[Austin_J]

Hi - I was wondering about how to drive a pair of headphones from the speaker level outputs on a regular amp. Are there products for this or is there an easy DIY solution?

I tried before with poor results (amp got hot and sound was poor with a 47 labs gaincard).

Thanks,

Austin

 

[CSMR]

I have an ASL UHC Signature headphone adapter on order. There are comments and reviews here. If you want one, send me a PM, and I can put you in contact with someone who sells them at a good price.

 

[mkmelt]

Headphone jacks were not commonly built into stereo amplifiers and receivers until well into the 1960s. Headphone adapters were offered that enabled you to connect headphones to the output of your amplifier. In addition to one or two headphone jacks, these adapters incorporated a pair of left/right level controls to adjust the volume and a switch to enable the speakers to be disconnected for headphone listening.

You can readily build your own headphone adapter. All you need is a 1/4 inch or 1/8 inch headphone coupling jack, a pair of 1/2 or 1 watt resistors (value between 50 and 200 ohms), speaker wire terminals (connector style of your choice), some suitable wire, and a small project box.

Experiment with the value of the resistors until you find the value that gives you an appropriate volume range when adjusting the volume control on the amplifier. You don't want the volume coming up too soon as you raise the volume control, or requiring that you turn the control all the way up for suitable listening level. A value that results in a normal listening level when the volume control is set to 10 or 11 O'Clock will provide a good range control of the listening volume. If you intend to also listen to speakers, it is a good idea to select resistor values so the headphone listening level closely matches the output level when using the speakers. Otherwise, if you forget to lower the volume and switch to the speakers, you will get a blast of audio from the speakers until you turn down the volume.

You generally don't need to use a matching transformer with a solid state amplifier. Output transformers are needed to enable tube amplifiers to drive low impedance speaker or headphone loads (typically 4 to 32 ohms). All output transformers will, to some extent, operate as bandpass filters and also introduce some phase shift. Unless the transformers are of a suitable high quality (and thus expensive) the bass response from the speakers or headphones will be noticably rolled off.

 

[Naga]

Quote:

Originally Posted by mkmelt Headphone jacks were not commonly built into stereo amplifiers and receivers until well into the 1960s. Headphone adapters were offered that enabled you to connect headphones to the output of your amplifier. In addition to one or two headphone jacks, these adapters incorporated a pair of left/right level controls to adjust the volume and a switch to enable the speakers to be disconnected for headphone listening.

we have a JVC receiver in the basement ( i like it alot ) and its got a built in headphone jack; i can drive 250 ohm Koss 4aaTs in that?


im such a noob, sorry

 

[Nak Man]

Quote:

Originally Posted by Naga can drive 250 ohm Koss 4aaTs in that?

Best bet is to try that yourself. Using phones jack will be safe for its intended use

unless you're thinking of using speakers output to drive your koss.

 

[Naga]

sorry, i just want some sort of conformation before i drive the ridiculus distance to the closest place that possibly has the Koss 4AATs

 

[mkmelt]

There is no reason why the JVC receiver should not be able to drive the Koss 4AAT (rated 250 ohm). I am curious why you have decided on those particular headphones as I own a pair. They are a sealed design, good for blocking outside noise, but there are better sounding headphones available for the money.

 

[Nak Man]

I'm quite sure old receiver will drive phones at louder volume than average current avrs - sound quality wise they're about the same, may not be up to par with dedicated phones amps (that may cost even more than whole receiver !).

In addition, Koss phones in average are highly sensitive, so you should have no problem at all.

The beauty of using old receiver / integrated is that most running phones jacks straight from power amp section, instead of using a separate op amp. Thus it may be possible to 'tailor' output impedance to better match your phones using resistors, either from phones jack or from slight internal mods.

 

[recephasan]

Check this out

 

[DanT]

Quote:

Originally Posted by recephasan Check this out

EDIT: Nevermind I see it now

 

[Naga]

Quote:

Originally Posted by mkmelt There is no reason why the JVC receiver should not be able to drive the Koss 4AAT (rated 250 ohm). I am curious why you have decided on those particular headphones as I own a pair. They are a sealed design, good for blocking outside noise, but there are better sounding headphones available for the money.

ive heard good things about them; for the price ( ~80$ off the shelf ) i think its a good balance b/w quality and durability ( tho I will take measures to baby them ) ; dont think i have seen anything in the range like that

i also hear they have a breakin period of 100 hrs

I am not done with my research yet tho

 

[Naga]

I'm quite sure old receiver will drive phones at louder volume than average current avrs - sound quality wise they're about the same, may not be up to par with dedicated phones amps (that may cost even more than whole receiver !).

[ /quote] what is avrs?

?


Quote:

Originally Posted by Nak Man In addition, Koss phones in average are highly sensitive, so you should have no problem at all.

i have a cheaper Koss pair ( $40 on sale for $20 ) rite now, and they are indeed very sensitive; shallow on bass tho; unlike the 20$ Sony V150 Headphones that feel over-boosted from anything, but dont feel particularly sensitive to details


thanks for all the advice from everybody

 

[mkmelt]

Unless you are really set on getting the Koss 4AAT phones, keep looking.
These Koss phones are heavy (but comfortable due to a well padded headband). They are good at blocking outside sounds and not leak sound that would disturb others. I find that my ears feel overly warm after about an hour of use. They work well with older amplifiers and receivers that were designed for high impedance phones. The sound is non-fatiguing. The bass is not as extended as on some other phones. If I had to give them an overall grade, it would be a "B".

In your price range worth considering (in no particular order):

Grado SR-80 (open)
Sennheiser HD-497 (open)
Beyer Dynamic DT-231 (closed)

With a bit of a stretch, a pair of used/refurbished HD-580 would be within your price range. Those would be a good choice too.

 

[Naga]

i have looked at the HD 497s quite a bit, they seem like a good value too; ill keep them in mind ( main problem is they Look like something id have no trouble in breaking), i may go out this week to get the 4AATs, depends on time constraints

cant say im in a rush or anything, the amp is in the basement - just wish i could sort out the 80$ amps from the 600$ variety ( i mean, can the Cmoys drive a 250 ohm pair of 'phones? )