Input sensitivity, Gain and Preamp matching

Hey Al good to hear from you, as you stated, yes a few of the quietest early cd's have low recorded volume and your -6db seems about right for these.

So even if Pani has source outputs 2.5v this will be ample for 90% of the rest of recordings to play at full amp clipping, and if he has 4v from his source/s that will also take care of those quite -6db as well to drive the amp to clipping.
But, and a big BUT, when do we do our listening just below full output (clipping) of the poweramp anyway??? Unless we like blowing amps up to speakers.

All is moot anyway till we find out what source/s Pani has.

Cheers George

03-31-15: Georgelofi
But, and a big BUT, when do we do our listening just below full output (clipping) of the poweramp anyway???

We (or at least most of us) of course don't do that on anything approaching a continuous basis. But it should be kept in mind that the main usefulness of the upper part of the power capability of an amp is typically to support the BRIEF dynamic peaks of those recordings which have wide dynamic range (meaning a wide DIFFERENCE in volume between the softest notes and the loudest notes).

For example, listen to this excerpt from Stravinsky's "Firebird", from the 7 minute point to the end at 10:54, as the music descends to near inaudibility and then builds to a concluding note that on some well engineered minimally compressed recordings I have reaches 100 to 105 db at my listening position.

Or consider this very simple arrangement (female singer with piano accompaniment) of the old standard "All The Things You Are". That is one of the tracks I described analyzing in my previous post. Prior to the last 15 seconds of the track the RMS average level is a very low -31.1 db, with the very highest value during those 3 minutes being -13.2 db. Yet in the final few seconds a peak of -4.7 db is reached. As I'm sure you can calculate, that peak will require 437 times as much power as the average level.

My point is that unless the OP's 16 watt amplifier is being used with speakers having an efficiency in the area of the 103 db Ralph referred to, there will be SOME recordings which on brief peaks are likely to require most or all of the amp's power capability to be used. And unless his source components have output levels that are a good deal higher than average he won't be able to turn the volume control up high enough to be able to utilize that power capability, if his preamp provides little or no gain.

Regards,
-- Al

Pani,
My experience is based ONLY on TVC and not other types of passives. But nevertheless, I would like to share.
Your amp's sensitivity is actually very low. The way people would look at the sensitivity would be - if it requires less volts for full power, then it is high sensitivity. If it requires more volts for full power, then it is low sensitivity. For a passive to work with an amp, the max sensitivity that you should go for an amp would be 1.5V for full power. The lower the better. My amp is 1V for full power,and I use a TVC. Or else, like Al mentioned, you will not hear the "full potential" of your system. Also Ralph has mentioned about speaker sensitivity - this also plays very important role in a "passive based" system. Ideally your speakers should be 90+db.
At this point, it looks like active pre would be the way for you, unless you change some components in your system.

Most SETs have low gain because they are intended to be used with high efficiency loudspeakers (usually 98 db or more).

Milpai: My amp is 1V for full power,and I use a TVC. Or else, like Al mentioned, you will not hear the "full potential" of your system.

So long as you can get to the volume level you like to listen to IS ALL THAT MATTERS, even if a passive is full up there will be absolutely NO missing out on the dynamic peaks, so long as the listening volume is as loud as you want to go, even if full up. There is NO brick wall regarding transients.

In fact passives are usually better if they are full up, as there is less shunt resistance to ground, so the source (if a weak tube output) sees an even easier load, which equals better dynamics for them.

It's doesn't matter if you can't send you amp into overload (in fact it's a safety device) so long as the volume is right for YOU!.

Cheers George