MainLine vs Crackatoa

[hpleung]

Hi,

I have already built the Mainline which sounds fantastic but a little not enough power. First, how is the Crackatoa different than the Mainline sound wise? Additionally, does it have more power than the Mainline?

Thanks.

[Doc B.]

What are you trying to power?

[Happy Ghost]

I have already built the Mainline which sounds fantastic but a little not enough power.

I had a similar problem with the C2A driving HD 8xx... I put a Moreplay before it.. Problem solved.. and joy of building one more kit.. 

As always, YMMV 

[hpleung]

RE: What am I trying to power.

I like to experiment with lots of headphones; on the Susvara I found the mainline to be just barely sufficient at max power. Does the Crackatoa has a bit more power?

Separately, i have built the Kaiju and speaker amp the Susvara. Love it - and that has plenty sufficient power.

[Paul Joppa]

The available power depends on the headphone impedance and the signal voltage applied to the headphone amp.

OTL amps (Crack, Crack-a-two-a) produce the most power into high-impedance phones; amps with output transformers (S.E.X., Mainline) produce the most power into low-impedance phones.

For the specific question of Crack-a-two-a vs. Mainline, Crack-a-two-a makes more power into impedances greater than 150 ohms, Mainline makes more power into impedances less than 150 ohms.

Some phones or tablets have low output voltage and need additional gain to get the maximum power.

[Paul Birkeland]

Along with what PJ says, if you have a source with weak output voltage like a phone (usually around 300mV) and you turn the Crack or the Crack-a-two-a all the way up, you're nowhere near approaching the maximum output level.  A 2V DAC should be more than enough to get the job done though, just be sure if you're using it with a computer that all of the level controls are set to maximum. 

[hpleung]

Thank you PJ. The point about the high impedance versus low impedance is non-intuitive. I would not have guessed that; I originally though, an amplifier produces a fix amount of power but that translate into volume based on the impedance of the headphone (and its sensitivity).

To Paul Birkeland, I am using Denafrips ARES II. It should be fixed output volume from the DAC.

[Paul Birkeland]

That DAC has a ton of output.  What happens if you turn the Mainline all the way up?

[hpleung]

The mainline is already set to maximum volume and used with the Denafrip Ares II. Using the focal utopia, the volume is very sufficient. On the Susvara, the volume is just shy of my level of loud enough

[Paul Joppa]

The Susvara impedance spec is 60 ohms, and Mainline would make about 600mW into that load. S.E.X. could do 1000mW, but that's only 2dB louder - a barely audible difference. The OTL amps only make something like 30mW into 60 ohms.

Even Kaiju won't put out more than 2 watts into 60 ohms (a 5dB boost from Mainline).

[Loquah]

The Susvara is one of the more demanding headphones on the market and doesn't sound its best from the Mainline IME. You'll also struggle pairing it with OTL amps like the Crackatwoa (and other brand OTL amps) because of it's sub-150 ohm impedance. You're best off running the Susvara off a decent solid state amp or a tube amp designed for speakers (like the Kaiju) where you have more power available at 60 ohms. The biggest issue with the Susvara is its low sensitivity meaning that it does require a lot of power relative to most headphones on the market. It will still do well with anything producing around 500mW of clean power at 60 ohms, but I felt like it was stretching the limits on the Mainline.