Headphone Amplifier for SMSL SU-1

[LuCar]

By doing it this way, you're most likely boosting the Zero's bass response a lot.

Nothing wrong with that if it suits your preference, but something to be aware of nonetheless.

The SU-1 is designed exclusively for plugging into external Amps.

If you're looking for a compact DAC that's actually built to drive IEMs directly, then take a look at the Topping DX1.

That one will reproduce the Zero's tuning as intended by the designer.

Edit: Sorry, my mind jumped to the Truthear Zero. It's the Truthear Zero whose bass will be boosted when used directly from Line out.
The 7Hz Zero OTOH should stay pretty stable WRT frequency response.

Whether the SU-1 can cope with the increased current draw due to a load which it wasn't designed for, is another question.

Thanks. I also have a smsl m300se, which has an actual headphones amplifier. My daughter took over the m300se because it takes bluetooth as an input.

The Zero:2 are very sensitive. The SU-1 drives them more than adequately, at least from a volume standpoint. I'm listening to this setup right now and any volume above 40/100 in the PC is too loud for my taste. Anything above 50% is probably not safe for my ears. The bass sounds excellent, not overly boosted. Sound is extremely transparent. I will report if I blow up the SU-1, but I doubt it at this point since I've using the setup for hours a day for a few weeks.

 

[LDvo]

DX1 should be perfect for use with IEMs as per measurements by L7audiolab
https://www.l7audiolab.com/f/topping-dx1/
Especially the 50mv dnr is fantastic, so no noise at all with sensitive iems, unless some leakage in usb like @solderdude said, that can happen with any device.
I don't own the DX1 but i see it as a great all-in-one solution for IEM having the great convenience of a volume pot. Alternative is a good dongle (moondrop dawn pro, tanchjim space or space lite, truthear shio or even a 20€ jcally jm20) possibly with a usb volume control if you value it.
I would already have bought a DX1 if I wouldn't already have an old external sound blaster that i adapted as a usb volume control for my good dongles.

Completely agree.
I've read good reviews of SMSL SU-1, but cannot compare it to DX1 as i don't own SU-1.
I own Topping DX1: DAC with Headphone Amp - highly recommend if you can live without SPDIF inputs (especially if it's on sale).
Versatile, compact, inexpensive quality solution for any IEM or standard size headphones (if not power hangry).
Works great with my laptop, PC via USB output or mobile device (i replaced USB stock cable) - excellent no distortion sound
output to my amps, vintage gear, etc.
No noise at all as no external power supply and my laptop USB output is very clean too with better cables.
Optimal ChiFi solution for me for minimum investment from well-known brand i can trust.
(of cause Topping makes much more sophisticated devices if willing to invest).

 

[tuanpekoe]

I am using SMSL SU-1 with Crinacle Zero:2 IEM, both highly thought of here. The SU-1 is connected to the PC via USB. I'm using one of these (https://www.amazon.com/Connector-Female-Amplifier-Speakers-Theater/dp/B07DNXZBW4) to connect the RCA output of the SU-1 to the IEM. Sounds fantastic. Volume control using the PC.

You can use adapter RCA to female 3.5mm to get sound from RCA port. But it is not the best way to use a DAC like this.
In my opinion, you should pair SMSL SU-1 with a Headphone amplifier. Because SMSL SU1 has only RCA output, there is no 3.5mm in this device.
As you know, RCA has high output impendance. Meanwhile, Headphone (or IEMs) requires very low output impendance.