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So, I'm looking for that perfect amp... - Page 59

post #871 of 929
Quote:
Originally Posted by StanD View Post
 

Haven't heard the Portaphile, but I have heard the HE-6 and I doubt that deafening levels can be achieved with this amp. Perhaps your ears are more sensitive than mine. I'll bet that at full power the batteries will go kaput very quickly. Sharing one channel for a virtual ground is IMO a serious flaw. It will lead to clipping and increased distortion on certain volume peaks/transients when under more difficult driving conditions.

My Asgard 2 can drive my HE-500's to 1 Watt which requires almost 6.2 Amps which is far more than the 250 mA that the Portaphile can truly deliver (due to the common ground channel). The HE-6 will require 7 Amps at 1 Watt. Supplying 250 mA can be loud with the Portaphile/HE-6's but with no headroom so I would expect distortion when listening loud, especially TIM and grungy bass on peaks.


How did you get 6.2 amps?  Watts = I^2 x R, so 1 watt = (.162)^2 x 38 ohms (HE-500 resistance).  So,wouldn't that that be 162ma's and not 6.2 amps?  It would be 6.2Vs though, maybe that's what you meant?


Edited by Pappucho - 1/26/14 at 10:10am
post #872 of 929



DX50 with the PB2. Better colour coordination than with the silver Leckerton , which hadn't bugged me before, but might now.......

Swapped the AD 797s in. Very clear sound and great highs. I am really enjoying the different sound signature to the warmer 627s. At this stage, I don't know that either one is better - just nicely different.

I also decided to try out the old Firmware 1.22. It is also a very pleasing combination.

I tend to only play full albums so scanning isn't an issue for me, as I can play directly from the directory structure of the filesystem.
post #873 of 929
Quote:
Originally Posted by Pappucho View Post
 


How did you get 6.2 amps?  Watts = I^2 x R, so 1 watt = (.162)^2 x 38 ohms (HE-500 resistance).  So,wouldn't that that be 162ma's and not 6.2 amps?  It would be 6.2Vs though, maybe that's what you meant?

Oops, my bad, I pressed the wrong button on my programmable calculator. As you say, the one for voltage. Thanks for the catch. I have to revisit my babbling.

post #874 of 929
Quote:
Originally Posted by StanD View Post
 

Oops, my bad, I pressed the wrong button on my programmable calculator. As you say, the one for voltage. Thanks for the catch. I have to revisit my babbling.

 

No problem, I think another thing we need to consider is the output voltage of the line out of what you will be using.  The DX50's line out for example is rated at 1.5v's.  An amplifier with a gain of 7 will output a maximum of 10.5Vs (7 x 1.5vs) when using the DX50 line out.  This means that across a 50ohm load (HE-6) you need 210mAs (10.5V/50ohms) and across a 38ohm load (HE-500s) you will need 276mAs (10.5V/38ohms) to get the full 10.5Vs across the load.  These values represent what you will get at the output of the amplifier when the volume knob is set at the highest setting.  NO ONE listens to their amplifier that high.  Most will keep it around the 12:00 position which is about half that voltage out (around 5-6Vs) so you will need roughly half that current.

 

The ideal amplifier should have enough voltage swing at the desired gain and enough current to adequately drive headphones from a particular source. 

post #875 of 929
Quote:
Originally Posted by Pappucho View Post
 

 

No problem, I think another thing we need to consider is the output voltage of the line out of what you will be using.  The DX50's line out for example is rated at 1.5v's.  An amplifier with a gain of 7 will output a maximum of 10.5Vs (7 x 1.5vs) when using the DX50 line out.  This means that across a 50ohm load (HE-6) you need 210mAs (10.5V/50ohms) and across a 38ohm load (HE-500s) you will need 276mAs (10.5V/38ohms) to get the full 10.5Vs across the load.  These values represent what you will get at the output of the amplifier when the volume knob is set at the highest setting.  NO ONE listens to their amplifier that high.  Most will keep it around the 12:00 position which is about half that voltage out (around 5-6Vs) so you will need roughly half that current.

 

The ideal amplifier should have enough voltage swing at the desired gain and enough current to adequately drive headphones from a particular source. 

Volume pots have a log taper, so 12 O'clock is not going to give you half the voltage. We don't perceive loudness nor pitch linearly.

Since amplifiers amplify voltage and must be able to supply enough current under load to achieve this, let's consider headphone sensitivity specs at 1V rather than 1mW.

HE-6:     96.5  dB/1V

HE-500: 103.2 dB/1V

 

What's dicey is how much headroom to allow for. 

 

Let's say you listen at 95 dB as a baseline, which is probably loud to many:

HE-6:    0.841 V or 16,83 mA or 14.16 mW

HE-500: 0.398 V or 10.24 mA or  3.98 mW

 

Let's say you'd like the peaks to reach 120 dB, the threshold of pain:

HE-6:   14.96 V or 299.25 mA or 4.48 W

HE-500: 6.92 V or 182.06  mA or 1.26 W

 

Just to show how we work in a logarithmic fashion, at 115 dB:

HE-6:     8.41 V or 168.28 mA or 1.416 W

HE-500:  3.89 V or 102.38 mA or 0.398 W

 

So if you need to hit peaks of 120 dB then the HE-6 is a bit much for many amps. How many of us want to hit 120 dB peaks? The HE-500 fares better than much of the fanfare at HeadFi calls for.

 

If 115 db is enough, then the HE-6 is still a challenge for many amps and the HE-500 makes the grade more often than some think. So how often do we need an exotic amp that can deliver 6W or more? Perhaps not as often as some would make us believe.

 

Special thanks to Rob Robinette for his Excel spreadsheet, a nice time saver.

post #876 of 929
Thread Starter 
Quote:
Originally Posted by Pappucho View Post
 

The ideal amplifier should have enough voltage swing at the desired gain and enough current to adequately drive headphones from a particular source. 

Enter the PB2 with its 32V voltage swing :veryevil:

 

Can't wait to try the HE-500 on this badboy...


Edited by Sorensiim - 1/27/14 at 12:11am
post #877 of 929
Thread Starter 

In case you were wondering, the finicky Heir Tzar 350 sounds decidedly delicious out of the PB2! Still on low gain, I have the volume control at just under 50% and everything is squeaky clean - assuming your source material is of proper quality.

post #878 of 929
Quote:
Originally Posted by Sorensiim View Post
 

In case you were wondering, the finicky Heir Tzar 350 sounds decidedly delicious out of the PB2! Still on low gain, I have the volume control at just under 50% and everything is squeaky clean - assuming your source material is of proper quality.

You getting two more for your kids? :D

post #879 of 929
Quote:
Originally Posted by highfell View Post


I also decided to try out the old Firmware 1.22. It is also a very pleasing combination..

LOL

Only had 24 hours to listen to this until FW 1.28 came out.

Loving the latest FW. The psychedelic guitar work on the genesis archive set 1967-75 sounds fantastic - great 3D soundstage.
post #880 of 929

Finally got the PB2 - much smaller than I imagined, considerably smaller/lighter than my Continental...  Also sounds better than I hoped, with my DX50 / SE846 rig.  Basically end-game.  I really feel it : endgamegoodenoughbetterthananyotherdamnedthing.  

Until DX90, I guess.  

 

Here is the HeadphoneLounge balanced cable I had made : my OCD/color-fetish inspired cable, made real by Ted, slightly against his will I believe but a typically fantastic job nonetheless.

 

post #881 of 929
Thread Starter 
Quote:
Originally Posted by Dopaminer View Post
 

Finally got the PB2 - much smaller than I imagined, considerably smaller/lighter than my Continental...  Also sounds better than I hoped, with my DX50 / SE846 rig.  Basically end-game.  I really feel it : endgamegoodenoughbetterthananyotherdamnedthing.  

Until DX90, I guess.  

 

Here is the HeadphoneLounge balanced cable I had made : my OCD/color-fetish inspired cable, made real by Ted, slightly against his will I believe but a typically fantastic job nonetheless.

 

I know exactly how you feel :beerchug:

 

Cables are looking great, how flexible are they?

post #882 of 929
Quote:
Originally Posted by Dopaminer View Post

Finally got the PB2 - much smaller than I imagined, considerably smaller/lighter than my Continental...  Also sounds better than I hoped, with my DX50 / SE846 rig.  Basically end-game.  I really feel it : endgamegoodenoughbetterthananyotherdamnedthing.  


Until DX90, I guess.  

Here is the HeadphoneLounge balanced cable I had made : my OCD/color-fetish inspired cable, made real by Ted, slightly against his will I believe but a typically fantastic job nonetheless.


Welcome to the PB2/DX50 balanced club smily_headphones1.gif
post #883 of 929
Quote:
Originally Posted by Sorensiim View Post
 

I know exactly how you feel :beerchug:

 

Cables are looking great, how flexible are they?

 

They`re awesome.  I wound them around a wine bottle for these pics, which I guess makes them look stiff.  The adaptor has the woven conductors and is really flexi, but the main cables are super pliable as well.  

 

Actually the only thing I am missing now is one of your super-short 3.5-3.5 interconnects . . .  

post #884 of 929
Thread Starter 
Quote:
Originally Posted by Dopaminer View Post
 

 

They`re awesome.  I wound them around a wine bottle for these pics, which I guess makes them look stiff.  The adaptor has the woven conductors and is really flexi, but the main cables are super pliable as well.  

 

Actually the only thing I am missing now is one of your super-short 3.5-3.5 interconnects . . .  

I posted a mini-tutorial on how to build those tiny ICs, I'm pretty sure whoever made you those cables should be able to build one of those as well ;)

post #885 of 929

the next CAVALLI  Portable AMP may be someting really worth to consider...when (if ?) it reaches the market.

 

 

 


Edited by bmichels - 3/8/14 at 9:53am
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