Great video as always. I especially loved the sound of cello. So much improvement! The ukulele turned out a bit midcentric although I am not a musician to know how it's supposed to sound. The best part for me is how cheap this instrument is. I can make it with parts from my drawer and OPA1642 is 2 euro. Of course mine will not be as fancy as yours. I'll probably put it in a tin can. It reminds me of a band called Carmen from the 70s that stood out with their meaty bass. They recorded people dancing on wooden floor with piezo pickups. It had so much oumph!
Great result, the cello sounded incredible with mixed mics. Have you experimented with bipolar-input op amps? Someone, may have been Richard Mudhar, did a similar buffer design, and ended up with lower THD with a bipolar opamp, I think an ne5534? than he was getting with a TL072, granted, the TL072 is a dinosaur with high noise, but the point he was making was that the piezo's output impedance, while high compared to something like an ECM capsule with a built-in FET, is still much lower than the types of things FET-input opamps are often used for.
Thanks for your kind words. The OPA1642 is an outstanding Audio Opamp. Better specs than the 5532 and TL072. To make this one work with phantom power, we need a low quiescent current, which this one has. The two mics use it as well. I have the identical circuit with a 1Gig resistor. I presented this at the last AES convention in NY. The THD and noise are 40db better than a FET based microphone. Figur/www.instructables.com/OPA-Based-Alice-Microphones-a-Cardioid-and-a-Figur/
@@SoundSleuth With the performance that you are getting from your mics, it makes me wonder if it's possible to make a competent measurement microphone. I use a cheap measuring mic that has high THD and noise. Good enough for room correction, but you can't measure nonlinearities of drivers. Loudspeakers simply have lower and lower distortion every year. Joseph Crowe recently made a comparison of distortion in microphones and in a practical test a simple ribbon tweeter outperformed the mics. The stand out model was Shure SM57. For it's price it actually outperformed the small diaphragm mics at around -80dB THD. The only model that did reveal the tweeter's response completely was Aco Pacific that competes with Bruel & Kjaer, so quite expensive!
@@SoundSleuthcould do a compound amplifier setup, OPA for the audio quality then opamp of choice for the other specs/design characteristics you need. Plenty of resources online about this but basically you have the feedback from the 2nd amp tied into the input of the OPA
Can I make a viewer request? There's no MS decoder boxes on the market any more, and the schematics aren't layman enough for someone like me to build one myself. You can now pick up pretty inexpensive fig8 electret mics, so it seems like it'd make for an interesting project if you'd have any interest taking it up.
it is all in here: www.instructables.com/Hi-Z-Opamp-Piezo-Buffer/ specifically here: prospeakerparts.com/products/steel-project-box-4-1-2-x-1-7-8-x-1-5-8-pre-punched-for-2-d-series-xlrs
Hello, Greetings from India. I tried purchasing the P48 Buffer but the shipping charges are soo high, I am unable to afford it, What should I do in this case?
@@joaosidonio7562 The level isnt high enough. The current drive is there. You can use the same opamp to drive headphones. I will write that one up separately.
That cello sounds amazing ❤
Did you mention what ohm resistance/impedance the box output is?
Output impedance is about 50ohms
@@SoundSleuth oh is that all, most of those piezo disk pick ups like K&K and JJB recommend a minimum of 1M ohm
@@clintwhite3021 input impedance is 1Meg. OUTPUT impedance is 50 ohms
@@SoundSleuth oops yep I originally mentioned to ask the input (not output) impedance haha
Ok cool thanks ☺️
Great video as always. I especially loved the sound of cello. So much improvement! The ukulele turned out a bit midcentric although I am not a musician to know how it's supposed to sound.
The best part for me is how cheap this instrument is. I can make it with parts from my drawer and OPA1642 is 2 euro. Of course mine will not be as fancy as yours. I'll probably put it in a tin can.
It reminds me of a band called Carmen from the 70s that stood out with their meaty bass. They recorded people dancing on wooden floor with piezo pickups. It had so much oumph!
My son has played live gigs with his Cello. The sound guys (and his band) love how comes out in the PA
Great result, the cello sounded incredible with mixed mics. Have you experimented with bipolar-input op amps? Someone, may have been Richard Mudhar, did a similar buffer design, and ended up with lower THD with a bipolar opamp, I think an ne5534? than he was getting with a TL072, granted, the TL072 is a dinosaur with high noise, but the point he was making was that the piezo's output impedance, while high compared to something like an ECM capsule with a built-in FET, is still much lower than the types of things FET-input opamps are often used for.
Thanks for your kind words. The OPA1642 is an outstanding Audio Opamp. Better specs than the 5532 and TL072. To make this one work with phantom power, we need a low quiescent current, which this one has. The two mics use it as well. I have the identical circuit with a 1Gig resistor. I presented this at the last AES convention in NY. The THD and noise are 40db better than a FET based microphone. Figur/www.instructables.com/OPA-Based-Alice-Microphones-a-Cardioid-and-a-Figur/
@@SoundSleuth With the performance that you are getting from your mics, it makes me wonder if it's possible to make a competent measurement microphone. I use a cheap measuring mic that has high THD and noise. Good enough for room correction, but you can't measure nonlinearities of drivers. Loudspeakers simply have lower and lower distortion every year. Joseph Crowe recently made a comparison of distortion in microphones and in a practical test a simple ribbon tweeter outperformed the mics. The stand out model was Shure SM57. For it's price it actually outperformed the small diaphragm mics at around -80dB THD. The only model that did reveal the tweeter's response completely was Aco Pacific that competes with Bruel & Kjaer, so quite expensive!
@@SoundSleuthcould do a compound amplifier setup, OPA for the audio quality then opamp of choice for the other specs/design characteristics you need. Plenty of resources online about this but basically you have the feedback from the 2nd amp tied into the input of the OPA
Can I make a viewer request?
There's no MS decoder boxes on the market any more, and the schematics aren't layman enough for someone like me to build one myself. You can now pick up pretty inexpensive fig8 electret mics, so it seems like it'd make for an interesting project if you'd have any interest taking it up.
Err. portable decoder boxes. Every option are giant rack mount versions.
This is mine from many moons ago. paia.com/msdecwork/
@Kai Paquin reach out to me via ryckebusch@gmail.com.
@@SoundSleuth Will do! Thank you!
Where did you get the box?
it is all in here: www.instructables.com/Hi-Z-Opamp-Piezo-Buffer/ specifically here: prospeakerparts.com/products/steel-project-box-4-1-2-x-1-7-8-x-1-5-8-pre-punched-for-2-d-series-xlrs
Hello, Greetings from India. I tried purchasing the P48 Buffer but the shipping charges are soo high, I am unable to afford it, What should I do in this case?
You can get the unpopulated PCB form PCBWay and build it your self. www.pcbway.com/project/shareproject/OPAAlice_Piezo_Mini_6c8eb529.html
Interesting, what is the effect alone from the piezo with high z without a microphone?
You can hear the Cello with the Piezo only, the microphones only, and then a mix of both in the video.
@@SoundSleuth How does it compare with standard piezo pre-amp circuit?
@@joaosidonio7562 it is better than standard FET discrete circuits both lower noise, and lower distortion
@@SoundSleuth can it drive a headphone? or can we attach a low impedance out for headphones?
@@joaosidonio7562 The level isnt high enough. The current drive is there. You can use the same opamp to drive headphones. I will write that one up separately.