9V headphone amp - diyAudio
Go Back   Home > Forums > Amplifiers > Headphone Systems
Home Forums Rules Articles diyAudio Store Gallery Wiki Blogs Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Headphone Systems Everything to do with Headphones

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Thread Tools Search this Thread
Old 3rd March 2007, 07:33 PM   #1
Nordic is offline Nordic  South Africa
diyAudio Member
Nordic's Avatar
Join Date: Sep 2005
Talking 9V headphone amp

I have posted a picture or 2 in another thread, but I have only just completed the documentation to go with the project.
It is available at http://www.head-fi.org/forums/showthread.php?p=2764048

Click the image to open in full size.

Click the image to open in full size.

Click the image to open in full size.
Attached Files
File Type: zip 9vtubeamp.zip (62.1 KB, 254 views)
  Reply With Quote
Old 3rd March 2007, 07:54 PM   #2
diyAudio Member
Join Date: Oct 2006

I'd really like to build this puppy. I built a CMOY and liked it, then a Meta42, also liked it, but it is quite fatiguing with my Grados. I expect that some tube-warmth would help tremendously.

What sort of life expectancy would you expect a regular 9V battery to deliver? Presumably, the amp could be run with a 9V walwart, couldn't it? Are PCB's available, or is it "make-your-own" or point-2-point?

  Reply With Quote
Old 3rd March 2007, 08:30 PM   #3
Nordic is offline Nordic  South Africa
diyAudio Member
Nordic's Avatar
Join Date: Sep 2005
It needs both, the 9V batteries power the cathodes, and draw so little current they will last for a very long time.

However the heater also needs alot of power +_6V at 365mA = 2VA. So, you do need a walwart (in which case remove the rectifier) or transformer capable of producing about 12V- 20V which gets fed into the LM317 which in turn then is set to 9V... the HV supply or B+.

The opamp also gets its power from this rail, but that is less than 100mA at max and about 10mA at idle. So if you use a walwart get something that can do about 1000mA or it will get plenty hot.

It sounds very good, MUCH BETTER THAN A CMOY, I am using an NE5322 opamp at the moment. On power it on, you will first hear nothing, then alot of soft humming, and then the music breaks through and the hum becomes almost imperceptable even during quiet pieces. VERY IMPORTANT TO DO ALOT OF BYPASSING BECAUSE OF THE MINIMALIST CIRCUIT...

It is very good practice, as you set it up, you will make mistakes which will not do any damage, however with the same type of circuit with larger voltage supplies, you could easily kill parts or yourself. So if you do something wrong, don't worry it will come to you, the only tricky bit is wiring the batteries the right way around, if you don't you will not get the 3.5VDC at the input to the chip as needed regardles of trimpot position...

I will during the week also post a tiny 12V mod wich does away with the battery, provided it sounds good enough.

The eagle files for personal editing and adjusting to your component sizes are attached.

If (and I dout it would happen) there is enough interest we could surely try a GB.

I do have some mods in mind so I will probably release a V2 , or a tiny addon board maybe 4 x 4cm, with a little more filtering, I preffer he bypass caps soldered directly to the bottom pads.
  Reply With Quote
Old 6th March 2007, 10:29 AM   #4
Nordic is offline Nordic  South Africa
diyAudio Member
Nordic's Avatar
Join Date: Sep 2005
Ok, the opamp rolling bit is done... and the winner, OPA2132

The NE5532 was pretty nice, but drifted a little and needed regular adjustment... sound was not objectionable but didn't have the impact of the other chips tested. Had loudest output.

OPA2227 incredibly neutral, but very unstable, with regular crackle comming through, and in my experience its main symptom of slight oscillation, reduced bass. It was a treat to set up the bias. I might design the next board with some considerations to make this section more stable... increased level of hum observed.

OPA2132... hum was first thing to drop drasticaly, I thought it was low before, this combination is amazing, and I rediscovering so much new stuff in well known tunes... that diffirence between hands clapping and rain falling on a roof, like destroyer likes to say. Was amazed in one song by Killers to hear the guy was snapping his fingers, always thought it was a percusive instrument...
  Reply With Quote


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
Another DAC + Headphone amp ghetto Digital Source 14 10th July 2008 04:02 PM
Using a headphone amp as a pre-amp? Basalt Solid State 4 19th November 2007 09:55 AM
ESL Headphone X-former bjackson Planars & Exotics 5 19th September 2005 03:45 AM
Headphone amp audioPT Headphone Systems 3 20th September 2004 10:17 PM
Zen v4 headphone amp Rob M Headphone Systems 11 21st May 2003 12:58 AM

New To Site? Need Help?

All times are GMT. The time now is 06:48 AM.

vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright 1999-2017 diyAudio

Content Relevant URLs by vBSEO 3.3.2