hifi headphone amp?

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soundguy

Well-known member
Joined
Jun 4, 2004
Messages
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Location
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can anyone reccomend a good "hi-fi" headphone amp? Kinda looking to buy something decent rather than build it. Gotta have balanced inputs and sound pretty clean.

any reccomendations?

dave
 
the grace box looks nice, however its like $1600. Im just installing this on my bench, so I think that might be overkill, well, at least for me it is.

Im guessing I'll just try something on the headwize forum, there's quite a bit of projects to chose from over there. Has anyone built anything they'd reccomend from the listed projects there?

thanks

dave
 
depending on how much you want to spend, the 990 op amp is great as a headphone amp, Audiophile level for sure. 600 ohm down to 75 ohm.
MCM electronics has some pretty nice kits for 5 to 15 watt output, get a couple of RE-11P-1 line in trans for the balanced ins part...
I have PCB boards for the 990 or 2520 ect and add a good dual pot and your ready to go.
WWW.jmkaudio.com click on the JM 130 mic pre scroll all the way down for a Pic of the PCB.
Just a thought...
 
so, now Behringer isn't good enough? i've built J-FET and 6AS7 amps similar to the ones fron Headwize. they didn't cut it. nor did any SRPPs i've tried. Le Monstré is the best headphone amp i've heard
 
http://www.tnt-audio.com/ampli/t-amp_e.html

I havnt tried this as a headphone amp yet, as it needs some small mods to work properly with higher output Z than 16ohms but is tiny, cheap and sounds fantastic especially for the $30 asking price.

I bought 2 of em to just have around as portable good sounding amps for location recording etc, but I was talking with Joe yesterday over lunch about trying them as headphone amps...

No balanced ins, and you need to change the output filter but still a lot cheaper than even a Bear-Ringer...and probably a shitload better sounding.


M


ps, this is the new version about to be released:
http://www.retrothing.com/2005/10/son_of_tamp_ii_.html
 
You could buy a used but good stereo reciever and just plug into that. It owuld probably only cost a couple of bills, be plug and play, you could patch it into multiple phones if needed.
 
Ahh...what're you doing asking about something you can buy???

A couple of the GR opamps make great headphone drivers, it's what I use at home with my Beyer 770's.

The 990 would be good too.

Buy. Sheesh. What's the world coming too? :)
 
Some people like the LM1875 as a headphone amp. It's also simple to make. A small headphone amp is another of my many not-yet-done projects...

How much power (and voltage) is actually needed for the different headphone types? I guess the range is 16-600 ohms.

Best regards,

Mikkel C. Simonsen
 
[quote author="Dan Kennedy"]

Buy. Sheesh. What's the world coming too? :)[/quote]

man, that was a proper chastizing!

I cant buy time, so Im trying to buy a product. Im best off building something though...

Are you ready for the noob question of the day?

what do I need to do to this to accomodate a balanced input?

http://headwize.com/projects/showfile.php?file=stokes_prj.htm

Im assuming is well more complicated than just wiring the negative input to pin 2 on the opamp...

dan, do you have packaged opamps for sale?

dave
 
I'd add an additional diff amp ahead of the level control in the traditional four equal value R configuration. You could manage with the existing amp reconfigured but you would be mucking with a lot of details about the overall feedback.
 
For balanced input for existing unbalanced designs would a 10k:10k bridging input transformer work ok?

Side note:
Correct me if I'm way off base in thinking, but couldn't just about any power amp be adapted for headphones? Most headphones have a higher Z than the usual 4 or 8ohms of speakers, so would most low power amps that can comfortably drive down to 8 ohms be more than sufficient?

OR how about even a simple "API" based headphone amp using a spare 325 line amp module, easy balanced input and output... Although I'm not sure how well it will drive your average 75ohm headphones. Perhaps someone smart may know...
 
> How much power (and voltage) is actually needed for the different headphone types? I guess the range is 16-600 ohms.

Nobody ever really asks that question. Try these:

http://headwize.com/ubb/showpage.php?fnum=3&tid=2432

http://headwize.com/ubb/showpage.php?fnum=3&tid=2521

The real question, as in loudspeakers, is: how loud, how clean? I was making a nice noise in my office with a sub-Watt amp and an RCA duocone speaker, often running under 1/10th Watt. OTOH I've been unable to get loud enough, clean, with 200 Watt amps. I've made 200 Watts of racket with 75 Watt amps. The headphone power I need to listen to the TV when the house is asleep is way-way less than the power I need to monitor live recording in the same room with the band. Headphones vary a lot. Impedance issues confuse things. So 5mW may be plenty, or 500mW may be not excessive.

> couldn't just about any power amp be adapted for headphones?

Sure. 50-Watt 8Ω amps are common garage-sale finds. Most of then are common-ground output, so can be wired to a standard common-gound headphone jack. If it makes 50 Watts in 8Ω in 600Ω it will make 50W*8Ω/600Ω= 0.66W or 660mW , in 100Ω you get 4 Watts or 4,000mW, in 32Ω you get over 12 Watts or 12,000mW. Since headphones need more than a mW but almost never a whole Watt, you are in some danger of frying the phones. And since you listen to speakers from >3 feet away, but phones are right on your ear, and the actual efficiency is not so very different, noise that is inaudible on loudspeakers may be annoying in headphones.

One old technique is to add a 270Ω series resistor, but this can give very large power in higher-Z phones, and I have seen a 30 Watt amp fry Koss Pro4s this way (not while on my head!). It may also under-damp low-Z phones, though I have not yet found the low-Z phone that seemed to need damping.

In the threads above I derive a 7V 29Ω output spec that seems to give "ample" power into most commercial headphones. The speaker amp makes around 20V, so we need a voltage divider with loss of about 7/20 = 1/3 and output Z near 29Ω. 100Ω and 47Ω is in the ballpark.

This also cuts noise somewhat.

The 8Ω-rated amp will see from 147Ω (no phone) to 100Ω (shorted phone). 100/8= 12 sets of resistors can drive 12 ears to ample level with total immunity to shorts. If the amp doesn't die at 4Ω you can double this. (The 100Ω resistor must be 1/2 Watt or more to resist smoking under gross abuse.)

If the amp is rated 8 Watts in 8Ω, just put a 27Ω resistor between it and each headphone, maximum of 3 to 6 shorted outputs or 6 to 12 un-shorted 32Ω phones. If rated 200 Watts, use 180Ω and 32Ω divider resistors, you can hang dozens of these on the amp.
 
[quote author="Ethan"]
OR how about even a simple "API" based headphone amp using a spare 325 line amp module, easy balanced input and output... Although I'm not sure how well it will drive your average 75ohm headphones. Perhaps someone smart may know...[/quote]

I think the 2520 is actually driving 75 ohms into the output transformer, right?

Could I just take a 325 circuit and omit the output transformer?

dave
 
Using a power amp for headphones only will not load the amp like it needs, it wants to see a 8 ohm load, you could put a 8 ohm resistor across it, that would work better.
An advantage of the 990 it can run off +-24 volts, for 600 ohm phones that would drive them better.
 
Yes just leaving off the output transformer on a 990 or 2520 circuit and adding a 47ohm resistor in series with the output will work fine. Or you could use these :)

hybrid%20top%202%20200.jpg
hybrid%20side%20200.jpg


http://www.jlmaudio.com/JLM Hybrid opamp.htm
 
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