# Analog vs. Optical/Digital...worth it?



## Socalstangman (Sep 20, 2011)

Im trying to work out a deal locally with some one who has a Bit one. It seems to me the best way to hook this up is with the optical input. Is there really a big difference between a full digital set up over an analog one? Heres why I ask...

He also has some Audison amps with the Bit In already installed so I would need to buy a HU with an optical out. Now, Im not opposed to this other than the fact it would be a little pricy, Im not afraid to spend the money if its worth it. He doesnt have anything set up so I cant hear it, to be honest I never heard a digital setup. Any thoughts on this?


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## Hisma (Dec 30, 2015)

*Re: Optical vs. Digital...worth it?*

fwiw, I have a HU with SPDIF and plain RCA pre-outs ran at the same time. I did this so I could compare the difference in sound and decide which is better for myself. 

The only difference I notice between them is SPDIF requires less gain than my pre-outs. Which is perfectly understandable as it provides a higher voltage to my DSP (minidsp 6x8). Other than that, I don't find much discernible difference in SQ. They sound equally clean. Even despite using cheap RCA cables. 

I'm not an expert by any means so take my anecdote with a grain of salt. But based on what I experienced I would not limit myself only to HUs that had optical out.


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## Socalstangman (Sep 20, 2011)

*Re: Optical vs. Digital...worth it?*



Hisma said:


> fwiw, I have a HU with SPDIF and plain RCA pre-outs ran at the same time. I did this so I could compare the difference in sound and decide which is better for myself.
> 
> The only difference I notice between them is SPDIF requires less gain than my pre-outs. Which is perfectly understandable as it provides a higher voltage to my DSP (minidsp 6x8). Other than that, I don't find much discernible difference in SQ. They sound equally clean. Even despite using cheap RCA cables.
> 
> I'm not an expert by any means so take my anecdote with a grain of salt. But based on what I experienced I would not limit myself only to HUs that had optical out.



Thank you. This is exactly the kind of responses I was hoping for. If I do this it will be a lot of money and time. To be honest, if I do it I want to be blown away and see a significant difference. If I cant or my goal is to lofty than I wont do it.


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## Hisma (Dec 30, 2015)

*Re: Optical vs. Digital...worth it?*



07maximan said:


> Thank you. This is exactly the kind of responses I was hoping for. If I do this it will be a lot of money and time. To be honest, if I do it I want to be blown away and see a significant difference. If I cant or my goal is to lofty than I wont do it.


I seriously doubt you'd be blown away by the difference. A clean signal is a clean signal. My setup is only digital to the DSP, not all the way into the amp, but my opinion still stands.


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## Socalstangman (Sep 20, 2011)

*Re: Optical vs. Digital...worth it?*



Hisma said:


> I seriously doubt you'd be blown away by the difference. A clean signal is a clean signal. My setup is only digital to the DSP, not all the way into the amp, but my opinion still stands.


See, now this might be a slight difference compared to what Im talking about. The setup in question would be full digital all the way to the amps as well.


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## Onyx1136 (Mar 15, 2009)

*Re: Optical vs. Digital...worth it?*

I've compared optical to RCA before as well, and I couldn't hear any difference between the 2. And, in a well installed system with good gain structure and low noise floor, no one should be able to hear a major difference between the 2. The major advantage to optical, or any digital connection, is that it eliminates concerns about induced noise in long runs of cable through an environment that is overrun with RF noise.


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## Socalstangman (Sep 20, 2011)

*Re: Optical vs. Digital...worth it?*



Onyx1136 said:


> I've compared optical to RCA before as well, and I couldn't hear any difference between the 2. And, in a well installed system with good gain structure and low noise floor, no one should be able to hear a major difference between the 2. The major advantage to optical, or any digital connection, is that it eliminates concerns about induced noise in long runs of cable through an environment that is overrun with RF noise.


Before I drop a ton of cash on this, Ive been doing a lot of research and it sems most feel the same. That a good analog system perfomrs as well as a digital one. Most say that if you have a car prone to producing noise digital is the way to go.

Thanks for the advice. Ill move on from a digital set up.


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## oabeieo (Feb 22, 2015)

*Re: Optical vs. Digital...worth it?*

If anyone has ever heard the preview channel on Sirius XM that's the best way I can describe the diffrance in digital to analog.

The issue is an analog system is fine until it needs to be digitized again. Overall SQ stays relatively the same , however the 2nd time out of the DAC I can hear a tiny bit of the Sirius XM preview Channel syndrome . Or whatever that flat digitized almost a soft clipping sound. 

I truly have to be listening for it and have to switch back and forth several times with several different types of music to even notice it but by god it's there and I can absolutely hear it and it drives me crazy. 

I have a p99 going analog into a minidsp running at 96k so that's a very good sample rate for ADC and I can still hear it. When I switch to optical input sound is gone. 

I have to put extra emphasis on "can barely hear it" also.

I will be getting a deck with optical for sure because I need the minidsp for some custom filters otherwise I would scrap the minidsp and just use the p99 right into amps, which sq is fantastic


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## Socalstangman (Sep 20, 2011)

*Re: Optical vs. Digital...worth it?*

The problem with optical is that there are very few HU's that have it. All the processors seem to, you think more companies would put an optical on the HU's.


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## Catalyx (Oct 13, 2011)

*Re: Optical vs. Digital...worth it?*

Optical is digital, do you mean digital vs. analog?


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## Socalstangman (Sep 20, 2011)

*Re: Optical vs. Digital...worth it?*



Catalyx said:


> Optical is digital, do you mean digital vs. analog?


Haha, yeah youre right. I dont know what I was thinking. Its funny no one else caught that...maybe a mod a could change it.


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## Babs (Jul 6, 2007)

*Re: Optical vs. Digital...worth it?*

I noticed an improvement in fidelity, a lower noise floor, and better output from (iPhone to HDMI to Toslink to Helix DSP) vs (iPhone to 80PRS to RCA's to Helix DSP).


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## Coppertone (Oct 4, 2011)

*Re: Optical vs. Digital...worth it?*

Lol, we knew what you meant even if the title wasn't worded as such.


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## Socalstangman (Sep 20, 2011)

*Re: Optical vs. Digital...worth it?*



Coppertone said:


> Lol, we knew what you meant even if the title wasn't worded as such.


Lol, I figured since I was getting the responses I had hoped for.


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## BigAl205 (May 20, 2009)

I changed the thread title for ya


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## brother_c (Sep 21, 2015)

Babs said:


> I noticed an improvement in fidelity, a lower noise floor, and better output from (iPhone to HDMI to Toslink to Helix DSP) vs (iPhone to 80PRS to RCA's to Helix DSP).


Same results for me. Lower nose floor, higher SNR, greater dynamic range all same same and with high quality audio files definitely worth it.


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## Socalstangman (Sep 20, 2011)

BigAl205 said:


> I changed the thread title for ya


Thanks man, I appreciate it


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## Socalstangman (Sep 20, 2011)

[QUOTE=brother_c;4050937]Same results for me. Lower nose floor, higher SNR, greater dynamic range all same same and with high quality audio files definitely worth it.[/QUOTE]

So are you digital in and analog out?


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## brother_c (Sep 21, 2015)

I use my phone as a source with a usb to spdif converter. Then spdif digital coaxial to DSP, and from there analog to the amplifiers.


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## Socalstangman (Sep 20, 2011)

brother_c said:


> I use my phone as a source with a usb to spdif converter. Then spdif digital coaxial to DSP, and from there analog to the amplifiers.


Interesting. Where did you get that convertor? I did a search and it seems there are a few of these. 

The SQ is good with this set up?


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## brother_c (Sep 21, 2015)

I use a component board, this one

I2SoverUSB - I2S over USB Audio

There are lots of USB DAC's that have a digital output also, and have an internal battery. These might be the easiest solution and you can use the DAC for headphones or home audio. There was just a thread for USB to SPDIF converters for iPhones. Android there are lots of options anywhere from $40 on Amazon to over $200 for some high end home audio type. 

The sound quality is excellent with Tidal HIFI and HD Tracks. Like many have said though if its only mp3 or itunes aac, you may not notice as much if any difference. With CD quality or better (not mp3 converted to flac like floating around in some torrents) digital audio it is nice improvement.

The HU can still remain connected to the DSP with analog in, so it's an add on if your DSP has a digital input.


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## Catalyx (Oct 13, 2011)

07maximan said:


> Interesting. Where did you get that convertor? I did a search and it seems there are a few of these.
> 
> The SQ is good with this set up?


http://www.diymobileaudio.com/forum...o-discussion/289993-ios-s-pdif-converter.html

^ I spent just under $40 to get 24/96 digital output from my phone.


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## iyamwutiam (Nov 20, 2006)

I have a friend in Italy who is using the Bit 1 to Audubon with Bit In and is very happy. The DRC allows you to set up each amp from your seat as well. I would go digital all the way if you can.

Sent from my SM-N910T using Tapatalk


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## jsolo53 (Dec 8, 2015)

brother_c said:


> I use my phone as a source with a usb to spdif converter. Then spdif digital coaxial to DSP, and from there analog to the amplifiers.


Me too, except for optical instead of coaxial. There is a significant SQ improvement vs the 3.5mm jack on the iphone. This equates to which DAC sounds best. The DAC in the iphone sucks as does the DAC in my car's factory HU. The DAC in my 3sixty.3 simply sounds better. BTW, a 3sixty.3 is higher res than the Audison - the RF will do 24-96.


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## matdotcom2000 (Aug 16, 2005)

On some units there is a huge difference from optical to digital especially dending on the source unit and the processor... I was not able to tell a big difference from analog to digital when I was using the helix dsp pro for instance when I was comparing the digital and analog output on the pure i20... but from optical to digital on the alpine W957 there is huge difference from analog to digital... veryyy noticable... so much so I change alotttt of my system to accommodate because of the difference...


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## Onyx1136 (Mar 15, 2009)

jsolo53 said:


> Me too, except for optical instead of coaxial. There is a significant SQ improvement vs the 3.5mm jack on the iphone. This equates to which DAC sounds best. The DAC in the iphone sucks as does the DAC in my car's factory HU. The DAC in my 3sixty.3 simply sounds better. BTW, a 3sixty.3 is higher res than the Audison - the RF will do 24-96.


Actually, the DAC in the iPhone is quantifiably one of the best DAC's in any audio device on the planet. It's been discussed at length here. There's an excellent analysis of the analog audio performance at Ken Rockwell's site. Link to follow. 

Apple iPhone 6 Plus Review


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## nineball76 (Mar 13, 2010)

Onyx1136 said:


> Actually, the DAC in the iPhone is quantifiably one of the best DAC's in any audio device on the planet. It's been discussed at length here. There's an excellent analysis of the analog audio performance at Ken Rockwell's site. Link to follow.
> 
> Apple iPhone 6 Plus Review


Maybe a great dac for a mobile phone, but it's hardly comparable to the DAPs released over the last couple of years. The Onkyo sports dual sabre ess9018 and is just about the best sounding anything I've ever listened to.


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## nineball76 (Mar 13, 2010)

But I will concede that my old iPhone 6+ sounded years ahead of my current Sony Xperia Z5 premium. I just don't even bother trying to enjoy it now. Workouts have been delegated to the Onkyo. The amp in the Sony can't handle these 16 ohm ciems


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## Socalstangman (Sep 20, 2011)

Yeah but Apple doesn't play FLAC files.


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## NealfromNZ (Sep 3, 2013)

One less audio stage to run through if your going digital to digital DSP.

Digital music, converted to bit stream ( no loss) straight into dsp.

analogue hu starts with digital, DAC converts to analogue , DSP resamples analogue into digital, processes audio back to analogue.

Same source in my system has both. Digital has no background noise such as faint hiss.

However , some sources that have digatal out resamples the digital stream for volume control so you don't nesscarly get straight unaltered digital signal until full volume. ( DAC chipset dependent)

Other issue for digital ( especially toslink ) can be jitter. Again , down to how the DAC works.


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## madcowintucson (May 21, 2015)

I have tried running my HTC 10 to hdmi to optical and it works. I have used the optical input on a sound bar and also just the hdmi on my TV. Music plays just fine and streams from slacker radio or any other source in my phone. Can't do calls though which is fine.


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## nineball76 (Mar 13, 2010)

07maximan said:


> Yeah but Apple doesn't play FLAC files.


No iTunes won't play flac, Apple will with just about any other player app.


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## jsolo53 (Dec 8, 2015)

Onyx1136 said:


> Actually, the DAC in the iPhone is quantifiably one of the best DAC's in any audio device on the planet. It's been discussed at length here. There's an excellent analysis of the analog audio performance at Ken Rockwell's site. Link to follow.
> 
> Apple iPhone 6 Plus Review


Haven't been to ken rockwell's site since I was shopping for a camera. Respect him for cameras. In the audio realm, based on how it sounds it's hard to believe the iphone dac is one of the best. In the car, its SQ is a distant second from the dac in my DSP. In the house, it's light years behind the DAC in a good audio system.


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## Onyx1136 (Mar 15, 2009)

You guys really should take the time to read his review a few times before you dismiss it. It's not some subjective listening test evaluation. It's an analytical testing of the output by a machine that's used to test commercial broadcast equipment. If someone can provide the same sort of data for their "audiophile grade" DAC's in other equipment, we'd all love to see an apples to apples comparison. I know everyone around here is a golden eared audiophile savant, but I trust quantifiable data much more than someone's biased listening test. I know this stuff's not as fun when you take the voodoo and mysticism out of the equation and you back up your claims with numbers and tests and such, but it's just how I prefer to operate.


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## MrGreen83 (Jun 11, 2015)

Only way to go Full DA with the Audison DSP's (currently) is by using an Audison Voce amplifier. 

Me and my installer have been going back & forth about running it in my vehicle and he kept it real with me. Because I told him.....I don't wanna spend all this MONEY to jump on this Audison "Full DA" bandwagon...and then not notice a SUBSTANTIAL difference. 

He said....if I'm driving....all car & outside noise accounted for....I won't tell a big difference. But if I'm sitting still demo"ing my vehicle or just listening period...then I will. And whether it'll be a SUBSTANTIAL difference is up to the listener's ear. 

So for the average audio enthusiast.....I don't think it'd be worth it. But that's just MY opinion....if you can afford it and you feel as tho it'll be an upgrade....go for it. 

I myself had too many other upgrades I wanted to do to my vehicle, to take a chance on spending that money and possibly not hearing a difference. 

Anxious to see what you decide! 


Sent from my iPhone using Tapatalk


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## [email protected] (Apr 15, 2011)

Onyx1136 said:


> You guys really should take the time to read his review a few times before you dismiss it. It's not some subjective listening test evaluation. It's an analytical testing of the output by a machine that's used to test commercial broadcast equipment. If someone can provide the same sort of data for their "audiophile grade" DAC's in other equipment, we'd all love to see an apples to apples comparison. I know everyone around here is a golden eared audiophile savant, but I trust quantifiable data much more than someone's biased listening test. I know this stuff's not as fun when you take the voodoo and mysticism out of the equation and you back up your claims with numbers and tests and such, but it's just how I prefer to operate.


It isn't hard to get a Dac of some sort to be proficient most Dacs below a certain price point sound very similar and are technically very good but if you want to process and time align that signal you will have to convert it from analogue to digital and back to analogue this is adding unnecessary conversions and at the end of it you are using the dac in the processor so it would be better to feed the processor a digital signal in the first place.. 
As a side note I do a lot of my listening with headphones and don't need golden ears to tell you there are better dacs around than the one in the iPhone 6...


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## nineball76 (Mar 13, 2010)

Onyx1136 said:


> You guys really should take the time to read his review a few times before you dismiss it. It's not some subjective listening test evaluation. It's an analytical testing of the output by a machine that's used to test commercial broadcast equipment. If someone can provide the same sort of data for their "audiophile grade" DAC's in other equipment, we'd all love to see an apples to apples comparison. I know everyone around here is a golden eared audiophile savant, but I trust quantifiable data much more than someone's biased listening test. I know this stuff's not as fun when you take the voodoo and mysticism out of the equation and you back up your claims with numbers and tests and such, but it's just how I prefer to operate.


I'm not basing my decision on what sounds good by someone else's review. Not knocking the iPhone, I had the 6+ and it was good. Not anywhere near the audiophile equipment level, but average user good. I'd say it's weak point probably stands at the headphone amp. More than likely the phone was designed to work best with the freebie ear buds that come with it, and not with custom ear monitors or other slightly harder to drive, highly dynamic type of headphone. My iems are 16 ohm, grado is 32, both are considered easy to drive by audiophile standards, yet the iPhone had to be maxed out to get any volume from them. To be fair, it's a consumer driven cellular phone. Not a dedicated digital audio player. At full volume on the iPhone 6+, i was at about 125/250 on my Onkyo DP-X1. 

This is why you don't want to go out via headphone from a device like the iPhone, the amp.


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## MrGreen83 (Jun 11, 2015)

iPhone and Pure I20....Astell and Kern Ak100. Both are optical inputs. Or that new Sony RSX-GS9! 


Sent from my iPhone using Tapatalk


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## nineball76 (Mar 13, 2010)

MrGreen83 said:


> iPhone and Pure I20....Astell and Kern Ak100. Both are optical inputs. Or that new Sony RSX-GS9!
> 
> 
> Sent from my iPhone using Tapatalk


Can't get the Pure anymore since the lightning outputs a digital signal already and will connect to any usb dac. Easier to get the USB 3 camera kit and a USB to optical converter.


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## jhue73 (Sep 27, 2016)

best dac i have heard was in an alpine cd hu back in the 90s, it had burr-brown chips. the alpine cde-153bt i have now sucks in comparison. what hu would sound like the 90s alpine hu?


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## gregerst22 (Dec 18, 2012)

The pioneer 80prs uses three 24 bit burr-brown DACs. It sounds pretty good.


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## jhue73 (Sep 27, 2016)

gregerst22 said:


> The pioneer 80prs uses three 24 bit burr-brown DACs. It sounds pretty good.


ok thanks. is there any double din dvd hu with burr-brown dac?


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## yogegoy (Feb 11, 2011)

Never going back to using RCA's, Optical just cures my mechanical noise but not the pop when connecting or disconnecting from the dock of the Pure i20.


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## Babs (Jul 6, 2007)

jhue73 said:


> ok thanks. is there any double din dvd hu with burr-brown dac?


There are no double-din's I've seen with the extent of DAC's as utilized in the 80PRS and nothing even remotely close to the 99RS or Sony GS9. 

That said however, this does not mean there aren't double dins that would rival or possibly even better the 80PRS in output quality. The 957 Alpine gets my vote because of it's optical output, which would rather eliminate the last DA conversion anyway.


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## jhue73 (Sep 27, 2016)

Babs said:


> There are no double-din's I've seen with the extent of DAC's as utilized in the 80PRS and nothing even remotely close to the 99RS or Sony GS9.
> 
> That said however, this does not mean there aren't double dins that would rival or possibly even better the 80PRS in output quality. The 957 Alpine gets my vote because of it's optical output, which would rather eliminate the last DA conversion anyway.


if your using optical out then the dac your using is in your dsp. if i could eliminate a dac and be all analog it would sound better period, but if im going to listen to cd and digital media i cant do that. 

dont get me wrong the output quality on the alpine cde-153bt is good and very clean with no noise what so ever, but the dynamic range and clarity sucks.


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## Frijoles24 (Apr 19, 2010)

the reason im not a fan of apple units is that it sounds like the loudness war is incorporated inside the unit. Anything at -70db and louder distorts like crazy in the car. even with high resistance drivers, its never as clear as portable units made for sound.

Im sure they are using great dacs, but the other components from dac leading to the output is ****. Ive modded my ipod 5.5g taking output directly from dac, and there is a difference. 
The funny thing is the use of different materials (silver, copper, alum) for the wire leading from dac to filter cap to output made the difference too. 

Of course all this is subjective to my liking.


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## jhue73 (Sep 27, 2016)

Babs said:


> There are no double-din's I've seen with the extent of DAC's as utilized in the 80PRS and nothing even remotely close to the 99RS or Sony GS9.
> 
> That said however, this does not mean there aren't double dins that would rival or possibly even better the 80PRS in output quality. The 957 Alpine gets my vote because of it's optical output, which would rather eliminate the last DA conversion anyway.


i guess i have to spend 3 times the money to get the same quality now as i had back in the 90s.


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## Frogsrule (Aug 25, 2016)

If your analog source outputs 800mV or something ridiculous like that, then anything is better including optical.


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## jhue73 (Sep 27, 2016)

Frogsrule said:


> If your analog source outputs 800mV or something ridiculous like that, then anything is better including optical.



doesnt really matter if its 800mv or 8v as long as your gains are set correctly. if your amp gains are set correctly then it will see the same voltage in the input stage, if not all your doing is distorting your amps input.


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## Frogsrule (Aug 25, 2016)

jhue73 said:


> doesnt really matter if its 800mv or 8v as long as your gains are set correctly. if your amp gains are set correctly then it will see the same voltage in the input stage, if not all your doing is distorting your amps input.


well, no.


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## Onyx1136 (Mar 15, 2009)

Frogsrule said:


> well, no.


More info please. I likes to learn.


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## Hisma (Dec 30, 2015)

Onyx1136 said:


> More info please. I likes to learn.


well explained here -
Head Unit Pre-Out Line Voltages and their significance to your audio system

there is a reason people spend money on line drivers to boost their pre-out voltage...


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## jhue73 (Sep 27, 2016)

Frogsrule said:


> well, no.


well, yea...lol


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## jhue73 (Sep 27, 2016)

Hisma said:


> well explained here -
> Head Unit Pre-Out Line Voltages and their significance to your audio system
> 
> there is a reason people spend money on line drivers to boost their pre-out voltage...


i have had a dozen hu's with 500mv to 8volt and i assure you that the best sounding hu wasnt the 8volt.

boosting low quality preout doesnt make it better.


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## jhue73 (Sep 27, 2016)

maybe i was wrong, i just put rca's on the output of my 500 watt amp and hooked it to the input of my 1000watt amp and wow it sounds so much better, it has resolution for days....lol:laugh:


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## Theslaking (Oct 8, 2013)

Watts don't have anything to do with output voltage. SMH.


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## jhue73 (Sep 27, 2016)

Theslaking said:


> Watts don't have anything to do with output voltage. SMH.


well yes it does my 500watt amp produces about 35volts on the output doesnt it?....lol:laugh:


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## jhue73 (Sep 27, 2016)

35volt preout has to sound better than 2volt doesnt it?....lol


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## Theslaking (Oct 8, 2013)

Nothing quite often sounds better than something


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## jhue73 (Sep 27, 2016)

now thats the truth if i ever heard it.


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## jhue73 (Sep 27, 2016)

now if i could only get my wife to understand that....lol


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## Frogsrule (Aug 25, 2016)

OK, the real reason to use an optical connection is that it's far more impervious to noise than a single ended analog connection. Your 800mV output is only 800mV at 0dB and with the volume all the way up. If you're listening to a great recording with, oh, let's say a 12dB crest factor AND THE VOLUME CONTROL IS ALL THE WAY UP, then the peaks in the music will be at 800mV and the average level will be 200mV. 

In a perfect world, where there was no opportunity for noise to enter the system and where the noise floor of your amplifier was nonexistent, then your statement about simply setting the gains "correctly" would be correct. Sadly, in cars, that isn't correct. 

This doesn't mean that you need 8V, but the output of most portables and phones is less than 1V and in many cases, the audio output is tied directly to the power supply ground.


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## elijahscott (Jun 23, 2017)

Frogsrule said:


> OK, the real reason to use an optical connection is that it's far more impervious to noise than a single ended analog connection. Your 800mV output is only 800mV at 0dB and with the volume all the way up. If you're listening to a great recording with, oh, let's say a 12dB crest factor AND THE VOLUME CONTROL IS ALL THE WAY UP, then the peaks in the music will be at 800mV and the average level will be 200mV.
> 
> In a perfect world, where there was no opportunity for noise to enter the system and where the noise floor of your amplifier was nonexistent, then your statement about simply setting the gains "correctly" would be correct. Sadly, in cars, that isn't correct.
> 
> This doesn't mean that you need 8V, but the output of most portables and phones is less than 1V and in many cases, the audio output is tied directly to the power supply ground.


are you saying optical ran to the dsp would be better than coax? 25ft runs for either. 
Also, I'm going to be using an iPhone fed into SMSL X-USB XMOS. On the input gain side would I set gain level as 1v as thats what the iPhone output is rated at I believe. On my dsp I can switch the jumpers to range from 5v - 10v output. 
Would it be better to output as much as I can to keep gain level low on the amps? 
Or output less gain on the Dsp and more on the amps?


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## drop1 (Jul 26, 2015)

My take on this whole subject is of there were a BIG difference rcas would have gone way side long ago. Every high end amp would have digital inputs. 
They would have too because if it truly was "that much better" the bulk of us here would not accept anything less for the huge amounts of money we spend. It's not like it's hard to design a digital input amplifier compared to an analog.
Many head unit manufacturers have tinkered with digital outputs to dsp's yet analog input are still the primary.
If digital input were that spectacular half the people on this site would be pushing everyone in that direction when giving advice, but it doesn't get pushed and there is a reason for that. Rcas are ancient tech, but it works and works well.


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## Holmz (Jul 12, 2017)

If the digital optical is presenting the signal at line level (24-bits) and the gain is controlled in the DSP, then it will likely sound better at low volume. Otherwise on is only using ~19 bits most of the time, and turning it down gets to a low level. Then when it gets ADC'ed it either gets amplified, or you have just a handful of bits. (Not sure how they ALL work)

If the volume is high then it should be good analogue.

If the analogue is going some distance then it gets some noise and cable impedance effects. But most cars are not overly long.


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## Babs (Jul 6, 2007)

drop1 said:


> My take on this whole subject is of there were a BIG difference rcas would have gone way side long ago. Every high end amp would have digital inputs.
> They would have too because if it truly was "that much better" the bulk of us here would not accept anything less for the huge amounts of money we spend. It's not like it's hard to design a digital input amplifier compared to an analog.
> Many head unit manufacturers have tinkered with digital outputs to dsp's yet analog input are still the primary.
> If digital input were that spectacular half the people on this site would be pushing everyone in that direction when giving advice, but it doesn't get pushed and there is a reason for that. Rcas are ancient tech, but it works and works well.


RCA's are also versatile.. Will feed a DSP or amps directly either. As I probably mentioned before, running phone for media into the USB-DAC input of the Sony head unit, I'd say it's every bit the "SQ" as any direct digital source I've tried, including an HDMI to optical converter, the Fiio X5ii coaxial SPDIF, and I imagine the USB HEC in the Helix. It all boils down to the quality of the components (DAC's, preamps, etc) and then the final tune. 

That said though since I'll be "downsizing" a bit of gear, since I have the Director doing well for control, and two capable direct digital methods (not optical but coaxial and USB) for signal delivery to the Helix Pro-2, the nice GS9 Sony is rather redundant.. So given the car's age, I'll probably pull it for sale and plop the OEM back in. I'll probably regret it but oh well.  

If I hadn't installed a Helix Director, didn't have a USB HEC or Fiio DAP, I'd rock the Sony to DSP via analog all day long and consider it world class, worthy of the best I can tune the car.


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## t3sn4f2 (Jan 3, 2007)

elijahscott said:


> are you saying optical ran to the dsp would be better than coax? 25ft runs for either.


Are you referring to his "single ended analog connection" comment? If so, he is referring to an analog "RCA" interface, not an "RCA" digital coax interface.



elijahscott said:


> Also, I'm going to be using an iPhone fed into SMSL X-USB XMOS. On the input gain side would I set gain level as 1v as thats what the iPhone output is rated at I believe. On my dsp I can switch the jumpers to range from 5v - 10v output.
> *Would it be better to output as much as I can to keep gain level low on the amps?
> Or output less gain on the Dsp and more on the amps?*


Depends on too many unknown variables to estimate. You want to have enough output level headroom to allow for DSP functions, but not too much that you have to get into your amps possibly audibly noisy gain range.


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