Looking for Better Jitter Reduction in a DAC
@willemj , maybe I wasn’t clear about #4. The problem still exists when the preamp is out of the system (DAC direct to amp input). When using the amp gain control, music is very loud at about 11 or 12 o’clock on the dial, about 80 dB at listening position. Before I purchased this amp, I checked with Ralph (atmasphere) who believed preamp and amp were a good match. 100 kOhms input impedance with variable gain. With preamp inline, I leave the amp gain pot at about 3 o'clock. |
Maybe the solution is just an in-line voltage divider. All it takes is 2 resistors to drop the voltage a little. RCA in/RCA out and 2 resistors. This would at least show if this is the problem or not. Another cause could be DC-offset. IF there is DC on the SE or balanced signals all the time, or DC that increases with volume, this can cause many amps to have problems, even self-destruct. Measure this with no music playing with a DC voltmeter at different volume levels. Should not be more than 10 millivolts. .01V. Steve N. Empirical Audio |
It is a bit hard to figure out from this end, of course. I still think you may have a gain mismatch (2.8V into a power amp with a 1.0V sensitivity). It does depend a bit on the design of the amplifier's gain control. Does it come after an input stage? If so, that input stage could still be driven into clipping. A cheap experiment would be to get some inline attenuators from Parts Express: https://www.parts-express.com/harrison-labs-12-db-rca-line-level-audio-attenuator-pair--266-244 Short of using a scope to inspect the signal, you could also listen to a cd with different levels of a test signal, and listen if and when the sound starts to distort. Alternatively, what you hear with the digital source may in fact be perfectly fine, but unusual for your ears. You hear a difference with your analogue sources, but why would they be superior? Go to a live concert of a symphony orchestra and you will at times hear the pretty harsh sound that some would call 'digital', but that is just the real thing. Do not forget that FM radio is seriously challenged sonically, with high levels of distortion, reduced high frequency response, and limited channel separation. The same is true for vinyl. Both may sound nice and warm, but it is not quite the real thing. |
@willemj , thanks. Attenuators may be the easiest way to test this situation. And good point about analogue. I have season tix to the Philadelphia Orchestra and the brass section can definitely sound harsh at times, plus that is the nature of the trombone or Wagner tuba in some symphonies. But violin in a well damped concert hall should not present harshness, well maybe during a solo. Steve N, DC offset was checked when I had new dedicated lines installed, not long ago. Forgot to mention that my SS Sunfire amp with high gain also presented this problem after I received this DAC. BTW, my Chord DAC sounded very smooth. |
