[money4me247]

 
Would anyone recommend looking into finding some speaker wire to rca adaptors and grabbing a sys for my bookshelf speakers? They're already using a dedicated low-end amp which is sufficient, but I'm sure this stack would sound better, especially adding a DAC to the mix.

sys works the other way around. really for x2 sources into one amp. (x2 input rca with x1 output rca)
 
for the other way around, the magni 2 uber already has a preamp out. maybe you can just upgrade. if your speakers already have an amp, you can get rca splitters for your dac.

 

[lonewolfe2015]

  sys works the other way around. really for x2 sources into one amp. (x2 input rca with x1 output rca)
 
for the other way around, the magni 2 uber already has a preamp out. maybe you can just upgrade. if your speakers already have an amp, you can get rca splitters for your dac.

 
Fortunately I grabbed both in the Uber variant, should have been more specific.
 
Also the cheap lepai amp powering the bookshelf has an RCA input (using the aux from the laptop to it). So would leaving the bookshelf to cheap amp and then grabbing another pair of RCA to RCA and hooking up the Magni 2 Uber to it work? It'd end up being Laptop --> Modi 2 Uber --> Magni 2 Uber --> Lepai Amp --> Polk Bookshelf
 
I have no idea how it would affect the quality going from a good amp to a cheap amp. But it would get the DAC in there to clean up the source...

 

[money4me247]

 
Fortunately I grabbed both in the Uber variant, should have been more specific.
 
Also the cheap lepai amp powering the bookshelf has an RCA input (using the aux from the laptop to it). So would leaving the bookshelf to cheap amp and then grabbing another pair of RCA to RCA and hooking up the Magni 2 Uber to it work? It'd end up being Laptop --> Modi 2 Uber --> Magni 2 Uber --> Lepai Amp --> Polk Bookshelf
 
I have no idea how it would affect the quality going from a good amp to a cheap amp. But it would get the DAC in there to clean up the source...

should remove the other amplifier from the chain for best results. amplifiers can have coloration & distortion so when you double amp, your sound quality is limited by the worst component in your chain. what kind of input does your bookshelf speaker have?

 

[Music Alchemist]

  If the power *and* impedance are both given, that fixes both the voltage and the current.

 
Care to elaborate?

 

[lonewolfe2015]

  should remove the other amplifier from the chain for best results. amplifiers can have coloration & distortion so when you double amp, your sound quality is limited by the worst component in your chain. what kind of input does your bookshelf speaker have?

Just speaker wire, they're nothing too special or expensive so I won't go out of my way to bridge them in. But if I can make it work with a relatively cheap purchase I'd be curious what the best way is.
 
http://smile.amazon.com/Polk-Audio-TSi100-Bookshelf-Speakers/dp/B00192KF12

 

[money4me247]

 
Just speaker wire, they're nothing too special or expensive so I won't go out of my way to bridge them in. But if I can make it work with a relatively cheap purchase I'd be curious what the best way is.
 
http://smile.amazon.com/Polk-Audio-TSi100-Bookshelf-Speakers/dp/B00192KF12

I think something like this would work, though I never tried it myself.
 
http://www.amazon.com/IEC-Speaker-Wire-Male-Cable/dp/B003U44LA8

 

[David Aldrich]

If you're talking about simple DC resistance then the following provide all you need. Transducers are a little bit more complicated using AC but for basic power handling you can get close enough.
 
V - Voltage (Volts)
I - Current (Amperes)
P - Power (Watts)
 
V = I*R
 
That's the basic form.
 
P = V*I
 
P = I^2 * R
 
You can derive any value if you know the other two.

 

[Rem0o]

If a device is current limited, on a given load, the voltage will be limited so V =  I_limited * R.  

 

[Music Alchemist]

Latest comment, from a PM. Thought I'd share:
 

When you said

Another thing I learned today is that voltage and current specs are irrelevant for normal headphones, since when the amp has enough power, that means it also has enough voltage and current.

I was talking about the "it also has enough voltage and current" part. Of course it has a set voltage and current at those specific loads, as governed by Ohm's law, but that doesn't mean it has enough voltage and current for all loads, and that's where it falls apart.

Like with the Fulla, the 108 dB SPL is just an estimate and you're assuming the Fulla can actually output that much voltage at 600 ohms when it might not actually do so, which means the current and voltage specs are relevant for normal headphones.

If you look at the Leckerton UHA-4, it's current-limited, and you wouldn't know that unless you knew the maximum current and/or the power outputs were actually given. If you didn't know that, any calculations you do for lower impedance loads is going to be incorrect. Fortunately Leckerton does provide those numbers.
http://www.leckertonaudio.com/products/uha-4/

16 ohms: 20 mW [0.5656 Vrms, 35.36 mA]
32 ohms: 40 mW [1.13 Vrms, 35.39 mA]
100 ohms: 50 mW [2.23 Vrms, 22.42 mA]
300 ohms: 15 mW [2.12 Vrms, 7.07 mA]

If you didn't have the 32 or 16 ohm measurements, you couldn't possibly know the current limitations of the amp.
P = (2.23^2) / 32 = 155 mW

 
I'm not a math person at all, but some of you may appreciate this discussion.

 

[Exacoustatowner]

Ive had the science and math and calculated that the 183 mw from my Oppo should have been fine for my 90 db at 1 mw HiFIMan HE-560. But then at what frequency is that 90 db measured? Music is not a 1 KHz tone.
In reality it cannot reproduce the sudden wallop on a tympani without compressing it. It does not sound distorted. I thought it acceptable. Then I plugged my phones into my Denon Reciever- and realized I was missing bass and dynamics. Fast forward to Amazion sending me the Lyr instead of Mjolnir. After break in I realized the Denon was also compressing-as compared to the Lyr! That same Tympani wallop which sounded OK on the Oppo, and more impact full on the Denon- made me Jump with the Lyr

 

[David Aldrich]

The response characteristics of an amp/headphone system is much more complicated than just DC resistance power measurements. Often headphone impedance is specified at DC and can change drastically as frequency changes. If you run into current or voltage limits you'll start losing sections of the frequency spectrum depending on the impedance curve.

 

[Music Alchemist]

Ive had the science and math and calculated that the 183 mw from my Oppo should have been fine for my 90 db at 1 mw HiFIMan HE-560. But then at what frequency is that 90 db measured? Music is not a 1 KHz tone.
In reality it cannot reproduce the sudden wallop on a tympani without compressing it. It does not sound distorted. I thought it acceptable. Then I plugged my phones into my Denon Reciever- and realized I was missing bass and dynamics. Fast forward to Amazion sending me the Lyr instead of Mjolnir. After break in I realized the Denon was also compressing-as compared to the Lyr! That same Tympani wallop which sounded OK on the Oppo, and more impact full on the Denon- made me Jump with the Lyr

 
Are you sure the dynamic peak was at 90 dB, though? It could end up being louder.
 
Also, are you sure you were listening at the same SPL levels when comparing the amps?

 

[Exacoustatowner]

The dynamic peak is way above 90db. I should measure it.
For DSD or other "Hi Res" recordings the dynamic range can be quite large. My listening level was averaging 70 db

 

[Exacoustatowner]

Exactly, although impedance tends to be quite constant for Orthodynamic/ Planar Magnetics. Such as my HiFIMan He 560. Not so for dynamic HP or speakers. As you say, it's not that simple and likely I am far from knowing all the factors!

quote name="David Aldrich" url="/t/601151/schiit-owners-unite/9600#post_11449210"]

The response characteristics of an amp/headphone system is much more complicated than just DC resistance power measurements. Often headphone impedance is specified at DC and can chance drastically as frequency changes. If you run into current or voltage limits you'll start losing sections of the frequency spectrum depending on the impedance curve.
[/quote]

 

[Music Alchemist]

The dynamic peak is way above 90db. I should measure it.
For DSD or other "Hi Res" recordings the dynamic range can be quite large. My listening level was averaging 70 db

 
Yeah, you'll need to get all the facts straight before making a final assessment of the situation. Let us know what you find out!
 
By the way, 16-bit has more than enough dynamic range to handle all recordings in existence. The only reason some high-res downloads sound different is because they were derived from a different master. When you convert the files to lossless (or even lossy 256 kbps AAC) 16-bit / 44.1 kHz, they are indistinguishable from the originals.