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We will have to agree to disagree. If we view listening tests as unproductive and usually misleading, evaluation of equipment is then quite alien to our actual capability to discern and make choice, which includes enjoyment.
Dwelling in a world of measurements and visual treats alone, Yes is informative to a degree and looks very impressive, but should always be, IMO secondary to actual listening experience.
IMV this is more a problem with higher voltages, not really relevant at line level. The resistors in the attenuator must be of similar quality as all other resistors in the signal path, of course.
So we test power amps at 5 watts into 4 Ohms which is 4.45 volts rms output. 26dB is a typical power amp gain so input needs to be 223mV rms to acheive this level.
I think SINAD at this level would be more informative.
Also what input level to the pre amp? I would suggest typical DAC output of 2 volts rms
5 watt SINAD would be peak value then. I don't know why anyone would buy your power amp for peak power of 5 watts. That could one data point. But I think it is too low of a target.
I have measured various resistors with relays with apx555. Voltage coefficient is very important. The harmonics is less than the accumulated noise but it will rise when attenuated even -1db.
So we test power amps at 5 watts into 4 Ohms which is 4.45 volts rms output. 26dB is a typical power amp gain so input needs to be 223mV rms to acheive this level.
I think SINAD at this level would be more informative.
5 watt SINAD would be peak value then. I don't know why anyone would buy your power amp for peak power of 5 watts. That could one data point. But I think it is too low of a target.
Are there better recommendations out there for the same/less dough? I have always been baffled by what seem like high prices from all companies for what is basically a channel switcher and volume control for active speakers. Is there other valuable functionality here that I am missing? Would really like a transparent way to run a T/T and DAC into a pair of Genelecs but it seems like choices are $39 on-line junk or fairly expensive units.
I have been haunting all the hifi stores in New England for a couple years trying to solve the pre-amp problem, and the unspoken industry consensus seems to be "$2000 is cheap-- if you don't want to spend at least that, come back when you inherit some money".
Interesting - can you show a graph and which type of resistors you've measured? I know only the results of Douglas Self's measurements in his book Small SIgnal Audio Design.
The harmonics is less than the accumulated noise but it will rise when attenuated even -1db.
I have been haunting all the hifi stores in New England for a couple years trying to solve the pre-amp problem, and the unspoken industry consensus seems to be "$2000 is cheap-- if you don't want to spend at least that, come back when you inherit some money".
Interesting - can you show a graph and which type of resistors you've measured? I know only the results of Douglas Self's measurements in his book Small SIgnal Audio Design.
Of course. At full volume the attenuator does not attenuate, the signal just passes a relay and not a resistor.
His measurements are over ppm. Apx555 here has distortion harmonics of near -150db which is 30db less than ppm. Any precision analogue designer knows that sub ppm is a completely different world.
Even then, Douglas self has stated in the amplifier design book that feedback resistors of the amplifier are extremely important because of the voltage coefficient. Any voltage division will have voltage coefficient in the equation. Just let amir measure -3db or so attenuation and see how the harmonic goes. I predict it will increase to around -130db or even -120db instead of the -150db mark without any attenuation.
Akitika PR-101 as a kit is $379 plus shipping. I replaced my Pass Labs XP-10 with it, which at $5,250 was over 10 times the price. I can't say that the Akitika pre sounds 'better' since I did not ABX test the two but I'd say it doesn't sound worse at the very least. It also has far more features then you get with a typical esoteric linestage.
I have been haunting all the hifi stores in New England for a couple years trying to solve the pre-amp problem, and the unspoken industry consensus seems to be "$2000 is cheap-- if you don't want to spend at least that, come back when you inherit some money".
For 6 high level sources the LAP-2 by Funk Tonstudiotechnik is a very good product, but not really cheap (starting at ~ € 1100). It measures almost perfectly.