[BMBROWN911]

The other day I saw a thread on here about a guy who decided to try powering his Sennheiser HD600 from his speaker amp and said that it had worked out really well. That got me curious and I decided that it was something I would be interested in trying but before I tried it with my HD600's I wanted some practice on some other phones that I don't mind blowing up. So I initially tried it with a pair of KSC55's . When I stripped the cable each side had it's own ground so I figured it would just be a piece of cake and wire it to the speaker taps just like a regular speaker and lo and behold I'm getting no sound at all. I also decided to try it with an old pair of Bose Triports and it was the same deal. The cable had separate grounds for each channel but when I ran the wire to the speaker taps I would get no sound. Am I missing something here. I think it would be real cool to get this to work once even if it's with crappy headphones. I love to tinker with everything but I'm not sure why it wouldn't be working. The stereo amp I'm using works fine so It's not the amp. Any ideas?

 

[wakibaki]

Are you sure the phones are working?
 
You can test them with a battery.
 
The phones are 60 ohms and will in all probability tolerate 1.5V briefly, but it would be better if you had a resistor of a few hundred ohms in series if you test them like this. Take a single AA battery (1.5V) and momentarily connect it across one pair of wires (with the resistor in series if you have one). Hold one wire in contact and brush the battery terminal with the other or with the free end of the resistor if you have one.  You should hear a crackle and pop from the phones if they are working OK (could be quite loud).
 
If your amp has much of a DC offset it could unfortunately already have destroyed the phones, but this is unlikely in a decent commercial design. It's odd, however,  that 2 pairs of phones don't work. Are you sure the source is correctly selected?
 
w

 

[nikongod]

You did strip the insulation off of the wires, right? 
 
You may have a hard time finding a speaker amp with acceptably low noise for conventional low impedance headphones, but its fun to play with these things. 

 

[Fred_fred2004]

Does it work with a speaker?

 

[BMBROWN911]

I tried the battery test on the Triports and got nothing but wouldn't you have heard a pop or something if they had blown? Also I noticed that when I stripped the cables the colored ones which I assume are not ground have practically zero copper to them. Just some of kind fiber in them. I can literally see maybe 1-3 strands in them. Is that normal? It was also like that with the Koss KSC55's. This kind of has me confused.

 

[nikongod]

 
Quote:

You did strip the insulation off of the wires, right? 
 

 
That's a no. 
 
You should look for a tutorial on reterminating these kinds of headphones with cheap enamel coated wires. Put a 4-pin male XLR on them. Wire a 4pin female XLR to the amp. 

 

[BMBROWN911]

I expected better out of Koss as far as the wiring but not surprised about the wiring from the Bose phones. Surprises me that they were able to pass any kind of a signal at all when they still had their headphone jacks attached. How disappointing. When you say that's a no are you saying I didn't strip the wires correctly? 

 

[nikongod]

 
Quote:

I expected better out of Koss as far as the wiring but not surprised about the wiring from the Bose phones. Surprises me that they were able to pass any kind of a signal at all when they still had their headphone jacks attached. How disappointing. When you say that's a no are you saying I didn't strip the wires correctly? 

Yepp, you didn't strip the wires right. 

 

[BMBROWN911]

Care to explain how to do it correctly. Never had trouble stripping cables and wires before. All I did was take the casing off the cable. 

 

[Uncle Erik]

The wires inside are usually coated with enamel.  Even if you strip off the colored plastic, the enamel remains on the wires.
 
I usually use acetone to remove the enamel.  You can also sand it off or dip it in a solder pot.

 

[BMBROWN911]

Thanks for the reply. I will give it a shot and see if it works. Cheers!

 

[fubar3]

Quote:

When I stripped the cable....

Headphone wires have a dainty construction, I would try to avoid any modifications unless the phones are broken.  Why not get a headphone jack and wire it to the speaker terminals?  You need a resistive divider, say 100 in series and 10 to ground as initial attenuator values.
 
An amplifier intended for speakers will have terrific power gain relative to a headphone amplifier. I would expect increased noise and distortion. So a good headphone amplifier can provide better quality and is easier to relocate to a comfortable place in your home.

 

[BMBROWN911]

This was just an experiment to see if I could get it to work. I had some old Bose Triports that had their headphone jack chewed off by one of the dogs and an old100 watt speaker amp sitting around that isn't really worth anything so I figured there was no harm in at least trying it. I was actually able to make it work and I was actually quite surprised at how much better it made the Triports sound. As you can imagine the bass jumped a bit in what is already a very dark and bassy headphone. It also brought out some details. It definately sounded better then they normally do but they are still Triports and yes there obviously was added noise but just a slight hiss that wasn't even noticeable when playing the music. This experiment will not be expanded to my HD600's as I'm already driving them with a Schitt Lyr which is plenty of power already. As I said this whole thing was an experiment with some old crappy equipment. It was at least fun tho to get it working. Cheers!

 

[nikongod]

 
Quote:

 
An amplifier intended for speakers will have terrific power gain relative to a headphone amplifier. I would expect increased noise and distortion. So a good headphone amplifier can provide better quality and is easier to relocate to a comfortable place in your home.

Power gain is the wrong term, and basically meaningless here.
The term you are looking for is *voltage* gain. Many speaker amps have voltage gain in the 26db range. Certainly more than most conventional headphone amps, but only 6db more than the "rule of thumb" 20db for headphone amps. Im not such a fan of the 20db rule for headphones, but mneh, it provides a reference. 
 
I do agree that the amp may be audibly noisy. I also agree that the distortion from a speaker amp putting 1mw into 32ohms may be higher than a purpose built headphone amp doing the same work although the distortion may still be inaudible - particularly when the noise component is considered.
 
In any case, if it worked out nicely, and the OP liked the results cool! I do like headphones off of speaker amps too, but it does not always work out right so I would go into it with some caution.

 

[BMBROWN911]

Just curious about whether or not rigging your headphones up this way is in any way similar to a balanced headphone setup? Not necessarily the signal but the actual headphones themselves. Since your grounds are now separated instead of combined at the headphone jack? Would this be similar to a balanced ground setup or anything?