[CrystalT]

What would best improve my existing chain, because I'm quite sure I'm not getting the best out of it.
 
Currently Laptop /w Foobar & Asio - Focusrite VRMbox (Usb Dac/Amp combo) - Pioneer VSX-9900k (dedicated stereo amp with a headphone out that I'm using for my K340)
 


 
 
 
My Dac is a focusrite VRMbox, which for most headphones, can power on its own, being a dac/amp combo. However, my AKG K340 don't quite get enough power from it at 100% volume, so I've been dual-amping them by running a 1/4th TRS > RCA audio cord to my stereo amp's AUX in, and plugging the headphones in to the reciever's headphone amp. From what I can tell, the Focusrite's signal is clean enough that dual-amping is a viable strategy. Even at ridiculously high volume I hear no clipping, and the reciever isn't running hot, but I'm still sure that I can get a little more out of my existing set up.
 
Should I get a more powerful usb dac/amp? Should I recable my K340 to be unbalanced RCA? I could also recable it to go in to the passive speaker ports on the reciever, or should I get a usb DAC with line-out?

 

[jaddie]

Quote:

What would best improve my existing chain, because I'm quite sure I'm not getting the best out of it.
 
Currently Laptop /w Foobar & Asio - Focusrite VRMbox (Usb Dac/Amp combo) - Pioneer VSX-9900k (dedicated stereo amp with a headphone out that I'm using for my K340)
 
<snip>
Should I get a more powerful usb dac/amp? 
 

If by "powerful" you mean "higher performance", then no.  If you mean "higher output without another amp" then possibly.
Quote:

Should I recable my K340 to be unbalanced RCA? I could also recable it to go in to the passive speaker ports on the reciever, 

Recabling will do nothing.  The speaker outputs of your amp could be tried without recabling, but not really recommended because of the high output level.
 
The Pioneer amp is a weak spot. Many stereo amps achieve their headphone outputs with simple build-out resistors, which protects headphones from high levels, but raises the output impedance far too high.  If they don't use resistors, and do have a dedicated headphone amp, it's not likely to be as well conceived as a real headphone amp.  I think the Pioneer is one area that you could improve on.
 
The DAC's performance should be fine, but since it won't drive your K340 as well as you'd like, you could improve there are just get a good combo DAC/amp that does both well.  The O2+ODAC Combo comes to mind.  Then you could ditch the Pioneer.  You'll have a simpler system as a side benefit. 
 
And, of course, better headphones are always nice, which would make the biggest change of all.  
 
So, let's see, I've suggested replacing every part of your setup except the cables, right? 

 

[CrystalT]

Please make a more concise post. You basically said "replace everying you own."

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[jaddie]

Ok, for the biggest improvement in sound quality, replace in this order:

Headphones

Amp

DAC

If you replace the DAC with one that has a better headphone amp, you can do away with the separate amp entirely.

If you replace your stuff in this order, you can stop at any point where you're satisfied or run out of money.

Pretty much exactly what I said before. I'm sorry, that's as concise as I can make it.

 

[CrystalT]

What is the least expensive usb powered dac/amp combo able to power my akg headphones?

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[jaddie]

Quote:

What is the least expensive usb powered dac/amp combo able to power my akg headphones?

Sent from my SPH-L300 using Tapatalk 2

Well, I have no idea what your goals are.  Any amp can drive the vintage K340 headphones, if that's what you have.  Since you mentioned recabling, I figured that must be it rather than their current model with unfortunately the same model number.  It's not a hard headphone to drive at all, but since your DAC doesn't seem to do it by itself, almost any good headphone amp would help.  Not sure why, when you've gone to the trouble of legendary vintage headphones, you'd want the least expensive DAC/AMP, but you'll have to research that one, I really don't survey them all.  Some DAC/Amps have features and functions others don't.  
 
Have fun.

 

[brunk]

Quote:

What is the least expensive usb powered dac/amp combo able to power my akg headphones?

Sent from my SPH-L300 using Tapatalk 2

Eh, maybe the Meridian Explorer. Check it out.

 

[CrystalT]

I am a believer that any sufficiently built dac will perform on par with things many times its price. My focusrite unfortunatly just cant power the 400 ohm akgs to the listening levels i want. 100% brings it to quiet listening levels. Not quite loud enough for critical listening. The amp i have is capable of driving it to where it needs to be, but its an inefficient set up.

Im just looking for the least expensive dac/amp combo that can reliably drive between 400-600 ohm headphones.

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[jaddie]

Just ran some calculations for you.  Your headphones are rated for 94dB @ 1mw, 400 ohms.  Your Focusrite VRM Box has an output rated at 30mW into a 50 ohm load, and then there's a misprint in the manual, it says 15mV  into 150 ohms, it should be 15mW into 150 ohms, which calculates to 1.5V max.  If you hit your headphones with a full 1.5V you'll be at 101dB peak, max, with average levels at between 80 and 90dB SPL, which isn't ear-splitting loud, but pretty respectable.  You shouldn't be listening much louder than that long term anyway.
 
But...the control software has a -6dB setting, which the manual states is needed for some material that is mastered hot if you use any of the VRM functions.  I would assume in your case that all that VRM stuff is turned off, as it should be.  Check your VRM Box software for the -6dB setting, and set it to "0" instead, if it's not there already, and try your headphones again plugged directly in.  The VRM should be adequate, perhaps only slightly low.  You're complaining that it's very low, so I would suspect the -6dB setting is active.  

 

[jaddie]

If the control software setting doesn't pan out for you, what you're looking for is an amp capable of at least 2 or 3 volts output max, power rating is immaterial, with about 10 to 15dB of gain available.  Max output voltage isn't usually spec'd, you'll have to calculate it.  But as an example, the O2+ODAC Combo has a max output voltage of just under 5 volts (4.5 volts @ 613mW into 33 ohms). 

 

[Currawong]

Are the K340s you are talking about the new model or the old vintage electrostatic/dynamic ones? The vintage ones will require a far more serious amp for best results.

 

[CrystalT]

The old ones.

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[CrystalT]

The control setting shouldnt be active as i never installed it. Im using the plug and play driver.

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[jaddie]

The control setting shouldnt be active as i never installed it. Im using the plug and play driver.

Sent from my SPH-L300 using Tapatalk 2

How can you tell if the -6db function is on by default or not? Might want to check that.

 

[CrystalT]

Well the -6db function should be native to the VRM software which I never installed. It SHOULD just be the cirrus logic chips working as a plug and play device without any proprietary settings.
 
my curiosity got the better of me - without the vrm drivers, it's +0 by default.