Oomph or pressure?

One final point.  It will take a very good active linestage to surpass the Emia/Intact Audio autoformer.  In my case, the Emotive Epifania started out as an excellent sounding preamp, but I have tweaked it to death over the past 10 years by swapping out different resistors, capacitors, chokes, and wire to find the best sounding combination.  I also eliminated the switching so it is a dedicated single-input linestage.  When I got the autoformer I followed the same approach---no switching, just a single input, and the same wires that I settled on with the Emotive preamp.  So they each have some advantage over your typical commercial products.

52tiger
Emia autoformer as my preamp. It sounds fantastic but one thing I noticed is I have to turn the volume up quite a bit to get any oomph out of it. thanks, Scott

Nothing wrong with having to do that, as Nelson Pass explains below.
Scott, passives rule!!, they are the most transparent/dynamic way of getting the source signal to the amp with control over the volume. Only better is direct source to amp (but you need a level control in the source) 

Nelson Pass,

"We’ve got lots of gain in our electronics. More gain than some of us need or want. At least 10 db more.

Think of it this way: If you are running your volume control down around 9 o’clock, you are actually throwing away signal level so that a subsequent gain stage can make it back up.

Routinely DIYers opt to make themselves a “passive preamp” - just an input selector and a volume control.

What could be better? Hardly any noise or distortion added by these simple passive parts. No feedback, no worrying about what type of capacitors – just musical perfection.

And yet there are guys out there who don’t care for the result. “It sucks the life out of the music”, is a commonly heard refrain (really - I’m being serious here!). Maybe they are reacting psychologically to the need to turn the volume control up compared to an active preamp."

Cheers George

And yet there are guys out there who don’t care for the result. “It sucks the life out of the music”, is a commonly heard refrain (really - I’m being serious here!). Maybe they are reacting psychologically to the need to turn the volume control up compared to an active preamp.

Precisely the complaint of this thread. Nelson goes on to say:

I suppose if I had to floor the accelerator to drive 55 mph, maybe I’d think the life was being sucked out of my driving. Then again, maybe I like 55. Nice and safe, good gas mileage…

Is impedance matching an issue? Passive volume controls do have to make a trade-off between input impedance and output impedance. If the input impedance is high, making the input to the volume control easy for the source to drive, then the output impedance is also high, possibly creating difficulty with the input impedance of the power amplifier. And vice versa: If your amplifier prefers low source impedance, then your signal source might have to look at low impedance in the volume control.

This suggests the possibility of using a high quality buffer in conjunction with a volume control. A buffer is still an active circuit using tubes or transistors, but it has no voltage gain – it only interposes itself to make a low impedance into a high impedance, or vice versa.

- essentially pointing out the same problems I did earlier in this thread.

Since all digital sources make way too much voltage to clip any amp made, a buffered control is a good idea, as it isolates the volume control from the output, and the buffer circuit helps to control the interconnect cable. Note that Nelson is careful to point out that this is an active circuit. We build similar circuits for customers that don't need the gain (but using tubes with a direct-coupled output).

Yes he does, for amps with low input impedance (<20khoms) that aren’t passive friendly, you need a unity gain buffer (no gain as he infers) and those amps thankfully are very not common place, and are around 5% of the market share. some Class-D and some First Watt, Pass Labs

Any amp that is 33kohm or "industry standard input of >47kohm" or higher is fine for any passive pre without the need for a unity gain buffer.

As for active preamps with gain they are not needed in this world any more, and are a left over from phono days when a preamp needed gain.

Even Pass Labs now has lowered the gain of many of their amps from the common 28-34db, down to the low 20’s, just so his and other high gain preamps can be used with most of the volume range they have, instead of being at 9 o’clock for loud!!

Since all digital sources make way too much voltage to clip any amp made

Not just digital even analogue sources, tuners, phono stages etc etc. Have more than enough voltage to clip just about any poweramp.

Cheers George

Sal,
Autospell got me again! I surely meant appropriately named in referring to the Emotive Audio Epifania. I believe that my post however made it clear that I’m complementing the Epifania and its heightened level of involvement you cited.
Charles