How to create 12V power from the 15V source in an MU rig?

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Dave Peck
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How to create 12V power from the 15V source in an MU rig?

Post by Dave Peck » Fri May 10, 2019 3:33 pm

I'm going to re-panel a Rossum Morpheus filter Euro module and install it in my MU/5U modular. I'm checking with the manufacturer to see if the module can be powered from the +15/-15V DC power system that is already in my modular, but in case it cannot, I'll need to find a simple cheap way to provide the required +12/-12V DC.

I could buy a dedicated 12V power supply like this:
https://www.mouser.com/ProductDetail/ME ... aFMw%3D%3D

... and use a simple modified ribbon cable to connect it to the module, but I'm wondering if folks here have already dealt with this and come up with a better way to provide 12V power for just one or two Euro modules in a MU / 15V system?

Does someone offer a cheap & simple 15VDC to 12VDC regulator board for a couple of bucks? I would prefer not to MAKE a circuit, I would rather just throw a few bucks at the problem.

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Re: How to create 12V power from the 15V source in an MU rig

Post by diophantine » Fri May 10, 2019 3:41 pm

Dave Peck wrote:Does someone offer a cheap & simple 15VDC to 12VDC regulator board for a couple of bucks?
Yup! https://oshpark.com/shared_projects/IMyjiSay

I use one to power a row of Euro (Klee + two Livewire modules) in my Frac system.

I should have a couple extra boards; if I find one tonight, it's yours - I'll PM you.

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Re: How to create 12V power from the 15V source in an MU rig

Post by dslocum » Fri May 10, 2019 3:47 pm

Define "A couple of bucks". :miley:

A couple years ago I made myself a MU to Euro power board that I could use on my test bench setup. It has 7812 / 7912 regulators and a few DOTCOM and Euro16 connectors. Working well for me. Let me know if you'd like a bare board.

Otherwise, I'd be open to designing / offering something for the Muffs community as a group buy.
Dave Peck wrote:I'm going to re-panel a Rossum Morpheus filter Euro module and install it in my MU/5U modular. I'm checking with the manufacturer to see if the module can be powered from the +15/-15V DC power system that is already in my modular, but in case it cannot, I'll need to find a simple cheap way to provide the required +12/-12V DC.

I could buy a dedicated 12V power supply like this:
https://www.mouser.com/ProductDetail/ME ... aFMw%3D%3D

... and use a simple modified ribbon cable to connect it to the module, but I'm wondering if folks here have already dealt with this and come up with a better way to provide 12V power for just one or two Euro modules in a MU / 15V system?

Does someone offer a cheap & simple 15VDC to 12VDC regulator board for a couple of bucks? I would prefer not to MAKE a circuit, I would rather just throw a few bucks at the problem.
Doug Slocum
Synthetic Sound Labs
www.steamsynth.com
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"...this whole thing was started by a dream and a mouse." - Walt Disney
"Flatulence sounds aren't just for brass and reed instruments anymore, thanks in large part to Dr Moog." - Ockeghem

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Post by dslocum » Fri May 10, 2019 3:54 pm

Here's a quick photo:

Image
Doug Slocum
Synthetic Sound Labs
www.steamsynth.com
------------
"I guess all the Forest Mims Radio Shack books I read finally paid off!"
"I ordered twice as many _______ as I thought I'd need, only to find out that I'm still less than half way to having enough."
"...this whole thing was started by a dream and a mouse." - Walt Disney
"Flatulence sounds aren't just for brass and reed instruments anymore, thanks in large part to Dr Moog." - Ockeghem

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Post by sduck » Fri May 10, 2019 9:08 pm

I'm glad Doug's solution and that oshpark thing exist now! Back a few years ago when I was doing a lot of euro conversions those didn't exist, and I would build up a converter on protoboard for each. It's not a big deal to do so, but not something you'd bother with if there was a readily available solution.
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Post by Dave Peck » Fri May 10, 2019 9:16 pm

update - member diophantine is sending a board to me. Thanks!! :nana:

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Re: How to create 12V power from the 15V source in an MU rig

Post by Rex Coil 7 » Mon May 13, 2019 9:01 am

8-)
Last edited by Rex Coil 7 on Tue May 14, 2019 12:38 pm, edited 1 time in total.
5U MODULAR NORMALIZING PROJECT (for your entertainment) viewtopic.php?t=78836&highlight=
.. given the choice between conformity and self respect, I choose the latter.
.. dominion - noun: control or the exercise of control .. power .. possessed and controlled domain .. sovereignty .. having dominion over the world .. supreme authority .. absolute ownership .. power .. authority .. jurisdiction .. control .. command .. power. (Websters).

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Post by Synthbuilder » Mon May 13, 2019 9:08 am

dslocum wrote: Image
I like that you've used a vintage 1976 Fairchild 7912 to ensure your Euro module doesn't sound too modern. :hihi:

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Post by Rex Coil 7 » Mon May 13, 2019 9:19 am

8-)
Last edited by Rex Coil 7 on Tue May 14, 2019 12:38 pm, edited 1 time in total.
5U MODULAR NORMALIZING PROJECT (for your entertainment) viewtopic.php?t=78836&highlight=
.. given the choice between conformity and self respect, I choose the latter.
.. dominion - noun: control or the exercise of control .. power .. possessed and controlled domain .. sovereignty .. having dominion over the world .. supreme authority .. absolute ownership .. power .. authority .. jurisdiction .. control .. command .. power. (Websters).

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Post by josaka » Mon May 13, 2019 12:28 pm

think a board like this would have a lot of takers.. more euro ports though..

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Post by beautyofdecay_ » Thu May 16, 2019 6:49 am

I have been using the Trace Power TMR 3-1222 DC-DC converter with succes.
Input 9-18V DC, output +12V and -12V DC @125mA max.

https://power.sager.com/tmr3-1222-3982838.html

Just 1 component...

Just make sure the DC-DC converter's max output current is high enough for your application.

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Post by dslocum » Thu May 16, 2019 7:19 am

Ha... Yeah I wasn't able to get a vacuum tube regulator in the correct values! :hihi:
Synthbuilder wrote:
dslocum wrote: Image
I like that you've used a vintage 1976 Fairchild 7912 to ensure your Euro module doesn't sound too modern. :hihi:
Doug Slocum
Synthetic Sound Labs
www.steamsynth.com
------------
"I guess all the Forest Mims Radio Shack books I read finally paid off!"
"I ordered twice as many _______ as I thought I'd need, only to find out that I'm still less than half way to having enough."
"...this whole thing was started by a dream and a mouse." - Walt Disney
"Flatulence sounds aren't just for brass and reed instruments anymore, thanks in large part to Dr Moog." - Ockeghem

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Post by megaohm » Thu May 16, 2019 11:29 am

All of these reg boards omit the diodes.
Not sure if that is a good idea. Some data sheets discuss this and others don't.
Because of that I have many 78xx data sheets from a variety of manufacturers.
All together they form a clear picture?
The LM340/LM78xx Series , National Semiconductor July 2006 page 11 does the best job discussing these diodes.
They are for protection in case of a fault.

From what I understand, there should be a diode (1N400x) connected anode to reg output and cathode to reg input. This prevents the regulator's output from being higher than the input.

A second diode should be connected cathode to reg output, anode to 0V.
This will shunt negative voltages to ground.

I found a link to that same datasheet except by TI (page 13 and 16).
http://www.ti.com/lit/ds/symlink/lm340.pdf
www.MegaOhmAudio.com

Will work for pistachios

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Post by megaohm » Thu May 16, 2019 11:36 am

NOTE!!!!!!!!!!!!!!!!!!!
For the negative regulator you need to reverse the diode connections I described above.
www.MegaOhmAudio.com

Will work for pistachios

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Post by Dave Peck » Thu May 16, 2019 1:15 pm

beautyofdecay_ wrote:I have been using the Trace Power TMR 3-1222 DC-DC converter with succes.
Input 9-18V DC, output +12V and -12V DC @125mA max.

https://power.sager.com/tmr3-1222-3982838.html

Just 1 component...

Just make sure the DC-DC converter's max output current is high enough for your application.
Those types of DC-DC converter modules would be a good choice for most euro modules and that's what I had originally thought of using. Just stick one on the back side of each euro module to convert power for each module separately.

Unfortunately the Morpheus draws 135 ma @ +12V. And there aren't many of these converter modules that offer that much 12V current from a 15V source. And those that do cost more than a small AC-DC power supply that can power several modules.

But if I had been doing this for something other than a Morpheus this is probably what I would have used.

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Post by dslocum » Thu May 16, 2019 1:31 pm

The general idea that I come away from on this is that the INPUT cap on the 78xx regulator must be significantly greater than the output cap.

That way, when the system powers down, there will always (hopefully) be a more positive voltage on the INPUT side than the load (output) side.

The diode across the input to output in these examples helps "dump" the charge back to the input, rather than thru the 78xx regulator, which wasn't designed for this sort of thing.
megaohm wrote:All of these reg boards omit the diodes.
Not sure if that is a good idea. Some data sheets discuss this and others don't.
Because of that I have many 78xx data sheets from a variety of manufacturers.
All together they form a clear picture?
The LM340/LM78xx Series , National Semiconductor July 2006 page 11 does the best job discussing these diodes.
They are for protection in case of a fault.

From what I understand, there should be a diode (1N400x) connected anode to reg output and cathode to reg input. This prevents the regulator's output from being higher than the input.

A second diode should be connected cathode to reg output, anode to 0V.
This will shunt negative voltages to ground.

I found a link to that same datasheet except by TI (page 13 and 16).
http://www.ti.com/lit/ds/symlink/lm340.pdf
Doug Slocum
Synthetic Sound Labs
www.steamsynth.com
------------
"I guess all the Forest Mims Radio Shack books I read finally paid off!"
"I ordered twice as many _______ as I thought I'd need, only to find out that I'm still less than half way to having enough."
"...this whole thing was started by a dream and a mouse." - Walt Disney
"Flatulence sounds aren't just for brass and reed instruments anymore, thanks in large part to Dr Moog." - Ockeghem

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Post by megaohm » Thu May 16, 2019 6:59 pm

That is smart!
Didn't think of that.
But the diode may still be a good idea in this app because we can't predict with certainty what capacitance the output side will see since it depends on cap choice used in the euro module.

But in circuits that use regs for ref voltages that idea should work perfectly.
Should save a diode and the pcb space it takes up.
Thanks for sharing that/pointing that out!
:tu:

dslocum wrote:The general idea that I come away from on this is that the INPUT cap on the 78xx regulator must be significantly greater than the output cap.

That way, when the system powers down, there will always (hopefully) be a more positive voltage on the INPUT side than the load (output) side.

The diode across the input to output in these examples helps "dump" the charge back to the input, rather than thru the 78xx regulator, which wasn't designed for this sort of thing.
megaohm wrote:All of these reg boards omit the diodes.
Not sure if that is a good idea. Some data sheets discuss this and others don't.
Because of that I have many 78xx data sheets from a variety of manufacturers.
All together they form a clear picture?
The LM340/LM78xx Series , National Semiconductor July 2006 page 11 does the best job discussing these diodes.
They are for protection in case of a fault.

From what I understand, there should be a diode (1N400x) connected anode to reg output and cathode to reg input. This prevents the regulator's output from being higher than the input.

A second diode should be connected cathode to reg output, anode to 0V.
This will shunt negative voltages to ground.

I found a link to that same datasheet except by TI (page 13 and 16).
http://www.ti.com/lit/ds/symlink/lm340.pdf
www.MegaOhmAudio.com

Will work for pistachios

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Post by Synthbuilder » Fri May 17, 2019 3:17 am

I have found some benefit in using 1N5819 Schottky diodes as the shunt reverse polarity protection diodes. Some devices, infamously with the V2164 but less well known are op-amps like the TI version of the LT1013, will go into serious meltdown without those diodes if one of the power rails goes missing.

The ones across the regulators can be 1N400X still.

Tony

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Post by dslocum » Sat May 18, 2019 6:18 pm

Guys,

Hope this helps...

I have two of these PCBs. I'll send them FREE if you pay for postage. PM for details.
dslocum wrote:Here's a quick photo:

Image
Doug Slocum
Synthetic Sound Labs
www.steamsynth.com
------------
"I guess all the Forest Mims Radio Shack books I read finally paid off!"
"I ordered twice as many _______ as I thought I'd need, only to find out that I'm still less than half way to having enough."
"...this whole thing was started by a dream and a mouse." - Walt Disney
"Flatulence sounds aren't just for brass and reed instruments anymore, thanks in large part to Dr Moog." - Ockeghem

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Post by Dave Peck » Sat May 18, 2019 7:48 pm

dslocum wrote:Guys,

Hope this helps...

I have two of these PCBs. I'll send them FREE if you pay for postage. PM for details.
Hi Doug, If this offer was pertaining to me, thanks very much! But I have already received the 'Oshpark' 15V to 12V DC/DC regulator board that was mentioned earlier in the thread, sent to me along with some of the parts from wiggler Diophantine. The rest of the parts are already ordered from Mouser and will be here Monday. Looks like I'm set but thank you for the offer!

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Post by dslocum » Mon May 20, 2019 2:48 pm

Dave Peck wrote:
dslocum wrote:Guys,

Hope this helps...

I have two of these PCBs. I'll send them FREE if you pay for postage. PM for details.
Hi Doug, If this offer was pertaining to me, thanks very much! But I have already received the 'Oshpark' 15V to 12V DC/DC regulator board that was mentioned earlier in the thread, sent to me along with some of the parts from wiggler Diophantine. The rest of the parts are already ordered from Mouser and will be here Monday. Looks like I'm set but thank you for the offer!
Dave / All,

It was a general offering for any and all Muffs. 8-)
Doug Slocum
Synthetic Sound Labs
www.steamsynth.com
------------
"I guess all the Forest Mims Radio Shack books I read finally paid off!"
"I ordered twice as many _______ as I thought I'd need, only to find out that I'm still less than half way to having enough."
"...this whole thing was started by a dream and a mouse." - Walt Disney
"Flatulence sounds aren't just for brass and reed instruments anymore, thanks in large part to Dr Moog." - Ockeghem

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Post by Dave Peck » Mon May 20, 2019 5:04 pm

Update - 12V power adapter is completed and is up and running, the Morpheus Module tests OK in the system.

Now I just need to order the new MU adapter panel from Front Panel Express and install it. I just heard back from the guys at Rossum with some instructions for properly wiring the connectors & grounding the module.



Image

Image

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Post by Dave Peck » Wed May 29, 2019 7:01 pm

Update - it's finished! Works great. I love this filter!



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Image

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