[Armaegis]

I don't have any personal experience with that... but judging from the connectors that looks like it actually converts speaker level back down to line level so you can plug into another amp. I suppose technically you can connect a headphone to the rca outputs if you rigged up the correct cabling, but I won't even hazard a guess as to how it'll sound. It doesn't even have specs to look up; who knows if its even capable of trasmitting power or if it'll go kablouie when you try to transfer a couple watts through it (recall that an amp input impedance is rather high, so transmitted power would likely be in the mW range)

 

[Hutnicks]

  I don't have any personal experience with that... but judging from the connectors that looks like it actually converts speaker level back down to line level so you can plug into another amp. I suppose technically you can connect a headphone to the rca outputs if you rigged up the correct cabling, but I won't even hazard a guess as to how it'll sound. It doesn't even have specs to look up; who knows if its even capable of trasmitting power or if it'll go kablouie when you try to transfer a couple watts through it (recall that an amp input impedance is rather high, so transmitted power would likely be in the mW range)

Yes. Odd little item. The spec I saw said it is adjustable from 0 to 1000mV and can handle amp outputs up to 55 watts.
 
I have one lying around. If I get a minute I'll pop it open and post up a pic of the circuit.
 
AHA.
 

 

 
Not a whole lot of gee whiz going on in here. I was drawn to the isolation provided by the transformers as a possible solution to using a small digital amp board for headphones. Never got it out of the parts bin to try it though.

 

[Chris J]

Oh for the luvapete, it's an L-pad guys. There's a hundred schematics and plans online. Heck, you can buy premade adjustable ones for cheap: http://www.parts-express.com/cat/speaker-l-pads/306

Add a box, some wire, and a pair of binding posts and call it a day.

oh, wow!
Reverse engineered alien technology!

 

[Armaegis]

 
Yes. Odd little item. The spec I saw said it is adjustable from 0 to 1000mV and can handle amp outputs up to 55 watts.
 
I have one lying around. If I get a minute I'll pop it open and post up a pic of the circuit.
 
  Not a whole lot of gee whiz going on in here. I was drawn to the isolation provided by the transformers as a possible solution to using a small digital amp board for headphones. Never got it out of the parts bin to try it though.

 
Huh, I'm guessing it's an L-pad into a step-down transformer into a regular pot to control output. Actually probably just a 1:1 simply for isolation. Easier that way.
 
If that box is rated for 55W... that's about 21V coming in (assuming 8ohm rating). The only resistor I can see is 220ohm, so I'm assuming the vertical ones are what's holding a steady 8ohm load while the 220 is in series.  Let's say the parallel resistor is 10 because why not and it account for whatever wobbliness on the receiving end.  Do your math for 21*10/(220+10) = 0.9V
 
Well lookitthat, we're right at line level. Go through the isolation transformer to reduce hum (because lordy knows a car is going to have ugly noise problems), drop a cheap pot at the end and voila, you now have your 0-1000mV output.

 

[Hutnicks]

   
Huh, I'm guessing it's an L-pad into a step-down transformer into a regular pot to control output. Actually probably just a 1:1 simply for isolation. Easier that way.
 
If that box is rated for 55W... that's about 21V coming in (assuming 8ohm rating). The only resistor I can see is 220ohm, so I'm assuming the vertical ones are what's holding a steady 8ohm load while the 220 is in series.  Let's say the parallel resistor is 10 because why not and it account for whatever wobbliness on the receiving end.  Do your math for 21*10/(220+10) = 0.9V
 
Well lookitthat, we're right at line level. Go through the isolation transformer to reduce hum (because lordy knows a car is going to have ugly noise problems), drop a cheap pot at the end and voila, you now have your 0-1000mV output.

Makes sense. An isolating L Pad to get rid of the inevitable interference of a system with everything from an alternator to your head end sharing the same ground.

 

[squirrelman]

So I was looking at the Hifiman box out of curiosity and saw it mentioned that it isn't for sensitive headphones, I was wondering if there is another box out there that I could use with my LCD-XCs?  I am curious to try them out with my speaker amp (It is a Dennis Had built running with Tung-Sol 6550 at ~12W).  

 

[Chris J]

Have you tried running your LCDs straight off the amp?
You say your amp is only 12 Watts into 8 Ohms.
I would try wiring your 'phones straight into it.

 

[esmBOS]

Have you tried running your LCDs straight off the amp?
You say your amp is only 12 Watts into 8 Ohms.
I would try wiring your 'phones straight into it.

I also have a 2 x 12W into 8 Ohm amp and it's way to powerful for my LCD3f straight off the binding posts! No play on the volume control what so ever. Mine is a Elekit 22 hybrid, which should be quite similar to yours. I'd suggest you start by adding a 10 Ohm resistor in parallel. That ALMOST did it for me 

 
 
edit: Check comment below.

 

[davidsh]

 

Have you tried running your LCDs straight off the amp?
You say your amp is only 12 Watts into 8 Ohms.
I would try wiring your 'phones straight into it.

I also have a 2 x 12W into 8 Ohm amp and it's way to powerful for my LCD3f straight off the binding posts! No play on the volume control what so ever. Mine is a Elekit 22 hybrid, which should be quite similar to yours. I'd suggest you start by adding a 10 Ohm resistor in parallel. That ALMOST did it for me 

This will not give you more play on the volume control with any ordinary amp

 

[squirrelman]

Thanks for the replays, I don't really want to mess around with resistors and what not, I was hoping there was a box kind of like the Hifiman one I could just buy and be good with.

 

[Chris J]

This will not give you more play on the volume control with any ordinary amp

Agreed!
It will only pull more current from the amp, and that ain't gonna fix any "I don't have enough play on the volume control" problems!

 

[mtoc]

Folks, have a serious question, could we use tube speaker amp to drive HD800, the output-Z is usually 4 ohm and 8 ohm, would we burn something or sound bad like hell?

 

[Armaegis]

For tube amps that specify 4 or 8 ohm outputs on their speaker taps, this is usually to provide ideal loading conditions on the tube for optimal performance.
 
Standard practice here is to put a resistor across the outputs in parallel with your headphone. For example, putting some 10ohm resistors across the speaker taps in parallel with the 50ohm HE-6 will produce an equivalent load of 8.33ohms, perfectly in range to use the 8ohm outputs on the amp.

 

[Rossliew]

Can anyone advise if it's ok to connect headphones directly (without resistors in place) to one of those Mcintosh amps which have autoformers?

 

[Stereomojo]

Hello geniuses!

I have several low output amps, A couple that use EL 84's and even a couple of Tripaths. I don't think I need to worry about resistors, so here's my question:

How do I go from four speaker posts to one 1/4 inch Headphone connector like a 650 or 400s? Is there something I can purchase that will do the trick that doesn't cost a lot like the hi-fi man box?