[matti621]

The Topping A30 or the JDS Atom?

 

[megabigeye]

Are you talking about power? The Beyer T 1 is rated at 600Ω and 102dB @ 1mW. That means it takes only 64mW to reach 120dB, which will cause hearing damage within minutes.

Either amp will drive the T 1 beyond 120dB. The JDS is capable of 125mW into 600Ω, which will get the T 1 nearly to 123dB; the Topping can do 143mW, which will get it slightly beyond 123dB.

 

[matti621]

Are you talking about power? The Beyer T 1 is rated at 600Ω and 102dB @ 1mW. That means it takes only 64mW to reach 120dB, which will cause hearing damage within minutes.

Either amp will drive the T 1 beyond 120dB. The JDS is capable of 125mW into 600Ω, which will get the T 1 nearly to 123dB; the Topping can do 143mW, which will get it slightly beyond 123dB.

The T1 reaches up to 1200 ohm impedance.
It appears the voltage the amp is capable of is a good indication for its audio quality. Tube amps excell at driving high impedance cans and have much higher voltage.

 

[megabigeye]

On my phone, anyway, it looks like it's closer to 1400Ω at 100Hz. Assuming both amps offer constant voltage at that impedance, the Atom is capable of 5.2mW and the A30 can do 6.1mW, both of which should should drive the T 1 over 105dB at that frequency/impedance. Quite loud.

If you're really uncertain, you should ask in the threads for each respective device. You might also consider contacting JDS directly; if there Atom can drive the T 1, the A30 should, too.

EDIT: Oops! I realized my math here is wrong (and I made a typo (stupid phone)). Atom is capable of 53mW, A30 is capable of 61mW.

 

[megabigeye]

I REALIZED I MADE A MISTAKE IN MY MATH ABOVE: the Atom can do 53mW at 1400Ω, not 5.3mW, which will produce more than 114dB. A30 can do 61mW, which should be just south of 117dB. Both painfully loud.

By the way, if you want to figure this stuff out on your own it's quite simple with a bit of basic algebra.
Two things to remember: 1) Voltage (for the most part) remains constant no matter the load (impedance); and 2) The relationship of power to volume is logarithmic– every additional 3dB of volume requires a twice as much power.

Watts = Power = P
Volts = Voltage = V
Amps = Current = I
Ohms (Ω) = Restistance/Impedance = R

P = V*I
I = V/R
Therefore:
P = V²/R
and:
V = √(P*R)

Using the Atom as an example, we know that at 600Ω that it's capable of 125mW (0.125W), so:
0.125W = V²/600Ω
V = √(0.125W * 600Ω)
V = 8.66V

Then, since voltage should remain constant, we can plug that voltage in to figure out how much power it can do into 1400Ω:
P = 8.66V²/1400Ω
P = 0.053W = 53mW

The T 1 has a sensitivity of 102dB at 1mW, so it requires 4mW to reach 105dB, 8mW for 108dB, 16mW for 111dB, 32mW for 114dB, etc... I'm much too lazy to remember how to do logarithms to figure out precisely how loud it'll be at 53mW, but you're certainly welcome to do that.

 

[matti621]

Thanks a lot. By the way, I contacted JDS and they said as long as the DAC output 2Vrms it's fine. (My HRT II+ outputs 2.2Vrms).

 

[megabigeye]

Awesome.

Also, I realized I made ANOTHER math error. The T 1 requires 2mW to reach 105dB, not 4mW, which caused the rest of those calculations to be wrong. D'oh! No wonder I didn't do well in high school math!