Piezo - Mixing - EQ

[KenD]

This question is about using active EQ with individual piezo saddles for each string.

Sometime back a TBer (from Australia I recall) advised that, to enhance string definition and clarity, each saddle should run to the piezo preamp separately, rather than being summed first and then sent to the preamp. Thus, using something like this Richter piezo preamp:

RICHTER ELECTRONIC ENGINEERING

My question is - can the output of the piezo preamp then be run to an active EQ stack such as Richter, John East or similar? Are there contra-indications, incompatibilities, other problems that preclude that approach?

 

[dwizum]

Personally I don't really see a need to have an individual preamp or buffer channel for each string, unless you want to EQ or boost them individually, i.e. differently. There won't be an inherent difference in outcome otherwise.

But yes, in general, you can use the output from your piezo buffer as an input channel into an active preamp. If the piezo buffer output will be the only input into the second preamp then you're pretty much good to go - most piezo buffers have output impedances that are well within what most preamps will handle with good results.

The only real potential sticking point would be if you're going to also add a second channel to the second preamp, i.e. a magnetic pickup or something like that. You'd want that second channel to match whatever your piezo buffer was putting out. The easiest way to do this is to use two of the same buffer, one for each channel. Or use a buffer/preamp that's made for mixing two passive signals and forget the separate modules.

 

[KenD]

Personally I don't really see a need to have an individual preamp or buffer channel for each string, unless you want to EQ or boost them individually, i.e. differently. There won't be an inherent difference in outcome otherwise.

But yes, in general, you can use the output from your piezo buffer as an input channel into an active preamp. If the piezo buffer output will be the only input into the second preamp then you're pretty much good to go - most piezo buffers have output impedances that are well within what most preamps will handle with good results.

The only real potential sticking point would be if you're going to also add a second channel to the second preamp, i.e. a magnetic pickup or something like that. You'd want that second channel to match whatever your piezo buffer was putting out. The easiest way to do this is to use two of the same buffer, one for each channel. Or use a buffer/preamp that's made for mixing two passive signals and forget the separate modules.

Thanks for this. I don't have enough electronics knowledge to argue one way or the other. However, if there is no difference or advantage to be had between pre-summing vs. separate channels, why does a product like the Richter exist?

 

[abarson]

Thanks for this. I don't have enough electronics knowledge to argue one way or the other. However, if there is no difference or advantage to be had between pre-summing vs. separate channels, why does a product like the Richter exist?

There will always be someone who will obsess over something, and someone else to recognize a market for that obsession.

 

[KenD]

There will always be someone who will obsess over something, and someone else to recognize a market for that obsession.

The Richter unit does have individual volume control for each string (plus master output control) so that could be useful in achieving a balanced output.