MUFF WIGGLER Forum Index
 FAQ & Terms of UseFAQ & Terms Of Use   Wiggler RadioMW Radio   Muff Wiggler TwitterTwitter   Support the site @ PatreonPatreon 
 SearchSearch   RegisterSign up   Log inLog in 
WIGGLING 'LITE' IN GUEST MODE

[ORDER] 4hp, the 4-ear headphone amplifier in ... 4hp
MUFF WIGGLER Forum Index -> Music Tech DIY Goto page 1, 2, 3  Next [all]
Author [ORDER] 4hp, the 4-ear headphone amplifier in ... 4hp
av500
UPDATE: see ordering information and BOM below...

Introducing "4hp", the 2+2 headphone amplifier module in ... 4hp!

Compact and skiff friendly, only 35mm deep.

I made this because I needed something to drive headphones for the Happy Knobbing 2016 modular meeting. two separate channels each with their own volume knob, so you can share your bleep bloops with a friend!

The input jacks can be either wired as "through" so that you don't need a mult to pass a signal to the headphones - or you can wire them for two separate headphone channels. Also, jacks should be normalled left to right so that a mono signal shows up on both ears.

The amp is designed to "blow your ears away", the (dirt cheap) NJM4556 opamps used can deliver up to 200mA per ear. The amp has unity gain because your typical modular levels of 10Vpp are enough to drive all kinds of cans. If needed one can add gain by cutting some PCB traces and adding SMT resistors. In the standard BOM, the internal 68R balancing resistors limit the current to about 150mA per ear at 5V, but they can be reduced down to 1R if needed. See more about the NJM4556 here: http://nwavguy.blogspot.de/2011/07/o2-design-process.html

You can even drive small ~8Ohm loudspeakers at normal "room" level

If you want to reduce the gain you can wire a resistor from the jacks to the PCB, effectively limiting the potentiometer range. Depending on your headphones, you might want to do that in order to get a bit more range on the knob. Potentiometers are 9mm dual type, they are not as common but available from some sources like Smallbear:

http://smallbear-electronics.mybigcommerce.com/alpha-dual-gang-9mm-pc- mount/

If you cannot get audio taper pots you can also use linear taper and install a resistor across to change the taper as explained here:

http://sound.westhost.com/project01.htm

The output is DC coupled so that there is no need for huge coupling capacitors, but the input is AC coupled to prevent frying your headphones with DC biased signals. You can also short/omit the coupling caps if you want to use this as a DC coupled CV driver for whatever you want to connect.



full kit:

av500
bill of material, build guide, schematics and panel drill template

Mouser basket: https://www.mouser.de/ProjectManager/ProjectDetail.aspx?AccessID=2fa7e 5af8d

Mouser does not have 9mm dual potentiometers, here are some sources:

http://smallbear-electronics.mybigcommerce.com/alpha-dual-gang-9mm-pc- mount/

http://www.ebay.com/itm/280877943574

http://www.ebay.com/itm/181177919204

http://www.ebay.com/itm//371729007802

http://www.ebay.com/itm/181177919836

http://www.ebay.com/itm/131906155606 (needs desoldering)

these might also work if you cut away the tabs and drill out the mounting holes to 9mm:

Alps RK09L12B-LOG100K from e.g. http://www.reichelt.de/6mm-Pots-stereo/RK09L12B-LOG100K/3/index.html?A CTION=3&GROUPID=3136&ARTICLE=73825&OFFSET=16&

(NOTE: in order to see the attached documents, you need to be logged in to muffwiggler.com)
av500
ORDERING INFORMATION:

PCB + panel: €20 + €5 shipping worldwide

full kit: €55 + €7 shipping worldwide

worldwide shipping as a tracked and registered letter

to order, send me an email to vp (at) vpme (dot) de with your full shipping address, then I will reply with Paypal details.
FetidEye
here be interest
euromorcego
here also interest!
puzo
yes please
vinylvandal
i would be interested in this!
Suf-fuD
interest here too...
basicbasic
Me too me too! hyper
adnauseam
Awesome! I'd buy one or two
antf4rm
Looks great! Nice work.
BananaPlug
thumbs up
peloazul
thumbs up
hsimonis
interest here as well
av500
one PCB sent off to a trusty beta-builder today. panels will be ordered. heads will phone (or ring?)
infovore
very nice, very interested. will it be possible to re-implement the schematic for our own use?
av500
infovore wrote:
very nice, very interested. will it be possible to re-implement the schematic for our own use?


I don't think I did anything too clever with the schematics, so sure smile
infovore
av500 wrote:
infovore wrote:
very nice, very interested. will it be possible to re-implement the schematic for our own use?


I don't think I did anything too clever with the schematics, so sure smile


Ah, cool - might see if I can make a little 1U SMD version...
oberkorn
looking good thumbs up
will take one PCB/panel set when you are ready
vinylvandal
looks really cool. what is the depth of the moduie?
janost
vinylvandal wrote:
looks really cool. what is the depth of the moduie?


35mm?
av500
janost wrote:
vinylvandal wrote:
looks really cool. what is the depth of the moduie?


35mm?


35mm! It's peanut butter jelly time!
masterofstuff124
Ooooo yah im into this!
av500
panels finally arrived - but now I'm away for two weeks, so bear with me for just a little but longer...


EATyourGUITAR
this is a really nice project. we needed this in DIY.
MUFF WIGGLER Forum Index -> Music Tech DIY Goto page 1, 2, 3  Next [all]
Page 1 of 3
Powered by phpBB © phpBB Group