First amp project

RoadToNever · 1st January 2012, 07:39 PM

Hi everyone!

I'm looking around for a simple first amp project for desktop use with high measured signal quality and gain control. The headphones I want to drive are between 16 and 250Ohms respectively.
So far I've had my eye on a modified Cmoy: NwAvGuy: Cmoy With Gain

ethanolson · 05:08 AM

That should be a great place to start. That particular amp is a very good Cmoy design, and should have no trouble driving your headphones. My only serious reservation is the DC voltage offset.

RoadToNever · 2nd January 2012, 06:18 AM

Thanks, ethanolson. Good to know that it's a good Cmoy design. Regarding DC offset, I plan to use DC wall power exclusively and If it's good(not great) to NwAvGuy's standards it's fine for now. I can't seem to find a PCB or perfboard/stripboard layout for that particular circuit. You wouldn't happen to know?

FREDtheDOG · 2nd January 2012, 09:55 AM

Sorry that circuit wont work with wall power, it depends on having 2 batteries to genertate the virtual ground

If you use a wall wart you'll need a voltage divider type circuit

Davey · 2nd January 2012, 03:00 PM

Well, you can buy "wall-warts" that provide +/- DC power......

Roadtonever,

The modified Cmoy is a nice, simple project but why don't you consider building the O2 amp sans batteries? It's simple too and thanks to RS and terrific group of DIY suppliers the parts/pieces/pcb are easily available.

Cheers,

Dave.

Willakan · 2nd January 2012, 04:42 PM

Indeed, someone who was new to DIY electronics reported it was easier than building a CMOY, mainly thanks to the incredibly detailed documentation and that it uses a PCB, unlike most CMOY amps, which must be built on a breadboard.

RoadToNever · 10th February 2012, 02:45 AM

Anyone have an idea about a good design for for more than one set of headphones? I'm thinking about building something similar to this, except 2 or 3 outputs: PreSonus

RoadToNever · 11th February 2012, 02:33 AM

Found this: PAiA - 9206KP Headphone Distribution Amp Kit (International version - ships without 110V power supply), Headphone Distribution Amplifier, 9206KP Looks perfect (low output impedance) except that it has twice more outputs then I need right now. Still looking....

ddietz · 11th February 2012, 03:19 PM

For the headphone distribution, check out the schematic. It is incredibly simple. Inverting voltage amp with gain of 10 for each channel. Uses a standard virtual ground split by resistors with smoothing capacitors. All channels are identical so you can easily duplicate Channel 1 however many times you need, 2, 6, 12, whatever.

Probably costs about $2 a channel if you use nice opamps. The dual audio log pots for level is the most expensive part. Cheap ones can be a couple bucks each. They also don't have to be 100K either, afaik, 10K-20K is fine.

Tajzmaj · 11th February 2012, 03:34 PM

If you really want to drive load low as 16E than just an op amp probably won't do the job. Try something with discrete output stage. Gyraf HP amp or SDS headphone amp are good ,,ready made,, projects. Check.
Regards, Taj

1st January 2012, 07:39 PM	#1
RoadToNever diyAudio Member Join Date: Jan 2012	First amp project Hi everyone! I'm looking around for a simple first amp project for desktop use with high measured signal quality and gain control. The headphones I want to drive are between 16 and 250Ohms respectively. So far I've had my eye on a modified Cmoy: NwAvGuy: Cmoy With Gain

2nd January 2012, 05:04 AM	#2
ethanolson diyAudio Member Join Date: Nov 2011 Location: http://binged.it/ukmr5Y	That should be a great place to start. That particular amp is a very good Cmoy design, and should have no trouble driving your headphones. My only serious reservation is the DC voltage offset. Last edited by ethanolson; 2nd January 2012 at 05:08 AM.

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2nd January 2012, 06:18 AM	#3
RoadToNever diyAudio Member Join Date: Jan 2012	Thanks, ethanolson. Good to know that it's a good Cmoy design. Regarding DC offset, I plan to use DC wall power exclusively and If it's good(not great) to NwAvGuy's standards it's fine for now. I can't seem to find a PCB or perfboard/stripboard layout for that particular circuit. You wouldn't happen to know?

2nd January 2012, 09:55 AM	#4
FREDtheDOG diyAudio Member Join Date: Sep 2008 Location: Perth West Australia	Sorry that circuit wont work with wall power, it depends on having 2 batteries to genertate the virtual ground If you use a wall wart you'll need a voltage divider type circuit

2nd January 2012, 03:00 PM	#5
Davey diyAudio Member Join Date: Dec 2001 Location: Bremerton, WA.	Well, you can buy "wall-warts" that provide +/- DC power...... Roadtonever, The modified Cmoy is a nice, simple project but why don't you consider building the O2 amp sans batteries? It's simple too and thanks to RS and terrific group of DIY suppliers the parts/pieces/pcb are easily available. Cheers, Dave.

2nd January 2012, 04:42 PM	#6
Willakan diyAudio Member Join Date: Aug 2011	Indeed, someone who was new to DIY electronics reported it was easier than building a CMOY, mainly thanks to the incredibly detailed documentation and that it uses a PCB, unlike most CMOY amps, which must be built on a breadboard.

10th February 2012, 02:45 AM	#7
RoadToNever diyAudio Member Join Date: Jan 2012	Anyone have an idea about a good design for for more than one set of headphones? I'm thinking about building something similar to this, except 2 or 3 outputs: PreSonus

11th February 2012, 02:33 AM	#8
RoadToNever diyAudio Member Join Date: Jan 2012	Found this: PAiA - 9206KP Headphone Distribution Amp Kit (International version - ships without 110V power supply), Headphone Distribution Amplifier, 9206KP Looks perfect (low output impedance) except that it has twice more outputs then I need right now. Still looking....

11th February 2012, 03:19 PM	#9
ddietz diyAudio Member Join Date: Mar 2011	For the headphone distribution, check out the schematic. It is incredibly simple. Inverting voltage amp with gain of 10 for each channel. Uses a standard virtual ground split by resistors with smoothing capacitors. All channels are identical so you can easily duplicate Channel 1 however many times you need, 2, 6, 12, whatever. Probably costs about $2 a channel if you use nice opamps. The dual audio log pots for level is the most expensive part. Cheap ones can be a couple bucks each. They also don't have to be 100K either, afaik, 10K-20K is fine.

11th February 2012, 03:34 PM	#10
Tajzmaj diyAudio Member Join Date: Mar 2011 Location: Ljubljana	If you really want to drive load low as 16E than just an op amp probably won't do the job. Try something with discrete output stage. Gyraf HP amp or SDS headphone amp are good ,,ready made,, projects. Check. Regards, Taj