[Setmagic]

I agree with the hi-pass filtering part, but was concerned about the risk of frying the headphone or IEM: I believe U1 amp power supply is 0 / +9V (it’s not symmetrical) so without blocking cap, 4.5V DC is flowing through the headphone…. But it may not be a problem after all!

Yes it is possibile when something goes really wrong like shorted amplification circuit or damaged device. But the most thing it's worse sound quality this way from factor. You can test it in Yours amps or devices.

 

[avitron142]

How would this differ from the Zishan Z2?

 

[XTF1]

IIRC, Z2 had +/-13V rail supply, so 0V (or close to 0 if rails were more like -12.5/+13V) DC through the headphone without blocking caps. “Blocking” caps are not really needed in that case, except for additional protection.

 

[ZigZagged]

Hello everyone, I'm interested in the ES9038 version of the Zishan U1 and I wanted to know if it is suitable for IEMs like Moondrop Aria, CCA C12 and NiceHCK NX7 Pro, is the output impedance too high? Also, any decent alternatives you'd recommend with a 50$ budget?

 

[XTF1]

Hello everyone, I'm interested in the ES9038 version of the Zishan U1 and I wanted to know if it is suitable for IEMs like Moondrop Aria, CCA C12 and NiceHCK NX7 Pro, is the output impedance too high? Also, any decent alternatives you'd recommend with a 50$ budget?

Output impedance of the U1 is around 10 Ohms, which is a little high for IEMs. It’s probably fine for Aria, (single DD) and NX7 (hybrid, but higher impedance), but may be a ? for C12: could ok, bad, or great for your taste!

Alternatives: what do you want to give up? If you want a battery-powered DAC/Amp that is also a powerbank for less than $50… I don’t think there is an alternative! If you give up the battery, there are plenty of decent dongles that will be fine for your IEMs. If you accept a more clunky solution, an inexpensive dongle + battery amp (no DAC) would do and can stay within $50 total. If you can pay more, the Tempotec IDSD can be found on sale around $60. There is also the Trasam HD3 Pro, but I’ve never seen any review. If you pass $100, there are many more options. Including Z4 and other DAPs.

 

[ZigZagged]

If you accept a more clunky solution, an inexpensive dongle + battery amp (no DAC) would do and can stay within $50 total.

Any battery powered amps under 50$ (lower is better) you'd recommend? I have a few dongles already like CX-Pro CX31993, VE Avani and Odyssey HD.

 

[XTF1]

This entire section of Head-Fi is dedicated to portable HPA. You’re gonna find plenty of recommendations from folks that are much better qualified than me !!!
Under $50 is going to drive you into the “obscure’ ChiFi category Nothing wrong with that—that’s also where Zishan is—but a little bit of a lottery and certainly some tradeoffs. The Topping NX1S (yes, it has bass roll off…) may be one of the few known brands offer. The newer Aiyima H1 (less the $25 on AliExpress) looks pretty cool: replaceable 14500 battery, rollable opamps. But I have no idea how good it is and how it sounds.

 

[DBaldock9]

Any battery powered amps under 50$ (lower is better) you'd recommend? I have a few dongles already like CX-Pro CX31993, VE Avani and Odyssey HD.

The Walnut F2 (~$40) DAP/DAC can also be used as an Amp, by connecting your Input cable to the Line Out jack. On the Single-Ended Output, it has 2x Dual Op-amps driving the L+, and 2x Dual Op-amps driving the R+, which will provide quite a bit more output current than other small Amps. The Balanced output is provided by 2x Differential Line Driver ICs.

 

[povidlo]

Any battery powered amps under 50$ (lower is better) you'd recommend? I have a few dongles already like CX-Pro CX31993, VE Avani and Odyssey HD.

Check out Lusya EF04, MUSES02 version, for $35 USD from QingBee Store on AliExpress. 700 mW power output at 32 ohm.

According to Japanese reviewer who measured it, apparently it comes with a genuine MUSES02 op amp.

"I just ordered it because it's cheap, and it's very good. The MUSE02 specification product is genuine as a result of simple measurement of the OP Amp. Pins 1,2,3 and 5,6,7 come with infinity resistors. good. The fake ones are about 20 meg ohms. The sound is richer, more detailed, and more powerful. I recommend it."

https://www.aliexpress.com/item/1005003176732524.html

 

[232tomas232]

hello comrades. tell me how u1 can be switched to power from usb. to eliminate the constant charging of the battery and use it with a PC

 

[captione]

hello comrades. tell me how u1 can be switched to power from usb. to eliminate the constant charging of the battery and use it with a PC

Open up your U1, desolder the 2 wires that connects the battery pack, find a 2 pinhole marked "J1", make a short by connecting those two pinholes together in the back of the pcb and voila! You got yourself a USB-powered U1.

 

[232tomas232]

Откройте свой U1, отпаяйте 2 провода, которые соединяют аккумулятор, найдите 2 отверстия с маркировкой «J1», замкните их, соединив эти два отверстия вместе в задней части печатной платы, и вуаля! У вас есть U1 с питанием от USB.

да спасибо получилось. Есть еще одна проблема, которая меня беспокоит. Я хочу "обойти" буфер выходного транзистора. можете подсказать как сделать? Еще слышал, что в таких случаях надо менять привязку выхода ой. а я не знаю какие номиналы и куда ставить

 

[XTF1]

hello comrades. tell me how u1 can be switched to power from usb. to eliminate the constant charging of the battery and use it with a PC

In addition to @captione instructions, note that earlier U1 versions would go in (deep) sleep mode after ~15-20 minutes with no input signal (no music). The only way to wake up U1 internals is to unplug/plug the USB, which could be annoying in desktop use. The more recent FW versions require setting the volume pot. to 0 to enable the automatic sleep mode, which addresses the inconvenience. That being said, it is possible that U1 (the Amanero-like interface) become unrecognized on your PC after a while, so you may have to unplug/plug U1 from time to time anyway…

 

[232tomas232]

В дополнение к инструкциям @captione обратите внимание, что более ранние версии U1 переходили в (глубокий) спящий режим примерно через 15-20 минут без входного сигнала (без музыки). Единственный способ разбудить внутренние компоненты U1 — отключить/подключить USB, что может раздражать при использовании на рабочем столе. В более поздних версиях FW требуется настроить регулятор громкости. на 0, чтобы включить автоматический спящий режим, который устраняет неудобства. При этом вполне возможно, что U1 (интерфейс, похожий на Amanero) через некоторое время перестанет распознаваться на вашем ПК, поэтому вам все равно придется время от времени отключать/подключать U1…

yes thank you it worked. There is another issue that worries me. I want to "bypass" the buffer of the output transistor. can you suggest how to do it? I also heard that in such cases it is necessary to change the binding of the output oh. but I don't know what denominations and where to put

 

[Setmagic]

@232tomas232
Find traces on PCB, reconnect by wire directly to jack 3,5mm and rember to disconnect transistor as well from power supply and rail, it's really important.
It's simpler way just use LO output