Double Bass Using FDeck's HPF-Pre for an electric cello?

[bopeuph]

Hey guys,

Been a while. I have a question for a theory of mine. I sent fdeck an email with the question, but I figured while I wait for his response, I'd ask the question here.

I've been interested in getting my hands on an electric cello. A local luthier has a hollow body one where the electronics don't work, so he's ready to have it taken off of his hands cheap. I really am interested in a solid body one, but with the cost of this one, I can't turn it down.

I've been extremely happy with the HPF-Pre combined with my Underwood, and because these Chinese instruments have very poor electronics, I figured what fdeck has would make a great replacement. The only pic of the instrument in question that I could find is attached so you can see it. These instruments have a strip of piezo that goes under the bridge, kind of like the Realist, but it's one single strip across both feet rather than two.

I'm not very knowledgeable in electronics, but I assume if I had just the board of the Series 1, I could solder the wire from the pickup onto the input jack solder point, and connect the output, pot, and phase switch to a backplate via wiring.

Has anyone had any experience with his piece like this for an internal installation? Any suggestions?

This experiment would be a good trial for when I eventually get a solid body instrument. I intend to find another one where the electronics don't work, grab it up cheap, and do something similar.

 

[Ric Vice]

I've been interested in getting my hands on an electric cello. A local luthier has a hollow body one where the electronics don't work, so he's ready to have it taken off of his hands cheap. I really am interested in a solid body one, but with the cost of this one, I can't turn it down.

I've been extremely happy with the HPF-Pre combined with my Underwood, and because these Chinese instruments have very poor electronics, I figured what fdeck has would make a great replacement. The only pic of the instrument in question that I could find is attached so you can see it. These instruments have a strip of piezo that goes under the bridge, kind of like the Realist, but it's one single strip across both feet rather than two.

I have all three Versions of the HPF, and they work really well inline between an instrument and amplifier. It does boost the signal coming of the pickup by 2 db, so it gives you a little increase, but I think he did that to offset the loss you get by inserting the device into the signal chain.

I'm not very knowledgeable in electronics, but I assume if I had just the board of the Series 1, I could solder the wire from the pickup onto the input jack solder point, and connect the output, pot, and phase switch to a backplate via wiring.

You'd have to talk to Francis about this. He designed the box to be a standalone unit, and there may be things about the design that would not work as an internal pre amp.

This experiment would be a good trial for when I eventually get a solid body instrument. I intend to find another one where the electronics don't work, grab it up cheap, and do something similar.

DYI projects are interesting, but some of mine have gotten more expensive than I'd planned. I'd suggest borrowing someones graphic EQ to see what things need to be addressed, rather than going right to the FDeck. If you have to replace the pickup and change out the pre amp, it may not be worth the money. It would give you control over low frequency feedback and set the input impedance higher, but in the final analysis, a rose by any other name is still a rose. Cellos tend to be very different beasts than Double Basses. Their care and feeding is quite different.

Ric

 

[DoubleMIDI]

Depending on the room you have for electronics inside the cello, I would think either connect the piezo directly to the output jack (if there is not much room) or build one of the simpler impedance buffers of FDeck yourself (I used the "quick 'n' dirty", which is quick, but not dirty, just missing the high pass filter of the HPFpre). You should have room for a 9V battery and a one or two cm2 for the few parts needed. If you have two pots for volume and tone at the cello and more room, you might want to build a HPFpre yourself to fit it in your instrument. Probably needs a lot of time, but a regular board from Francis might not fit into your space together with the battery.

BTW, an impedance buffer even makes the piezo signal from a violin sound better, so it should do even more than that to your cello.
The high pass filter should do the job for your cello, even if the frequency range is not the optimum for cello. I thnk it would be nice to have it, but the impedance buffer is more important, I think. Simply connecting the piezo to the output jack, you have all options, but a box more.
Do not connect a volume pot on the input sode of the impedance buffer, all pots only on the output side of the buffer. Passive piezo connection to output jack -> do not connect any internal pots!

BTW, you might have a better sounding signal without these chinese electronics inside...

 

[bopeuph]

Holy jeez, why didn't I think of that!? I could just run the piezo to an output jack on the back of the instrument, and then use the HPF-Pre I already own! If I don't like it, I could just find another separate preamp! Simpler, cheaper, and awesome! And since I have no electrical knowledge, I'd have to pay someone to come up with many of these ideas, and like Ric said, that could get expensive.

If I did do this, I wouldn't bother with a volume knob. In my experience (maybe it's because of my Fender passive basses), the sound is always the best when the volume on the bass is all the way up, and I adjust the volume on the amp.

Either way, since this instrument is a hollow body, there's lots of room to install something to it.

Whenever I do get a solid body, I am wanting to also add a magnetic pickup, most likely creating it with a p-bass style pickup to be able to follow the contour of the bridge easier. This would make it easier to have a preamp made that could allow me to mix signals the way I want to.

 

[bopeuph]

Thanks for the input, guys. That has really made me more excited about the whole deal.