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Double Bass Input Impedance for Polytone MinBrute III?

kjazz1958

kjazz1958

Mar 22, 2004
10
2
#1
I have an '84 Polytone MiniBrute III (15") and I am planning to use a Fishman Full Circle pickup. I've read that some amps require a preamp for best sound, but have been unable to find the specs for the input impedance on the amp. Gollihur did not know. I read somewhere that a minimum of 1 Mohm and optimally closer to 5 Mohms is best with this particular pickup.

Does anyone know?
 
#2
That information is probably forever lost to time. Fishman sets the input impedance on their Platinum Pro and Pro Stage Preamps at 10 Meg Ohms.
From their manual "Input impedance: 10M Ohms" When the Polytone's were designed, the most common pickup was an Underwood which would
sound ok at 1 Meg Ohm. As you probably know, the Polytone Pickup wasn't a piezo, so I could be wrong but my guess is that the inputs on a Polytone will need a Buffer Preamp like the FDeck HPF Preamp or RedEye pre from FireEye Development . Just my take however.
 
#4
A Mini Brute isn't really an ideal way to get a MBOL effect. Even with a preamp. But what they can do is provide a great tone that fills a room with warm tone and sounds great, particularly with jazz piano trios. I've often found that my bass sound is very satisfying plugged into mine without using a preamp. The simple EQ the Polytones feature can do a lot to temper the typical quack that comes with using a pizeo pickup without a preamp. Perhaps while listening to the amp while right next to it the sound is anything but MBOL but to hear it in a room with a band can be very nice! I wouldn't be afraid to just bring your bass and a cable if you have a Mini Brute. I don't get to use mine very often because the places I most often play in have backline but when I have the opportunity I have been favouring it's use instead of my AI Clarus with Conta EX speaker. It just sounds good!
 
#5
I appreciate everyone's response! When I get my bass back from some setup work, I will give it a whirl. I've been enjoying the Polytone with my fretless '69 Jazz bass. I rather like the voice it has, and I've used many other rigs over the years for smaller clubs and venues. If it's a total disaster (but I agree with Mike Carr that it will not be), I'll dig out my old Underwood! It's in a drawer along with at least 3 other pickups I've tried over the last 35 years. All seem to have some trade-offs to me. Like all things, the variables are many and include your actual bass, playing style, the room, the mood you are in, and the alignment of the moon and stars.
 
#6
kjazz1958 said:
I appreciate everyone's response! When I get my bass back from some setup work, I will give it a whirl. I've been enjoying the Polytone with my fretless '69 Jazz bass. I rather like the voice it has, and I've used many other rigs over the years for smaller clubs and venues. If it's a total disaster (but I agree with Mike Carr that it will not be), I'll dig out my old Underwood! It's in a drawer along with at least 3 other pickups I've tried over the last 35 years. All seem to have some trade-offs to me. Like all things, the variables are many and include your actual bass, playing style, the room, the mood you are in, and the alignment of the moon and stars.
Click to expand...
I really like my sound when I use my Underwood with my Mini Brute!
 
#7
If you plug your Full Circle straight in to the Polytone and feel fully satisfied with the response, it could be smart to quit while you're ahead.
My ears always get the final say over any spec sheet or internet gossip.
That said, 19 times out of 20, my ears tell me my DB piezos sound best with the HPF-Pre inserted.
 

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