up a Shuttle 3.0-8T to try out in small coffee shop type low-volume gigs. Will be interesting to see how the 8 inch driver/tweeter compares to the bigger cabs.

Well, no comment there

Nice head, but a single 8 is not my idea of a good time at any volume.