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A Simple To Build Power Meter  

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Speaker Builder
(@speaker-builder)
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Joined: 3 months ago
Posts: 251
30/05/2019 1:36 pm  

Here is the schematic for a very easy to build power meter.  None of the parts are especially critical, but you do have to adjust a bit based on amplifier power.

Simple VU Meter

Build two for stereo (obviously).

For R2 you need to select a value that gives you at least full scale deflection of the meter at your amplifier's maximum output. 33k should work for most amplifiers.

For C1 you need to pick a voltage rating above the maximum voltage your amplifier feeds to your speakers, 1uf at 50 Volts is good enough for up to about 150 watts.

VR1 is used to calibrate the meter. Run your amp up to the edge of clipping and set the meter to read +3 VU.

M1 can be any 100ua panel meter that strikes your fancy with a VU marked scale.

Also note this is one of the very few VU meter designs that will work with the BTL outputs on most chip amps.

 


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NizzyAmps
(@gregniznik)
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Joined: 6 months ago
Posts: 5
30/05/2019 3:36 pm  

Thanks

Nice simple design. 

Can this be calibrated to wattage, or is it simply for a relative VU scale?

 


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Speaker Builder
(@speaker-builder)
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Joined: 3 months ago
Posts: 251
30/05/2019 7:40 pm  

The needle's movement is linear by voltage.

For wattage your meter would need a logarithmic wattage scale... similar to what you would see on a McIntosh amp.

image


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123Toid
(@123toid)
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Joined: 2 years ago
Posts: 550
01/06/2019 12:16 am  

Very nice build!  I like this alot!  I may just have to use this sometime. Thanks for the share


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Speaker Builder
(@speaker-builder)
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Joined: 3 months ago
Posts: 251
01/06/2019 8:11 pm  

Heh, heh ... Go for it!


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