A tale of gain
 

I've been having some issue with harsh treble with my system…you know, the kind where you wince when the volume gets turned up and with the volume turned down, it just doesn't sound right. Some recordings were worse than others, but pretty much anything from the DAC was just too harsh. (Ironically, digital music from cable coming through a HT pre-pro into the ET3SE sounded better than the DAC.)

Removing the Aurious Pro Max footers from the pre in favor of the stock rubber feet took away some of the harshness, but it was still there.

<multiple sessions of swapping wires, tubes, etc., thinking about getting rid of the DAC and buying a turntable, and treble still too harsh> :madani:

I was showing a friend the variable output on the DAC and, surprise, less harshness in the treble when the DAC output level is less than its max. Me thinks, maybe the output level on the DAC, at 100, is too high for the preamp.

So, I've been experimenting with various combinations of DAC output level and pre gain. Apparently, with my DAC any level above 50 gives you the Redbook full dynamic range. And I'm thinking, which piece of equipment would I rather provide the bulk of the gain: the DAC or the ET3SE?

Suffice to say that with the DAC dialed down and the pre turned up that harshness has gone away and I get a host of other benefits (better front to back layering, better articulation of differences in volume of individual musicians, much more detail in vocals that was being hidden somehow) as well without any increase (that I can tell) in noise.

So, whether the DACs output level was too high for the pre or having the DAC provide much of the gain pre-DA conversion is harsh, it just sounds right relying on the pre for more of the gain.

Still thinking about that turntable, tho'.

Try exchanging the ET3SE 6922 tube - perhaps you have a tube that is prone to oscillate at high frequency - it is not directly listenable, you need an oscilloscope to see it, but creates an harsh sound. As the impedance of the ET3SE varies with level, sometimes this type of problem dependents on the position of the level control.

I think you're on to something. I know using my Premier 16 and Audio Aero DAC I had better results with lower gain on the AA and higher gain on the CJ.

TT is best though:yes::yes:

My guess is that the high voltage output of the DAC and it's SS output amps is just overdriving the ET3 input. If the volume setting of the preamp is much lower for the DAC than for a source that sounds good, you can bet the DAC has too much output. I'd much rather have the gain done by the c-j than by any but the finest DACs. Check with c-j about the input sensitivity of the ET3 and then with PS Audio about how much it's putting out. Bet you'll find the DAC is over driving the pre. Do I remember that the PSA DAC is intended to be used as a pre-amp as well? Then surely too much gain from the DAC and maybe an impedance mis-match as well.

Bob

What's the output voltage on the DAC?

My dealer had issues with the ET5 and LP70s combo, just too much gain. I understand the the ET3 and ET5 are similar circuits and therefore might have similar gain ( I have not checked)

I have found with CT5 and LP70S that 20 is fine for low level listening and 30 to 40 for more boisterous listening depending on the loudness war affliction. My DAC has something like 2.2 volts which is average I understand. It's been sounding particularly nice right across the board recently for some reason, no interest in vinyl at all as the digital is ticking all the boxes.