Success Rolling Opamps in EE Minimax DAC

Anyone care to comment on the influence of the power supply on performance. There are competing DAC designs claiming the importance of power supply chokes or elaborate regulation and transformers to serve as important elements.

I suppose this is the sum of all the parts concession I can make but wonder too why the smaller parts are not given more respect or attention.

Kudos to Doug for shifting the direction.

La45- Your point is well taken about smaller or "simple" parts. The speed and Efficiency of Capacitors in the Power Supply and elsewhere cannot be overstated. The impedance or ESR of these devices has a stranglehold over the sonic merits of any audio device. A slow response Cap yields a lethargic and unenthusiastic presentation with lack luster dynamics. However, it also screws with pitch accuracy and intonation. There is no doubt that each component imparts a sonic fingerprint on the signal, but none come close to the musically destructive affects of slow caps IMO.

The biggest problems is that electrolytic caps are constantly aging and losing performance as the electrolyte dries out inside, a process that is unavoidable due to heat cycling and use. Sure they will work for years but not a peak efficiency. They must be tested and changed routinely as surely as a vacuum tube. They are not unlike a rechargeable battery, where the chemistry inside begins to age and perform underpar. I plan on purchasing a ESR meter soon to test capacitors for performance. From what I've seen, it's a far more revealing tool than a capacitance meter.

Many thanks to Doug for all the info on OpAmp rolling.

Be careful with ESR. If we talking DAC then we have most likely volatge regulators. Many voltage regulators don't tolerate low ESR very well. They tend to oscillate when ESR is too low or too high. Also supply current is more even going mostly to cover op-amps bias currents. Momentary currents are very small because of high impedances and easily covered from ceramic decoupling caps. I can see bigger problem in interaction between these ceramic caps and inductance of power supply electrolytic caps - creating parallel resonant circuit that tends to ring.

Kijanki- All valid points that need to be considered in the big picture. My hope is to have a measurement record of the ESR when the equipment is new and monitor the capacitor health as time goes on.

hi doug:

there are many opamps available.

i don't want to listen to too many for obvious reasons.

if i were to replace the single opamp feeding the tube, i would to select one which "slows" things down, is less transparent and has more of a classic tube sound.

anotherwords a bit of veiling or hf roll off wouldn't hurt.

since you have experience with opamps, could you suggest one or two.

i am not looking for greater soundstage or resolution, but rather to get more of a euphonic (classic-tube) sound from the dac.