Use smartphone with headphone amplifier
Aug 18, 2020 at 4:13 AM Thread Starter Post #1 of 19

thee mutz

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Hello, I'm interested in a good, cheap headphone amplifier like for example the Sabaj PHA 2. I want to use my Samsung smartphone as the music source. The phone has a 3.5 mm headphone out, the amplifier has only rca inputs. Is it just a matter of buying a 3.5 mm jack plug to rca plug adapter cable and I'm OK? Is it that simple?
 
Aug 18, 2020 at 6:12 AM Post #2 of 19
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Aug 18, 2020 at 7:06 AM Post #3 of 19
Thanks for your answer. So if i buy an dac/amp and connect it to the phone it will automatically overrule the dac/amp of the phone?
i have to connect the headphone out from the phone to the usb in from the dac/amp?

i use old AKG 600 ohm headphones, so i need a bit more power than the phone can deliver.... i think. I mean the headphones sound great to me and the max. volume is ok with me, but i read everywhere and heard also from a colleague who has a seperate headphone amp that it is not necessarily about more volume, but better dynamics and more body, especially with these 600 ohm headphones...
 
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Aug 18, 2020 at 7:49 AM Post #4 of 19
i have to connect the headphone out from the phone to the usb in from the dac/amp?
No!
The headphone out of the phone is analog, you can connect this to a analog input e.g. a RCA input.
If you want to go this way on a budget, look here: https://www.audiosciencereview.com/...ents-of-new-jds-labs-atom-headphone-amp.5262/

You connect the USB of the phone with the USB of the DAC.
You bypass the whole DAC/amp section of the phone.
You probably need a USB OTG cable to get it to work.
https://www.thewelltemperedcomputer.com/SW/Android/Android_USB.htm
 
Aug 19, 2020 at 5:41 AM Post #7 of 19
You cannot usually connect a headphone out to a line input. These are designed for different purposes. RCA inputs are usually analogue line level inputs. Which exact phone model do you have? You will probably want to find a line out from your phone that would connect to a headphone amp if you want to use the DAC in your phone. As others have explained, you can bypass the phone's internal DAC using an OTG cable and connect it to a DAC/amp.
 
Aug 19, 2020 at 6:07 AM Post #8 of 19
Samsung S 10 E.

According to Roseval i can connect the 3.5 mm headphone out to the rca in from the amp. with the use of an adapter cable, or did i misread something?

I do not want to bypass the dac from the phone, just more power to drive the 600 ohm headphones.
 
Aug 19, 2020 at 6:30 AM Post #9 of 19
Thanks for your answer. So if i buy an dac/amp and connect it to the phone it will automatically overrule the dac/amp of the phone?
i have to connect the headphone out from the phone to the usb in from the dac/amp?

You have to connect the phone's USB port to the USB input on the DAC-HPamp using an OTG cable. Your phone probably has a converter - my S9 came with one.


i use old AKG 600 ohm headphones, so i need a bit more power than the phone can deliver.... i think. I mean the headphones sound great to me and the max. volume is ok with me, but i read everywhere and heard also from a colleague who has a seperate headphone amp that it is not necessarily about more volume, but better dynamics and more body, especially with these 600 ohm headphones...

Portable amp like that one you're looking at might not make a meaningful difference since portables run with limited voltage (better portable amps at least can provide enough current), which is what high impedance headphones need. And sometimes quoted voltage output doesn't mean it's the same voltage when the amp circuit sees a high impedance load.

If you're not going to walk around with that headphone (more so if it's an open back headphone), look into desktop DACs and HPamps. If you have no plans to try out low impedance, low sensitivity headphones, maybe use an OTL headphone amplifier.
 
Aug 19, 2020 at 7:09 AM Post #11 of 19
Have you thought about checking out iFi audio?

They do both portable and desktop gear and their desktop ZEN CAN is getting great feedback on here at the mo (as does most of their products to be honest.)

You really out to have a dac/amp combo so I'd check out their hip-dac for portable use and their ZEN DAC. You can add a separate headphone amp (ZEN CAN) at a later stage. It will add extra power.

For mobile, use you simply need an OTG cable for the hip-dac. It couldn't be easier.
 
Aug 19, 2020 at 9:23 AM Post #12 of 19
I thought the topping L 30 is a powerful desktop headphone amp?

Quick specs : 3500mW, SNR 141dB

Detailed Specs : 500mW into 32ohms, 0.0001% THD; 80mW into 300ohms at 0.00009% THD, SNR 141dB

That could mean any of the following:
1. 40mW into 600ohms at 0.00009% THD, SNR 141dB
2. 240mW into 600ohms at 2% THD, SNR 89dB (there's no actual math for every amp, this is just an approximation of how things can go downhill as power output goes up)
3. Or anywhere in between those two at any of those three parameters


Maybe you can recommend me a budget ( max. 130 euro ) headphone amp that is powerful enough?

Can't you get another 5euro?
https://www.schiit-europe.com/index.php/producten/amps/magni-heresy-headphone-amp-and-preamp.html

Also you should get a desktop DAC that way you can send a clean 2V signal into the amp.
https://www.schiit-europe.com/index.php/producten/dacs/modi-3-affordable-do-all-dacs.html

I'd much rather save up for both of those than rush something now and not get as much improvement.
 
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Aug 19, 2020 at 11:14 PM Post #14 of 19
there is one thing i still do not understand: why do i need a seperate DAC? There is a DAC in my smartphone / ipad, are they of inferior quality? Can it not deliver enough power to the amp?

Not power ie watts, just voltage with clean output. If I level matched my S7 via the 3.5mm output vs the USB input on my DAC+HPamp for example I'd have to turn down the phone and then crank up the amp to try (read: try) to equalize noise and distortion. All it does is minimize noise but the low end of the DAC in the headphone amp still does better.

If you have to lower the voltage output to minimize noise and distortion you have to rely on the amp's power and gain, and in hi-fi equipment, short of a flawed circuit like forcing a single ended output to produce 4V at the cost of noise, the amp is more likely the source of noise and distortion. If the source already has those the amp will just amplify those then add its own; turn it down, and you make the amp work harder so you just end up with some noise and distortion getting amplified then the amp getting pushed adds more. That's why starting with a clean 2V signal is important.

That being said you don't necessarily need some fancy $600 DAC to get a clean 2V signal.
 

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