[Paullb]

Hello,

Can people please list combinations that have worked well, including a brief description of the sound/synergy and speakers used. On paper I have been looking at Quicksilver Mono 120s; they are a good match specs wise and the two would hopefully provide a combination of tube magic and LDR transparency.

[tortugaranger]

Hello,

Can people please list combinations that have worked well, including a brief description of the sound/synergy and speakers used. On paper I have been looking at Quicksilver Mono 120s; they are a good match specs wise and the two would hopefully provide a combination of tube magic and LDR transparency.

This question comes up often enough from prospective customers. I don't have a list of customers' source/amp so I can't address your question directly. However, I will share  my perspective on this based on our experience with a fairly large customer base at this point.

Notwithstanding the various cautions regarding passive preamps vis-à-vis impedance matching and such, the practical reality is we've had less than a handful (< 5) instances of impedance (sufficient bridging ratio) being a problem. Take your amp's input impedance and divide it by your sources' output impedance. If you get say 20:1 or greater there's a 95+% chance you're good to go. You could have an even lower ratio and still not have a problem. A key variable and one that you can't predict is how robust your sources' output stage is. Again, the practical reality is most sources today have sufficiently robust output stages.

A couple of unambiguous cases where our preamp did not fit with a customer's system were where the customer had very low wattage (< 5 watt) tube amps running into less than super high efficiency speakers. These instances had nothing to do with impedance and everything to do with under-powered gear that needed more volume control headroom. They needed actual gain in their preamps to have sufficient listening volume. Had I known they had this type gear I would have waived them off.

We never hang anyone out to dry with our preamps. We have a generous 30 day in-home audition policy. You'll know if you have a problem and if so we refund 100% of the purchase price of returned units less your cost to ship it back.

Hope this helps. 

[jparkhur]

Lots of things to discuss, but I have little time.  Here is what has worked for me with the LDR pre from Tortuga.

ACA Nelson Pass Amp Camp Amps, 5 watts, current set up in my system with open baffle Tang Band 1808's works well for me. 
First Watt F6 was great, no issues
Declare 84 tube amp, not good.  More of a power issue I think.
F5 great amp and combination
ATI 1502, it was fine, but I think this amp is more for theater systems.  Sound was just ok, lacked clarity and depth
Fleawatt 3116 Chip amp was great.  No issues driving OB's, Klipsch 2.2's, Zu Cubes, DIY to good levels and good sound
Fleawatt 3116 mono's, good
DIY 1625 Mono Block tube amps 55 wpm, wonderful sound

[Paullb]

Thanks Tortuga Ranger and jparkur,

So matching technical wise isn't that difficult - good to know. So if LDRs pass the signal cleanly with little embellishment, neither making the sound sweeter nor leaner, then system matching is more a matter of personal taste rather than some combinations just sounding bad?

[ssglx]

I use either a single or dual Monarchy SM-70 Pro's and get terrific sound. My Tortuga is transparent and has sparkle, but is actually warm and full sounding, as opposed to other passives I've tried (TVC and volume pot).