Do We Need Linestages ????

[rollo]

Both of my tube preamps make my music sound more pleasant. I prefer to have a preamp over having a DAC/pre combo.

   Spot on !

charles

[pursuitofnow]

The amps I use require 2 volts and sound even better with 4-8volts. Everything from dynamics, density, and imaging are just better. So I would think it really depends on your amp to determine if linestages are "needed".

[P.I.]

It has been my experience that both voltage output of > 3v is essential along with adequate drive current.

Some years ago I listened to my passive driven by a Cary 306 and also a preamp with a lot of current at the same voltage.  The pre was decisively betterin terms of PRAT.

A big part of what makes it all work are output and input impedance IME.

[rollo]

  Agree Dave it is essential to have >3V from source and low input sensitivity of less than 1V for ultimate passive pre performance.
Doug a great preamp, a classic when working. 


charles

[steve]

I am a little confused. Do you gents mean greater than 3 or 4 volts output capability, when using a passive control, or another condition? 

Probably a stupid question, but I ask because usually that kind of actual signal voltage output will have the cones parachuting to the floor.   

Cheers

steve

[steve]

  Agree Dave it is essential to have >3V from source and low input sensitivity of less than 1V for ultimate passive pre performance.

charles

I missed your post Charles, which answers my question, and I agree.

cheers
steve

[rollo]

   ARGHAH !! DAC with 3V or more is what the Doctor ordered when using a passive Pre.

charles

[steve]

   ARGHAH !! DAC with 3V or more is what the Doctor ordered when using a passive Pre.

charles

Yes, we already agreed with you. Upset?

cheers
steve

[Response Audio]

Not a fan of using a source straight into an amp. Even with a passive pre, you dont get the dynamics and impact you would with a preamp. Looses emotion in my opinion.

[rollo]

Not a fan of using a source straight into an amp. Even with a passive pre, you dont get the dynamics and impact you would with a preamp. Looses emotion in my opinion.

   Great point which I agree with. After fooling with several passive designs the active preamp is KING for me. When all the bases are covered with a passive one may get more clarity however looses the soul and emotional impact.


charles

[P.I.]

Not a fan of using a source straight into an amp. Even with a passive pre, you dont get the dynamics and impact you would with a preamp. Looses emotion in my opinion.

   Great point which I agree with. After fooling with several passive designs the active preamp is KING for me. When all the bases are covered with a passive one may get more clarity however looses the soul and emotional impact.


charles

+1... unless the source has enough voltage and current to adequately drive the amp input at a friendly output impedance through the passive.

[steve]

I agree, and of course use a line stage preamp. As we all know, external passive controls that use an interconnect cable have that evil capacitance.

I did a little calculating, and with 4 volts rms musical signal, using a 100k ohm volume control,
the signal current through the pot is only 40 ua (microamps, or millionths of an amp); not much.

With 4 volt rms musical signal, 10k pot, 400 ua, or 0,4 ma (milliamp) through the pot; again not much.
10k is also about as low a resistance load as one can use with capacitive output preamplifiers as bass
response starts or is already dropping.

It is imperative to minimize capacitance in this signal path. With an input volume pot in the pre or the
amp, the capacitance is basically, Miller capacitance, with a smattering of input and stray capacitance.

cheers
steve