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Vexing Problem

Dear Reader,

I'm just a little vexed by a new issue with my digital front end. When I begin a session of listening it sounds terrible. I don't mean a sound that isn't what one would expect from my expensive stereo. I mean terrible like a boom box driven to distortion, even when playing at low volume. It happened when running Tidal/Roon through a Sonos Connect with an optical connection to a DAC, in this case the DAC option board in an Accuphase E-470. The indicator in Roon showed no clipping, but when I attenuated the signal by 7dB it seemed to help. The same problem when just using the analog outs from the Sonos Connect. But then the problem went away. The next day I happened to receive my new Bluesound Node 2i and hooked it up. Terrible. Same thing. Fiddling around with the DSP settings again in Roon might have helped. I don't know for sure because the issue disappeared again. I listened joyfully for a few hours last night.

Getting home from work today, SAME THING! The same over modulated sound. I went into my usual troubleshooting mode, trying all sorts of things, and the issue seemed to resolve itself again. Different players, different DACS. So it would seem like a problem with WiFi signal strength or download speed. But those have been checked and verified: fast, strong, and stable. I'm confused. Any ideas?

By the way, in my trouble shooting mode I took the time to carefully volume match and sync Kate Bush's Aerial between vinyl and digital, even between the analog outs of the Node 2i and its coaxial out to the DAC-40 module of the Accuphase. At this point my vexing little problem had already ended, and it was fun to compare the different sounds. In a blind test between the three positions of the selector knob, my wife liked the vinyl the best, as did I. But all three sounded absolutely luxurious. The analog front end in my system consists of a Luxman PD-171A with an Ortofon Cadenza Black and a Luxman EQ-500. Speakers are ATC 40's and a pair of JL Audio D-110's. A ravishing combination.

Thank you for your time,
~Oran


128x128oranfoster
oranfoster's avatar
oranfoster OP
127 posts
 
@nonoise , Thank you for the link; I really enjoyed the engaging article. For what it's worth, when I discover music that I love when streaming I'll often seek it out on vinyl. And when we started our bakery/cafe I purchased a license from ASCAP, at least partially helping to pay musicians for their essential work. 
 
And MC, Of course my analog front end captures at least some of the magic that your magnificent kit does.... I'm just trying to solve a major technical issue with my set-up.
mickeyb
565 posts
 
I unplug my ic’s and then reconnect. I find my usb dac to computer can be at fault. I don’t know why but it happens once in a blue moon. It can seem muddy and bright at the same time. Highly distorted. I unplug, exit tidal, replug, start tidal again and its fine. It’s a curious usb cable and supposed to be one of the best. Who knows. Agree with vinyl sounds best but I do love streaming at times. 
oranfoster's avatar
oranfoster OP
127 posts
 
Thanks Mickey, I did that and more..... and.... the problem seems to have gone away. 
I often find that even the simplest of gadgets often need rebooted.

hopefully it's been resolved!

cheers, 
~Oran.
audio2design
1,351 posts
 
Could be a hardware issue with the Accuphase. Odds are the DAC external and internal have high analog signal levels. Something could be wrong with the Accuphase that clears up once it heats up. It certainly would not be unheard of.

Given that attenuating the signal in Roon seems to make the issue better, this seems like a logical conclusion. That will reduce the analog signal level entering the amp.

Reducing the volume via the amp may not alleviate the problem depending on where the problem is.

If it happens on both channels, to me, it sounds like an issue with a power supply supplying the input circuitry. If the voltage is low, it will clip / distort the input.  Bad solder joints can also resolve via soldering, or movement, only to come back again.
speakermaster
738 posts
 
I would say that the lock between your digital sources and your dac board in the accuphase is having an issue in some way maybe the digital cord needs some run in time i am not sure seems like a strange problem.
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