CMoy power question?

[kramer5150]

quick newbie question...
I see a lot of you running them with 2 9V cells, are the cells in series or parallel (18V or 9V with double the mAh capacity) ?
I'd like power my cmoy with a 15 V/DC Laptop power supply. I have an extra Toshiba PS and Id like to use it... if possible.

Im using the burr Brown OPA2132 op amp, and my caps are all at least 50V.

Thanks, all comments are welcome.

Garrett


EDIT:

If it helps any heres the daya sheet for the BB op amp:

Link

 

[StevieDvd]

My 2 cmoys are running on 2 x 9v (reading 18v on meter) and sounding all the better for it.

Steve

 

[kramer5150]

Quote:

Originally Posted by StevieDvd My 2 cmoys are running on 2 x 9v (reading 18v on meter) and sounding all the better for it. Steve

Thanks Steve... do you have problems with your OP amp overheating or getting noticeable warm? Im concerned with long term reliability too.

thanks,
Garrett

 

[bg4533]

Quote:

Originally Posted by kramer5150 Thanks Steve... do you have problems with your OP amp overheating or getting noticeable warm? Im concerned with long term reliability too. thanks, Garrett

The OPA2132 should be good up to 30V. From the sound of things it should never get hot if the circuit is properly implemented. I wouldn't worry about increasing the voltage (while still inside specs) hurting the OPAMP's lifespan. Even if it does slightly hurt it, the OPAMP will probably last far longer than you will ever use it.

Are you sure your caps are greater than 50V? The electrolytics most people use are rated from 25V. 16V and 25V are also not uncommon. 50V caps are quite a bit larger than 25V and would be pointless since even a 35V cap is usually overkill.

Using laptop power supplies is something I have wondered about myself. How do they compare to something like the Elpac WM080?

 

[StevieDvd]

Must admit I have not worried about the long term effect but as far as I've been playing with opamp rolling I don't recall them getting overly warm.

Mine are encased in hammond enclosures so not easy to check the temp of the opamps.

From a quick check of some old info the web page on Tangent has some info on opamps you may find useful

http://www.tangentsoft.net/audio/opamps.html

 

[Earwax]

Quote:

Originally Posted by bg4533 Using laptop power supplies is something I have wondered about myself. How do they compare to something like the Elpac WM080?

Although it seems that most here will advise against laptop(switching) power supplies, I can't tell the difference between an elpac 24V, a thinkpad 16V switching PS or a 12V AA battery pack on my cmoy with a 2107.

 

[kramer5150]

Oops I meant 25V caps...

If it helps any here is the PS I'm planning to use. I might buy a big enough enclosure to house the whole thing + the cmoy amp.

thanks,
Garrett

 

[Voodoochile]

It's worth trying out. Measure the unloaded output voltage before you connect the cmoy, though. That's a 4A PSU, and unloaded the voltage may swing quite a bit higher. Your cmoy isn't going to drain a tenth of that current.

I have a nice adapter from a Dell laptop that I wanted to use, but it was just too noisy. I thought about building some fitering for it, but at that point, you are pretty well on your way to making a PSU anyway.

Some adapters and wallwarts are quiet though. I really like the way that laptop adapters are not 'wallwarts'. If the Elpac WM080 was built in that form factor, I'd like it a lot more than I do, if only for aesthetic reasons.

 

[kramer5150]

Quote:

Originally Posted by Voodoochile It's worth trying out. Measure the unloaded output voltage before you connect the cmoy, though. That's a 4A PSU, and unloaded the voltage may swing quite a bit higher. Your cmoy isn't going to drain a tenth of that current. I have a nice adapter from a Dell laptop that I wanted to use, but it was just too noisy. I thought about building some fitering for it, but at that point, you are pretty well on your way to making a PSU anyway. Some adapters and wallwarts are quiet though. I really like the way that laptop adapters are not 'wallwarts'. If the Elpac WM080 was built in that form factor, I'd like it a lot more than I do, if only for aesthetic reasons.

Great thanks!!! Yeah its a 4A supply so I can hook up all kinds of lights and things to it, with plenty in reserve.

On your Dell P/S, did the noise persist regardless of how close it was located to the amp circuit? Id like to enclose the P/S in the same enclosure as the cmoy, but if it introduces noise I may have to leave it outside.

Thanks,
Garrett

 

[tangent]

Quote:

most here will advise against laptop(switching) power supplies

If you've already got the supply, Voodoochile's right: can't hurt to try. I only strongly advise against switchers when someone's proposing buying something new. In that case, it's a bad gamble, and you're better off getting something you know will work well.

 

[Voodoochile]

Quote:

Originally Posted by kramer5150 On your Dell P/S, did the noise persist regardless of how close it was located to the amp circuit? Id like to enclose the P/S in the same enclosure as the cmoy, but if it introduces noise I may have to leave it outside.

Yes, it was noisy regardless of proximity. I tested it with the psu on the floor, with a cord coming up to the amp on the bench. Not a faint, low hum, either. More like there was an electric razor plugged into an accessory outlet within the amp's chassis. Not good at all.

 

[bg4533]

Quote:

Originally Posted by Voodoochile I really like the way that laptop adapters are not 'wallwarts'. If the Elpac WM080 was built in that form factor, I'd like it a lot more than I do, if only for aesthetic reasons.

I hate the design of the WM080 because I am already short on outlets and the bricks make it even more of a pain.

 

[Voodoochile]

Yes... and it's a BIG brick. It would be so nice if it was on the floor and there was another 4' of power cord coming out the other side.