Picking DAC/Amp for Dan Clark RT

[adrian]

I'm looking for a single ended integarted DAC/headphone amp for Dan Clark RT headphones, which are 12.5 ohm and 87 dB sensitivity. Expecting to use USB input. I am not sure how to pick. It seems like there are a bunch of good-performing Chinese brands, but they maybe have questionable reliability. I saw a thread about somebody's Topping product "exploding" which sound pretty troubling. In Amir's sabaj a10d review it malfunctioned until he power cycled it, which doesn't seem encouraging. So how should I pick a good option? Should I be scared of the Chinese brands like Topping, Sabaj, SMSL with regards to reliability and QC?

 

[AudioStudies]

I have several Topping products and never had a problem with any of them. Also, I think Apos Audio offers a warranty on new Topping products that they sell.

 

[jae]

I wouldn't be worried. Order from Apos audio if you're in the US or Amazon and you should be fine. I'd suggest a Topping DX3 Pro Plus.

 

[adrian]

The DX Pro Plus review is a little hazy about what's going to happen in the low impedance low sensitivity situation. Amir says something about it going into protection when he turned it to 0 dB with the Dan Clark Stealth, but he didn't say how loud it got. Can I assume that if I'm at 12.5 ohms instead of 23 ohms I should be 3 dB louder?

 

[AnalogSteph]

This is one of those headphones that may actually warrant going for a higher-power, more robust amp... a separate DAC + HPA stack may be your best bet here.

The DX3 Pro+ makes it to about 1.8 Vrms into 12 ohms. Which is a more than decent ~270 mW, or 111 dB SPL peak with 87 dB/mW, which ought to be quite sufficient. Still, it's clearly very much current-limited at this point, and the thermals would have me slightly worried.

A DX7 Pro+ makes it to 2.4ish Vrms into 12 ohms. Better but a lot more expensive, too.

Let's have a look at some dedicated amps:

JDS Labs Atom Amp+, a little over 3 Vrms.
SMSL HO100, almost 4 Vrms. (IEC Class I device though)
Schiit Magni Heretic, 4 Vrms.
An L30 II can still drive an impressive >6 Vrms into 12 ohms (~3.3 W or so) without a hitch.
Sabaj A10h is almost as unbothered as the L30 II but offers less gain.
SMSL SH-8S, a little short of 6 Vrms, too. (IEC Class I device though)
L50 is basically the same as L30 II, maybe a bit better.

Topping L70 Headphone Amp Review

Cheap dac old and range topping mobile phone oleds aren't anything like the same thing, nit even the same sport. That said this looks brilliant.

audiosciencereview.com

Here's the maximum output power vs load of Topping's most powerful headphone Amps:
View attachment 248021

IMHO: Best budget option - L30 II with a matching inexpensive DAC (dongle if need be). Should be sub-$300 all in, possibly even sub-$200. Even substantially more expensive combo DACs won't have that much oomph.

 

[adrian]

So if the L30 II gets too hot, is there something that comes to mind that would be a better choice? Also L30 has no DAC, which is a complication. My space where I want to put things is not large, so with a separate DAC I think I end up with one of the devices behind the other one and underneath something else. So integrated DAC/amp would work better.

 

[adrian]

I noticed that the amps shown on that graph seem to be balanced, which for some reason means higher power. Like L70 gives 5W at 30 ohm balanced, but only 2W single ended. I was planning to stick with single ended.

How much power is needed anyways?

 

[staticV3]

How much power is needed anyways?

Here's how much power you need to reach a certain SPL at 425Hz (Amir's calibration frequency):


However, as you can see here, music is typically loudest at low frequencies (bass):

And thanks to the Aeon RT Closed's built-in bass shelf, it's about 3.5dB more sensitive below 100Hz.
So at frequencies below 100Hz, the power requirements are as follows:

 

[staticV3]

The DX3 Pro+ makes it to about 1.8 Vrms into 12 ohms. A DX7 Pro+ makes it to 2.4ish Vrms into 12 ohms. Better but a lot more expensive, too.

Here are interpolated max power vs load graphs based on WolfX-700's data:

As you can see, the DX3Pro+ is more powerful actually.

Up until recently, Amir's max Vrms vs Load sweeps produced pretty bad data for all DUTs, so I would trust Wolf's measurements there:

 

[adrian]

That's interesting. So that suggests that the DX3 Pro+ is probably adequate. The Wolf plot shows it at about 1.5 W, which is over 110 dB at 425 Hz. Do I have that right? It seems like the Sabaj A20D is a decent candidate, but significantly more expensive. (Also design is annoying with those loops on the front sides, which will get in the way.)

 

[AnalogSteph]

Here are interpolated max power vs load graphs based on WolfX-700's data:

As you can see, the DX3Pro+ is more powerful actually.

That's a lot more in line with the DX3Pro+ specs, too. Over 1 watt would be plenty, I think. The L30 II does remain even more powerful though (3.5 W into 16 ohms and 2.7 W into 32 ohms spec, as well as 560 mW into 300 ohms).

 

[adrian]

Where can I find the Wolf data you're using? I had a realization last night that the DAC doesn't need to be near the amp (I know, it's obvious), which means I do have space to use two separate boxes. (I guess somehow I was blinded by all the pictures of the "stack".) I currently have a Schiit Heretic on hand, so I could just add a DAC to it. Is there some compelling reason to return it and do something else? I get the impression that for the most part, these devices are all delivering roughly comparable single-ended power.

 

[staticV3]

Where can I find the Wolf data you're using?

Here is the link: https://www.l7audiolab.com/

WolfX-700 uses the same APx555b Analyzer as Amir, but puts more effort into the precision and reliability of his measurments I feel like.
If there are reviews of the same device by Amir and Wolf, then I usually stick to Wolf's.

 

[Saturn94]

So integrated DAC/amp would work better.

You might take a look at JDS

Element III MK2 _ Shop JDS LABS

We’ve reimagined our flagship amp+DAC to create a listening experience you will notice and appreciate. Element III operates on our second-generation XMOS hardware and firmware, blissfully integrated with a custom encoder. You’ll hear perfect channel balance down to the black noise floor...

jdslabs.com

I’m using their Atom+ amp to drive my Drop+DCA Aeon X Closed headphone; plenty of oomph and sounds great!

I like that JDS is made in the US and has a reputation for excellent products and customer service.