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World's best DAC Dongle for DAC quality only? Driving car line-in, so amp performance irrelevant?

davidnash

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I have a use case which I feel is perhaps very common, but not commented upon much in Amir's amazing reviews here.

I want the world's best audio quality DAC Dongle to use in my in-car setup.
The DAC will sit between my Android phone (Fold 2) and the 'aux in' of my car (BMW M6 E64 2008). As the dongle merely needs to power the vehicle's input which I'm assuming will be similar to line-in, I feel that many of the metrics assessed by Amir's reviews may not be too relevant to me - I'm not trying to drive insanely high impedance headphones, and I am guessing therefore the power charts maybe do not matter to me so much? I merely want to provide the highest quality audio feed to my vehicle's line-in. Crucially I think the Dongle's amplifier abilities are probably of little importance to me (?), while the DAC is crucial.

Details of my setup
I currently use Tidal (including Masters quality) but am tempted by the recommendations for Qobuz on this forum.

I have no idea what the 'aux in' specs of the car are, but I suspect the aux in was developed assuming it would take a basic headphone output from any portable audio device on the market in 2008. I'm guessing it roughly adheres to 'line-in' specs, but can't be 100% sure - after all, it is probably expecting to be connected to the headphone output of an iPod or something (given a vehicle developed around 2005/2006).

The M6 has a decent stock sound system by vehicle standards, but I am planning to upgrade it to something probably costing around £5-10k ($7-13k) in the next year or so. I would like my DAC solution now to remain the best solution for when that happens (at which point I will be feeding a genuine line-in connection on a fantastic car amplifier).

My goal
I greatly care about DAC quality, and spent far too many days researching my home HiFi DAC before settling on my RME ADI-2 DAC (v2) to complement my Naim amp/Focal 1027Be setup. From the reviews I could find, this $1k DAC was said to rival $10k DACs, and the RME also has other features very useful in it's role as Pre-Amp in my hifi setup (such as 5 hardware levels of output volume, to give a very low noise floor at any volume, plus EQ etc).

So for this project, having read all the 'typical' review sites, I was about to buy a Dragonfly Cobalt, but just at the last minute I found this site, and am now so glad I didn't buy that rubbish.

I purely want the best possible DAC quality, and I think (but maybe I am wrong by not understanding the technical side enough), that the amplifier side of the Dongle doesn't matter much to me. Money isn't really a consideration (but I don't want it to be insane, I think max £300/$400 should be more than enough for vehicle audio).

My options
The three top contenders I have identified having studied Amir's reviews are the THX Onyx, the Hidizs S9 (obviously in unbalanced mode for connecting to the line-in) and the E1DA 9038D.

But I am definitely open to any better options.

Given I use Tidal Masters quite a bit, I feel like a Dongle that supports MQA (such as the Onyx) could be relevant and beneficial for me. But then MQA gets totally slated in the comments to Amir's Dragonfly Cobalt review, so maybe I shouldn't care and should switch to Qobuz...

My questions
1. Obviously my main question is below, but before answering that, maybe I need to confirm some of my assumptions. Am I correct that to drive line-in, the power of the amplifier does not matter much, because it is essentially not needing to do much work to simply provide a line-level output, as the car's amp will obviously be doing the amplification? Wikipedia confused me because it states that "The impedance of a line input is typically around 10 kΩ". To me this sounds like it is saying therefore driving line-in is a 17x harder job than driving a 600 ohm pair of professional cans. But I feel that I am just not understanding the concepts sufficiently, and surely a line-in level input can't require much power?

2. Main question: Which Dongle has the best DAC quality? / Which Dongle would have the overall best quality for driving a line-in input (in case amplifier does matter to drive line-in)?

3. Amir talks in many of the reviews about power draw, and the fairly significant impact that can have on a phone battery. This matters a lot to me as the phone is providing sat-nav for me as well on very long journeys. Amir mentioned a couple of times 'the impact if you don't have the phone plugged in'. This is the bit which leaves me confused - given the dongle plugs into the phone's USB-C socket, how can the phone be plugged in to get power? Do any of the high-end dongles allow a USB-C charging cable to be connected to it, and then pass the charging current back to the phone? Or can I use a USB-C hub, so that I can connect both USB-C charging cable and DAC dongle to the phone at the same time? USB-C hubs exist with ability to take input power and pass it to the phone, but could the use of a hub reduce sound quality?

If it's not a great idea to use a hub, then I think I will need a Dongle that supports a USB-C cable to allow charging the phone. That might drastically reduce my options. Currently I'm using a £20 Chinese thing from Amazon that does do this, and the quality is better than phone, but not great.

Thanks!
Thanks so much for all your help everyone, and sorry to write so much!

I feel like many people out there must be in the same situation of wanting to get the best possible connection to their car, so perhaps this discussion could be quite beneficial to the community.

All my best,

David
 

voodooless

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I’m pretty sure that the SINAD of the car amp is such that the DAC is quite irrelevant. Spending £300 on it seems crazy to me. Just get the £10 Apple dongle and keep the rest. As always, if you want to upgrade your sound system, do it where it matters: the speakers. If they are still stock, then that would be the obvious starting point.
 
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davidnash

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Thanks for your reply. Obviously SINAD of the amp could be greatly improved - as I mentioned I am planning to massively upgrade the system (amp & speakers) in the next few months. But the current system is also quite good for an in-car system.

I want to start with the DAC, because source is critical before all else. Getting the source right has a huge impact - I've proven this through trying 3x £20 dongles all with wildly different results (one not bad quality but quite quiet, another much louder but not good quality, another charges the phone but isn't great quality).

I also don't want to have to upgrade the DAC again, once I've made all my other upgrades. I need something better now - I've proven that with my 3 £20 attempts - and I think it's better to spend £100-300 now, rather than £150 now (or more sets of £20), and then another £300 in 6 months when I have an awesome system which you would then agree merits a decent DAC! And all the options I've found cost considerably less than £300 anyway... Plus there are black friday discounts right now...

This is also by far the simplest, easiest and cheapest upgrade I can make right now, vs tons of research on multiple components, spending £5-10k and losing the car for half a week to have it fitted.
 

raistlin65

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Tempotec Sonata HD Pro dongle has highly accurate 2V output. I use it as my DAC connected to a THX 789 in my desktop set up. It was indistinguishable from a Topping D50S.


Just be sure to turn the volume up all the way on it the first time you use it.

Amazon currently has it on special for Black Friday for $46

 
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davidnash

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Thanks, yes I've seen that recommended a lot on this forum. But I feel there must be something better - I know Dongle form factor will be a limiting factor, but given my in-home DAC rivals $10k ones, surely I can do better than a $50 one for my car...

And at least the THX Onyx seems to unlock the potential of Tidal Masters tracks better than this would?
 

BDWoody

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The DAC will sit between my Android phone (Fold 2) and the 'aux in' of my car (BMW M6 E64 2008).

Ok, speaking of music... just gotta say the S85 in that car is one of the few I may give the nod to over the S65 in my 09 M3 in terms of just that glorious noise they make. Sounds like you're planning to keep it. I can't see getting rid of mine either.
I have an LG G8 phone, which includes a quite decent DAC. I just go direct into the aux in from my phone and it works perfectly.

I'd suggest the apple dongle, but really most any of the well reviewed one's as suggested here should perform very well.
 

Chrispy

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What is the stock head unit? You can't just stream directly to it?
 
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davidnash

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Yes oh that beautiful S85. And the not so beautiful 12mpg when you do 500 miles/week...

The stock head unit is old tech, so no bluetooth, and even if there was, I really wouldn't want bluetooth due to the compression. Sorry, I'm a real audiophile nerd...

I've actually just spent $1k yesterday upgrading the headunit to an Android system which would support BT, but I'm planning to actually bypass it for my audio needs (it's a bit weird but on the E64 the head unit doesn't actually include the amp, it's more like just a screen) - the upgraded head unit functions like an Android tablet so I can use Torque and other apps on it, but I'm looking for seriously high quality audio, so don't want to use it's bluetooth features. (I'm actually thinking I may be able to use Android Auto to stream music to that headunit over a cable (keeping the audio in it's digital form), so the headunit can display what is playing and control next track etc, and then plug my DAC into one of the headunit's USB ports, which will then plug directly into the vehicle's Aux in (which unusually is totally unrelated to the headunit). But for the purposes of this discussion, I think we can ignore this point.)
 

Chrispy

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I'd just use a thumb drive in a usb port, doubt the dac will make much difference outside of the head unit's capabilities.....especially in a car's environment....

ps Sweet car!
 
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davidnash

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Yes, the engine is so loud my signal to noise ratio is going to suck anyway, but I really thought if anywhere I could find people championing getting the highest possible audio quality, it would be here!! I think the head unit will have an impact on jitter & timing (hence probably skip it out of the chain and just suffer those same defects only from the phone rather than two devices), but still I want to get the best possible solution I can with all the limitations I'm going to have to live with, given my source is a phone and environment a very loud car...

Plus a decent DAC might get me to occasionally dig out my IE80s and actually use them...

The goal is ultimately to produce a car with the best in-car sound system ever (or at least nearly)... (I've also just upgraded the battery to an insane capacity AGM, and upgrading the alternator this week...)
 

Chrispy

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Personally I'd rather listen to the car most of the time :) Or is it one of those that enhances the exhaust sound thru the audio system? :) Seriously, doubt the dac is going to make a serious difference, dacs have been solid for ages in a variety of gear.
 
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davidnash

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You are right, the first 12 months of having the car I hardly listened to any music... But now I do 500 miles/week, it's become a bit of a necessity on motorways/highways. And no, the engine is so loud none of that artificial engine sound rubbish is needed!!

Surely the DAC has to make quite a big difference, otherwise sites like this with Amir's amazing scientific reviews wouldn't be needed... And Naim/Chord etc couldn't sell enough $10k DAC products to produce a viable business if the products really don't give an uptick...
 
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davidnash

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What about my first question - Am I correct that to drive line-in, the power of the Dongle's amplifier does not matter much, because it is essentially not needing to do much work to simply provide a line-level output, as the car's amp will obviously be doing the amplification? Wikipedia confused me because it states that "The impedance of a line input is typically around 10 kΩ". To me this sounds like it is saying therefore driving line-in is a 17x harder job than driving a 600 ohm pair of professional cans. But I feel that I am just not understanding the concepts sufficiently, and surely a line-in level input can't require much power?
 

voodooless

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Surely the DAC has to make quite a big difference, otherwise sites like this with Amir's amazing scientific reviews wouldn't be needed...
ehm, not really. If this site has shown something, it is that a DAC does not matter that much at all.
And Naim/Chord etc couldn't sell enough $10k DAC products to produce a viable business if the products really don't give an uptick...
Are you sure about that? The US Homeopathy market was $ 4,609.55 million in 2020.. do you think any of that stuff gives any uptick?
 

Chrispy

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You are right, the first 12 months of having the car I hardly listened to any music... But now I do 500 miles/week, it's become a bit of a necessity on motorways/highways. And no, the engine is so loud none of that artificial engine sound rubbish is needed!!

Surely the DAC has to make quite a big difference, otherwise sites like this with Amir's amazing scientific reviews wouldn't be needed... And Naim/Chord etc couldn't sell enough $10k DAC products to produce a viable business if the products really don't give an uptick...
I think you mistake the results of much of the dac products here...actual audibility is not the norm, more a measure of engineering/purity. In a car doubt any dac implementation will make a difference in audible terms unless really bad. I used to have to drive a lot, I do understand but think just having a good variety of music is far more important than the dac.....

ps The sales of silly audio has nothing to do with performance particularly....and cars don't make good analogies either. A high performance vs low performance car is simply a much more tangible thing than differences in most dacs.
 

BDWoody

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Yes, the engine is so loud my signal to noise ratio is going to suck anyway, but I really thought if anywhere I could find people championing getting the highest possible audio quality, it would be here!!

Surely the DAC has to make quite a big difference, otherwise sites like this with Amir's amazing scientific reviews wouldn't be needed... And Naim/Chord etc couldn't sell enough $10k DAC products to produce a viable business if the products really don't give an uptick...

There is a lot of placebo being sold out there.

Don't completely discount the idea... Amir is here to let us know the apple dongle is almost certainly indistinguishable from a (name the fancy/expensive box) if you control for natural bias with blind, level matched testing, using real music in a real room (or car). Beyond some point, the improvements arent going to be audible.
 
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davidnash

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ehm, not really. If this site has shown something, it is that a DAC does not matter that much at all.
Oh wow. I kind of want to ask what is the point of all the reviews then, but I think that is too dangerous a question.

Ahh, I think Chrispy just answered that with the purity point anyway.

The US Homeopathy market was $ 4,609.55 million in 2020.. do you think any of that stuff gives any uptick?
Lol. Good point, and 2 months ago I would have said no. But I've been having digestive issues for the last 12 months, and someone forced me to try some Chinese herbs, and 3 days later I was 80% better! So maybe some of it works... I think we digress...
 

voodooless

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Oh wow. I kind of want to ask what is the point of all the reviews then, but I think that is too dangerous a question.
Nope, it’s an excellent question. The reviews are there to weed out the bad stuff and show that good stuff does not need to cost a lot of money.
someone forced me to try some Chinese herbs, and 3 days later I was 80% better!
Herbs != Homeopathy ;)

In any case. If you really want to upgrade your car audio, you might want to invest into something like this: https://www.minidsp.com/products/car-audio-dsp/cdsp-8x12-dl

You can feed that thing digitally, so can skip the DAC. It also has all the processing needed to make a car sound decent.
 

Rottmannash

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I listen like you- line out from dongle to line in of both cars. I use the 9038D, the Qudelix 5K, and the Hiby R5. They are all indistinguishable, except for the 9038D which overdrives the head unit on one car at full volume so have to attenuate the signal. If you want PEQ get the Qudelix but if you want clear, clean sound I'd recommend the 9038D.
 

Chrispy

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Sometimes, like audio tweeks, all you need is a suggestion for better health....or better habits, or exercise, or .... but chinese herbs/homeopathy never did it for me (and I have some experience with such)
 
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