Overspill?

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Re: Overspill?

Postby japi » Mon Dec 01, 2008 1:20 am

dmitri wrote:Btw, you did try to lower gain levels, didn't you?


I have lowered gain to 0, helped a little but I think i'm still loosing dinamic range
Thanks for the schema, i'll be making some test in a few days
A trimpot is ok ?
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Re: Overspill?

Postby gastric » Tue Dec 02, 2008 3:16 pm

Does MegaDrum have a known good range for the piezo output.

If so, are we able to easily measure our raw pad output with a multimeter?

If so, then I'd think we could compute what type of resistor to solder into the piezo output to reduce the output to match MegaDrum's known good range.

That would seem to be a little more systematic and we could do that prior to even connecting the pad to the MegaDrum.
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Re: Overspill?

Postby dmitri » Tue Dec 02, 2008 3:38 pm

It's not just about a piezo. It's a combination of a piezo, a type of a pad and materials used. And the number of these combinations is countless.
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Re: Overspill?

Postby japi » Tue Dec 02, 2008 3:39 pm

Dmitri, would a trimpot work ok for my needs?
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Re: Overspill?

Postby dmitri » Tue Dec 02, 2008 3:43 pm

japi wrote:Dmitri, would a trimpot work ok for my needs?

Of course. This is exactly how Yamaha does with its pads.
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Re: Overspill?

Postby japi » Tue Dec 02, 2008 3:54 pm

Thanks!
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Re: Overspill?

Postby gastric » Tue Dec 02, 2008 4:14 pm

dmitri wrote:It's not just about a piezo. It's a combination of a piezo, a type of a pad and materials used. And the number of these combinations is countless.


So I hook alligator clips to the end of my TRS cable prior to plugging it into the MegaDrum, hit the pad, and I'm measuring the output from the completed pad.
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Re: Overspill?

Postby dmitri » Tue Dec 02, 2008 4:33 pm

gastric wrote:
dmitri wrote:It's not just about a piezo. It's a combination of a piezo, a type of a pad and materials used. And the number of these combinations is countless.


So I hook alligator clips to the end of my TRS cable prior to plugging it into the MegaDrum, hit the pad, and I'm measuring the output from the completed pad.

Connect a 4k7 resistor in parallel with clips to simulate MegaDrum input impedance. Then ideally the strongest hits should not produce voltage peaks above ~4.5v.
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Re: Overspill?

Postby japi » Sat Dec 06, 2008 3:35 am

gastric wrote:If so, are we able to easily measure our raw pad output with a multimeter?
That would seem to be a little more systematic and we could do that prior to even connecting the pad to the MegaDrum.

Dmitri, does the highlevel works as a reference for sensitivity?
I have soldered a trimpot, and set it to 80k. Now with gain set at 0, I get a maximum high level of ~550 when hitting hard on the pad. Is that number ok or should I lower more? My trimpot goes up to 200k.
My pad has much more dynamic range now, but I wait for your comments to see if it can be improved further.
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Re: Overspill?

Postby dmitri » Sat Dec 06, 2008 12:26 pm

japi wrote:
gastric wrote:If so, are we able to easily measure our raw pad output with a multimeter?
That would seem to be a little more systematic and we could do that prior to even connecting the pad to the MegaDrum.

Dmitri, does the highlevel works as a reference for sensitivity?
I have soldered a trimpot, and set it to 80k. Now with gain set at 0, I get a maximum high level of ~550 when hitting hard on the pad. Is that number ok or should I lower more? My trimpot goes up to 200k.
My pad has much more dynamic range now, but I wait for your comments to see if it can be improved further.

The bigger difference between Threshold and HighLevel the better. 550 is alright.
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