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DIY Stompboxes => Building your own stompbox => Topic started by: Toy Sun on February 24, 2023, 09:27:47 PM

Title: Build a DC voltmeter into a pedal for seeing bias?
Post by: Toy Sun on February 24, 2023, 09:27:47 PM
Anyone ever try it? Sounds fun. Easy to get a cheapo voltmeter module from ebay...

Thanks,
John
Title: Re: Build a DC voltmeter into a pedal for seeing bias?
Post by: GibsonGM on February 25, 2023, 11:11:50 AM
I think many or most of us have looked at the bias of a pedal with a DMM...inserting one into your pedal should be very easy to do, if you wanted, tho it would probably just read that one value all the time, so it would be 'gimmicky'.   An exception might be if you did this with various fuzzes with a bias control, such as a Mosrite Fuzzrite, where changing bias IS a useful feature (tho usually just done by ear).    Try it out! :)   
Title: Re: Build a DC voltmeter into a pedal for seeing bias?
Post by: Rob Strand on February 25, 2023, 09:18:52 PM
The pot position already tells you the bias.   If you calibrated the extremes of the pot and labelled them the interior pot settings could be eyeballed from the pot position.  (All assumes the battery voltage is constant.)
Title: Re: Build a DC voltmeter into a pedal for seeing bias?
Post by: amptramp on February 26, 2023, 07:55:13 AM
I have always wanted to build a power amp in a valve cover of a car and use the oil filler cap hole as a place to mount an analog meter.  If you build one, you can be satisfied that no one else has one like it.  Cast aluminum valve covers make great heat sinks. And they are shielded.

I'm all in favour of adding a digital meter to a stompbox and a bias control is a great reason to do so.
Title: Re: Build a DC voltmeter into a pedal for seeing bias?
Post by: Gus on February 26, 2023, 09:02:08 AM
Some links from the past a fuzz with a meter

https://www.diystompboxes.com/smfforum/index.php?topic=10987.0 (https://www.diystompboxes.com/smfforum/index.php?topic=10987.0)

https://sounds.ampage.org/files/nitroburner_schem2.jpg (https://sounds.ampage.org/files/nitroburner_schem2.jpg)

https://sounds.ampage.org/files/nbitroburner30jpg.jpg (https://sounds.ampage.org/files/nbitroburner30jpg.jpg)
Title: Re: Build a DC voltmeter into a pedal for seeing bias?
Post by: Toy Sun on February 26, 2023, 02:10:05 PM
Thanks for the feedback and links. It's true, this is only something to consider where biasing really impacts the tone. And for sure, knob position will tell you where you are set (doh!).
Title: Re: Build a DC voltmeter into a pedal for seeing bias?
Post by: Phend on February 26, 2023, 05:25:44 PM
Go for an oscilloscope.
Title: Re: Build a DC voltmeter into a pedal for seeing bias?
Post by: Phend on February 26, 2023, 05:49:19 PM
Dug this up, have .., not a pedal, haven't built one but could be put in a Stomper .
Title: Re: Build a DC voltmeter into a pedal for seeing bias?
Post by: Rob Strand on February 26, 2023, 07:31:34 PM
I always thought Keith Emerson's setup was cool.

https://www.synthtopia.com/content/2014/04/25/moog-music-intros-new-emerson-modular-system/keith-emerson-modular-synthesizert02/
(https://www.synthtopia.com/wp-content/uploads/2014/04/keith-emerson-modular-synthesizert02.jpg)
Title: Re: Build a DC voltmeter into a pedal for seeing bias?
Post by: deadastronaut on February 27, 2023, 06:49:35 AM
phend: looks like he put a cheap DSO 150 scope in there....


how do i know?...i have one.  8)
Title: Re: Build a DC voltmeter into a pedal for seeing bias?
Post by: Phend on February 27, 2023, 07:41:59 AM
Actually the DSO 138 model. It has no enclosure like the 150. Just bare bones.
Had to make standoffs and special buttons. Cut the square hole in the face plate etc.
Cost $28.99 usd for the scope.

For $16.99 you can get 10 of these..
(https://i.postimg.cc/grVHWKBp/51-IBUAWUZm-L-AC-SX679.jpg) (https://postimg.cc/grVHWKBp)
Title: Re: Build a DC voltmeter into a pedal for seeing bias?
Post by: FiveseveN on February 27, 2023, 08:13:28 AM
My assumption was that you'd put the display in a temperature-sensitive (Ge) circuit so you can tweak it to some "optimal" value under different circumstances. And of course there may be more than one preferred value/range.
Here's a commercial example: https://www.silktone.org/store/p13/fuzz.html
Title: Re: Build a DC voltmeter into a pedal for seeing bias?
Post by: duck_arse on February 27, 2023, 08:55:19 AM
Quote from: Rob Strand on February 26, 2023, 07:31:34 PM
I always thought Keith Emerson's setup was cool.

https://www.synthtopia.com/content/2014/04/25/moog-music-intros-new-emerson-modular-system/keith-emerson-modular-synthesizert02/
(https://www.synthtopia.com/wp-content/uploads/2014/04/keith-emerson-modular-synthesizert02.jpg)

person on the left seems to think it's a theremin.


this digital voltmeter in a fuzz or similar idea - this would be a circuit with a multplexed display, spewing out digital noise left and right, wouldn't it?