Hello,
I would like to build a small zen amp of 2 watts to drive a pair of 8 ohm headphones. I will use it to drive the tweeters in my biamped system at school for my desk. But I have a few questions. What would be the rail supply voltage and what size transformer. Also how large of a heatsink would I need?
Thanks in advance,
Opie
I would like to build a small zen amp of 2 watts to drive a pair of 8 ohm headphones. I will use it to drive the tweeters in my biamped system at school for my desk. But I have a few questions. What would be the rail supply voltage and what size transformer. Also how large of a heatsink would I need?
Thanks in advance,
Opie
Are you sure your headphones are 8 ohms? Most are 32 ohms or higher. You don't need anywhere near 2 watts to drive headphones.
Assuming they are at least 32 ohms, the "Szekeres" amplifier at www.headwize.com (under Library/Projects) is a Zen-type amp. Single gain stage, no feedback. Sounds great. Nelson Pass has recommended this (conceptually speaking).
Assuming they are at least 32 ohms, the "Szekeres" amplifier at www.headwize.com (under Library/Projects) is a Zen-type amp. Single gain stage, no feedback. Sounds great. Nelson Pass has recommended this (conceptually speaking).
Yes, you can drive headphones from an amp meant for your tweeters. Sounds like a great idea.
Check out projects 70 and 83 at www.sound.au.com. Also check out Geoff's site at:
http://www.gmweb.btinternet.co.uk
In most cases, you will have to scale down the power levels to a 2W level, but with a very simple amp this should not be too difficult. Just ask for help.
Check out projects 70 and 83 at www.sound.au.com. Also check out Geoff's site at:
http://www.gmweb.btinternet.co.uk
In most cases, you will have to scale down the power levels to a 2W level, but with a very simple amp this should not be too difficult. Just ask for help.
I built the ZEN headphone amp for my 32 ohm Grado cans and it is spectacular. The circuit I used was at Headwise, in the library / project section.
http://headwize.com/projects/showfile.php?file=pellerano_prj.htm
I had a little 60hz hum from the project power supply, so I switched to a capacitance mulitiplier, regulated supply.
http://headwize.com/projects/showfile.php?file=pellerano_prj.htm
I had a little 60hz hum from the project power supply, so I switched to a capacitance mulitiplier, regulated supply.
I'm not to sure if you have your application right but I'll try and answer your question anyway.
2W into 8-ohms will will need pwr=V*V/R => sqrt( 16 ) Volts = 4 Volts peak so 8-volts P-P.
So, given that you'll want some headroom, you can go with, say a 12-volt rail voltage.
At that voltage level, you would also be able to increase your bias current up to double what most zens run at, so 5-amps or even 6. Or you could run it at a lower bias and have less heat as well.
--
Danny
2W into 8-ohms will will need pwr=V*V/R => sqrt( 16 ) Volts = 4 Volts peak so 8-volts P-P.
So, given that you'll want some headroom, you can go with, say a 12-volt rail voltage.
At that voltage level, you would also be able to increase your bias current up to double what most zens run at, so 5-amps or even 6. Or you could run it at a lower bias and have less heat as well.
--
Danny
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