Denon DM-39s built in DAC

[Sam Spade]

Hello all,

 

I am getting more interested in computer audio and have a technical question. I recently bought a Denon DM-39s micro system for the office and am really enjoying it. Currently, I have my Mac hooked up to it via mini to RCA (I know, I know RCA is bad).

 

According to the Denon site, the unit has a built in DAC (192 kHz/32-bit D/A).

My question is, does the DAC only operate when using the USB input on the front of the unit, or does it also kick in when using the RCA and/or optical port on the back? Interestingly, neither the Denon site nor the WhatHiFi review give any indication about this.

 

I have Audirvana (the free version as I am still experimenting) running on the computer and a few FLAC files. The FLAC files play through the unit no problem.

My other question is if I got a separate DAC (I am considering a Dragonfly 1.2), would it override the onboard one or could it be made to do so?

 

Thanks,

[Sam Spade]

Hi again,

 

This is the unit I am talking about.

[Sam Spade]

Hello,

 

So, I finally got a real answer from Denon. The short answer is no, with respect to the RCA connection in the back interacting with the DAC. However, all three digital sources are processed by the DAC, so the CD player, the USB port in the front, and the optical in on the back. When using the USB either for iPod or USB stick it will only accept MP3 files up to 320k. It will also play WMA files up to 192k.

 

The optical port on the back will accept 2 channel audio only – but it works with the AppleTV which outputs a 48K signal.

 

Anyway, so now I have to choose a DAC…

[unsleepable]

I don't your Denon, but can't you use the USB port to connect it to the computer? Is it only for iDevices maybe?

 

In any case, the jack port in Mac computers usually doubles as an optical port. The connector is slightly different, longer—it reaches further in, which makes the computer enable the optical port. You could use it to connect to your Denon—you'd just need a mini-TOSLINK to TOSLINK cable.

 

 

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[wgscott]

The optical will do what you want.

[Sam Spade]

Hello,

 

Thank you for your replies. I have an optical cable and have had it hooked up to the unit. It played sporadically, so I had it looked at. They updated the firmware for the unit and it works for the AppleTV just fine, however, it no longer works when hooked up to the computer.

 

Had a closer look at the user manual and it says:

“Other digital audio signals than 2 channel linear PCM cannot be input through DIGITAL IN (OPTICAL) connector of this unit.”

Is it possible to get my Mac to send a PCM signal? If so, I would be in business. I am running iTunes 10.7 (64 bit).

Thank you for any help you can offer.

[unsleepable]

The optical port of the Apple TV is different to the one of the Mac. Are you using a mini-TOSLINK cable? It can't be the same cable for both.

 

What Mac do you have?

 

The signal is PCM, you don't need to worry about that.

 

 

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[thrand1]

Hello,

 

Thank you for your replies. I have an optical cable and have had it hooked up to the unit. It played sporadically, so I had it looked at. They updated the firmware for the unit and it works for the AppleTV just fine, however, it no longer works when hooked up to the computer.

 

Had a closer look at the user manual and it says:

“Other digital audio signals than 2 channel linear PCM cannot be input through DIGITAL IN (OPTICAL) connector of this unit.”

Is it possible to get my Mac to send a PCM signal? If so, I would be in business. I am running iTunes 10.7 (64 bit).

Thank you for any help you can offer.

 

Check the sample rate that you are using within Audirvana (or even within Audio MIDI?) when using the optical. The optical out of your Mac is likely 24 bit/96kHz- try playing around with the sample rate and see if you get any sound when using the optical in port on the Denon. If you aren't using Audirvana, and you adjust the sample rate within Audio MIDI, be sure to close and restart iTunes after doing so- I think changes done while iTunes is open don't take effect until you restart the app. If using iTunes only, also check Audio MIDI to make sure the Built-in Output is set to something like 2 channel, 24 bit, 96 kHz to start...if that doesn't work, try 48kHz (similar to the Apple TV). I'd also suggest seeing if replacing the cable works.

[CatManDo]

The optical input is meant to connect a TV (but any other digital source will work too), so it could be limited to 16bit/48kHz, although the manual doesn't mention a limitation.

 

It's not an audiophile device, so it's not designed to play hi-rez files or streams. The 32bit/192kHz info is just for the specification of the built-in DAC chip (this is standard today even for budget components), and is only used for marketing purposes, without any practical relevance.

[Sam Spade]

Hello,

 

Yes, I am using a TOSLINK cable with mini-plug adaptor. I have two cables, a glass-fiber one and a Monster something-or-other. Both work. I have a MacBook Pro i7 2.4 GHz. 15inch with 8Gigs of RAM.

 

The little red light is on if I unplug the end going into the Denon, so I know the MBP is sending a signal.

 

I have tried changing the bit rate as per your suggestions and no luck. The front of the Denon displays an error message: “Signal Unlock”.

 

I have no idea what this means. I may take the unit back and get them to look at it again.

 

Is there a way I can verify if the MBP is sending a PCM signal? Does it say in the specs somewhere?

 

When the guys at the repair center tested the unit they had it hooked up to a DVD player with a TOSLINK cable and the Denon was playing sound no problem.

 

I am considering getting a Dragonfly and being done with it, but I would like to figure out if there is a problem with the unit, before my warranty runs out.

 

Thanks for all your advice!

[CatManDo]

The front of the Denon displays an error message: “Signal Unlock”.

 

I have no idea what this means. I may take the unit back and get them to look at it again.

 

Here's an explanation:

 

Denon DM39 displays Digital IN Signal Unlock | AVForums

 

I don't have a Mac, but there should be a setting somwhere where you can limit it's digital output to 16/48 PCM. The computer can also output Dolby Digital surround for movies, but since music DACs don't accept Dolby Digital there is usually an option to convert Dolby Digital to PCM.

[wgscott]

Make sure "Digital Out" is selected as your output device, and try sending 48kHz or 41kHz first to verify that those work. Some optical cables and/or DACs (like the one in my Peachtree Nova) have trouble with locking onto 96kHz optical signal.

[Sam Spade]

The optical input is meant to connect a TV (but any other digital source will work too), so it could be limited to 16bit/48kHz, although the manual doesn't mention a limitation.

 

It's not an audiophile device, so it's not designed to play hi-rez files or streams. The 32bit/192kHz info is just for the specification of the built-in DAC chip (this is standard today even for budget components), and is only used for marketing purposes, without any practical relevance.

 

Hi CatManDo,

 

Do you own this unit?

[Sam Spade]

Hello,

 

So no luck with changing things in AudioMIDI on my Mac. My only options are: Integer 16 - 24 bit 2 chnl., or 32 bit Float, or encoded digital audio. None of them work. I have no idea how to get 2 chnl PCM out of my MBP.

I just did some checking and according to the inter-webs, the audio data in a standard AIFF file is uncompressed pulse-code modulation (PCM). So, I really do not understand why it is not working – very odd.

Any thoughts?

[Popson]

The optical input is meant to connect a TV (but any other digital source will work too), so it could be limited to 16bit/48kHz, although the manual doesn't mention a limitation.

 

It's not an audiophile device, so it's not designed to play hi-rez files or streams. The 32bit/192kHz info is just for the specification of the built-in DAC chip (this is standard today even for budget components), and is only used for marketing purposes, without any practical relevance.

 

I can stream HD flac files (96khz/24bit) and Dsd from my laptop (using foobar) to the DM39 digital input via hdmi and from the pc jack (have a toslink to 3.5 mm converter). So it does more than what it says on the tin.