susie_1987
Member
I would like to check out all the vref points on my pcb, but I don't know that the voltages are supposed to be. Thoughts on where I can find them?
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Where can I find reference voltages for the photon vibe?
- Thread starter susie_1987
- Start date
Mcknib
Well-known member
You can estimate voltages from the schematic power section fairly accurately
Every component in the path will drop some voltage you can consult the datasheets for fwd voltages etc for example a 1N5817 around 0.4v (check datasheet forward voltage) a L78L15 regulator as much as 2v (check datasheet dropout voltage)
As a starting point if you want to trace it through check what voltage your power supply puts out and check voltage drop for yourself if it puts out 9v for example once it goes through D2 it should be around 8.6v (with the voltage drop) going into IC4 then double that coming out of IC4 so 17.2v at your +18v point, then 17.2v into IC5 less drop through R29 regulating it to 15v but dropping a little voltage again so probably around 14v at IC5 output pin (VO) going into the top of R2 and again dropping a little v, the voltage goes along and is then equally divided in half at R2 and 3 the voltage divider junction (both being the same value 100K meaning an equal split or half getting dumped to ground the other half to power VREF) so 7v ish for your VREF and 17.2v for your +18v
If you look at the MAX1044 datasheet there are example circuits and some explanation of how they work, in this case as a voltage doubler but as you'll see it has many more uses
Because I'm lazy I reference this bookmarked post by @Chuck D. Bones around 6 comments down to help work out expected charge pump voltages
I'm the type that'll read something and forget what it said 10 seconds later so I'm an avid bookmarker, for referencing stuff my little brain can't absorb for very long
Incidentally I don't stand by my voltage predictions
Every component in the path will drop some voltage you can consult the datasheets for fwd voltages etc for example a 1N5817 around 0.4v (check datasheet forward voltage) a L78L15 regulator as much as 2v (check datasheet dropout voltage)
As a starting point if you want to trace it through check what voltage your power supply puts out and check voltage drop for yourself if it puts out 9v for example once it goes through D2 it should be around 8.6v (with the voltage drop) going into IC4 then double that coming out of IC4 so 17.2v at your +18v point, then 17.2v into IC5 less drop through R29 regulating it to 15v but dropping a little voltage again so probably around 14v at IC5 output pin (VO) going into the top of R2 and again dropping a little v, the voltage goes along and is then equally divided in half at R2 and 3 the voltage divider junction (both being the same value 100K meaning an equal split or half getting dumped to ground the other half to power VREF) so 7v ish for your VREF and 17.2v for your +18v
If you look at the MAX1044 datasheet there are example circuits and some explanation of how they work, in this case as a voltage doubler but as you'll see it has many more uses
Because I'm lazy I reference this bookmarked post by @Chuck D. Bones around 6 comments down to help work out expected charge pump voltages
Triangulum problem
I’ve just recently built the Triangulum build. It’s a working build but something sounds off. When I turn the level up to a decent level or about half way up I get a really bassy heavily saturated sound that starts to cut out and break apart when heavy power chords are hit. Like it’s being...
forum.pedalpcb.com
I'm the type that'll read something and forget what it said 10 seconds later so I'm an avid bookmarker, for referencing stuff my little brain can't absorb for very long
Incidentally I don't stand by my voltage predictions
Last edited:
susie_1987
Member
I have pretty exhaustively checked all the posts on the photon vibe. The lfo seems to be working, albeit not perfectly. I bought my tc1044scpa from small bear, yet in all my builds that use it (delegeate compressor as an example), there is a very pronounced whine. When I plug it in no effect is audible and the voltage regulator sections smells burnt. Perhaps my l78l15 is backwards? Also, the light completely dies sometimes when I turn all the potentiometers up as if there were a short. Signal goes through the pedal when it is engaged, though.
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