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Help! SMSL SU-1 doesn't work.

Figaro82

Member
Joined
Mar 10, 2025
Messages
9
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hello everyone, I'm a new member. I have a problem with an SMSL SU-1 that came to me today.
I want to use it between TV and Amplifier.
the problem is this:

Connected in this chain: TV Optical > SU 1 > amplifier (RCA in different input like)
Selected on TV Audio-TV output.
The amp only produces noise.

TV output head: Ok
Amp input head: Ok
Direct optical TV connection > Amplifier: Ok

SU-1 tested with USB 5V socket power supply, 5V 1A power supply, 5V 2A power supply and Power bank too.
If you have no suggestions, I fear the device is malfunctioning.

Samsung TV 55h6800 with Google Chromecast
Denon Avr 3312 amplifier
 
Just making sure, you have selected the optical input on the SU-1? Cycle through the inputs by pushing the button.
 
Make sure your TV isn't sending out Dolby. That would likely be the default. Very few stand-alone DACs can decode these formats. Check if the TV has a setting for "PCM" or "LPCM". (They are both the same thing but the video guys throw-in the "L" for "linear".)

Or skip the separate DAC and connect the TV directly to your AVR.
 
Connect your TV with HDMI to the AVR.
 
Check and confirm that your TV is sending out PCM.
 
hello everyone, I'm a new member. I have a problem with an SMSL SU-1 that came to me today.
I want to use it between TV and Amplifier.
the problem is this:

Connected in this chain: TV Optical > SU 1 > amplifier (RCA in different input like)
Selected on TV Audio-TV output.
The amp only produces noise.

TV output head: Ok
Amp input head: Ok
Direct optical TV connection > Amplifier: Ok

SU-1 tested with USB 5V socket power supply, 5V 1A power supply, 5V 2A power supply and Power bank too.
If you have no suggestions, I fear the device is malfunctioning.

Samsung TV 55h6800 with Google Chromecast
Denon Avr 3312 amplifier
As many other members suggested, issue more likely is output format on your TV. You should be able to find under settings the format, just set it to PCM and you should have sound out properly.
Avoid auto/Dolby etc., select PCM.
 
Make sure your TV isn't sending out Dolby. That would likely be the default. Very few stand-alone DACs can decode these formats. Check if the TV has a setting for "PCM" or "LPCM". (They are both the same thing but the video guys throw-in the "L" for "linear".)

Or skip the separate DAC and connect the TV directly to your AVR.
I already tried to connect skipping DAC: it works with optical and with HDMI too.

I'll check the TV out PCM.
 
Ok, problem solved.
every time I enabled the audio output from TV, it switched to "Neo DTS" format. The stupidest thing in the world.
Now it works, even if it is quite cumbersome to always have to change Output and Output Format.
Thanks everyone.
In any case, even with the DAC, the files with 24 bit source (anazon music/tidal) only play at 16 bit.
Shouldn't it be a limitation of Chromecast, maybe of the TV?
Any solutions?

Tv Samsung 55h6800
Google Chromecast
SMSL Su-1
Denon AVR 3312
 
For improve quality of DAC conversion, and with the aspettative do be able to play at 24 bit from source (anmazon music/tidal). But is still playing at 16 bit.

Tv Samsung 55h6800
Google Chromcast
SMSL Su-1
Denon AVR 3312
So why are you using the DAC?
 
For improve quality of DAC conversion,
It won't though - because the AVR will normally convert the analogue signal to digital, for internal processing, then convert back to analogue again using its internal DAC before amplification. So you are adding a DAC and an ADC step, each of which will slightly (though likely inaudibly) degrade the signal. Not to mention the possibility of picing up addition analogue noise in the interconnect between DAC and AVR.

You are almost always going to be better off going with a digital connection into an amp if it has one, rather than performing an external conversion.
 
For improve quality of DAC conversion, and with the aspettative do be able to play at 24 bit from source (anazon music/tidal). But is still playing at 16 bit.

Tv Samsung 55h6800
Google Chromcast
SMSL Su-1
Denon AVR 3312
So why are you using the DAC?

It won't though - because the AVR will normally convert the analogue signal to digital, for internal processing, then convert back to analogue again using its internal DAC before amplification. So you are adding a DAC and an ADC step, each of which will slightly (though likely inaudibly) degrade the signal. Not to mention the possibility of picing up addition analogue noise in the interconnect between DAC and AVR.

You are almost always going to be better off going with a digital connection into an amp if it has one, rather than performing an external conversion.
So there is no way to avoid the amplifier conversion step? I was hoping that using an external DAC would replace the internal one, skipping it completely. Maybe going into phono could work, since there are no converters there.
 
Maybe going into phono could work
No, you can't connect a DAC to the phono input because it is designed for a phono signal and has different signal processing.
Try to find an option on the AVR to let the signal go directly without processing.
 
For improve quality of DAC conversion, and with the aspettative do be able to play at 24 bit from source (anazon music/tidal). But is still playing at 16 bit.

Tv Samsung 55h6800
Google Chromcast
SMSL Su-1
Denon AVR 3312



So there is no way to avoid the amplifier conversion step? I was hoping that using an external DAC would replace the internal one, skipping it completely. Maybe going into phono could work, since there are no converters there.
Using phono input with a normal line level signal may damage your phono input. Phono input has a much higher sensitivity than the regular line level inputs.
 
Using phono input with a normal line level signal may damage your phono input. Phono input has a much higher sensitivity than the regular line level inputs.
Thanks a lot...In effect I realized was a very stupid idea.
No idea about some analogic in.
 
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