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Need help not wasting money - need amp for upright with piezo

#23
@Billgore Does your Avenson DI have a "thru" out to run directly to an amp? If so, you may have what you need already.

I don't even have close to an exhaustive knowledge of amp specs, but many of the newer class D amps made today have higher, piezo-friendly input impedances. I have been enjoying running my Yamahiko-equipped DB into my Genzler amps and haven't had any problems. There are many amps that do have an impedance that is too low for piezos. Those will benefit from some kind of preamp to provide the necessary input impedance. Again, the DI on your tailpiece may already suffice for that.

As @jmlee mentioned before, the FDeck HPF preamps are quite handy. I keep one in my bag just in case I need an HPF, or in those rare instances I am plugging into an amp other than my own. Francis Deck @fdeck is a member on Talkbass!
 
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#24
Scott Lynch said:
@Billgore Does your Avenson DI have a "thru" out to run directly to an amp? If so, you may have what you need already.

I don't even have close to an exhaustive knowledge of amp specs, but many of the newer class D amps made today have higher, piezo-friendly input impedances. I have been enjoying running my Yamahiko-equipped DB into my Genzler amps and haven't had any problems. There are many amps that do have an impedance that is too low for piezos. Those will benefit from some kind of preamp to provide the necessary input impedance. Again, the DI on your tailpiece may already suffice for that.

As @jmlee mentioned before, the FDeck HPF preamps are quite handy. I keep one in my bag just in case I need an HPF, or in those rare instances I am plugging into an amp other than my own. Francis Deck @fdeck is a member on Talkbass!
Click to expand...
Most DI's thru outputs are NOT buffered, therefore that solution won't work.
 
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#26
Personally I've had great results with the Tech21 Q\Strip preamp. The input is piezo friendly, it has an HPF (although not adjustable), a parametric EQ, 1/4" and XLR outs, works on phantom power or 9V, pads, etc. A real do-it-all box.

Both types of piezos I've used on upright had some nasty frequencies that needed to be removed. A para EQ is a must IMO.
 
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#27
Scott Lynch said:
@agedhorse I was not aware of that, thank you for the information! In that case a buffered preamp makes sense as a viable solution.
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Only if the pickup really requires over 1Meg load, or the input impedance is significantly lower than 1Meg.
 
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#28
jmlee said:
My Full Circle pickup runs initially into one of Fdeck's HPFs which have a nominal 10 Mohm input impedance, and from there the signal runs into whatever I want to use for amplification—or sometimes just what's on hand somewhere.
Click to expand...

I also use an fdeck with my Walter Woods or any provided backline amp, I get the impedance matching and the HPF helps control feedback.

The Acoustic Image combo amps are great, but they do not get really loud. Fine for jazz, bluegrass and other gigs where stage volume is not crazy loud. I've used AI in a 5-piece country band with steel, electric piano and drums and it kept up fine. They are expensive new (over $1000) but used ones show up for $500 and below pretty often.
 
#30
I've been quite happy with the sound of piezos on my uprights (Full Circle on my current bass, Realist Lifeline on my previous one) going straight into either a Markbass CMD-121P combo or my older Genz-Benz Shuttle 6.2 head. Back when I used an Underwood pickup it sounded better with a higher impedance input, so I used a Fdeck preamp.
 
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#32
This...

20221216_093638.jpg

:)
 
#34
oren said:
I've been quite happy with the sound of piezos on my uprights (Full Circle on my current bass, Realist Lifeline on my previous one) going straight into either a Markbass CMD-121P combo or my older Genz-Benz Shuttle 6.2 head. Back when I used an Underwood pickup it sounded better with a higher impedance input, so I used a Fdeck preamp.
Click to expand...
Yes, the early Underwood pickups were often used with amps having an input impedance of less than 1Meg, so a buffer was beneficial. Since the crystals are quite small inside the brass wings, there was a lot of benefit to buffering with those amps.

Since many amps these days are 1Meg or greater, there is much less benefit to a higher input impedance, and there is significant drawbacks with regard to noise (cable and circuit) as well as RF interference (especially close to RF sources such as radio transmitters).

I was working on pro audio and acoustic products (specifically active direct boxes and pick-up systems for acoustic instruments) around the time that the Underwood pickups became popular, Don's mechanical design was the first practical design for bass guitars (also used on cellos and even viola/violin) because it was easy to install. They did suffer from a lot of broken crystals because players couldn't follow the installation and handling instructions though. Underwood was another San Francisco Bay Area company that pushed the industry forward, this was a great (and fun) time to be working in audio. The fact that they are still relatively popular is a testament to the quality of the basic design.
 
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#35
agedhorse said:
Yes, the early Underwood pickups were often used with amps having an input impedance of less than 1Meg, so a buffer was beneficial. Since the crystals are quite small inside the brass wings, there was a lot of benefit to buffering with those amps.

Since many amps these days are 1Meg or greater, there is much less benefit to a higher input impedance, and there is significant drawbacks with regard to noise (cable and circuit) as well as RF interference (especially close to RF sources such as radio transmitters).

I was working on pro audio and acoustic products (specifically active direct boxes and pick-up systems for acoustic instruments) around the time that the Underwood pickups became popular, Don's mechanical design was the first practical design for bass guitars (also used on cellos and even viola/violin) because it was easy to install. They did suffer from a lot of broken crystals because players couldn't follow the installation and handling instructions though. Underwood was another San Francisco Bay Area company that pushed the industry forward, this was a great (and fun) time to be working in audio. The fact that they are still relatively popular is a testament to the quality of the basic design.
Click to expand...
I bought my Underwood back in the early 80's. That is what I use straight into my WD 800 today. I did have a harsh sound with it at first, but Don's daughter, Belinda suggested I flip one of the wings180 and it help it a lot.

:)
 
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#36
DJ Bebop said:
I bought my Underwood back in the early 80's. That is what I use straight into my WD 800 today. I did have a harsh sound with it at first, but Don's daughter, Belinda suggested I flip one of the wings180 and it help it a lot.

:)
Click to expand...
Yup, there are a lot of tricks to these pickups, and there's a whole lot more to it than impedance. It's much easier and takes less effort top guess, which is why blaming impedance for unrelated challenges is so popular.

I'm glad to see that the company is still family owned, Don was always a good guy to work with.
 
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#38
DJ Bebop said:
I bought my Underwood back in the early 80's. That is what I use straight into my WD 800 today. I did have a harsh sound with it at first, but Don's daughter, Belinda suggested I flip one of the wings180 and it help it a lot.

:)
Click to expand...

DjBebop care to explain? Do you mean just taking one element and installing it the other way (so the cable is closer to the middle of the bridge) or flipping it over the other way? Thinking about this has me worrying about breaking the wire.
 
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#39
Brad_Pearson said:
DjBebop care to explain? Do you mean just taking one element and installing it the other way (so the cable is closer to the middle of the bridge) or flipping it over the other way? Thinking about this has me worrying about breaking the wire.
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Not the best pic and some card stock in the way before I did my wood shims...

20230103_091115.jpg


I remember Balinda saying to try this only if you are not getting a fuller sound after a normal install as some units shipped with the elements out of phase.

Also trying to reverse the side/order you put them on the bridge. The opposite way of the original instructions. Again only if you are not getting a good sound already.

Mine never sounded good at first, always nasally, even through a preamp. Switched it around and boom, that was it!
 
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