Quick CMOY Question

SnoopKatt · 27th July 2012, 05:50 AM

I just got a CMOY headphone amplifier (I would've built it myself, but I have some health issues currently preventing me from building it, and I was able to buy it pretty close to the cost of the parts). I really like the sound of it, but using a 9 V battery for something that won't leave my desk seems like a waste of batteries. If I connect the 9 V battery terminals to a DC power jack and buy a regulated wall power supply, will that safely power the amp?
Thanks!

Fredfred2004 · 27th July 2012, 06:03 AM

Yes that works fine, if its in a tin make sure to keep the power insulated from the tin

Leodegarius · 27th July 2012, 07:19 PM

If it's by your computer, and you have a tower computer, not a laptop, you might be able to hack into the power supply of the PC and run power from one of it's Molex connectors. Often times people use computer power supplies to run car audio stuff at 12V inside their home.

SnoopKatt · 29th July 2012, 04:45 AM

Thanks for the quick response guys! Will something like this do, or will I need something that can supply more current:

Amazon.com: Wall Adapter Power Supply - 9V DC 650mA: Electronics

I will definitely insulate the wires inside (it is the metal mint can).

I did think about putting it inside my computer. That would work beautifully as far as output goes, as I could drill a hole for each component in the 5.25 bay, but that might make the input a little tricky. Then again, I probably could disconnect the front input jack, and splice the wires with the input into the headphone amplifier. What do you guys think?

Fredfred2004 · 29th July 2012, 05:42 AM

I think putting it in the computer case might be a mistake, the tin of the cmoy typically carries the virtual ground, you could very easily short the metal of the tin to the metal of the computer case which will be at the powersupply earth. The rail splitter will then let out the magic smoke :-)

skogs · 29th July 2012, 08:35 AM

Maybe you could power it using an USB port from your computer? Adding a mini-usb socket to your tin box, so that you can connect it with a regular usb-cable.

barefootwhistler · 29th July 2012, 08:36 PM

I was under the impression that the CMOY amp has two 9 volt batteries in series for a nominal 18V between the positive and negative. If yours is running on a single battery, then the wall-wort has more than enough power capability. If it is powered by two batteries, then you might opt for a higher voltage (i.e. 18V). However, 9V should be enough unless you have very low sensitivity headphones, which I doubt. Depending on the op-amp in your amplifier and the voltage rating of the capacitors, you should have a very wide range of voltage options that would work.

SnoopKatt · 11:58 PM

Quote:

Originally Posted by Fredfred2004

I think putting it in the computer case might be a mistake, the tin of the cmoy typically carries the virtual ground, you could very easily short the metal of the tin to the metal of the computer case which will be at the powersupply earth. The rail splitter will then let out the magic smoke :-)

That's a good point; I didn't think about the virtual ground. I picked up a DC Jack from RadioShack just now, and after examining the jack, it looks like the whole chassis is supposed to be the earth ground! I also picked up some rubber grommets, but it looks like it will be way too big with the grommets, as there's only about half an inch on the sides of the case. Are there any small, fully insulated DC power jacks? Edit: nevermind, found one.

I thought about USB power, but I'm worried this will need a little more juice.

That's good to know that there is a wide voltage range. Makes picking out a power supply a lot easier.

Thanks for all of the input guys!

Fredfred2004 · 30th July 2012, 12:01 AM

I use these on my rechargeable cmoys

1614 10 - LUMBERG - CHASSIS SOCKET, PSU, PANEL MOUNT | element14 Australia

I think they are on ebay as well

Leodegarius · 30th July 2012, 05:11 PM

USB runs at 3.5 to 5V and 500mA, if I am not mistaken. If you wanted it into the computer, could you use a rubber mat to insulate the tin case, or make a rubber sleeve for it?

27th July 2012, 05:50 AM	#1
SnoopKatt diyAudio Member Join Date: Oct 2008	Quick CMOY Question I just got a CMOY headphone amplifier (I would've built it myself, but I have some health issues currently preventing me from building it, and I was able to buy it pretty close to the cost of the parts). I really like the sound of it, but using a 9 V battery for something that won't leave my desk seems like a waste of batteries. If I connect the 9 V battery terminals to a DC power jack and buy a regulated wall power supply, will that safely power the amp? Thanks!

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27th July 2012, 06:03 AM	#2
Fredfred2004 diyAudio Member Join Date: Jun 2012	Yes that works fine, if its in a tin make sure to keep the power insulated from the tin

27th July 2012, 07:19 PM	#3
Leodegarius diyAudio Member Join Date: Jul 2012	If it's by your computer, and you have a tower computer, not a laptop, you might be able to hack into the power supply of the PC and run power from one of it's Molex connectors. Often times people use computer power supplies to run car audio stuff at 12V inside their home.

29th July 2012, 04:45 AM	#4
SnoopKatt diyAudio Member Join Date: Oct 2008	Thanks for the quick response guys! Will something like this do, or will I need something that can supply more current: Amazon.com: Wall Adapter Power Supply - 9V DC 650mA: Electronics I will definitely insulate the wires inside (it is the metal mint can). I did think about putting it inside my computer. That would work beautifully as far as output goes, as I could drill a hole for each component in the 5.25 bay, but that might make the input a little tricky. Then again, I probably could disconnect the front input jack, and splice the wires with the input into the headphone amplifier. What do you guys think?

29th July 2012, 05:42 AM	#5
Fredfred2004 diyAudio Member Join Date: Jun 2012	I think putting it in the computer case might be a mistake, the tin of the cmoy typically carries the virtual ground, you could very easily short the metal of the tin to the metal of the computer case which will be at the powersupply earth. The rail splitter will then let out the magic smoke :-)

29th July 2012, 08:35 AM	#6
skogs diyAudio Member Join Date: Oct 2006	Maybe you could power it using an USB port from your computer? Adding a mini-usb socket to your tin box, so that you can connect it with a regular usb-cable.

29th July 2012, 08:36 PM	#7
barefootwhistler diyAudio Member Join Date: Jul 2012 Location: Wichita, KS	I was under the impression that the CMOY amp has two 9 volt batteries in series for a nominal 18V between the positive and negative. If yours is running on a single battery, then the wall-wort has more than enough power capability. If it is powered by two batteries, then you might opt for a higher voltage (i.e. 18V). However, 9V should be enough unless you have very low sensitivity headphones, which I doubt. Depending on the op-amp in your amplifier and the voltage rating of the capacitors, you should have a very wide range of voltage options that would work.

30th July 2012, 12:01 AM	#9
Fredfred2004 diyAudio Member Join Date: Jun 2012	I use these on my rechargeable cmoys 1614 10 - LUMBERG - CHASSIS SOCKET, PSU, PANEL MOUNT \| element14 Australia I think they are on ebay as well

30th July 2012, 05:11 PM	#10
Leodegarius diyAudio Member Join Date: Jul 2012	USB runs at 3.5 to 5V and 500mA, if I am not mistaken. If you wanted it into the computer, could you use a rubber mat to insulate the tin case, or make a rubber sleeve for it?