DIY Sig Gen/Amp unit for Chladni patterns

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pat foster
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Re: DIY Sig Gen/Amp unit for Chladni patterns

Post by pat foster » Wed Aug 09, 2017 5:15 am

Very slick! Much more elegant than the old stereo reciver/laptop setup.

For my speaker, I hang it from a spring so that it gets pulled down to use.

Pat

yakka
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Re: DIY Sig Gen/Amp unit for Chladni patterns

Post by yakka » Thu Aug 17, 2017 5:04 pm

i down loaded a signal generator app to my phone and bluetooth it to a speaker my son uses and it seems to work well, NOT MY IDEA saw it on facebook. am i missing something.
regards
yakka

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Trevor Gore
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Re: DIY Sig Gen/Amp unit for Chladni patterns

Post by Trevor Gore » Thu Aug 17, 2017 5:53 pm

Been there, done that. Tried a phone as well as an iPad and a PC, wired link and Bluetooth link. Yes, we made all of those work, but the usability for demonstration/teaching purposes was not what I wanted, and it was after trying the PC/iPhone/iPad/Bluetooth idea that I decided to build the unit in this thread.

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Re: DIY Sig Gen/Amp unit for Chladni patterns

Post by dsutherland » Wed Jul 27, 2022 5:47 pm

Hi Trevor,
I had a good read of this article and it was very interesting and I even imagined I might be able to replicate your design but unfortunately it is way outside of my skillset.

On the note of people blowing their speakers I was wondering if you think this Griffin signal generator with amplifier will work? I have purchased the same speaker you have.

https://www.fishersci.co.uk/shop/produc ... r/13119180

I made my first 5 guitars under Darrell Wheeler before setting up my own workshop. Now on number 12 and looking to get more measurable results with methods in the first book.

Kind regards,
Dave
I wish this was my full time job!

CURRENT BUILDING STATUS: 14 acoustics (8 completed, 2 at spray stage), 6 ukes (3 completed, 3 at spray stage), 3 electrics (1 completed, 1 at spray stage)

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Trevor Gore
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Re: DIY Sig Gen/Amp unit for Chladni patterns

Post by Trevor Gore » Thu Jul 28, 2022 7:59 am

dsutherland wrote:
Wed Jul 27, 2022 5:47 pm
On the note of people blowing their speakers I was wondering if you think this Griffin signal generator with amplifier will work?
Hard to say, Dave. The specs just say sig gen and amplifier. A bit like saying car with engine. See if you can get more detail out of Griffin, such as frequency range and RMS output power.

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Re: DIY Sig Gen/Amp unit for Chladni patterns

Post by dsutherland » Fri Jul 29, 2022 3:09 pm

Hi Trevor,

Thanks so much for getting back to me.

I was able to find the following:

Signal Generator and Amplifier
IPC-4885-W
Introduction.
The IPC-4885-W is designed for use in the study of A.C. Circuits, Amplification
and General Electronics. Its uses include driving a Loudspeaker or Vibration
Generator as well as many other electronic based experiments.
Signal Generator Mode.
The IPC-4885-W can be set to provide Sine, Square or Triangle output
waveforms using the three-position ‘Waveform’ switch.
The output frequency ranges from 0.1Hz to 100kHz and is adjusted using both
the six-position ‘Range Hz’ switch and the multi-turn rotary ‘Frequency’ control.
The actual output frequency is continuously monitored and shown on the LED
Display.
The output amplitude of the waveform ranges from zero to a maximum of 10V
peak to peak using the rotary ‘Gain’ control.
The output signal can be taken between either the 4Ω or 600Ω white (4mm)
sockets and the common green (4mm) socket. The 600Ω signal output can be
attenuated by a factor of x1, x0.1 or x0.01 using the three-position ‘Attenuator’
switch. Note: the common green (4mm) socket is connected to the case earth
of the unit.
The maximum output signal power is 4W (rms) into a 4Ω load (using the 4Ω
output socket) and will drive loudspeakers or other low impedance devices of
4Ω to 15Ω.
Amplifier Mode.
The IPC-4885-W can also be used as a stand-alone Amplifier with a Voltage
Gain (Av) ranging from zero to 100 (+40dB) via the rotary ‘Gain’ control and a
frequency response of 1Hz to 100kHz (-3dB bandwidth). Note: the Amplifier
has an input impedance of 1MΩ and a maximum input voltage of 200mV peak
to peak (irrespective of the Gain setting).
To operate the IPC-4885-W in the Amplifier Mode simply turn the ‘Waveform’
switch to the -- position, confirmation of this mode will be indicated by the
LED Display showing 1 on the left-hand digit.
The amplifier’s input signal is connected between the blue (4mm) socket and
the common green (4mm) socket, while the output signal can be taken
between either the 4Ω or 600Ω white (4mm) sockets and the common green
(4mm) socket. Note: the amplifier output has all the same parameters and
functions as the Signal Generator Mode, as detailed above.


Really appreciate any feedback you have.

Hopefully this works otherwise back to the drawing board for my setup.

Thanks again,
Dave
I wish this was my full time job!

CURRENT BUILDING STATUS: 14 acoustics (8 completed, 2 at spray stage), 6 ukes (3 completed, 3 at spray stage), 3 electrics (1 completed, 1 at spray stage)

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Trevor Gore
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Re: DIY Sig Gen/Amp unit for Chladni patterns

Post by Trevor Gore » Sat Jul 30, 2022 11:00 am

With only 4 W RMS power, I don't think that's enough (c.f. 30 W RMS on the unit I built). You can probably get away with 15 W RMS. Modifying this unit for more power would require a new power supply and power amp module, or putting the output through a cheap stereo amp (e.g. like this or this).

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Re: DIY Sig Gen/Amp unit for Chladni patterns

Post by dsutherland » Mon Aug 01, 2022 4:49 pm

Thanks for getting back to me Trevor. Shame the unit won't work. Back to the drawing board
I wish this was my full time job!

CURRENT BUILDING STATUS: 14 acoustics (8 completed, 2 at spray stage), 6 ukes (3 completed, 3 at spray stage), 3 electrics (1 completed, 1 at spray stage)

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Re: DIY Sig Gen/Amp unit for Chladni patterns

Post by kiwigeo » Tue Aug 02, 2022 9:18 am

Ive got a Bradley unit with a 50 watt amp. I've found I need to have it turned up fairly high to get decent Chladni patterns with some tops.
Martin

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