Running cell phone thru headphone amp before connecting 3.5mm to HU?

[sjv13 10+ year member]

I have an iPhone 4s that I use for my music right now and I plug it into my HU via USB cable. I pay for Spotify and they have 320kbps downloads, so it's the perfect set up right now.

The problem is that I want to get a new phone (a Windows 8 phone more specifically). I'm debating between the Nokia Lumia 920 and the HTC 8x. The 8x has a built in amp that boosts the output of the 3.5mm jack to 2.55 volts (apparently normal is about 1 volt?). I tested the difference using my iPhone between the USB cable and 3.5mm jack on my HU, and I can tell especially the bass sounds a lot better using the USB cable. But I'm thinking that maybe this built in amp in the HTC phone will make the 3.5mm perform better.

Does this thought process even make sense? Does increasing the voltage of the audio source lead to a better/cleaner signal? Any thoughts?

Click to read more...

 

[jockhater2 10+ year member]

I have an iPhone 4s that I use for my music right now and I plug it into my HU via USB cable. I pay for Spotify and they have 320kbps downloads, so it's the perfect set up right now.
The problem is that I want to get a new phone (a Windows 8 phone more specifically). I'm debating between the Nokia Lumia 920 and the HTC 8x. The 8x has a built in amp that boosts the output of the 3.5mm jack to 2.55 volts (apparently normal is about 1 volt?). I tested the difference using my iPhone between the USB cable and 3.5mm jack on my HU, and I can tell especially the bass sounds a lot better using the USB cable. But I'm thinking that maybe this built in amp in the HTC phone will make the 3.5mm perform better.

Does this thought process even make sense? Does increasing the voltage of the audio source lead to a better/cleaner signal? Any thoughts?

I don't think so. You just want your phone to play the music and that is it. The HU/amps do the signal boosting.

That is why on my ipod I use a LOD cable. To bypass my ipods built in amp

 

[sjv13 10+ year member]

I don't think so. You just want your phone to play the music and that is it. The HU/amps do the signal boosting.
That is why on my ipod I use a LOD cable. To bypass my ipods built in amp

What's an LOD cable?

 

[jockhater2 10+ year member]

What's an LOD cable?

Line Out Dock

Here is what I used to use

New FiiO L3 LOD Line Out Dock Cable for iPod and iPhone | eBay

but I just got a new HU and switched to

LOD to RCA | eBay

 

[jockhater2 10+ year member]

when you use your phones amp. You are double amping your signal. It should be making the quality worse.

 

[gckless 5,000+ posts]

I doubt you would notice a big difference versus the 3.5mm on the iPhone. The DAC on any phone isn't that great. With that amp, all you are doing is boosting the signal, not adding any EQ. Maybe the DAC is better, and has a better EQ and so forth on it, who knows.

My suggestion would be to keep using that iPhone for music. Or sell it and buy an iPod to keep in the car.

 

[gckless 5,000+ posts]

when you use your phones amp. You are double amping your signal. It should be making the quality worse.

That is not the reason it sounds worse. That's like saying a line driver makes all signals sound worse. Not the case. The reason is the DAC on the phones.

 

[sjv13 10+ year member]

Line Out Dock
Here is what I used to use

New FiiO L3 LOD Line Out Dock Cable for iPod and iPhone | eBay

but I just got a new HU and switched to

LOD to RCA | eBay

Oh, ok. That's not necessary for me because I can just use the UBS in on the HU. That's an interesting cable though. Can't say I've seen one like it before.

I doubt you would notice a big difference versus the 3.5mm on the iPhone. The DAC on any phone isn't that great. With that amp, all you are doing is boosting the signal, not adding any EQ. Maybe the DAC is better, and has a better EQ and so forth on it, who knows.
My suggestion would be to keep using that iPhone for music. Or sell it and buy an iPod to keep in the car.

Everything you just said was exactly what I was thinking, but I just wasnt sure. The problem is that I use Spotify for all my music which requires an app. The cheapest iPod touch now is $300... Maybe I'll just get the iPad mini for $330...

 

[gckless 5,000+ posts]

Everything you just said was exactly what I was thinking, but I just wasnt sure. The problem is that I use Spotify for all my music which requires an app. The cheapest iPod touch now is $300... Maybe I'll just get the iPad mini for $330...

Oh yeah, Spotify streams doesn't it? So you're going to need phone signal regardless. Well, I would say your choices are to either dump spotify or figure out how to make the Windows phone work. Your call.

 

[jockhater2 10+ year member]

Oh, ok. That's not necessary for me because I can just use the UBS in on the HU. That's an interesting cable though. Can't say I've seen one like it before.

Everyone who gets really into headphones and buys grados/headphones like them. Usually buy an external amp to power there headphones. And they always use an LOD cable to bypass there MP3 players DAC.

That is where I found out about the cables. I don't like using the USB because that charges the ipod which ruins it's battery. So I use the LOD cable to bypass the DAC and get a purer signal.

 

[sjv13 10+ year member]

Oh yeah, Spotify streams doesn't it? So you're going to need phone signal regardless. Well, I would say your choices are to either dump spotify or figure out how to make the Windows phone work. Your call.

Spotify can do both. It can stream or download. It only streams 320 if you have the paid version. And you can only download if you have the paid version. I have over 200 songs downloaded onto my actual phone, so I dont eat up data playing my fav songs over and over. It's really worth it for $10 a month.

 

[sjv13 10+ year member]

Everyone who gets really into headphones and buys grados/headphones like them. Usually buy an external amp to power there headphones. And they always use an LOD cable to bypass there MP3 players DAC.That is where I found out about the cables. I don't like using the USB because that charges the ipod which ruins it's battery. So I use the LOD cable to bypass the DAC and get a purer signal.

Oh, cool. That's good to know. I have an pair of Klipsch Image s4. Would I notice a difference if I used one of these LOD cables?

 

[jockhater2 10+ year member]

Oh, cool. That's good to know. I have an pair of Klipsch Image s4. Would I notice a difference if I used one of these LOD cables?

Nope those are only 18 ohms.

An LOD for your headphones would only really benefit if you had headphones like these. They are 600 ohms. So your ipod/phone would not be able to power them. And to use an LOD with your headphones. You would need a headphone amplifier.

Beyerdynamic T1 600 Ohm Tesla Headphones | Full Compass

 

[sjv13 10+ year member]

Nope those are only 18 ohms.An LOD for your headphones would only really benefit if you had headphones like these. They are 600 ohms. So your ipod/phone would not be able to power them. And to use an LOD with your headphones. You would need a headphone amplifier.

Beyerdynamic T1 600 Ohm Tesla Headphones | Full Compass

Ah, okay. Makes sense.