I’d like some flexibility with whatever I choose as a source switch/level control in case I decide to use a different power amp.See http://ielogical.com/assets/Audio/PassiveLC1.png here http://ielogical.com/Audio/#LastHurrah. It is possible to use a single resistor value to give perfect passive tracking for any amp impedance. Only caveat is ensure source has low output impedance, say less than 500R and power amp has reasonably high input, say 20k+
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Mr. Modjeski seems to endorse passivesYes his amps are loved by passives and with my customers that use them.
My power amp is a CJ Evolution 2000 its input impedance is 100k ohms, and input sensitivity is 900 mV to full output.
It should also love passives, with that 0.9v input sensitivity. And that 100k input impedance you could of had a 20k Alps passive, not just 5k,
A 20k Alps pot would have been fine for just about any source then, which by the way you have not told what you have as the source.?? because if it has high’ish output impedance it won’t be comfortable with that 5kohm Alps pot as it will load down it's output and also create a voltage divider.
Sorry, I had mentioned my sources in a previous post, but this thread has many, many posts by many people! I primarily listen to LPs, but I do have a DAC (Cambridge DacMagic Plus), and an Audioquest Beetle to stream Spotify over Bluetooth. I initially entered this thread to ask Roger his opinion about using a tube amp with my Maggies, but realized, after considering my system, that my preamp is likely the weak link. That realization lead me to learn more about improving the switching and level control functions... whether by a traditional preamp, or by using the combination of a passive device with a dedicated phono preamp. I had a passive in a different system, so I tried it in the main system to check it out.
Thanks for the link.. I’ll check it out. My comment regarding the phono preamp with aux inputs and level control was made selfishly because I am very much interested in outstanding LP playback, and only listen to my digital sources casually (for background music, or if I’m not in the mood to flip records). Therefore a high quality phono preamp with a couple auxiliary inputs and a volume control is very attractive to ME
krelldreamsWhat would your phono stage be, hopefully I can find it’s output impedance and if it has capacitor coupling and if that’s big enough, to work into a 5kohm Alps pot., if not it will roll off the bass prematurely, "creating a leaner sound"
As far as the DacMaigic goes (at<50ohm output impedance) there’s no problem for it to see, your 5kohm Alps pot. But it has an output coupling cap also and with the 5kohm Alps pot that coupling cap has to be at least 5uf in size to be -3db at 10hz if smaller than this it could prematurely roll off the bass also, "creating a leaner sound".
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