Bench Power Supply thoughts

[analogtodd]

Ok,
So I'm about to do a BUNCH of work on my MCI 500 channel strips, and I figured the quickest way to do what I need to do is, have a jig made up on my workbench to test them.

So, I need some:
+/- 32v
+/- 15v
+5v
+24v

Whats the best approach? Should I get some Acopian Linear Power Supplies and put together what I need? Without spending 1k anybody have any better ideas?

[tINY]

Do you have a spare power supply for your board?



-tINY

[David Kulka]

The original MCI 500 power supply was humongous with a huge current rating, you wouldn't want to use that for bench testing! One little slip up and you'd have a fire on your hands.

With so many voltages there's no way to do it that's both elegant and easy.

If budget allows, the best way would be a combination of bench supplies with all the right voltages. You could switch them all on and off with a power strip. Bench supplies will have overload limiting and current protection. More importantly, they will probably have current meters for each voltage output which, once you become accustomed to the modules, will quickly let you know if anything is drawing too much or too little current. Another advantage is that if you have a shorted module, you can reduce certain supplies and safely service it at safe voltages without frying anything.

Another choice would be a random of new / used power supplies that include all the right voltages. It will look messy and won't give you nearly as much control as the bench supplies, but it would work.

You could build the whole thing from scratch, but it seems like a lot of work. With bench or new/used supplies, you could use them for something else after the project is done.

Save a lot of mental energy and time for the test harness itself. You'll need to include the insert, logic signals, group signals, etc. This is sort of fun design work, but it takes time. You might consider a rotary switch, to allow easy listening and monitoring of the buss, direct, send, L/R mix, etc.

[tINY]

Too bad nobody makes lunch boxes for those....



-tINY

[analogtodd]

Yeah, the power supplies are MONSTEROUS!

Looks like bench power supplies have gotten fairly cheap, I just didn't want to have to buy 3 dual supplies just to get the job done, but maybe...

I've got a couple ideas to cobble together some stuff, and it'll take up a lot less space than the power supplies.

[ripple_fx1]

How about buying or building your desk a spare supply from the Acopian modules, then fuse it way down for your testing?

[Henke]

If you have a couple of hours to spare and any fundamental knowledge in electronic circuits, which the topic indicates that you may have, it wouldn't be too big a hassle for you to roll you own basic psu on a veroboard, using a (properly fused) power transformer and handful of rectifier diodes, caps, resistors and LM317/337 regulators. Could that be an option for you?

[Dan Kennedy]

In my younger years I would've built up a supply, now I just cruise the surplus outlets.

For $40 each or so you should be able to find some decent HP or Accopian or
Lambda boxes that'll work together with voltage and current settings that'll save your ass.

$250 or so.

Most of them can be 40 years old and still work just fine.

[brianroth]

These kits get you at least part way there:

JLM Power Supply kits

Best,

Bri

[ripple_fx1]

A boatload of D-cells, some dropping diodes and fuses.

[ulysses]

Rather than buying or building a smaller power supply, just use the big console PSU and build a set of current limiters to place in line with each voltage rail. Build it into a box with a connector for the PSU's umbilical on the back and the module connector(s) on the front. Probably put some audio connectors on it as well for easy connection to your test equipment. Current limiters/regulators are easy to build and use very few components. Could be done on perf board or other prototyping boards with a minimal effort.

[Wavebourn]

Go to Costco and buy a box of Kirkland batteries. Cheap and flexible. Connect as many in series as you need.

[analogtodd]

I think I found a pretty decent solution, and its about the same price as 100 batteries.

[Wavebourn]

Originally Posted by monkeyt

I think I found a pretty decent solution, and its about the same price as 100 batteries.

Do you need 150 Volt?

[analogtodd]

almost... if you add it all up

[Wavebourn]

Originally Posted by monkeyt

almost... if you add it all up

64 volts don't need 100 batteries.
Add taps between them...

But if you found already better solution, it is fine!

[vince @ speck]

Originally Posted by monkeyt

Ok,
So I'm about to do a BUNCH of work on my MCI 500 channel strips, and I figured the quickest way to do what I need to do is, have a jig made up on my workbench to test them.

So, I need some:
+/- 32v
+/- 15v
+5v
+24v

Whats the best approach? Should I get some Acopian Linear Power Supplies and put together what I need? Without spending 1k anybody have any better ideas?

Some of the solutions that I'm reading are bordering on the "wacky".

You didn't mention how much current you require for your testing. Not a lot I would imagine if your testing the modules individually.

I'm guessing that you could easily get a compliment of linear power supplies for the project on ebay....all for around $200 used. Power One, International Power, and Condor make compatible supplies with virtually the same part numbers.

Get a dual output +/-24 (like a HBB24-1.2A) and modify with a couple of resistors for +/-32. Then get a dual output +/-15 (HBB15-1.5A), a single output +24 (HD24-4.8A), and single +5 (HD5-6A). Some of these supplies are on ebay now for about $10.

[brianroth]

Originally Posted by vince @ speck

Some of the solutions that I'm reading are bordering on the "wacky".

You didn't mention how much current you require for your testing. Not a lot I would imagine if your testing the modules individually.

I'm guessing that you could easily get a compliment of linear power supplies for the project on ebay....all for around $200 used. Power One, International Power, and Condor make compatible supplies with virtually the same part numbers.

Get a dual output +/-24 (like a HBB24-1.2A) and modify with a couple of resistors for +/-32. Then get a dual output +/-15 (HBB15-1.5A), a single output +24 (HD24-4.8A), and single +5 (HD5-6A). Some of these supplies are on ebay now for about $10.

Vince,

That was my first thought, except I dunno if a Power-One, etc 24V module can be cranked up to 32V. That being said, a somewhat lower voltage for the MCI 500 rails may not cause problems in a "test bed"..

Hence my suggestion of the JLM.

Best,

Bri

[analogtodd]

Just for completeness, I figured out I already had a 5v power-one, I found an open-frame Lambda 900ma 24v supply on ebay for $10, and I bought an HP bench power supply that does dual +/- up to 40v. At +/-32v its still pumping up to about 400ma which is PLENTY for one module.

I've got all that running into an edge connector that the modules fit into. I'm fudging together a goesintta/ouuta box for test signal now.

Total for all that was well under a $100

This is fun, its almost like I know what I'm doing!