Question Denon AV-4308 USB File Format Error


Well-known Member
Hi everyone.. I recently purchased via ebay a almost mint 4308 froma a guy that had his unit in storage for 8 years so basicly has had very little use.

I purchased it to replace my possibly faulty Denon X4100W.

Everything absolutely works on the 4308 and having this unit for now a month it completely trumps over my X4100W from 2015. The DACS on the 4308 are nothing short of absolutely outstanding! I listen to alot of 2-channal music using pure direct mode and the 4308 despite being a much older unit has impressed me so much takes me back to the days of my Denon 3805 realy does.

Anyways... I have everything working perfectly even Internet HD radio work perfectly with WiFi.

However I can't seem to get the unit to read the FLAC files from my USB stick.

Iv formatted it to FAT32 using the full format command not the "quick format". It's a 32GB Samsung drive. So I have copied over several albums in Hi-Res 24bit/96hrz albums these are the Blu-ray edition.
Rush - Moving Pictures
Rush - Signals
Beatles - Srgt Pepper
Beatles - Abbey Road

The 4803 reads the stick perfectly fine I have opted to use the rear USB socket instead of the front. I go into the menus and it reads all the tracks perfectly so that means the flash stick is working. However as soon as I go to play those tracks which are all FLAC so their should be no issue with the AMP seeing and reading those files it goes to read them and just comes back with "FILE FORMAT ERROR".

What I'm I doing incorrectly here.

I get a perfectly good network connection to my router via the WiFi anyway. And I have been playing Internet HD Radio for a while now all via WiFi and it buffers and plays back fairly fast.

I have a Denon Blu-Ray 3313UD Blu-ray player and I have some physical Yes Albums in Blu-ray hires formats. I use 2 HDMI cables from the Blu-ray player one for the picture and one for sounds as the Denon 3313ud player has a pure direct mode which I use.

So when I play back those Yes Blu-Ray Albums the 4308 does acknowledge DTS-HD Master and plays them back absolutely brilliantly via HDMI cable to the AMP.

So any ideas... The manual does state it will okay back FLAC, AAC, MP3 ect. :thumbsdow
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Distinguished Member
If it's not working you should let me have it to complete my set (I own a 2808 and 3808)

I had a quick scan of a PDF of the manual and there's a second table giving supported sampling rates for flac files of 32/44.1/48 kHz it doesn't say it supports 96 kHz files.

TBH a few years ago me and some mates had an entire day of hear the difference with CD quality stuff and hi Res files. We found the version of dark side of the moon we had in 24/96 was obviously better than the CD but it still was better even after I downsampled the files to 16/48, so it was the original master that was better not necessarily the bit rate or sampling frequency. The tests were all done using a big stack of Linn components and Linn speakers so way better than anything I've ever owned.


Well-known Member
Hi @Jamie Thanks for the reply buddy 😊. I think you kinda got the wrong end of what I was asking :thumbsdow. I'm certainly not selling the 4308!!!. Iv only had it for 1 month are you kidding me lol. This thing is fxxing awesome.

No offence I don't think you actually read what I was asking here ! The question.

Cheers for the info anyhow nice here from others anyway. So I await hopefully soon to here from others that have had the same issue with this for maybe a possible fix ... Cherrs guys. 😊👍


Distinguished Member
I was kidding on that part. I'm well impressed with my bargain 3808 and can only presume the 4308 is ever slightly better. I also only picked up mine recently. Denon were defenitely on top form 12 years ago, the later models certainly feel more built to a price and semi disposable compared to ours.

On the contrary I believe I understand your question which is why won't my flac files play from a USB stick

The manual specifies the bit rate it supports for flac and it doesn't include the files you're trying to play, a possible solution could be to use some software to downconvert the files so they will play, in my experience the main benefit of higher quality files is actually the master or original they are sourced from, they still can sound better than a CD rip when downconverted


Well-known Member
@Jamie Hiya buddy. 😊 Thanks agian for the reply it much appreciated!.

Yeah I was a bit like that with my previous comments because I am a Denon & Marantz fan my self. I used to have some Yamaha AV amps years back but it was Denon that absolutely won it for me.

I'm 40 years old now and I absolutely concur regarding your comments. As you stated all AV AMP made by Sony (QS& ES Ranges) , Denon Marantz and Yamaha from late 1990's to around 2010 was most certainly Denons finest hours. Blimmy golden age in my book A11SR.. A1SR...

I saw those been showcased back when what Hi-fi ran their shows at Hammersmith. I was in my early 20's had some money to spend but those particular AV amp were well out my league I was definitely doing a hommer Simpson drool 🤤. Lol

Anyhow I had a Denon 3803 for a short time then Denon realised what absolutely ground braking equipment the mighty 3805 AV AMP and Denon 3910 DVD player. 3 months after I had purchased the 3803 I part exchanged it with my local dealer Harrow Audio and purchased both units I just had to have them period. To this day I still have that very 3805 in more or less mint condition and the 3910. When I serviced the 3805 earlier this year I had noticed what looks like Denon must have used just before "black gate caps" went out of business in 3805. As they are 2x huge filter caps all in black with Denon Audio in gold writing on them. Wizz along to 2015 I purchased a Denon X4100W. Now that has sadly I believed developed a fault with the HDMI baord as it tends to give static noise on all channals and Denon repair centre basicly said forget repairing it looking at £300 + Vat or so.

So that packed up to one side and I am somewhat pissed off it only lasted 5 years.. And my trusty 3805 from late 2004 works 💯 without fault and never had a repair in its life.

The X4100W cost me around £1300k a rather alot of money for me.ahhhh so packed up to one side now.

So I had looked at some Yamahas from around 2010 period 2067 or 3067.

However I realy love my Denon/Marantz I am a Denon fan boy. I own from new a Marantz SA-15S1 a reference player from 2007.

So I gave it some throught and decided for a while on a A11SR but the DACs would be far to old by now. I wanted something that had some pretty decent DACs and components fitted. So doing some research on around that period came across 3808 and 4308. As time has gone by obviously prices have come down on the 2nd hand market.

So I opted for a 4308. The specs for its time is eye popping! This thing is absolutely cramed to the max. Denon for 2007-08 wanted to create a AV amp that certainly give the competition a run for its money, however with a audiophile quality which is something very few can achieve.

So looking at the specs Denon fitted I believe 4X Burr-Brown DACs per channal! I new Arcam used Burr Brown as well they are considered the very best in their class I think 🤔.

Also 4803 has 3X PSU fitted... Iv acutally seen them. Also Denon has used what looks like pretty high grade ELNA Audio specialist Filter Caps in the PSU unit chain amongst some Nichicon & ELNA caps used on the rest of the AMP.

Now I bid my time looking for a 4308 for weeks months this year with many on ebay coming and going a the time. It beats me how so many people take photos of their gear and they are absolutely filthy, caked with dirt and dust. You would not advertise your car looking like crap so why do so many people list their equipment looking in such used bad condition and then state in good nick 😱.

I never used my X4100W as a media unit so I did not need 4K also I don't need Atmos I live in a studio apartment so I have only 5 channal setup. And I can live without ARC as that came post 2012 I think 🤔.

I wanted and AV AMP that sounded dam good in 2-channal mode and the 4803 ticked all the boxes for me.

So a I came across a guy was selling on ebay what looked like a near mint 4803!. He has no box, no remote no manual, no accessories setup mic ext.

However when asking loads of questions.. I could not believe it bingo.. He had it from new used it a bunch of times and it had been in his Safe Storage lockup for 8 years. So that actually meant the model is around 12 years old with only 5 years worth of millage usage on thsoe parts.

I had spare remotes from my Denon 3805 and a aussdy mic from my x4100W. Or I could have purchased a complete 4803 from another seller with original box mic manual ext. However what worries me was the state of the unit on the outside. If its caked with dirt and dust on the outside you can image how bad it was on the inside. All the parts would be overheating and the unit may have to have a re-cap.

So for the sake of no having a original box, remote, accessories and having a unit which not been used in 8 years in safe storage the absolute perfect environment to keep electricnic equipment kept at a constant temperature the parts inside will be perfect or as neat as.

So I quickly grabbed the unit and paid for it before anyone else did. When I received it I checked it my self the unit was more or less absolutely dust free back and front. I took the top off and looked inside I had my mains air compressor ready for a quick clean the gentleman was absolutely telling the truth I could not believe my fortune. The unit inside barely had a tiny layer or dust. All the components looks like they not had more than a years worth of use. All the CAPS and power regulators looked prefect.

I used the unit for a few hours and even the smell from the unit have off that newish smell they give off for a while.

My reacesrch payed off. The Auyssey MIC 100% worked with the amp calibration. And my for that time Denon 3805 remote worked good enough. Denon thankfully still used the same IR frequency. Scene then I managed to grab of ebay a mint Denon RC-1068 mic for it. And Manuallabs has the PDF manual anyhow.

As you stated Denon built their amps like tanks around that period. My Denon X4100W bulld is no way near to the quality of that period.

I mean I believe 4803 is the only AMP that Denon produced at that time and still stands now.. That had DAB Tunner, AM/FM Tunner, WiFi and Lan connection amonght everything else.

I also like the fact that during that period Denon slightly over engineerd their amps. Having both mains button and a standby butting as well.

The only issue their is unfortunately but I think 🤔 this was common that the Main display tends to dim in some areas but I feel this was a known issue rather than a fault.

Anyhow I'm not acutally that fussed that I can't play those files direct from the unit.

I have Denon 3313UD Blu-ray which even to this day apart from A1 is bult like a tank. That has a USB socket at the front and I have already managed to play back thsoe hires files using that unit and then the 4803 see those perfectly and reads fs24/96 on the AMP as soon as I hit play on the 3313ud player. It would have been nice to use the AMP directly but it hardly the biggest deal for me.

Its now been a month I believe over the past 3 weeks the unit has gotten better. Sonic wise. Bass has increased alot more and so has the top end. So It definitely needed some use once more being ide for so many years I suspect the CAPS needed running it once more.

I have one left thing to use on this and thats the bi-wrie - bi-amp feature. This thing is nuts.. It even had a correct option in the settings to acutally use the AMP in Bi-wire or Bi-AMP mode.

My X4100W only had Bi-AMP mode. I have mission SX speakers which I have Atlas ichor bi-wire speaker cables. I wanted to run the amp in for a month before I started to use that.

The next model or replacement mode 4310 Denon started to cut corners and omit features to their amps so looks like 2010 onwards is where things started to change.


Active Member
Looking at the manual it states that only 32/44.1/48 kHz FLAC files are playable


Well-known Member
@rpr Thank you. Well it's not the Amps fault anyhow. Hi-Res Blu-ray was years later anyhow. My Denon 3313UD is a 2014 model so explains why it reads it perfectly.

To be honest it seriously not an issue. It was more for convenience realy than a thing else. And for 2007/08 thay was the very best samperling rate available.

The AMP handles DSD 2.8/5.8 mhz files perfectly and Dolby True HD & DTS HD Master perfectly 100% which was far more important to me than having the amp read Hi-Res files via USB socket. To be honest that is absolutely the only negative I have found period. And that is not realy a "true negative" as that was the very best available at the time. Via USB method. As the AMP does read 24/96hrz via HDMI perfectly fine from my 3313UD Blu-ray player.

I can use my Denon 3313UD which works flawlessly using HDMI to the AMP and I have my beloved Marantz SA-15S1 and I can use pure direct mode on both. I. Have loads of SACD'S which Im a Huge fan of that format. I may look into getting a Denon Network audio player the Denon DNP730 they come on an off on ebay and that I feel would certainly make such a great compliment to the 4308. 🤗👍.
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