Forums - What’s involved in making my Select into a Headph

boead

Ex Member

What’s involved in making my Select into a Headph
12/24/05 at 14:35:15

What’s involved in making my Select into a Headphone Amp?

My Sennheiser’s are 300ohm’s, 97db and other headphone I’ll likely own are these AKG 701’s which are 62 ohm’s, 105 db.

I’d like to buy a MLB but I’m not spending $700+ on a headphone amp and then have to tube it to my taste.
My friend has a ASL EL84 SET headphone amp that just sounds really great with some choice tubes. You can have one for $300 used on Audiogon or Ebay easily!

Since my Select won’t be in use till sometime this spring or early summer, I’d consider converting or doing something so I can use it for my headphones.

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« Last Edit: 12/24/05 at 14:35:55 by bo »

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dr._sleep

Ex Member

Re: What’s involved in making my Select into a Hea
Reply #1 - 12/24/05 at 16:04:54

Try 100 ohm/2 watt resistor in series on each positive speaker binding posts to +L and +R earphone and a 10 ohm/2 watt resistor paralleled across + to - on each of the speaker terminals. Of course ground return of Headphones to - posts

dr._sleep

BINDING POST LEFT
(+)--------100 ohm----(+) left side headphone (tip)
\
10 ohms
/
(-)------------------(-) Headphone(sleeve)

BINDING POST RIGHT
(+)------------100 ohm------(+) Right side headphone
\ (ring)
10 ohms
/
(-)------------------------(-) Headphone (sleeve)

the(-) headphone share the same connection on the headphone jack.

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boead

Ex Member

Re: What’s involved in making my Select into a Hea
Reply #2 - 12/26/05 at 20:51:17

I just picked up the following resistors:

10-Ohm, 1 watt Metal-Oxide Resistors
100-Ohm, 1 watt Metal-Oxide Resistors
10-Ohm, 1/2 watt Carbon Composite Resistors
100-Ohm, 1/2 watt Carbon Composite Resistors

Which ones should I try?

RadioShack didn't have any 2 watt Resistors.

Also, are they directional? I didn't think so.

Thanks Doc.

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« Last Edit: 12/26/05 at 20:52:32 by bo »

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Rap

Ex Member

Re: What’s involved in making my Select into a Hea
Reply #3 - 12/26/05 at 21:24:41

I use to think resistors weren't´t directional, until I built a passive-pre with the law-faking config. I put one of the 1k resistors different than the other and you could hear it straight away Angry

at first I thought the pot was uneven or some in-room reflections were not right, I even try´d cables and tube-rolling all for nothing Cry

then I flipped one of the 1k resistors around and finally both channels had the same gain

I havn´t tryed switching the resistors both around but having them both in the same direction seems´to have an effect, both were 1kohm metaloxid 1% tolerance and 500ma.
>>mod ment to say 0.5 w not ma>>

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« Last Edit: 12/26/05 at 23:24:13 by Rap »

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boead

Ex Member

Re: What’s involved in making my Select into a Hea
Reply #4 - 01/13/06 at 04:01:18

http://www.divertech.com/asluhcsignature.html

Just got this device and its very nice so far.

More weight then with the resistors described above, less intolerable detail. Overall smoother presentation.

Gear is all cold tonight, its sounding better as it warms up. I don’t think this device is broken in either. Amp hums more then I’d like.

Will listen for some time and comment back.

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Brian Ex Member	Re: What’s involved in making my Select into a Hea Reply #5 - 01/13/06 at 05:09:23 Boead, do you listen to a variety of sources with your headphones? If it is your cd player only, you might try adding a headphone jack to it's output. I think it was at Goodcans website that I read of running headphones directly off the cd player. An impedance matching transformer might help.
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boead

Ex Member

Re: What’s involved in making my Select into a Hea
Reply #6 - 01/13/06 at 11:42:07

[quote author=Brian link=1135438515/0#5 date=1137128963]Boead, do you listen to a variety of sources with your headphones? If it is your cd player only, you might try adding a headphone jack to it's output. I think it was at Goodcans website that I read of running headphones directly off the cd player.

An impedance matching transformer might help.

[/quote]

Oh no, the headphones need a lot of drive. If I try running my Sennheiser’s on a portable player like an iPod its not much louder then a whisper. Even with a hotter output, the drive isn’t nearly enough.
Other headphones like the AKG K1000’s actually need a couple of watts to operate at all. Ask Steve D. about the insanity of headphones.

There are many headphones efficient enough to run off portables and sure a line level attenuator will work. Headphones like the Sony 5000’s, almost all Grados’s and some Sennheisers are very efficient but most aren’t.

ASL makes this, its what you are talking about.

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Brian Ex Member	Re: What’s involved in making my Select into a Hea Reply #7 - 01/14/06 at 02:50:43 I see.
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boaed

Ex Member

Re: What’s involved in making my Select into a Hea
Reply #8 - 01/23/06 at 07:11:57

http://www.divertech.com/asluhcsignature.html

Just got this device and its very nice so far.

More weight then with the resistors described above, less intolerable detail. Overall smoother presentation.

Gear is all cold tonight, its sounding better as it warms up. I don’t think this device is broken in either. Amp hums more then I’d like.

Will listen for some time and comment back.

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