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ADC - Analogue to Digital conversion


DavidL

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While there is a lot of useful information on DACs in the Equipment forum it is hard to track down info on ADCs.

 

I am sure that there are many computer audiophiles out there who in addition to wanting the best sound from their digital source material stored on hard disc or optical disc, would like to have access to their collection of music on LP in hi-res digital form.

 

User experiences of outboard ADCs (aka audio interface boxes) and internal ADCs (aka sound cards), particularly the comparative quality of sound, would therefore be very useful for those wishing to digitise LPs and other high-quality analogue sources.

 

HOW ABOUT A SECTION IN THE EQUIPMENT FORUM ON ADCs?

 

Here is a starter for this subject:

 

I am in the process of deciding how to archive my music collection on LP.

 

As a first attempt I have used the internal ADC on my Mac Pro, running Peak Pro software, to digitise the signal from my phono amp (Pure Sound p10), with the signal level adjusted externally to prevent limiting. The results sound OK but I suspect that I could do better if I had a better quality ADC.

 

I first looked at external Firewire ADCs as these would avoid the noisy computer environment and not tie me down to one computer. I found few ADCs designed for Hi Fi use on the market; there appears to be nothing between the Project USB phono stage (~ £100) and the Benchmark ADC1 (~ £1700). I therefore looked at hardware designed for recording live music e.g. the Firewire audio interfaces made by Apogee (Duet) and Edirol (FA-66). These have good reviews in the community they serve but I am not sure how appropriate they would be for archiving music from LPs.

 

Because of this uncertainty I looked again at sound cards. The Lynx L22 has had good reviews for sound quality but unfortunately only comes as a PCI card; I require a PCI Express card for the Mac Pro. The RME HDSPe AIO looks a suitable candidate as it is 192 kHz-capable and has had favourable comments on its audio performance in professional recording magazines.

 

Any comments or suggestions would be much appreciated.

 

David

 

ALAC iTunes library on Synology DS412+ running MinimServer with Samsung Galaxy Tab S2 tablet running BubbleUPnP for control >

Hi-Fi 1: Airport Extreme bridge > Netgear switch > TP-Link optical isolation > dCS Network Bridge AND PS Audio PerfectWave Transport > PS Audio DirectStream DAC with Bridge Mk.II > Primare A60 > Harbeth SHL5plus Anniversary Edition .

Hi-Fi 2: Sonore Rendu > Chord Hugo DAC/preamp > LFD integrated > Harbeth P3ESRs and > Sennheiser HD800

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David,

 

If the somewhat limited functionality of the Duet works in your desitred setup, I think you'd be hard pressed to find a better value, although I've not used it personally.

 

I do have experience with two other pro audio recording interfaces (with ADCs) and can heartily recommend them, altho they will be more expensive due to functionality that you might not need - the Grace Lunatec V3 and the Metric Halo ULN-2, the latter of which I use as DAC in my playback system, via Firewire from MacBookPro or via Toslink from AppleTV (for wireless playback using AppleTV as wireless client for AirTunes).

 

best of luck

clay

 

 

 

 

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.. DavidL,

 

Yeah, most people aren't going to stop and take time for answering this David. I think people shy away from this one because it is NOT really easy to explain comprehensively to someone who doesn't want to do their homework. That is, someone who just wants an answer and nothing more. An answer and nothing more isn't really possible. You have to understand some things.... It appears that you have done some homework. Get ready to do some more, OK?

 

You, writing about Pro or pro-sumer Firewire interfaces: "These have good reviews in the community they serve but I am not sure how appropriate they would be for archiving music from LPs." (but you could just as well be writing about USB or PCI/PCIe interfaces - they are about the same effectively, unless we are talking about a soundblaster-type card...). Let's just call them all "cards" OK?

 

Me. Answering: I think "pro" or "pro-sumer" is the way to go for ADC. How could it not be? The proof is in the pudding, they (ADC's) are made to record audio. .... With the exception of the need for LP's to have a phono preamp in order to make the signal compatible to a 'line level' - recording LP's isn't any different than recording live music. The same principles apply.

 

*Disclaimer*: Live music recording gear does have the thing called "Mic preamplifiers" - these are similar to the phono preamplifier, in that they are designed to record from a microphone (which is similarly different from 'line signals' as phono signals are different from 'line signals'). You need a pro ADC that has 'line inputs' - they all have them AFAIK. It is OK if the ADC also has 'mic inputs' or combo inputs that are switchable between line and mic, you just won't want to use the 'mic input' feature for recording the 'line level' that comes from your phono preamp. Ask more questions, if I didn't make that clear enough (what I just did there wasn't easy)...... This is going to work....

 

The "suitability" of these cards is almost universal (they work GREAT): as long as you can manage a conversion from the RCA (cinch) output of your phono pre to the usual 1/4" line input of these cards ( SOME have RCA ins and some have XLR ins as well), and the card you choose is also switchable between (-10dbv) and (+4dbu) - this is WAY too much to explain here (look here -: http://www.berkleemusic.com/discuss/message?forum_id=13331&message_id=9014136 -- for more input on this also search on the phrase "balanced vs unbalanced audio"). You should just know that you want the card to be able to operate at -10dbv. If you are already operating at +4, why am I writing this? 8^)

 

OK. Having said all that, you just need to try some of these cards to see which you like. For 'window shopping' - go to online musician supply places. My fave in the US is Sweetwater. I'll point you to the relevant place here: http://www.sweetwater.com/shop/computer-audio/audio_interfaces/ - once you find some that look suitable, check your local version of a musician supply or recording supply to see if you can get a suitable loaner. Online places loan out too. Try it, and then buy it. Or not...

 

Me? I use an RME Fireface400. I bought it when the street price was $999 here. It has gone up almost $300 since then though. You can get stunning sound from a $200 EMU 0404 all the way up to (and past) a Weiss Dac2 there are many many cards out there, and the ones in the range between ~$200 and $1500 don't sound all that different to me (IMO, YMMV, etc....) They just have different feature sets. The choice is up to you. Research and then chat up your local dealers for trials. .....then buy a used one on eBay.... heheheh - at least buy some cables at your local dealer though.....

 

regards,

markr

 

EDIT: You know, that last part about 'chatting up your local dealer and then buying on eBay", wasn't totally honest. Your local dealer, for almost the same price to maybe a slightly higher one, will give you much quicker service than you can get online. I do try to deal with my local guys whenever I can.

 

 

 

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In addition to the thread on this Forum I've had some very helpful input from a thread on HiFi Asylum, PC Audio. Aa a result I feel that the RME Fireface 400 looks the most promising from my perspective: external interface rather than sound card in a noisy computer, very good hardware capable of 192 kHz conversion, flexible user interface, good reviews of sound, a stand-alone capability and not too expensive.

 

(I might consider the Weiss ADC2 if I had £4400 to spare!)

 

David

 

ALAC iTunes library on Synology DS412+ running MinimServer with Samsung Galaxy Tab S2 tablet running BubbleUPnP for control >

Hi-Fi 1: Airport Extreme bridge > Netgear switch > TP-Link optical isolation > dCS Network Bridge AND PS Audio PerfectWave Transport > PS Audio DirectStream DAC with Bridge Mk.II > Primare A60 > Harbeth SHL5plus Anniversary Edition .

Hi-Fi 2: Sonore Rendu > Chord Hugo DAC/preamp > LFD integrated > Harbeth P3ESRs and > Sennheiser HD800

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.. my reason for purchasing the FF400 was for exactly the reasons that you state. If you want to record - and I wanted to record more than 2 channels at a time - I believe it to be about as good as you can get before you find yourself spending 2 to 3 times the money - period. This is MY OPINION, though it is an opinion shared by many others. It definitely isn't for everyone though. I think I said what I think about ADACs fairly well in the previous post ( the '~$200 - $1500' statement ).

 

Daniel - If only I had major major money available to me - who knows, maybe someday.... By the way, THAT is the way to 'shamelessly' plug your wares on a website without compromising your integrity. Thank you for your circumspect honesty here.

 

Good luck in your quest David and regards to the both of you -

- markr

 

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David,

I've been using the Apogee Rosetta 200 A/D and D/A with excellent results. Multiple bit and sampling rates up to 192 for recording and playback. Connected via firewire to the computer. It serves both recording and playback for me. Picked it up used (like new) on Audiogon. Comparing direct from vinyl or via the Rosetta is virtually indistinguishable. (I use the Aphex Model 124A interface to handle the -10/+4 situation). Good luck with your search.

 

RHA

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  • 1 month later...

markr, I read with interest your reply in helping on a difficult subject.

 

However, one of your primary reasons for selecting the FF400 as so that you could record more than two channels at one. What would be your suggestion for a 2 channel box. My primary desire is to convert my vinyl to hirez digital (LP's that were never available on CD). I am not looking for a cheap $30 solution, but hopefully less than $1300. Both your firewire and USB interfaces thoughts appreciated.

 

My current experience has been using my Thorens TD 125 MK II>Project Phono Box MKII>amp>PC with internal SoundBlaster Live! (real weak link!)>software Cool Edit Pro 2.1. I used this to convert some vinyl to CD. But now I want to go to the next level and convert my LP's to at least 24/96 if not 24/192. I am not opposed to moving my turntable to the room with my Mac mini server and do the recording on this computer if the results will be better.

 

Thanks for any and all help!

 

Alan B

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As noted earlier in this thread, I decided on an RME FF400 and I have spent the last couple of weeks starting to explore what it can do. I only bought a multi-channel I/O device as I could not find a 2-channel one that does everything that I was looking for. In fact of the 8 potential analogue input channels I've found I need to use 6:

(1) 1 pair for fixed gain "instrument level" input for the variable output of my MF X-CANV8P preamp, so I can adjust signal level in analogue domain,

(2) 1 pair for variable gain "instrument level" input for the fixed-gain output from my phono stage,

(3) 1 pair for variable gain "mic level' input for the fixed-gain direct output from my phono cartridge.

I'm going to use the "mic level" input in conjunction with the Pure Vinyl software to apply the RIAA correction by software in the digital domain rather than through the phono amp. I've downloaded the demonstration version of the software but not yet used it:

 

http://www.channld.com/pure-vinyl.html

 

My LP system comprises a modified Thorens TD160B Mk II with a Mission 774 arm and Ortofon 2M Black cartridge. Using (2) above I've recorded several LPs at 32 bit / 192 kHz with Peak Pro 6. I truncate these to 24/192 (with dither), and then downsample these to both 24/96 and 16/44.1 (truncated with dither). I've played these back from Peak Pro through the FF400 DAC and monitored this output with both Sennheiser HD400 'phones and an LFD integrated amp driving PMC DB1 speakers. Initial conclusions are:

I can't tell the difference between the 16/44.1 digitised LP and the corresponding commercial CD (where I have duplication), apart from the surface noise in quiet passages,

The 24/96 and 24/192 recordings are definitely better with more air, ambience and better top end. I can't really tell the difference between these 2 so I'll probably use 24/96 for long-term listening, but archive the 24/192 recordings. I've written some of the 24/96 recordings to a video DVD and listened to them on my main system; the improvements are noticeable.

 

 

ALAC iTunes library on Synology DS412+ running MinimServer with Samsung Galaxy Tab S2 tablet running BubbleUPnP for control >

Hi-Fi 1: Airport Extreme bridge > Netgear switch > TP-Link optical isolation > dCS Network Bridge AND PS Audio PerfectWave Transport > PS Audio DirectStream DAC with Bridge Mk.II > Primare A60 > Harbeth SHL5plus Anniversary Edition .

Hi-Fi 2: Sonore Rendu > Chord Hugo DAC/preamp > LFD integrated > Harbeth P3ESRs and > Sennheiser HD800

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  • 2 months later...

Thanks to all for a really informative thread - definately decided to get me one of these babies for simple vinyl ripping and improved dac, but damn, damn, damn - none of my laptops has a firewire port!! Will the Fireface 400 work when used with a usb -> firewire hub? - given the large deltas in data rates I'm fearing not...

 

Win XP -> Buffallo NAS -> Naim Nait 5 FC2 -> Klipsh Forte II [and a Notingham Analogue Space Deck, usurped; temporarily? I\'m not sure yet]

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  • 1 year later...

Here's something I found on the AudiophileProducts.com site:

 

http://www.audiophileproducts.com/24bit-192khz-dac-headphone-amp

 

Has anyone used this? Looks promising. It has an RCA in, and apparently you can record 24 bit/ 94khz, then use the DAC to play back at the same sampling rates from USB, toslink, or coaxial.

 

I only have consumer-level components with RCA jacks. Don't really feel like replacing everything with pro gear, just to get the balanced connections. Maybe this is the way to go for people like me.

 

Anyone have any experience with this ACD/DAC unit?

 

 

 

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  • 2 weeks later...

Hello All,

 

Fresh from the battle of building a music server with invaluable help from Chris and the denizens of this site, I've converted about 200 CD's so far and now turn to the war: converting my LP collection.

 

As a result, I'm looking for a good A/D converter, preferably at reasonable cost. I see that you've mentioned the Furutech GT40 ADC/DCA. Has anyone here tried the NAD PP3 or PP3i (reviewed in Stereophile last October), or would the analog inputs of the Xonar Essence STX card be capable of performing this feat?

 

I'm open to suggestions if there's appreciably better quality equipment available. Thanks in advance.

 

Cheers

 

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  • 2 weeks later...

I've heard several pros swear by the Korg 2000S; pricey, but used ones are available online.

 

Also hi-end, but good reputation are the Metric Halo units, especially the LIO-8 and ULN-8

 

Main listening (small home office):

Main setup: Surge protector +_iFi  AC iPurifiers >Isol-8 Mini sub Axis Power Conditioning+Isolation>QuietPC Low Noise Server>Roon (Audiolense DRC)>Stack Audio Link II>Kii Control>Kii Three >GIK Room Treatments.

Secondary Listening: Server with Audiolense RC>RPi4 or analog>Matrix Element i Streamer/DAC (XLR)+Schiit Freya>Kii Three .

Bedroom: SBTouch to Cambridge Soundworks Desktop Setup.
Living Room/Kitchen: Ropieee (RPi3b+ with touchscreen) + Schiit Modi3E to a pair of Morel Hogtalare. 

All absolute statements about audio are false :)

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Been also trying to find such ADC rigs. The Furutech looks interesting, but I'm doubtful that it will top my current, cheap setup. Right now, I'm using my Mac to digitize vinyl albums (24 bit, 96 khz) through Audacity and Pure Vinyl 3.0. They sound okay, but think I could do better. Been making tracks using Roxio's Spin Doctor, since I can't get PV to edit hi-rez files.

 

Has anyone actually used the Furutech GT40?

 

First time on this site--fantastic stuff here!!!

 

 

 

doublehelix

 

DoubleHelix[br]Apple/Mapelknoll/Krell/Benchmark/TC Electronic Impact Twin/Jolida/Krell/Thiel

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  • 3 weeks later...

Hello Nhih007-

 

I bought a Behringer FCA202 from Amazon for about $80. It's a Firewire ADC doing 96 Hz/24 bit. Works like a champ with my phono preamp, wired through my main preamp, feeding into my Mac via FW 400. This arrangement lets me adjust volume. The Behringer is wonderfully minimal, sporting no mic amps, bazillion inputs, etc.

 

Although not 192 KHz, it definitely beats the internal ADC in my Mac.

Highly recommended!

 

Also recommend Audacity for recording your music--it does AIFF outputs, easily imported into iTunes.

 

My wife and I actually prefer these vinyl transfers over purchased CD versions--did the comparisons--they are about 90% as involving as their vinyl originals, but possibly more fun.

 

 

 

Enjoy!

 

Best

DH

 

DoubleHelix[br]Apple/Mapelknoll/Krell/Benchmark/TC Electronic Impact Twin/Jolida/Krell/Thiel

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  • 3 weeks later...

David and others:

 

I just purchased the Benchmark ADC1 USB digital to analogue converter to convert some of my LP collection to digital (preferably flac files).

 

I will run my phono preamp output into the ADC1, then the USB output into my laptop. I have J River Media Center as my music player, but not sure it will receive the digital information and create files.

 

So my question is, I assume I will need proper software (my laptop is Windows Vista based) to create files of the digital information from the Benchmark, so what software to you recommend? I plan to record at 24 bit, 96khz, so high quality is preferred.

 

Thanks!!!!

 

 

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Can't give you specific recommendations for your PC-based system as I use a Mac, however I recommend that you start by trying out some of the freeware / shareware PC audio software first to help you crystallise exactly what you want. Note that there are freebie cut-down trial versions of some commercial packages. When you have done that (say convert / edit a couple of LPs) you can decide whether it is worth buying a comprehensive audio package. If you only wish to convert a few LPs you may not need to do this. I found it worthwhile investing in Peak Pro as I record concerts off radio (DAB and Freeview in the UK) and extract audio from video in addition to converting LPs.

One feature you should look for is high-quality sample-rate conversion, as you may wish (say) to convert your archived 24/192 digitised LP tracks to 24/96 for regular playback. Some of the free / cheap software out there has poor performance in sample-rate conversion (I'll leave you to Google for comparison tests).

Hope this helps

David

 

 

ALAC iTunes library on Synology DS412+ running MinimServer with Samsung Galaxy Tab S2 tablet running BubbleUPnP for control >

Hi-Fi 1: Airport Extreme bridge > Netgear switch > TP-Link optical isolation > dCS Network Bridge AND PS Audio PerfectWave Transport > PS Audio DirectStream DAC with Bridge Mk.II > Primare A60 > Harbeth SHL5plus Anniversary Edition .

Hi-Fi 2: Sonore Rendu > Chord Hugo DAC/preamp > LFD integrated > Harbeth P3ESRs and > Sennheiser HD800

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I use a (very) old G4 867 Mac desktop for digitizing LPs; I have an RME Digi96/8 sound card installed in that unit, which has an outstanding A/D converter.

 

The first thing to keep in mind is you want to do a good job once, and once only. Transcripting in real time takes real hours of your life, so you want a result that you honestly believe you will never want to re-do for quality reasons. This also means you will have to devote time to listen to your recording all the way through after you've made it, to make sure all is right.

 

Turntable -> Acoustic Signature Tango phono pre-amplifier -> RME

 

Software is Amadeus (now Amadeus Pro) and if necessary, Brian Davies' ClickRepair ... albums I've owned since new are noise-free but sometimes in the modern world we get albums from flea markets, etc. Files are 24/96 (in the past I used 24/88.2).

 

Transcripting from LPs is fairly easy for me, since I have a lot of experience using a variety of different decks in the past ... I have no idea how many times I've recorded to cassette or open reel in the past but it's definitely in the thousands if not tens of thousands of times, some live stuff in there ... so setting levels and syncing the whole operation is second nature.

 

The turntable quality is important, but not critically so. More important is the cartridge, proper setup of the table, and the quality of the phono preamp and sound card. Also consider a good record cleaning regimen.

 

ALWAYS monitor with headphones ... that leaves you with just worrying about a quiet table. No matter what the cost, virtually every table will sound worse ... we might even be able to eliminate the "virtually" there but I haven't worked with the five figure models so I can't say for sure. If you use speakers to monitor, it will degrade the sound due to airborne vibrations, and comparing the two methods it is easy to hear the difference, even on a cassette.

 

If you're unfamiliar with turntables (and maybe even if you are), one piece of advice I can give you is to avoid the temptation to set the cartridge tracking force too light. Use the top of the range suggested by the manufacturer (but no higher) ... it will track better and mistracking PERMANENTLY damages LPs. You will not wear out an LP by running a high-ish tracking force, although that is widely believed to be the case. It's simply not true.

 

It's akin to driving fast. Keep the rubber on the road, and sure ... the tires eventually wear. But, go airborne (the rough analogy of a mistracking cartridge) and much, much more damage results ... it's not a net benefit to find yourself upside down after taking out the guard rail with perfectly good tires spinning in the air. You've saved nothing.

 

If you can, use something analog to power the phones and set levels. A conventional preamp is ideal ... set the level in the analog domain and run your digital levels at 100%, and run the phones from the preamp. An integrated amp is not as good ... you can't set the level unless it has pre-outs. That way your sound card is not trying to do a D/A conversion to run the phones simultaneously with the A/D encoding. A tape or effects loop is no good ... the level is fixed, and you will have to use the digital level in that case.

 

Avoid speakers to monitor and all you need to worry about is a quiet motor and lack of mechanical noise, which moderate priced tables are capable of (to me "moderate" is something along the lines of a REGA 2 ... say $400~500 if you compare prices of new gear).

 

By far the best sounding LP to tapes I've made in the past were on a Thorens TD-124 mkII ... for some reason the bottom end on tape is incredible from that table.

 

Use the room offered in a 24-bit file to insure you never have digital clipping ... you don't really need to have peak levels close to 0dBFS when recording. A target of -3dBFS peak is fine.

 

Check the file afterward and if any clipping exists, find the clipped waveforms and use that part of the LP to set you levels a second time for the re-do. Clean records will allow you to run levels higher.

 

You can then normalize to -0.1dBFS or, my preference, -13dB Average level, which will allow you to make transcriptions that are all roughly equal in average level (perceived loudness) song to song and LP to LP.

 

Set up your computer so it can work without distraction. For an audio workstation, you should have no network access but perhaps more importantly no applications checking for network access; modern apps are quite insistent about going online and often don't behave well when denied. Go through the preferences of any app installed on an audio station as soon as you install them and turn off version checking, etc.

 

The G4 may seem old, but I find them to be better at dropout-free real-time work than the Intel machines. The Intels seem to get easily distracted if some rougue process starts demanding attention.

 

If you're on a strict budget consider a flea-market preamp (or integrated with pre outs) with a phono input ... something made in the 80's or earlier. Jerry Raskin's Needle Doctor was also blowing out some Audio-Technica phono pre's for around $45 a while ago. See if they're still available.

 

Personally I would avoid the inexpensive tables with built-in A/D converters. The built-in sound card in your computer is probably just as good if not better. Similarly, although you can do it, doing RIAA equalization in the digital domain is not my idea of a good transcription unless you have zero dollars to throw at the problem. Remember the part about doing the very best job you can, once and once only because your LP recording will be with you a long, long time.

 

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  • 2 years later...

Thread resurrection! I'm selling my Harman Kardon CDR30 in favor of something more modern and versatile: the Sony PCM-M10. So my digitizing chain will look like this:

 

Music Hall MMF5 with Ortofon red cartridge

Pioneer SC-05 AVR (just the phono preamp)

Sony PCM-M10

PC (LP Ripper)

 

My biggest concern is what happens to the signal in my SC-05 AVR. I hope it doesn't go through A/D and then D/A before getting to the line out.

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Given your other equipment... I would but a standalone phono preamp...

Thread resurrection! I'm selling my Harman Kardon CDR30 in favor of something more modern and versatile: the Sony PCM-M10. So my digitizing chain will look like this:

 

Music Hall MMF5 with Ortofon red cartridge

Pioneer SC-05 AVR (just the phono preamp)

Sony PCM-M10

PC (LP Ripper)

 

My biggest concern is what happens to the signal in my SC-05 AVR. I hope it doesn't go through A/D and then D/A before getting to the line out.

Eloise

---

...in my opinion / experience...

While I agree "Everything may matter" working out what actually affects the sound is a trickier thing.

And I agree "Trust your ears" but equally don't allow them to fool you - trust them with a bit of skepticism.

keep your mind open... But mind your brain doesn't fall out.

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