Dac not compatable with SBT?

[slimmac]

Hello,

I'm experiencing issues with a Squeezebox Touch connected to a Rotel 1570 when the sampling/bit rate of sources switch.

I have a SqueezeBox Touch connected via digital toslink directly to the Rotel (I've also tried coax digital).There is no analog connection made.

Whenever I play a 96Khz or 88Khz 24 bit source, and then select a 16Bit 44.1 KHz redbook source/song, the song becomes distorted. Its very low and garbled in sound.
I can always play 44.1 to 88 or 96 with no issues. However, if I play a Hi-RES file then a 44.1Khz file, the audio is low and highly distorted

This occurs with either a Wav or FLAC file.

All songs are being played on the SqueezeBox connected to the same input BTY. I've tried different inputs on the Rotel - same issue. The only way I can get the audio back, is to power down the Rotel and restart or switch the inputs on the Rotel.

So....initially it appeared to be the fault of the Rotel DAC's. HOWEVER....If I take the same files, and play them through my Oppo bluray player, connected using the same cable and input to my Rotel, all is well....So the issue is stemming from the SBT. The files play perfectly from the USB key.

I'm using the following Software and firmware versions on a Mac OS 10.7.2 tower with 14GB of RAM:

Logitech Media Server Version: 7.7.1 - r33735

If there is anybody out there who can make a suggestion on how to correct this, it would be GREATLY appreciated.

Thanks in advance!

[Soulkeeper]

The only way I can get the audio back, is to power down the Rotel and restart or switch the inputs on the Rotel.

So....initially it appeared to be the fault of the Rotel DAC's. HOWEVER....If I take the same files, and play them through my Oppo bluray player, connected using the same cable and input to my Rotel, all is well....So the issue is stemming from the SBT.

Are you sure your blueray player doesn't resample everything to one bitrate, so that the DAC never experiences anything changing when connected to it?

[Mnyb]

Having no problem with different bit rates and frequencies trough my home cinema processor.

It should be noted that the squeezebox always outputs 24bit it the sample rate that differs.

[Archimago]

No problems here either with 44/48/88/96 and back and forth. Have used numerous DAC's over the years from inexpensive "Zero DAC", Benchmark, and various NOS DAC's.

Worse come to worse, you can upsample everything to 24/96 with a custom-convert.conf file.

[slimmac]

No problems here either with 44/48/88/96 and back and forth. Have used numerous DAC's over the years from inexpensive "Zero DAC", Benchmark, and various NOS DAC's.

Worse come to worse, you can upsample everything to 24/96 with a custom-convert.conf file.

Hi guys. Still faced with the same issue. It appears to be a conflict between the Rotel and SBT.
An older generation Rotel has no issue with the frequency change. However, I've auditioned several 1570's and they all have the same problem.
Since it only appears to be happening with the SBT, Rotel doesn't believe its their issue. Rather an incompatibility.

Any other ideas how I can use the Rotel DAC and not have this issue? Is there some sort of setting that allows it to handshake better?

Thanks in advance!

[cfraser]

Some DACs, typically older but not necessarily *old*, have difficulty re-establishing (PLL) sync when the sample frequency changes. Not from 44 to 48kHz, but any freqs much more apart from that, and that's what happens. I've seen it plenty, and other people here have asked about other DACs that do the same thing (yeah, it's hard to search for...). Nothing you can easily do to fix it. I actually "retired" a DAC I quite liked for that reason; I had to get up out of my seat and walk over and manually "force" the thing to re-sync...too much work lol.

[slimmac]

Cfraser thanks for your response.
Makes sense I suppose. I'm surprised that the newer 1570 (4 years newer) couldn't deal with the change like the old model.

I also own an arcam rdac which works perfectly with the sbt.
If I connect the touch to the arcam via digital connection and then to the Rotel, I'm basically using a double Dac implementation. I could put the Rotel into a direct mode which doesn't allow the use of my sub.

Would you have any issues with the double dac setup if i want to use my sub?

[cfraser]

It is possible that in your newer DAC they did in fact improve it: improving the PLL circuitry *could* have the effect of not allowing it to get lock over as wide a frequency range, but rather it more tenaciously maintains the first frequency it locked on. You have found the dark side of it.

When it was designed, people probably didn't much move from 44.1/48 to 96 in one session, more likely 44 to 48 would have been common. Just my speculation...

Sorry, I don't really understand your question. I'm not familiar with *any* of the gear you mention, I was only speaking generally.

[Mnyb]

Cfraser thanks for your response.
Makes sense I suppose. I'm surprised that the newer 1570 (4 years newer) couldn't deal with the change like the old model.

I also own an arcam rdac which works perfectly with the sbt.
If I connect the touch to the arcam via digital connection and then to the Rotel, I'm basically using a double Dac implementation. I could put the Rotel into a direct mode which doesn't allow the use of my sub.

Would you have any issues with the double dac setup if i want to use my sub?

Possibly as all HT gear I know implement the sub filter in the digital domain so the analog inputs goes trough AD conversion ,when you use the sub , you usually can't use the direct mode or most mfg these days are very vague on what's really going on in thier product ,very few have actual analog pass thru , moder HT gear is best feed an digital signal .
So when using the sub you get the signal feed trough DA-AD-DA that is maybe not ideal re soundqality .

I think the fault is at the Rotel they just trying to pass the blame, you see this forum people have it working with countless kinds of DAC's and HT amplifiers ?

[slimmac]

Thanks again for all your input - its much appreciated.
In Rotel's defence, they sent me via FTP server, hi-res test files to test how the DAC handles them.
I played them in 2 ways:

1) VIA a USB stick connected to an Oppo BDP-95, which was connected to the Rotel using the same digital cable.
The files played perfectly.

2) VIA the same USB stick connected to the SBT, connected to the Rotel using the same digital cable.
The Rotel DAC would "stick" on the 88KHz to 44.1KHz sequence. Go figure!

So....I can't entirely attribute this issue to the Rotel. Rather, it appears to be a relationship that's sour :-)

Possibly as all HT gear I know implement the sub filter in the digital domain so the analog inputs goes trough AD conversion ,when you use the sub , you usually can't use the direct mode or most mfg these days are very vague on what's really going on in thier product ,very few have actual analog pass thru , moder HT gear is best feed an digital signal .
So when using the sub you get the signal feed trough DA-AD-DA that is maybe not ideal re soundqality .

I think the fault is at the Rotel they just trying to pass the blame, you see this forum people have it working with countless kinds of DAC's and HT amplifiers ?