[xaval]

Quote:

   
   
10ohm/10watt resistors in parallel. Resistors attached with bananas, headphones with 4-pin XLR female terminated in spades.

Thank you! 

 
I have more than one speaker amp and am considering playing with them without carrying the Stax energizer around. This could be really great.

 

[oqvist]

 
Quote:

This is a 3 part answer... Part 2 pertaining to the HP's themselves.
1. The amp itself.
Most regular amps like to see a load. Especially tube amps. So, if you're running hp's off the speaker binding posts of an amp it's a good idea to have the hp's connected (and/or with resistors in place to somewhat simulate a load).
2. HP protection.
Some amps 'click' or 'pop' when they turn on or off and therefore volume down is imperative, some like the Lyr (I have that too) have a relay delay to alleviate that issue. Also that can happen when connecting to the binding posts, so again I make connections when amp is off or at the very least muted.
3. The amp again.
I have personally blown an amp when connecting speakers by accidentally shorting +/-  while the amp in on - I learned from that and now make all connections while amp is Off.
 
Of course, I'm not an Audio Engineer and I'm sure someone will have a more scientific answer as to how/why/which precautions should be taken. I just speak from experience. Bitter, expensive experience.

 
Many amps do this at startup with the headphones connected. Lyr before the upgrade had a big issue with this. Connecting, disconnecting can create shorts too but that is less of a potential issue I suppose. Putting volume at 0 don´t alleviate the issue fully it seems as you can still  get a slight thump? If even headphone designs can be flawed like the original Lyr so to actually blow drivers  what about speaker amplifiers where it´s not even on the paper to connect headphones to the speaker terminals?  
But you could damage a speaker amplifier by starting it without a load? Also more modern transistor designs? Otherwise like happy camper suggest in my case I will have a balanced XLR connector I can easilly connect/disconnect would be the safest way. But maybe overkill for magneplanar drivers in general with more precautions then making sure the volume pot is way down
 
I am not an Audio Engineer either I want to get this 110 % clear how to operate headphones on speaker amplifier terminals so I don´t get similar experiences.

 

[Operakid]

Once you have the gain under control, as if you were using speakers with the speaker amp, the headphones will be no more vulnerable than speakers.  The resistive loading makes the heaphones see what they expect to see, they don't know if it is a headphone amp or speaker amp.
 
Where the headphones are vulnerable is if you are not properly loading and you are loud with just one click or movement of the volume control.  At that point, yes, a turn on or turn off click could blow them and you should neither run speakers nor headphones in a gain situation like this.
 
As far as an amp seeing a load, the resistor across + and - does that.
 
As far as shorting the amp, none of the thinks I have described in this thread will.
 
However, if you are not sure about what you are doing and therefore feel you might make a mistake, do not do any of the things described in this thread.    

 

[xaval]

Regarding the resistive loading, would a switcher box be adequate? I mean those boxes that allow you to connect 2 different loudspeakers? The idea would be to switch A for headphones and switch B for the loudspeakers - I'd have the best of both worlds I guess.

 

[Operakid]

Sure, with the switcher box before the resistor network for the headphones the amp would not know whether the headphone position involved speakers or headphones.  This is assuming the box in and of itself does not do things the particular amp does not like, as in momentary shorting or momentary open circuit.  I cannot speak to these things.
 
Also, that's assuming the headphones are properly padded down so that any electrical noise during changeover (impossible to envision everything about every switchbox available!) would not represent a huge pulse.  There are many reasons I caution folks to pad the headphones down so that the volume setting would be similar to the setting with average speakers.  With that "reduced effective gain" of the speaker amp normal transients and blips won't look like seismic events to the headphones.    

 

[Ducker]

How about the Can Opener?
 
http://www.vinylflat.com/canopener.html
 
Thanks.

 

[Operakid]

A limitation is the banana plug, meaning that grounds are shared and therefore there is no way to use balanced, and speaker amps give you that feature.  I'd also love to know what resistors (quality level) they are using.  Not brand, per se, but type (wire wound non inductive, film, etc).  
 
Also would be very interesting to know the resistors inside, what they load the amp at, what the attenuation is, and what the impedance the cans see is.  I would talk to the company about the above before using it with expensive headphones.  

 

[Mambosenior]

After a stretch of time running the 800 from the Threshold, I am more convinced than ever that (for my tastes, and in my opinion only) I am finally hearing the possibilities of this headphone...in spades. The same opinion also held true for my experiences with the HE-5LE.
 
I hesitate to write this in the (new) HD-800 thread because I don't wish to derail it and have also recently read pretty ridiculous comments about how a too-powerful amplifier could "blow up" the headphones. Hell, lack of attention while having them hooked up to even a weak HP can present the same disaster.
 
Please understand, this view of running the 800 with a speaker amp is simply untrue! All I've added to the amp are two 10W/10ohm Vishay resistors in parallel across the “+” and “-” taps. Even using a very reasonably priced Audio-gd NFB 11.32 (in variable mode with volume control) which services the Mac computer (USB) and an el cheapo Pioneer 610 DVD player (plays DVD-A, by the way) the sound is spectacular with well-recorded material (yes, the crap recordings still sound like crap). The gain goes up to 9 o'clock for most Rock, Jazz recordings and in Classical to about 10. Although I wish I had my better gear available at this location to test the set-up and see how much more different it would sound, I remain in awe of what I had been missing even listening with front-end gear that costs (roughly) barely $500.
 
In a previous post I had listed HP amps that I had used or tried with the 800. Although almost all rated from very good to excellent, none of them ever presented me with the level of resolution, naturalness of instrumental timbre and sheer musicality that I am hearing now. In case it's important to anyone here: I am a young, old guy (“it isn't the age, it's the mileage...” - Indiana Jones) who has been in music all his life.
 
(I thank, again, Operakid for the initial encouragement and how-to tips.)

 

[Ducker]

Thanks.  That helps a lot.
 
 
"A limitation is the banana plug, meaning that grounds are shared and therefore there is no way to use balanced, and speaker amps give you that feature.  I'd also love to know what resistors (quality level) they are using.  Not brand, per se, but type (wire wound non inductive, film, etc).  
 
 

 

[Operakid]

Now that I have tried lots of resistive networks, I would love to offer one or a series for different headphones.  Problem is, when I add the price of good RCA plugs, good bananas, a simple but nice box, very good sounding (but not crazy priced Mundorffs or anything like that) wire-wound, non inductive resistors, the parts would be well over $100, and labor at my actual cost $100, so over $200 with absolutely no profit.  Bummer.
 
And Mambosenior, thank you so much for the nice words.  I am laughing to myself when I listen to the quality using my favorite speaker amp, it is such a good way to go, and so much baloney (balogna for purists) about not being able to do it, as you say.
 
 I can only agree with your last paragraph.  Ridiculous sonic quality, and like you I am a veteran of lots of sound and music.  

 

[xaval]

Quote:

How about the Can Opener?
 
http://www.vinylflat.com/canopener.html
 
Thanks.

I figure this product is very similar to what I posted on post #41 of this thread. It has inside pics for anyone interested. I suppose it would be ideal if such a product could offer balanced connections...

 

[xaval]

Quote:

Now that I have tried lots of resistive networks, I would love to offer one or a series for different headphones.  Problem is, when I add the price of good RCA plugs, good bananas, a simple but nice box, very good sounding (but not crazy priced Mundorffs or anything like that) wire-wound, non inductive resistors, the parts would be well over $100, and labor at my actual cost $100, so over $200 with absolutely no profit.  Bummer.
 
And Mambosenior, thank you so much for the nice words.  I am laughing to myself when I listen to the quality using my favorite speaker amp, it is such a good way to go, and so much baloney (balogna for purists) about not being able to do it, as you say.
 
 I can only agree with your last paragraph.  Ridiculous sonic quality, and like you I am a veteran of lots of sound and music.  

For anyone with an already nice speaker amp would probably be a more than cost effective solution as a new head amp would certainly represent a far more expensive venture. Probably a good DIY project. With the right info on parts I wouldn't mind messing with my ART Headtap and try and build a better solution. I'd already be an enclosure ahead. Feel free to share more info on parts Operakid in case you're not looking into building and selling such gadget

 

[Chris J]

A bit off topic here, but I've tried plugging my headphones into the headphone jack on my Bryston 2B-LP power amp. The headphone jack has 120 Ohm resistors in series with the power amp output.
 
I thought it sounded fine, but I don't use this much as I can hear a trace of "hiss" with some 'phones.
 
BTW, not too sure what a "loading resistor" is supposed to do for a SS amp. Why bother?     Just curious................

I suppose some tube amps may not like to operate Open Circuit, or virtually Open Circuit.

 

[Operakid]

The standard is to have a 120 ohm resistor.  It can be debated whether this is appropriate or not depending on the headphone.  Also, this resistor is not off the main outputs of amps.  It all depends on the configuration of the piece of equipment.  The only way to know for sure is to check, or to use the main outputs with your own resistive network, maximized for your particular headphones (I am making a network for each of my different headphones) which was my point in starting this thread: to get info on this.  Turns out there is little so I went to the drawing board myself (designer/engineer/physicist), resulting in sound that I had no reason for confidence that it would be this great.           

 

[Operakid]

Quote:

A bit off topic here, but I've tried plugging my headphones into the headphone jack on my Bryston 2B-LP power amp. The headphone jack has 120 Ohm resistors in series with the power amp output.
 
I thought it sounded fine, but I don't use this much as I can hear a trace of "hiss" with some 'phones.
 
BTW, not too sure what a "loading resistor" is supposed to do for a SS amp. Why bother?     Just curious................

I suppose some tube amps may not like to operate Open Circuit, or virtually Open Circuit.

The loading resistor (across + and - terminals of amp) is to let the amp see a normal 8 or 10 ohm load instead of a much higher impedance load, which they are made for and could cause oscillation, and even if no oscillation will result in higher distortion.  There is power to throw away with speaker amps, even a 10 watter, so this is of no consequence.  But the amp is happy, and a series loading resistor makes the headphones happy, looking back at a higher impedance, as well as makes the often necessary attenuation possible.
 
I have to believe the right resistive network would result in as quiet operation as any other amp, including headphone amps, would show.