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Speaker amps for headphones - Page 99

post #1471 of 3116
Quote:
Originally Posted by zilch0md View Post
 

Meanwhile, I'm really digging the MG3 > resistor box > HD600, while fearing that I might never find an amp that can reproduce what I'm hearing now, with the LCD-2, which still has a bass energy that's superior to the HD600, when given more power - a trait that all LCD-2 fans love. The HD600 bass I'm hearing currently, is beautifully done, but more balanced with the rest of the spectrum - more "accurate" than the mildly excessive bass of the LCD-2.

 

Just move up to the Dacmini PX and plug directly off the speaker taps. You know you wanna :cool:

post #1472 of 3116
Quote:
Originally Posted by Chris J View Post
 
Investigate a used Bryston BHA-1.
Seems to be some agreement in owners that the LCD is a good match for the BHA-1.
I've never heard component either so no comment on my part.

 

Thanks Chris!

post #1473 of 3116
Quote:
Originally Posted by Armaegis View Post
 

 

Just move up to the Dacmini PX and plug directly off the speaker taps. You know you wanna :cool:

 

Haha!  You're bad!  But I hear you!

 

:D

 

Mike

post #1474 of 3116

@zilch0md If you wouldn't mind sending me that spreadsheet I would really appreciate it :) Either here or in PM. Happy Thanksgiving!

post #1475 of 3116
Quote:
Originally Posted by zilch0md View Post
 

FlySweep,

snip (Click to show)

I've had the HD600 for about a month, while waiting for the cables needed to run balanced from the MG3's resistor box, but it sounds so much better now, than it had when running single-ended from other amps.  In short, I concur with everything you've written above!

 

I have a theory about just exactly why the HD600 sounds so much better than my LCD-2 on the MG3 + resistor box:

 

Thanks to Armaegis' superior knowledge of the math required to do such calculations, I've recently learned that when the MG3 is putting out 32 Watts into 8 Ohms with 24VDC power, my attached TBI resistor box is only putting out 142 mW into the 50-Ohm LCD-2 and only 24mW into my 300-Ohm HD600. 

 

Contrast these figures to the CEntrance DACmini CX, which puts out 480mw into 50 Ohms and 80mW into 300 Ohms - roughly four times the power output of the MG3 + resistor box!  

 

Without the resistor box, but for the hiss experienced when either headphone is directly attached, I'd be getting 5100 mW into the LCD-2 and 853 mW into the HD600.  (On request, I can provide a spreadsheet I've created that documents and performs the needed equations - verifying Armageis' calculations.)

 

So...  Even though I absolutely love the natural, organic and analog yet detailed sound of the MG3 with LCD-2, I've learned that the resistor box leaves the LCD-2 sorely under-powered, given that Audeze recommends a minimum of 1000mW into 50-Ohm (where I'm only getting 142mW).  :p


The Sennheiser HD600 is much better matched to the power of the MG3 + resistor box, as evidenced in terms of heard dynamics, bass control, etc. That's a fact.  So...  Thus enlightened, I'm still looking for an amp that can provide the power my LCD-2 wants without the hiss of the MG3. 

snip (Click to show)

But,without going to a tube amp, where do I find the awesome sound signature of the MG3, while also getting something closer to 13W into 50-Ohms (the maximum power rating of the LCD-2)?   (I know...  the Odyssey Audio Cyclops Extreme - but I live by a hard and fast rule of never spending more than $1k for any single component.)

 

 

 

 

 

Mike

 

So why not mod the resistor box for more output power?  When I was working with Jan and the MG3, I found him to go a bit overkill with the resistor divider network.  Yeah, it did kill the hiss DEAD, but, it also kills the output power.  Try tweaking the resistor values in your spreadsheet to get more favorable power to the LCD-2 and see where you end up with the hiss.

You mentioned you had a spreadsheet.  I don't know how its configured, but it sounds like it might do the trick for investigating other resistor combinations...

post #1476 of 3116
Quote:
Originally Posted by brunk View Post
 

@zilch0md If you wouldn't mind sending me that spreadsheet I would really appreciate it :) Either here or in PM. Happy Thanksgiving!

 

Done - It could use some "peer review."  Thanks!

post #1477 of 3116

Listening to Patricia Barber's Too Rich For My Blood, from the album Cafe Blue.

 

The HD600 is such a giant-killer on the giant-killing MG3.

post #1478 of 3116
Quote:
Originally Posted by zilch0md View Post
 

 

Done - It could use some "peer review."  Thanks!

Thanks Mike, I'll see what I can do at refining it. It's a great resource! Maybe a few of us can collaborate on a wiki here for resistor networks :)

post #1479 of 3116
Quote:
Originally Posted by zilch0md View Post
 

Listening to Patricia Barber's Too Rich For My Blood, from the album Cafe Blue.

 

The HD600 is such a giant-killer on the giant-killing MG3.


Just like you Dallas people trying to kill off all of the Giants.  What are you going to do when you've succeeded in wiping them out... move on to killing off the Redskins?  Sorry, that's been tried and is now totally unacceptable behavior.  Same with killing off Eagles.  Totally uncool.  If the Cowboys are going to win the NFC East, they should have to win it on the playing field, not by killing their opponents by buying high-value audio gear. 

 

 

:D:evil:

 

Sorry for all of you folks who are not NFL football fans, that was intended to be an inside joke.  Not a particularly good one, but it's Thanksgiving, the day we celebrate Football in America by eating turkey and having to deal with our relatives...  And speaking of which, gotta go now...

post #1480 of 3116
Quote:
Originally Posted by zilch0md View Post
 

 

Haha!  You're bad!  But I hear you!

 

:D

 

Mike

 

I think I saw a PX on the sale forums not too long ago... haha!

 

The Nuforce Icon2 that I use is also on sale right now for $175 which is a steal of a deal (along with the S-X speakers for $20 which is ridiculous!). The only catch is that you'll have to make your own adapter since it uses RJ45 connectors for the speaker output (although they do come with one set of RJ45-Bananas)


Edited by Armaegis - 11/28/13 at 11:49am
post #1481 of 3116
Quote:
Originally Posted by potterma View Post
 

 

So why not mod the resistor box for more output power?  When I was working with Jan and the MG3, I found him to go a bit overkill with the resistor divider network.  Yeah, it did kill the hiss DEAD, but, it also kills the output power.  Try tweaking the resistor values in your spreadsheet to get more favorable power to the LCD-2 and see where you end up with the hiss.

You mentioned you had a spreadsheet.  I don't know how its configured, but it sounds like it might do the trick for investigating other resistor combinations...

 

Great minds think alike potterma!  I recall asking Jan not to overdo the resistance, but he argued that a headphone just doesn't need as much power as a speaker...  

 

I've thought about doing exactly what you've suggested here, and I know that because the LCD-2 is almost purely resistive, messing with the network won't influence the sound signature as much as it would with dynamic headphones - which, I think is another reason why the resistor box I'm currently using just happens to be wonderful with the HD600 (I'm suggesting that Jan hit on an ideal ratio for the dynamic HD600, while building a resistor network for the LCD-2.

 

So... I'll have to build another resistor network for the LCD-2, as I don't want to disturb the one I'm now using with the HD600. I don't find the build itself daunting - it's the design that still eludes me.  I can find numerous combinations of values to plug into my spreadsheet that will yield a higher power output to the LCD-2, but WHICH of countless combinations would be best?

 

 

Please correct me if any of this is wrong, but playing with the spreadsheet has revealed that I can increase output power of the resistor network shown above by reducing the value of R1 -or- by increasing the value of R2 -or- both.

 

So here's a question for which I can't seem to find an answer:  Is there any advantage/disadvantage to maintaining the current 5:1 ratio?  I've seen a lot of resistor networks that have a 3:1 ratio, as well as other ratios.  Why?  What criteria are honored to select the resistance values (other than just going for any combination that gives me more power than I'm getting now)?

 

For example, using the same schematic as shown above, my spreadsheet reveals that all of the following values will give me 1000 mW into 50 Ohms, instead of the 142mW into 50 Ohms, I'm getting with the TBI resistor box:

 

R1 = 10 Ohms,  R2 = 7.92 Ohms  (increasing only R2)

 

R1 = 2.53 Ohms, R2 = 2.0 Ohms (decreasing only R1)

 

And now, just a couple of the truly countless combinations that could each yield 1000 mW when changing both values...

 

R1 = 5 Ohms, R2 = 3.96 Ohms (decreasing R1 and increasing R2)

 

R1 = 3 Ohms, R2 = 2.38 Ohms (decreasing R1 and increasing R2)

 

Which is "best" and why?

 

Thanks!

 

Mike

post #1482 of 3116

First of all, most of you are using that resistor box to reduce noise. So I'm going by the assumption that is the foremost criteria (ideally, I'd tell you guys to ditch the amp and pick one with lower power and/or better specs that doesn't have noise issues with headphones).

 

If noise is palpable, you'll want at least a 12dB reduction and R1:R2 should be at least 3:1.

If noise is barely noticeable, you could get away with 6dB reduction, and the ratio should be 1:1

 

There are arguments that damping factor doesn't matter for planar magnetics. I've read them, I mostly agree with them, yet I've also tested on my own amps and I think I've heard a difference (going from a stark difference of 15ohm in series to <1). Maybe it's placebo, maybe not, but designing for a dynamic load doesn't hurt in the long run. To that end, we want R2 < Z/8 (where Z is the nominal impedance of the headphone)

 

Assuming Z is 32 at the lowest (if you're running iems off a speaker amp, you've already bought the funny farm), that means R2 should be at least 4 or lower.

 

So going back to earlier, if we're assuming R2=4 for example sake, and depending on how much noise we have, we either have R1=12 (some noise problems), or R1=4 (faint noise problems). If the noise was bad enough that even a 12dB reduction didn't do it, I don't care how musical it sounds and pick a different amp.

 

One last possible criteria is if you have an amp that requires (or works best at) a target output load. In which case you must have R1+R2 = manufacturer's specified load

edit: in this case there's a third arrangement possible: putting a resistor R3 across the amp terminals equal to the recommended load. This more or less takes the criteria off R1 and R2


Edited by Armaegis - 11/28/13 at 12:41pm
post #1483 of 3116
Quote:
Originally Posted by zilch0md View Post
 

 

Great minds think alike potterma!  I recall asking Jan not to overdo the resistance, but he argued that a headphone just doesn't need as much power as a speaker...  

 

I've thought about doing exactly what you've suggested here, and I know that because the LCD-2 is almost purely resistive, messing with the network won't influence the sound signature as much as it would with dynamic headphones - which, I think is another reason why the resistor box I'm currently using just happens to be wonderful with the HD600 (I'm suggesting that Jan hit on an ideal ratio for the dynamic HD600, while building a resistor network for the LCD-2.

 

So... I'll have to build another resistor network for the LCD-2, as I don't want to disturb the one I'm now using with the HD600. I don't find the build itself daunting - it's the design that still eludes me.  I can find numerous combinations of values to plug into my spreadsheet that will yield a higher power output to the LCD-2, but WHICH of countless combinations would be best?

 

Please correct me if any of this is wrong, but playing with the spreadsheet has revealed that I can increase output power of the resistor network shown above by reducing the value of R1 -or- by increasing the value of R2 -or- both.

 

So here's a question for which I can't seem to find an answer:  Is there any advantage/disadvantage to maintaining the current 5:1 ratio?  I've seen a lot of resistor networks that have a 3:1 ratio, as well as other ratios.  Why?  What criteria are honored to select the resistance values (other than just going for any combination that gives me more power than I'm getting now)?

 

For example, using the same schematic as shown above, my spreadsheet reveals that all of the following values will give me 1000 mW into 50 Ohms, instead of the 142mW into 50 Ohms, I'm getting with the TBI resistor box:

 

R1 = 10 Ohms,  R2 = 7.92 Ohms  (increasing only R2)

 

R1 = 2.53 Ohms, R2 = 2.0 Ohms (decreasing only R1)

 

And now, just a couple of the truly countless combinations that could each yield 1000 mW when changing both values...

 

R1 = 5 Ohms, R2 = 3.96 Ohms (decreasing R1 and increasing R2)

 

R1 = 3 Ohms, R2 = 2.38 Ohms (decreasing R1 and increasing R2)

 

Which is "best" and why?

 

Thanks!

 

Mike

 

If you're going to use it with the LCD-2 or other ortho, just ditch R2 and set R1 to give you the best volume control range.

 

se

post #1484 of 3116
Quote:
Originally Posted by Steve Eddy View Post
 

 

If you're going to use it with the LCD-2 or other ortho, just ditch R2 and set R1 to give you the best volume control range.

 

se

This right here Zilch0md. :)

post #1485 of 3116
Quote:
Originally Posted by brunk View Post
 

This right here Zilch0md. :)

Assuming that the voltage compliance of the MG3 will accommodate that configuration and provide the attenuation you desire...  Doing some quick numbers in my spreadsheet, I'm not sure you'll be happy with a simple series resistor.

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