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Speaker amps for headphones - Page 4

post #46 of 2599

How so?

post #47 of 2599
Thread Starter 

Mambosenior, thank you, I am so happy that information shared results in happier listening.  I feel very lucky that I ventured forth, and will continue to do so.  But not with manic urgency as I am getting great refined, smooth, detailed, warm, dynamic sound.  

post #48 of 2599
Quote:
Originally Posted by Operakid View Post

 

 

You may not need any parallel resistor at the amp terminals as these are all relatively low impedance headphones.  With the lower sensitivity headphones you would be throwing a lot of energy away through a parallel resistor.

 

However, that is a wide range in sensitivities.  Especially for those real efficient cans you may need a series resistor at the amp, a parallel resistor after that, and another series resistor before the headphones, like that voltage divider circuit a prior poster gave a link to.  I'd be careful with those 102 and especially 108db cans, not to blow them up with a speaker amp.  I personally would not be hooking them up without resistive loading.  

Thanks for the informative response. The amp would put out almost 3 watts into the 2 orthos directly from the speaker taps which would be plentiful headroom.

 

Perhaps I should make 2 headphone outs, one for the orthos and another shielded by resistors for the 2 sensitive phones.

post #49 of 2599
Thread Starter 

That sure sounds like a no-brainer solution!  Have fun, please let us know how it works out.

post #50 of 2599

Hi Operakid

This is a very useful thread.  

The HE6 sounded sublime directly from the speaker taps of my Manley Stingray, but I understand that without a resistor the amp can be potentially damaged. 

 

What capacity resistors do I use for HE6 & HD800s. Am clueless regarding impedance, wattage, etc etc

 

Thanks 


Edited by SHAHZADA123 - 3/13/13 at 8:52pm
post #51 of 2599
Thread Starter 

I would start with a 10 ohm 5 watt resistor in parallel (going from + to -) and a 20 or 25 ohm 5 watt resistor in series, after the 10 ohm resistor, in the + line.  Feel the resistors to see if they start getting real hot in use.  If so up the wattage.  

 

Some will bemoan the 25 ohm resistor, saying damping factor will only be 2.  My experience says try it anyway.  I have no damping factor on my current setup with the Senn HD800 as my series loading resistors are so high, yet the sound is very detailed, and bass is explosive, just the opposite of what we might  think a low damping factor would give.  This parallels my experience with speakers and amps, depending on the Q of the speaker and the characteristics of the amp one can have more explosive sound than a much higher damping factor amp that does not mate up as well with the speaker.  The moral is: you MUST try these things to know for sure.

 

If you end up feeling bass is softer or less powerful you could try  a 10 ohm series resistor.  These are not expensive, non-inductive Vishay-Dale wire wound resistors (I am finding these sound great in this application, though I am sure I'll be preached to saying I should use Mundorf or something even more exotic) cost $2-$5 each from Mouser in these sizes.  

 

Please let us know the results.

post #52 of 2599
Quote:
Originally Posted by Operakid View Post

I would start with a 10 ohm 5 watt resistor in parallel (going from + to -) and a 20 or 25 ohm 5 watt resistor in series, after the 10 ohm resistor, in the + line.  Feel the resistors to see if they start getting real hot in use.  If so up the wattage.  

 

Some will bemoan the 25 ohm resistor, saying damping factor will only be 2.  My experience says try it anyway.  I have no damping factor on my current setup with the Senn HD800 as my series loading resistors are so high, yet the sound is very detailed, and bass is explosive, just the opposite of what we might  think a low damping factor would give.  This parallels my experience with speakers and amps, depending on the Q of the speaker and the characteristics of the amp one can have more explosive sound than a much higher damping factor amp that does not mate up as well with the speaker.  The moral is: you MUST try these things to know for sure.

 

If you end up feeling bass is softer or less powerful you could try  a 10 ohm series resistor.  These are not expensive, non-inductive Vishay-Dale wire wound resistors (I am finding these sound great in this application, though I am sure I'll be preached to saying I should use Mundorf or something even more exotic) cost $2-$5 each from Mouser in these sizes.  

 

Please let us know the results.

For the less technically inclined, could you be bothered to take a pic of how it actually looks like to install those resistors? Thanks.

post #53 of 2599
Resistors 1.jpg 1,655k .jpg file

 

Resistors 2.jpg 1,716k .jpg file

 

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

post #54 of 2599
Quote:
Originally Posted by Operakid View Post

I would start with a 10 ohm 5 watt resistor in parallel (going from + to -) and a 20 or 25 ohm 5 watt resistor in series, after the 10 ohm resistor, in the + line.  Feel the resistors to see if they start getting real hot in use.  If so up the wattage.  

 

Very interesting thread! I have the 600 ohm version of Beyerdynamic DT 880's. Do the above recommended resistor values stay the same? Thanks!

post #55 of 2599
Do you always disconnect the headphones before starting or shutting off the amplifier?
post #56 of 2599
Quote:
Originally Posted by oqvist View Post

Do you always disconnect the headphones before starting or shutting off the amplifier?


Personally, no. It's a risk that when the Amp is running that you'll accidentally short the + and - terminals together and damage the amp.

One thing I always do (even with regular headamp) is the turn the Volume to mute before power up/down.

post #57 of 2599
Thread Starter 
Quote:
Originally Posted by Micaiah View Post

 

Very interesting thread! I have the 600 ohm version of Beyerdynamic DT 880's. Do the above recommended resistor values stay the same? Thanks!

 

I would use a 10 ohm resistor across the amp leads (+ and - of each channel) but would use a larger resistor in series (in the + lines only) than with the low impedance headphones.  Maybe try a 100 ohm and bring up the volume slowly, from zero setting, to be sure you do not have too much gain (I am always very careful about blowing the drivers in the headphones).  Despite the warning I am guessing this will get you in the ballpard, and if you are running the volume higher than you would like  go down from 100 ohms.

post #58 of 2599

 

Quote:
Originally Posted by eddiek997 View Post


Personally, no. It's a risk that when the Amp is running that you'll accidentally short the + and - terminals together and damage the amp.

One thing I always do (even with regular headamp) is the turn the Volume to mute before power up/down.

 

On the headphone end of the cable there wouldn´t be a problem or? I am thinking speaker amps may be even worse then some headphone amps on startup or shut down. I am not going to let my receiver run 24/7. Some designs like the SPL auditor/phonitor and the Lyr before they fix that issues for example wasn´t nice to headphones on startup.

I am only going to use my ortho which I imagine tolerate a bit more then dynamic drivers though.

post #59 of 2599
Quote:
Originally Posted by oqvist View Post

 

 

On the headphone end of the cable there wouldn´t be a problem or? I am thinking speaker amps may be even worse then some headphone amps on startup or shut down. I am not going to let my receiver run 24/7. Some designs like the SPL auditor/phonitor and the Lyr before they fix that issues for example wasn´t nice to headphones on startup.

I am only going to use my ortho which I imagine tolerate a bit more then dynamic drivers though.

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. :)

post #60 of 2599
Quote:
Originally Posted by eddiek997 View Post


Personally, no. It's a risk that when the Amp is running that you'll accidentally short the + and - terminals together and damage the amp.
One thing I always do (even with regular headamp) is the turn the Volume to mute before power up/down.
Using a XLR connector mid cable gives you the ability to disconnect the phones without messing with the posts.
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