[Folsom]

+1    sold my TVC immediately after hearing the Tortuga

That's awfully bold. I'm not convinced the TVC isn't better, but that doesn't mean it's the preference. The Tortuga uses devices that have a dab of capacitance. I think they sound great when I've used them as resistor replacements.

Anand, that's a bit sad, because relays introduce their own thing, too. I'm not saying they can't be good, but it doesn't come too easy. The Tisbury uses my favorite little attenuator from China, found on eBay. For the price they just don't have competition until you're well over $100 for just the attenuator piece. They are not perfect, but you can't beat them until you really start to spend some $.

[doak]

+1    sold my TVC immediately after hearing the Tortuga

Bought and tried to like a Tortuga a few years back.
REALLY disliked it. Sounded dead, dead, dead.
It's STILL basically a resistive device and I haven't heard any resistive attenuation devices that do not negatively affect dynamics.
Jumped back to magnetic control devices - AVC/TVC - and continue to be totally satisfied with the sound I get from them.
Heartily recommend the DIYHiFi Django series - many, many options to get EXACTLY what you want.
http://www.store.diyhifisupply.com/Django-TVC-Preamp

[Folsom]

doak, that may depend greatly on impedance matching. The TVC has no problems with impedance matching unless the output is much too high from the source.

[poseidonsvoice]

Well, I have both. My Lazarus as you all know uses (4) of Dave Slagle's excellent autoformers (the same as in the TAPX). I also have a balanced Tortuga kit here that I plan on implementing in a differential tube preamp design, just for kicks. Both Morten Sissener and John Chapman are wonderful gentlemen. Aum Acoustics is an implementation of Tortuga's LDR and looks sweet: http://aumacoustics.com/aum-acoustics-ldr-preamplifier/

All in good fun in the diy world...

Best,
Anand.