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Distortion with XLR Input on Cambridge EVO150 Need Help!

Mrdead

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I'll try to explain this the best way I can. I am running a CD Player's digital output (tried both COAX and OPTICAL) into the Holo May DAC. Then I have the XLR output from the May going into the XLR in's of a Cambridge EVO150. However, when I play the music the sound has a horrible midrange distortion as if the gain were overloading the speaker. It's like that even in low volumes. Firstly I tried swapping XLR cables, but nothing. Now here is the kicker, it works fine with RCA outs from the May and into the EVO. I have also tried switching CD players, and the same issue persists. I switched DACs, and the same issue yet again. I ran it through the Schitt Joutenheim as a pass-through, issue was fixed. I use the Primare NP5 streamer, the issue is fixed. Why does the EVO 150 not want to play well with CD players through DACs? Do you guys feel it's the XLR input on the EVO, why would it play the streamer just fine connected the same exact way and not the CD players. Note the CD players I have tried are the Primare DD15 Transport and the Lyngdorf CD2. Anything helps. Thanks!
 

Geert

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The output amplitude of the DAC might be to high for the EVO 150. Unfortunately Cambridge doesn't specify the input sensitivity of the amp so we can't tell for sure. Best thing to do is to test if there's still distortion when you reduce the volume of the DAC. If it has no volume control, I don't know for this DAC, then try to play music via the USB connection and decrease the volume in the media player app.

The Primare streamer you tested might have a lower output amplitude, hence no problem.

(Manufacturers not specifying in and output sensitivity is a worse crime than building equipment with mediocre SINAD).
 
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Mrdead

Mrdead

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The output amplitude of the DAC might be to high for the EVO 150. Unfortunately Cambridge doesn't specify the input sensitivity of the amp so we can't tell for sure. Best thing to do is to test if there's still distortion when you reduce the volume of the DAC. If it has no volume control, I don't know for this DAC, than try to play music via the USB connection and decrease the volume in the media player app.

The Primare streamer you tested might have a lower output amplitude, hence no problem.

(Manufacturers not specifying in and output sensitivity is a worse crime than building equipment with mediocre SINAD).
Agreed, as fun as the EVO150 has been with its myriad of features, I feel like it struggles to really provide a great-sounding experience for my speakers. I wish companies would be a bit more transparent. To be honest the Lyngdorf TDAI 1120 has a much cleaner sound. However, no XLR inputs to test the theory.
 

Geert

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From another forum: "I can barely get the volume up past 1/5 without it being too loud". This points to high input sensitivity, so potentially easy to overdrive.

I did some research in the Cambridge Audio CXA81 review topic, where I found out Cambridge uses 1,5V as input sensitivity for their power amp's. That's lower than the 2V output certain CD players and DAC's apply.
 

AnalogSteph

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Input sensitivity does not (generally) equal input clipping level. It is the latter that would be relevant in this case. This is, obviously, specified and tested even less commonly.

The Holo Audio May seems to output about 5.8 Vrms at 0 dBFS, balanced. I don't see a digital volume control anywhere, arguably a bit of an omission on a DAC of this caliber (it may be R2R but is quite good enough for that).

I won't be surprised if the EVO 150 can handle little more than 2 Vrms internally and the balanced input is unity gain as so often the case.
 

Geert

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Input sensitivity does not (generally) equal input clipping level.

It doesn't equal, but it's usually related as headroom is never unlimited. So you came to the same conclusion: the DAC is overdriving the amp's input.

Edit: different people on the head-fi.org forum complaining the Holo May overdriving preamplifiers. So Holo deliberately doesn’t include volume control because they believe that's the job of a preamp, and then use an output level that's completely of the charts and will cause problems with different preamps. But it is a R2R DAC, that's probably more important.
 
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