Does the streamer effect sound quality

How can a Streamer make any difference if the digital stream is fed directly to a DAC?  1's and 0's from Streamer A vs Streamer B can't sound different, right?  Not so fast there, Bubba. 

Only have experience with one Streamer connected to a quality DAC.  However, the Streamer offered sound "enhancement" features.  Claimed to 1) fix corrupted digital bits and 2) improve overall sound quality.  The reality is that disabling all "enhancements" produces better sound quality.  The more you mess with a signal, digital or analog, the more likely to corrupt the signal.  

Excellent point already made that quality of the source material will make a large difference.  Have no reliable insight into whether providers like Tidal, Spotify, Amazon, etc. process source files in any way.  I have done side by side comparison of a streamed track vs same from a CD.  There is a difference.  If the 1's and 0's are the same from either source, there should be no difference in sound quality.  Have to conclude something is different somewhere.

@cleeds Respectfully decline to identify brand names. Believe there is brand name bias, myself included, that can get in the way for this topic.  Will say all my components are from brands with long history in audio, not expensive, high performance for the cost.

@ghdprentice To further clarify streamer and CD transport feed digital to the same DAC via optical connections. Comparing the same track, streamer sound is noticeably congested.  Not enough different to say the streamer sound is bad, just different.  Is it the streaming service or the streamer?  Don't know.

@ghdprentice  The TOSLINK optical link was specifically designed for 2-channel audio for CD quality bandwidth.  The interface components at either end are of mature design, not a "throw in" item of questionable design. Optical cables are immune to EMI/RFI and ground loop problems. Optical can have jitter on the order of a few nano-seconds.  Any decent DAC will easily deal with that. 

SPDIF can suffer EMI/RFI and ground loop issues. A clock signal is embedded that has to be recovered.  Potential jitter is data dependent and there are low pass and high pass filtering effects to deal with.

Properly implemented either TOSLINK or SPDIF is more than adequate for high quality serious audio.