[xslimmiejimmiex]

Hey everyone,
 
I'm looking for a smaller alternative to my Kenwood VR-407 receiver for audio on my Win10 desktop computer:

1. ATH-AD700x for gaming
2. MDR-7506 for focused music listening
3. Q Acoustics 2010i for casual listening

 
Specs for equipment:
 
Q Acoustics 2010i:
Frequency Response (+/- 3 dB): 68Hz - 22kHz
Nominal Impedance: 6ohm
Minimum Impedance: 4ohm
Sensitivity: 86dB
Recommended Power: 15 - 75w
Crossover Frequency: 2.8kHz
* which come with cables:
16 AWG
Loop resistance - 0.021 Ohm/m
Capacitance - 50pF/m
Inductance - 0.47 µH/m
Dissipation Factor - 0.0006
* + I also have some Monster XP cables
 
ATH-AD700X
Frequency Response: 5 – 30,000 Hz
Max input power: 700mW
Sensitivity: 100dB/mW
Impedance: 38 ohms
Connector 1/8" (3.5mm mini stereo gold plated & 1/4" (6.3mm) adapter
 
MDR-7506
Frequency response: 10-20kHz
Impedance: 64 ohms
Sensitivity: 106 dB/W/m
Power Handling: 1,000mW
Connector: 1/8" and 1/4" adapter
 
FIRST off, I've done some research and just wanted some feedback on that, if possible please:
(1) For amplifiers/speakers, I've read:
overpower by 50-100%
- recommended power (aka RMS power handling OR program watts; ignore peak power capacity )= so (50% more than 15W) = 22.5W - 30W
- impedance of ohms = 6ohms
- find=  22.5W - 30W PER CHANNEL into impedance of  6 ohms
 
(2) For headphones:
a.) calculate impedance and sensitivity (http://www.digizoid.com/headphones-power.html)
b.) check impedance graphs of headphones:
c.) make sure amp's output impedance is 8x lower than headphones or less
 
For the ATH-AD700X
a.)                Loudness        voltage needed        current needed        power needed
Safe                85 dB SPL         0.03 Vrms         0.79 mA         0.02 mW
Moderate         100 dB SPL         0.19 Vrms         5 mA                 0.95 mW
Fairly Loud         110 dB SPL         0.62 Vrms         16.32 mA         10.12 mW
Very Loud         115 dB SPL         1.1 Vrms         28.95 mA         31.84 mW
 
b.)
c.) 38ohms / 8 = 4.75 ohms
 
MDR-7056:
a.)
Safe                 85 dB SPL         0.02 Vrms         0.31 mA         0.01 mW
Moderate         100 dB SPL         0.13 Vrms         2.03 mA         0.26 mW
Fairly Loud         110 dB SPL         0.4 Vrms         6.25 mA         2.5 mW
Very Loud         115 dB SPL         0.71 Vrms         11.09 mA         7.88 mW
 
b.) Measured impedance is about 80 Ω, with a maximum of 113 Ω at 64 Hz and minima of about 76 Ω at 1 kHz and 7 kHz. Phase angle varies from -13.8º at 33.1 Hz, +10º at 123.5 Hz to -17.1º at 20 kHz.
 
c.) 64 ohms / 8 = 8 ohms
*So based on headphones, get something 4.75 ohms or less (based on lower number being the ATH-AD700X) output impedance on the amplifier
 
So, OVERALL am I correct?:
- Need 22.5W-30W per channel into 6ohms
- 4.75ohms or less output impedance
 
SECOND
If I am correct in my research, I can obviously do my own digging, but if someone can provide recommendations for my ideal setup it would be much appreciated. Looking to have a smaller alternative that I can place on my desk to adjust controls and cabling when needed. Budget just depends really, I'm open to anything, but since I've been spending quit a bit lately, I'd prefer to spend only on what I need (that will last)...
 
What I've found recommended:

Yamaha A-S500 = recommended, but too large for my desk...
Minimum RMS Output Power (8 ohms, 20 Hz - 20 kHz) = 85 W + 85 W (0.019% THD)
Maximum Power(8 ohms, 1 kHz, 10% THD) = 105 W + 105 W
High Dynamic Power/Channel (8/6/4/2 ohms) = 130 / 150 / 185 / 220 W
Input Sensitivity / Impedance (Phono) = 3 mV / 47 kilohm
Input Sensitivity / Impedance (CD) = 200 mV / 47 kilohm
Output Level / Rec Out  = 200 mV / 1 kilohm
Frequency Response = 10 Hz-100 kHz ±1 dB
Total Harmonic Distortion (Phono, 20 Hz-20 kHz) = 0.025% Rec Out (3 V)
Total Harmonic Distortion (CD to Sp Out, 20 Hz - 20 kHz) = 0.015% (42.5 W / 8 ohms)
Signal-to-Noise Ratio (Phono) = 90 dB (5 mV, Input Shorted)
Signal-to-Noise Ratio (CD) = 100 dB (200 mV, Pure Direct, Input Shorted)
Residual Noise (IHF-Network) = 32 µV
Gain Tracking Error (0-99dB) = 0.5 dB or less

Teac A-H01 = seeing around $229 used
Supported impedance = 4 ohms to 8 ohms
Max output =
60W + 60W (4 ohms, 1kHz, JEITA)
30W + 30W (8 ohms, 1kHz, JEITA)
Freq response = 10Hz to 80kHz (+/-3dB)
s/n ratio = 100dB (LINE Input、IHF-A/input short)
THD = 0.05% (1kHz, 4 ohms)
Headphones, max ouput = 50mW + 50mW (32 ohms loaded)
SMSL SA50 50Wx2 TDA7492 Class D Amplifier = $68 + something for headphones…? I'd rather have an all-in-one device (DAC + amp?)
Power output =  2 x 50 watts @ 4 ohms, 2 x 25 watts @ 8ohms
Frequency response: 20-22,000 Hz
Dynamic range: 102dB • SNR: 81 dB

Topping TP20-MK2
Output power: 23 watts x 2 (4 ohms, 10% THD)
Tripath TA2020 T-Amp IC
Signal-to-noise ratio (SNR): 98 dB
Dynamic range: 98 dB
IHF-IM Distortion: 0.1% @ 1 watt (4 ohms)
THD Distortion:
0.03% @ 9 watts (4 ohms),
0.1% @ 10 watts (4 ohms),
0.1% @ 6 watts (8 ohms),
10% @ 23 watts (4 ohms),
10% @ 13 watts (8 ohms)
Power efficiency: 81% @ 20 watts (4 ohms), 88% @ 12 watts, (8 ohms)
Input sensitivity: 200 mV
NAD 3020 = 3020, $399
Minimum Frequency Response = 20 Hz
Impedance = 2 Ohm
Maximum Frequency Response = 20 kHz
Total Harmonic Distortion THD = 0%
RMS output power = 300W
 
NFB15
http://www.audio-gd.com/Pro/Headphoneamp/NFB1532/NFB15.32EN_Specs.htm
 
Audioengine N22
http://audioengineusa.com/Store/N22-Desktop-Audio-Amplifier
 
Thanks for any input and I look forward to getting my information in order. Take care everyone

 

[PurpleAngel]

Audio-GD no longer makes the NFB-15
Great unit, bought it myself over a year ago, just as Audio-GD was discontinuing them.

 

[xslimmiejimmiex]

  Audio-GD no longer makes the NFB-15
Great unit, bought it myself over a year ago, just as Audio-GD was discontinuing them.

Oh nice, I can't wait to get something compact; just need to know if my requirements are met...