AC/DC & POWERSTATION KIT BUILD THREAD

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Joe Malone
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Re: AC/DC & POWERSTATION KIT BUILD THREAD

Post by Joe Malone »

sheep_production wrote:hi

im building a neve project without phantom. im using a ac/dc ver 3. for power. i only need +24v for this. earlier in this post there is a drawing for24v +phantom. could u make me one for only 24v. so i dont have to stuff in what is not needed.

best regards

lasse
This is the same for all versions of AC/DC
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chuckd
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Re: AC/DC & POWERSTATION KIT BUILD THREAD

Post by chuckd »

Hey Joe,

I am using the OLD AC/DC (one in the photo of your reply above 2004 version) for a supply to a TG1 build. Which is +/- 28VDC
Currently I have this Avel Lindberg 28-0-28 2.67A transformer on it.

My circuit is sagging the + supply! So the transformer must be too low? I think?

What is the max secondary transformer I can put into this AC/DC? Can I use a 34-0-34 one?
Also is there a limit on how much current will flow through?


Thanks

Chuck

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Re: AC/DC & POWERSTATION KIT BUILD THREAD

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chuckd wrote:Hey Joe,

I am using the OLD AC/DC (one in the photo of your reply above 2004 version) for a supply to a TG1 build. Which is +/- 28VDC
Currently I have this Avel Lindberg 28-0-28 2.67A transformer on it.

My circuit is sagging the + supply! So the transformer must be too low? I think?
That transformer is more than enough to run a TG1. Have you got the LM regulators on the AC/DC kit well heatsinked to a large case or heatsink so tere thermal overheat protection isn't cutting in to turn them off?
What is the max secondary transformer I can put into this AC/DC? Can I use a 34-0-34 one?
You do not want higher AC volts as it will just waste more heat which will mean bigger heatsinks.
Also is there a limit on how much current will flow through?
1Amp per +/-V rail if fully heatsinked. With no heatsink thermal protection will cut in around 100 to 150mA of load.

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chuckd
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Re: AC/DC & POWERSTATION KIT BUILD THREAD

Post by chuckd »

Thanks for the help Joe!

Yes I have Heatsinks (not too big) but they are there. I'll have to stick my finger on them to see how warm they get.
Let's just say they do not get hot then...
Could it be that my transformer is leaking too?

One way to find out is to put a 2A fuse in there and see if it trips. Then I could say if the circuit is drawing more then the max rail allows. I will try that as well.

Chuck

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Re: AC/DC & POWERSTATION KIT BUILD THREAD

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chuckd wrote:Thanks for the help Joe!

Yes I have Heatsinks (not too big) but they are there. I'll have to stick my finger on them to see how warm they get.
Let's just say they do not get hot then....
Most of the small individual heatsinks that will fit without touching each other on the AC/DC will not be big enough to allow the AC/DC to run anywhere near its full current without the regs going into protection.
Could it be that my transformer is leaking too?

No. Main thing would be to check you have the phase and wiring from the transformer secondary correct. The drawing on the side of the transformer will show the 2 wire in the centre that should be joined to each other and wired to 0v (which is the front tag on the left of the AC/DC and then wire the other 2 ends to one of the AC in's each.
One way to find out is to put a 2A fuse in there and see if it trips. Then I could say if the circuit is drawing more then the max rail allows. I will try that as well.
2A fuses are to big and will not blow in there. You should be able to run 500mA to 1A fast blow fuses inline with the +/-28v to prove if you have a problem with the TG1 circuit. But if the heatsinking is not enough then the reg will go into protect so may not blow the fuse. One TG1 should only draw about 100 to 200mA max so I would think the problem will be in the TG1 or wiring.
Joe :-)
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chuckd
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Re: AC/DC & POWERSTATION KIT BUILD THREAD

Post by chuckd »

OK then I have been doing this wrong the whole time....500mA blows right away.
I always get confused by the way manufacturer label the secondary of a transformer.

Here is what I am using

http://www.apexjr.com/images/66938_sc7.pdf

Here is how I hook it up: On the AC side of the JLM AC/DC
secondary Red -> AC
secondary Yellow -> AC
secondary Center 0V -> GND

I wire up the circuit with the DC outputs and star ground all the grounds together ( mains, chassis , DC gnd, and Top smiley face bolt gnd, Circuit Gnd etc) If I do not connect them all together I usually get a loop so I make a point on the chassis and connect everything to it.


You were right the Regulators are getting really hot! and Shuting down.
Do my connections above make sense ? If so then it is the circuit that has a problem.


Thanks I hope this helps others as well!

Chuck

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Re: AC/DC & POWERSTATION KIT BUILD THREAD

Post by Joe Malone »

chuckd wrote:OK then I have been doing this wrong the whole time....500mA blows right away.
I always get confused by the way manufacturer label the secondary of a transformer.

Here is what I am using

http://www.apexjr.com/images/66938_sc7.pdf

Here is how I hook it up: On the AC side of the JLM AC/DC
secondary Red -> AC
secondary Yellow -> AC
secondary Center 0V -> GND

I wire up the circuit with the DC outputs and star ground all the grounds together ( mains, chassis , DC gnd, and Top smiley face bolt gnd, Circuit Gnd etc) If I do not connect them all together I usually get a loop so I make a point on the chassis and connect everything to it.

You were right the Regulators are getting really hot! and Shuting down.
Do my connections above make sense ? If so then it is the circuit that has a problem.
That is all correct.
Do the +/-28v stay up with no TG1 connected to the AC/DC?
Which one of the 2 x 500mA fuses is blowing +28v or -28v?
What circuit are you using for the TG1?
If you get stuck email me some photo's of the wiring and PCB and circuit and I will try to check it over for you.
Joe :-)
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d.redfern
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Re: AC/DC & POWERSTATION KIT BUILD THREAD

Post by d.redfern »

Hi, a couple of questions, firstly what heat sinks should I use obviously this depends on the voltage drop the regulator has to perform, but in terms of the size as It looks like the regulators are very close together and I fear that I wont be able to get a heat sink thin enough? I need heatsinks below 11C/W

Also I want to use the phantom power rail as a 35V rail to power an erase oscillator. It uses 0.2 amps. Will I need to make any modifications to the board to do this?

I'm making a tape delay with a filter and LFO and Dub Siren and I need +35V and 0V for the erase oscillator , 3x +/-15Vs and 0V for the tape delay, filter and LFO, 2x 9V and 0V for the tape motor/speed control and the dub siren, what are your thoughts?
Possible?

Cheers for any replies
Thanks
Doug

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Re: AC/DC & POWERSTATION KIT BUILD THREAD

Post by Joe Malone »

d.redfern wrote:Hi, a couple of questions, firstly what heat sinks should I use obviously this depends on the voltage drop the regulator has to perform, but in terms of the size as It looks like the regulators are very close together and I fear that I wont be able to get a heat sink thin enough? I need heatsinks below 11C/W
Usually best to bolt all regs to one heatsink or metal case with the insulator kits provided like our power supplies are designed to do. Need to know the current draw for all rails to work our C/W for the heatsink or heatsinks.
Also I want to use the phantom power rail as a 35V rail to power an erase oscillator. It uses 0.2 amps. Will I need to make any modifications to the board to do this?
Easy just set front strap to doubler and set to 35v with trim pot.
I'm making a tape delay with a filter and LFO and Dub Siren and I need +35V and 0V for the erase oscillator , 3x +/-15Vs and 0V for the tape delay, filter and LFO, 2x 9V and 0V for the tape motor/speed control and the dub siren, what are your thoughts?
Easy. One powerstation kit with 6Amp bridge rectifier and 2 x 15vac transformer. Set 48v rail to 35vdc as mentioned above. Set +V1 to +15vdc and -V1 to -15vdc this will run all tape delay, filter and LFO. Set +V2 to +9vdc but need to know the rough current draw of the tape motor and dub siren (have no idea what a dub siren is) Transformer VA size and heatsink C/W will depend on current used by the tape motor and dub siren?
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d.redfern
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Re: AC/DC & POWERSTATION KIT BUILD THREAD

Post by d.redfern »

Ok so I will only need a 2X15V trannie. I thought I would have needed something like a 25V or 28V trannie. When I put in rounded up estimate amps in for the parts it gives me 34C/W for the 15Vrails and 20C/W for the 9V rails and 84C/W for the phantom power rail. Will attaching regulators to the case dissipate enough heat? Or will I need a heatsink? could you suggest any heat sinks that will fit sizewise?
Thanks
Doug

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Re: AC/DC & POWERSTATION KIT BUILD THREAD

Post by Joe Malone »

d.redfern wrote:Ok so I will only need a 2X15V trannie. I thought I would have needed something like a 25V or 28V trannie. When I put in rounded up estimate amps in for the parts it gives me 34C/W for the 15Vrails and 20C/W for the 9V rails and 84C/W for the phantom power rail. Will attaching regulators to the case dissipate enough heat?
A metal case will give round 5C/W so is heaps of heatsinking on its own for all the regs.
Or will I need a heatsink? could you suggest any heat sinks that will fit sizewise?
Thanks
Doug
The small seperate reg U heatsinks are about 24W/C for each reg so not quite enough heatsinking for the 15v rails. We do have other mulitfin ones that fit each seperate reg which are 19C/W. But bolting to the metal case would be better and run the regs cooler.
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d.redfern
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Re: AC/DC & POWERSTATION KIT BUILD THREAD

Post by d.redfern »

great joe thanks loads its a great product, just waiting for it to arrive now I can't wait to get it all plugged in.
Doug

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Re: AC/DC & POWERSTATION KIT BUILD THREAD

Post by d.redfern »

I'm gonna buy this power transformer its got 2x15Vac secondarys and is rated at 80VA, th ac/dc calculator says I need 64VA so I'm guessing it'll be fine, it from rsonline, stock code 223-7973. Is there an problm with getting a larger VA rated transformer?
Cheers
Doug

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Re: AC/DC & POWERSTATION KIT BUILD THREAD

Post by Joe Malone »

d.redfern wrote:I'm gonna buy this power transformer its got 2x15Vac secondarys and is rated at 80VA, th ac/dc calculator says I need 64VA so I'm guessing it'll be fine, it from rsonline, stock code 223-7973. Is there an problm with getting a larger VA rated transformer?
Cheers
Doug
Yep that will be perfect 8)
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alistair
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Re: AC/DC & POWERSTATION KIT BUILD THREAD

Post by alistair »

Hi Joe-

I've got a funny little issue I can't figure out on my Powerstation.

It's set up to run 3x 24v lines, with C1 and C2 removed. When testing outside of it's case, it's working perfectly with no issues whatsoever.

However, in it's case, it's blowing fuses instantly on start up. I initially thought it was the voltage regs making contact, but I don't believe this is true. I'm able to easily measure resistance between the LM317's and the case (all close values aswell), and prior to blowing the fuse the last time, I could measure resistance between the LM337's and the case, however after blowing the fuse I now get a resistance that is constantly ticking up (starting at around 200ohms and working up- it doesn't seem to want to stop). I'm guessing this isn't normal?

All resistors seem to be checking out fine, and as mentioned, it's working great when not in the case. Any ideas?

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