AI Synthesis PSU questions

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wendallsan
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AI Synthesis PSU questions

Post by wendallsan » Mon Feb 10, 2020 10:49 pm

Hi all, I built a small fleet of AI Synthesis PSU's, in hopes that I could install them in small-ish cases and use them as internal power supplies. I have installed 2 of these into 2 168hp cases, and am seeing problems that I'm guessing are due to them not pumping out enough power.

One case is 702 mA +12V | 231 mA -12V | 41 mA 5V (I was planning to pick up A MU Volts to supply this 5V power)

The other case is 827 mA +12V | 706 mA -12V.

Should one of these PSU's be able to supply power to this much consumption? I'm finding that if I plug just one or two in, there is no problem, but when I connect them all up, the oscillators stop oscillating ... I looked at the AI Synthesis website and didn't find much in the build instructions about what could be expected for output.

Many thanks for any advice! :sb:
Last edited by wendallsan on Tue Feb 11, 2020 10:20 am, edited 1 time in total.
Student at Evergreen State College's "Advanced Electronics In Music" for the 2019-2020 school year. Built a Roland System 700 clone out of Pharmasonic PCB's. Currently building a DJ Thomas White Quad Lowpass Gate, MMI Modular Two Five Nine, and a Barton Bytewise Operator + Expander.

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Re: AI Synthesis PSU questions

Post by infinitemachinery » Mon Feb 10, 2020 10:57 pm

Reading the information for this PSU, it looks like the output is dependent on the output of the wall wart you use. They recommend 500 to 1000ma.

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Re: AI Synthesis PSU questions

Post by abelovesfun » Tue Feb 11, 2020 9:00 am

And the regulators. You can always reach me at my contact page.
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Re: AI Synthesis PSU questions

Post by wendallsan » Tue Feb 11, 2020 10:27 am

Hi all (and Abel! your modules rock), thanks for the replies.

I purchased the wall wart that was recommended for the job in the BOM, which is 1000mA. How does this shake out to positive and negative voltage? Will the wall wart supply 1000mA at +12V and -12V, or is it something less than that, maybe half goes to positive and half goes to negative so I should expect more like 500mA to each rail? Also, if these setups are likely to be 'permanent installations' is there a recommended overhead for a PSU vs its modules-- for example is it recommended do use only 75% of the suggested max amperage, etc?

If I do want to use this power supply with these cases, is there such a thing as a larger amperage wall wart that would supply the amps I'm looking for?

Many thanks! I feel like I might learn a thing or two about power supplies thanks to this thread! :sb:
Student at Evergreen State College's "Advanced Electronics In Music" for the 2019-2020 school year. Built a Roland System 700 clone out of Pharmasonic PCB's. Currently building a DJ Thomas White Quad Lowpass Gate, MMI Modular Two Five Nine, and a Barton Bytewise Operator + Expander.

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Re: AI Synthesis PSU questions

Post by Agawell » Tue Feb 11, 2020 11:46 am

if they are anything like the frequency central psus & I suspect they are almost identical then:

a 1A wall wart will show up as 500mA +ve and 500 mA -ve

a good rule of thumb is to use 80% to allow for a bit of on-rush - so each psu should be good for about 400mA of both +ve and -ve

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Re: AI Synthesis PSU questions

Post by wendallsan » Tue Feb 11, 2020 12:15 pm

Many thanks Agawell!

This gives me some numbers to work with. My highest amperage in these cases is ~825 mA, so 825 x 1.2 (to allow for a 20% overhead) x 2 = ~1980mA . I took a quick look on Amazon but didn't find any 2A AC-to-AC adaptors, which is probably the minimum of what I would need to make this work.

This also begs the question of how much amperage can one of these power supplies reliably take? I assume at some point things will get hot? I ask this BEFORE I try to plug 15A into it!
:deadbanana:
Student at Evergreen State College's "Advanced Electronics In Music" for the 2019-2020 school year. Built a Roland System 700 clone out of Pharmasonic PCB's. Currently building a DJ Thomas White Quad Lowpass Gate, MMI Modular Two Five Nine, and a Barton Bytewise Operator + Expander.

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Re: AI Synthesis PSU questions

Post by EATyourGUITAR » Tue Feb 11, 2020 12:47 pm

I could be doing it wrong but I calculated you need a 15vac or 18vac transformer with a minimum of 24VA (volt amps). the mains side should match the mains voltage for your country. if you can not find the part in a wall wart then you should definitely buy a real chassis mounted transformer. I suggest triad magnetics since they are cheap in stock modern compact transformers. obviously you should have a grounded metal chassis for the transformer but I have to say it just in case you don't know the rule.
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Re: AI Synthesis PSU questions

Post by wendallsan » Tue Feb 11, 2020 2:58 pm

How about this?

https://www.mouser.com/ProductDetail/Tr ... BBNwfIs%3D

Looks like 2000mA rather than the 1000mA that I have currently ...

I do see this warning:
***For Industrial and Commercial Use Only***


I apparently can only make industrial or commercial music with it??!! :goo:

Also, I'm not sure if pumping more amps into the PSU will damage it, can anyone speculate whether pairing this wall wart with it will be problematic?
Student at Evergreen State College's "Advanced Electronics In Music" for the 2019-2020 school year. Built a Roland System 700 clone out of Pharmasonic PCB's. Currently building a DJ Thomas White Quad Lowpass Gate, MMI Modular Two Five Nine, and a Barton Bytewise Operator + Expander.

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Re: AI Synthesis PSU questions

Post by joem » Tue Feb 11, 2020 5:40 pm

wendallsan wrote:
Tue Feb 11, 2020 2:58 pm
Also, I'm not sure if pumping more amps into the PSU will damage it, can anyone speculate whether pairing this wall wart with it will be problematic?
You don't really pump amps in. It's better to think of it as a circuit draws amps out. So if you hook up a 15A supply to the AI PSU, and then only hook up 1 module to the PSU, you won't have any more amps going anywhere than when you have a 1A supply hooked up to the same PSU and same module, since the circuit just draws the amperage that it needs, and no more. So the supply itself isn't the issue. The issue is the current being drawn from the supply.

I read somewhere about the Frequency Central Power (which has an almost identical design to the AI one electrically) that drawing more than 600 or 700mA on from either rail would result in the regulators getting pretty hot and that you'd at least need bigger heat sinks. Since the AI one doesn't have heat sinks (well, it uses the board as a heat sink), I'm not sure it'd be a good idea. At least put bend the regulators up from the board and put some big heat sinks on them.

I'm not an expert on this, though, so hopefully someone else (Abe?) can clarify.

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Re: AI Synthesis PSU questions

Post by Graham Hinton » Tue Feb 11, 2020 6:02 pm

wendallsan wrote:
Tue Feb 11, 2020 2:58 pm
Also, I'm not sure if pumping more amps into the PSU will damage it, can anyone speculate whether pairing this wall wart with it will be problematic?
It will be problematic and that is a certainty, not speculation.

You are being misled by everyone on this thread who are all ignoring the basic rules of physics. You cannot get more power out of a system than you put in. The wallwart mentioned is a transformer with a 12Vac 1000mA output (assuming your mains is exactly 120Vac, otherwise it is proportional). These are AC voltage and current, not DC, which may be multiplied together to give the VA rating = 12VA. This is the absolute maximum wattage available if the voltage and current are in phase, which may not be the case with inductive components. Linear voltage regulators are about 50% efficient because although the AC is continuous if used to power, say, a lightbulb the way it is rectified results in it only conducting for a fraction of the mains cycle. That leaves 6W available for BOTH outputs or 3W each. That is 250mA tops. Furthermore a 7800/7900 regulator won't deliver that without a heatsink. Heatsinks only work if they can radiate the heat out of the case as fast as it is generated, the heat doesn't just magically sink into them and disappear.

You have been sold a pig in a poke or, as they say in Germany, a cat in a bag.

DIY PSU kits are a big con. The blind leading the blind. Monkey see, monkey do. Anybody can get pcbs made these days, it doesn't mean they know what they are doing. Obviously.

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Re: AI Synthesis PSU questions

Post by abelovesfun » Tue Feb 11, 2020 10:02 pm

joem wrote:
Tue Feb 11, 2020 5:40 pm
wendallsan wrote:
Tue Feb 11, 2020 2:58 pm
Also, I'm not sure if pumping more amps into the PSU will damage it, can anyone speculate whether pairing this wall wart with it will be problematic?
You don't really pump amps in. It's better to think of it as a circuit draws amps out. So if you hook up a 15A supply to the AI PSU, and then only hook up 1 module to the PSU, you won't have any more amps going anywhere than when you have a 1A supply hooked up to the same PSU and same module, since the circuit just draws the amperage that it needs, and no more. So the supply itself isn't the issue. The issue is the current being drawn from the supply.

I read somewhere about the Frequency Central Power (which has an almost identical design to the AI one electrically) that drawing more than 600 or 700mA on from either rail would result in the regulators getting pretty hot and that you'd at least need bigger heat sinks. Since the AI one doesn't have heat sinks (well, it uses the board as a heat sink), I'm not sure it'd be a good idea. At least put bend the regulators up from the board and put some big heat sinks on them.

I'm not an expert on this, though, so hopefully someone else (Abe?) can clarify.
I've already offered assistance via email earlier in the thread and via pm.
Super Easy, Awesome DIY kits @ http://www.aisynthesis.com
modular ambient and composery music @ http://www.forcedamage.com/
https://www.facebook.com/forcedamagemusic

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Re: AI Synthesis PSU questions

Post by wendallsan » Wed Feb 12, 2020 5:44 pm

Hi all,

AI Synthesis has followed up with me directly and has answered all my questions about their PSU. They confirmed that the module provides up to 1000mA, and won't be able to provide more by feeding it more amps from a differently rated power supply, etc. They also explained that digital modules consume much more power than 'classic' analog modules, and many of these draw extra power on startup, so there may even be problems with them with certain power supplies if things are close. My project includes both digital modules AND amerage draws greater than what this PSU provides, so as some have already suggested, physics wins again.

:miley:

I want to thank Abel/AI Synthesis for their support and helpful response, and point out that I missed these details in the product description on their site, so they are not misleading customers or 'blindly leading other blind', I simply failed to read or understand this when I bought the product. This PSU, along with all the other AI Synthesis modules I've built to date, has been a VERY easy build and has works just fine (plus I think everyone needs a Matrix Mixer).

Thanks to everyone for your input on this and for your time and expertise. I want to be clear that I would much rather ask what others may seem as 'really dumb' questions here rather than learn the hard way and ruin potentially thousands of dollars worth of modules and hundreds of hours in build time. To me, that is MUCH less intelligent than looking like a fool to strangers on the internet.

:sb:
Student at Evergreen State College's "Advanced Electronics In Music" for the 2019-2020 school year. Built a Roland System 700 clone out of Pharmasonic PCB's. Currently building a DJ Thomas White Quad Lowpass Gate, MMI Modular Two Five Nine, and a Barton Bytewise Operator + Expander.

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Re: AI Synthesis PSU questions

Post by SyndieBot2000XL » Fri Feb 14, 2020 8:32 pm

For the record I’d be happy to buy a cat in a bag - though I imagine the cat may not like it very much :cat2:
It began as a mistake.

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Re: AI Synthesis PSU questions

Post by Graham Hinton » Sun Feb 16, 2020 9:11 am

wendallsan wrote:
Wed Feb 12, 2020 5:44 pm
They confirmed that the module provides up to 1000mA
That circuit is incapable of supplying 1000mA anyway you want to massage the figures.

SyndieBot2000XL wrote:For the record I’d be happy to buy a cat in a bag
When you've just paid a higher price for and were expecting a piglet? Just the sort of customer kit suppliers thrive on.

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Re: AI Synthesis PSU questions

Post by EATyourGUITAR » Sun Feb 16, 2020 11:05 am

https://aisynthesis.com/wp-content/uplo ... llwort.pdf

this is not what I thought it was. disregard my previous comments about transformer specifications. I agree with Mr Hinton that you won't get to heaven without heatsinks. probably more like 600mA per rail per power supply. buy 4 of these if you like it so much.

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Re: AI Synthesis PSU questions

Post by Bartimaeus » Sun Feb 16, 2020 1:18 pm

If you have a "small fleet", why not just install two PSUs in each case instead of one? You'll need a couple extra wall warts but surely that isn't too big an issue? Like when people use multiple uZEUS modules in a big case.

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Re: AI Synthesis PSU questions

Post by EATyourGUITAR » Mon Feb 17, 2020 7:22 am

Bartimaeus wrote:
Sun Feb 16, 2020 1:18 pm
You'll need a couple extra wall warts
or one big one
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Re: AI Synthesis PSU questions

Post by wendallsan » Mon Feb 17, 2020 11:51 am

Hi all,

I've done exactly what was suggested and set up one case to be powered by two of these PSU's, which is working great. The other case has some real power hogs in it, so even two of these PSU's would be pushing things, so I've opted to pick up a different power supply for that one (arriving tomorrow). I'm saving the last 2 PSU's in hopes that they'll work out well for the Pharmasonic 717 sequencers when they come out, as I have plans to build two of those, and we'll see what kind of power they consume once they arrive.

:sb:
Student at Evergreen State College's "Advanced Electronics In Music" for the 2019-2020 school year. Built a Roland System 700 clone out of Pharmasonic PCB's. Currently building a DJ Thomas White Quad Lowpass Gate, MMI Modular Two Five Nine, and a Barton Bytewise Operator + Expander.

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