Can't find the Voltage Regulator I need. Will this work?

Ok, you got your soldering iron and nothing is going to hold you back, but you have no clue where to start or what to build. There were others before you with the same questions... read them first.
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digitalzombie
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Post by digitalzombie »

I'm trying to build a Tremulus Lune from commonsound/4ms, and the parts list calls for a 7809 voltage regulator. From the pictures it looks like one of those half cylinder transistors with the three pins in a triangle form. Problem is on Mouser the only 7809 available is one of the straight line box-type so I'm not sure it's the right one.
http://www.mouser.com/ProductDetail/Fai ... SDKcvkU%3d

I'm doing some of my part sourcing on Pedal Parts Plus, and the only Voltage Regulator they carry is a MC78LO5ACP
http://www.pedalpartsplus.com/mm5/merch ... de=voltreg

Of course I can't seem to find data on it, or what I would even be looking for. I'm just trying to do this as a build-by-numbers, so if someone could help me out that'd be amazing.


*EDIT*! I just found a thread on the commonsound forum where the designer mentioned it also goes by the name 78L09, so I looked that up on Mouser and found it in the right case. So, mods if you want to delete this thread or keep it up for the future cunfuzzled like myself then it's up to you.

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diagrammatiks
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Post by diagrammatiks »

the 78l09 is a 500ma part and the 7809 is a 1A part.

either will work.

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scoop
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Post by scoop »

But do you really need a voltage regulator if you're using a 9v battery or standard 9v adaptor?

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Zokk
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Post by Zokk »

scoop wrote:But do you really need a voltage regulator if you're using a 9v battery or standard 9v adaptor?
+1
a clean 9V psu or battery will do the job perfectly.

moreover your regulator won't have enough voltage to work correctly, unless you feed it with at least 12V. If you have a cheap wallwart you can measure its output voltage on load to have a idea.

I would suggest to forget about this 7809 and simply increase the psu filtering capacitor to 220uF or more and add a simple polarity protection diode. But 220uF is enough and works perfect in my builds without the 7809.

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scoop
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Post by scoop »

Ok yeah, so I bet the 9v regulator in 4ms builds are there so that the euro rack versions run off the same build instructions as the pedal versions.

Since I already have 9v regulators lying around, do you suppose I might be able to build a klon centaur? I figure the klon uses icl7660 to get 18v out of a 9v source. Mojo aside, would ths be the same as using a 7809 to get 9v out of an 18v source?




Also, Good luck with the tremulous lune build digitalzombie! A friend of mine made one, the wave shapes are sweet "symmetry" was much cooler than "fine" but there's some way to get both those knobs I'm not sure.

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Post by Zokk »

Beware, if you run the LM7809 with 18V on input it will be very hot, the best would be a 12V input, or use some efficient heat sink.
If you have already a synth psu with +/-15V it's also possible to feed the LM7809 with the +15V, but think about heatsink anyway.

Voltage regulators and charge pumps are not really the same... look at the datasheets.

Concerning the two pots (symmetry & fine) yep both can be wired. Look at the wiring diagrams for the "stock" perfboard version and simply add the symmetry mod. That's what I've done already. But symmetry is way more interesting than fine (but some may find useful to be able to tune the LFO perfectly to be in sync with the beat).

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digitalzombie
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Post by digitalzombie »

scoop wrote:But do you really need a voltage regulator if you're using a 9v battery or standard 9v adaptor?
After watching a tutorial on voltage regulators, I gotta say I don't really see the point of it either...
Zokk wrote: I would suggest to forget about this 7809 and simply increase the psu filtering capacitor to 220uF or more and add a simple polarity protection diode. But 220uF is enough and works perfect in my builds without the 7809.
All I know is, people have made working builds based on the given directions, and I'm not confident enough in my own circuit building prowess to muck about with someone else's design. Can you suggest what I can look up to better understand what you're talking about and how it works?

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Post by Zokk »

To my limited knowledge, in this circuit a voltage regulator would have three purposes:
1/ isolate the circuit from other if they are connected to the same psu (it would implies a voltage drop for the Tremulus in this case) in order to reduce noise
2/ protect the circuit from voltage overload
3/ as said by Scoop, it could allow the use of a synth psu for the eurorack version

So if you already have a clean isolated 9V psu you won't need it anyway cause your 9V will be already clean and filtered. I can tell you that even with a not isolated psu the circuit is dead silent (but I used a 220uF cap on the power rail).

Oh, and I just think about something important: LM7809 and the 78L09 have not the same pinout!!! so a LM7809 conversion will be tricky.
Here is the right mouser ref for the part recommended by 4ms:
http://fr.mouser.com/ProductDetail/ON-S ... A0OsQ6sb6d

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digitalzombie
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Post by digitalzombie »

Thanks. I ended up just ordering the components from 4ms as well as the board. I thought sourcing the parts myself would save me a ton of cash, but it only ended up being $10 savings. At least I learned a good thing or two about part sourcing.

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