I used to think passive preamps were superior to active preamps given right the setup, but

For what it's worth, Emmanual Go, producer of the superb lineup of First Sound tube preamps initially marketed a passive preamp.  Eventually he began to engineer, manufacture, and sell dual mono actives with separate power supplies.  I recently paid Mr. Go to install the two "S" upgrades in my FSPD III and an incredibly quiet, dynamic, and musical preamp jumped yet another notch in performance.  It is the only component I've owned during 45 engaged in this hobby that I've never considered selling.  

Mitch2 6-17-2016 4:59 am EDT
It is not just about gain but I believe also about ... frequency variations with impedance.

This is a good point that warrants additional emphasis, IMO. If the component that is driving a resistive-based passive preamp has an output impedance that is essentially constant over the frequency range, and if the component that is being driven by the passive preamp has an input impedance that is also essentially constant over the frequency range, then what might otherwise be an impedance incompatibility will simply result in a slight reduction in gain (putting cable effects aside, which are a separate issue, and assuming that the mismatch is not so extreme that the source cannot comfortably supply the necessary current).

But if for example the source component has a coupling capacitor at its output, resulting in a substantial rise in output impedance at deep bass frequencies, or if the output impedance varies significantly in other parts of the spectrum for whatever reason, using that same passive preamp may result (depending on the specific numbers that are involved) in objectionable irregularities in frequency response and/or phase response.

Perhaps that factor, differences in how source component output impedances vary as a function of frequency, is one contributor to the divergence of opinion about passives.

Regards,
-- Al

What we’ve found in actual practice with our LDR preamps in combination with countless different customer sources and amps is that impedance matching is rarely a limiting factor.

And yet, you are planning on introducing a buffered version of your preamp.  I am sure your LDR attenuator preamps sound very clear and natural, and I know how attractive that can be from the Goldpoint/Endler/JaySho (i.e., Bent) preamps I have had here, but I will not be the least bit surprised if you find that your LDR attenuator with a good buffer stage sounds even better.  At a minimum, it should broaden the range of components that mate well with your preamps.

I had a DAC with passive volume control, then a DAC with active volume control. The latter one sounded better.

Nowadays I don't care about the buzzwords the product is advertised with, I go for bang for the buck and my ears.

Myself being in audio gof over 40 years now have bought from the A groups 
In recommended componends and have had some great equipment
I have found having an active Linestage preamplifier dynamics and imaging 
Especially complex orchestra dound more real especially Vacuum tube.
Recently I did something totally different .since I have owned single ended amplifiers  and wanted to see what was all the fuss .I can say by keeping things 
Very simple in one gain stage the sonic purity is second to none.after yhst experience I had a very gifted Electronics designer build me a DHT preamplifier Single ended -Direct Heated Triode Preamplifier completely transformer based 
Including the Audio output section.the only capacitors are 2 Big poly oil caps and 
Copper bypass caps . Using 6 Lundahl  transformers and chokes.
Using the WE 274 rectifier tube, WE 101D aufio tube ,as well as a choice to use the 26 tube.these are far more linear then a 12ax7,or 6sn7 indirect heated tube.
These tubes run very cool and the magic is incredible . The transformers Make a huge step up in sonics accuracy and dynamics and Bass using a 300b
Or 2-3 does also work but it is a power tube first and a waste of heat to achieve the same goal. If this were commercials sold it would be at least  $1 3k
I have yet to find a another passive or active preamp that is built this well with all premium parts including all Neotech Single Crystal wire used throughout 
Including their best Silver Gold Alloy signal wire.  The famous Coincidence DHT 
101D preamplifier uses solid state rectification and capacitor coupled.
Which is very good but a solid step below rectifier, Transformer coupled unit.
Once you experience a top DHT model done correctly ,9 out of 10 would want one if they can justify the price.