[RDavidson]

I've had a few very transparent preamps along the way. The one I owned for the longest time (so far) was the Wyred 4 Sound STP-SE. I also had a Bent Audio AVC-1. My current preamp, and the best performing (most transparent / most resolving) of them all, can be seen in this thread. It's the silver one. I designed the case. Dave at ZenWave built it. http://www.audiocircle.com/index.php?topic=138965.0

[mrvco]

I've had a few very transparent preamps along the way. The one I owned for the longest time (so far) was the Wyred 4 Sound STP-SE. I also had a Bent Audio AVC-1. My current preamp, and the best performing (most transparent / most resolving) of them all, can be seen in this thread. It's the silver one. I designed the case. Dave at ZenWave built it. http://www.audiocircle.com/index.php?topic=138965.0

Wow, that looks awesome.  Tortuga's preamps are definitely on my shortlist, but that takes their LDRs to a whole new level.  I was under the (obviously mistaken) impression that the F7 needed a solid state pre.  I picked up a lightly used W4S Mpre so I can go ahead and sell my current integrated.

[RDavidson]

Wow, that looks awesome.  Tortuga's preamps are definitely on my shortlist, but that takes their LDRs to a whole new level.  I was under the (obviously mistaken) impression that the F7 needed a solid state pre.  I picked up a lightly used W4S Mpre so I can go ahead and sell my current integrated.

The Mpre is a nice unit and quite versatile. I'm a fan of Wyred gear. Well built. No nonsense. Very high bang for the buck. Their customer service is also great. The F7 has a somewhat low input impedance of 10k ohms and gain is 14db at 2.5V. Shouldn't be an issue for most modern preamps. My "Mutant Ninja Tortuga" has a pretty low output impedance (Can't remember the spec, but it is low enough that it shouldn't present an impedance matching problem) though output voltage is only about 1.5V. Note, the tube output stage is a buffer, which is meant to prevent impedance mismatches anyway. I don't have enough output voltage to reach full output of the F7, BUT the caveat is that I have Omegas. They're super easy to drive and have high sensitivity. Unless I want to blow my eardrums, 1.5V is PLENTY.

[doggie]

The Mpre is a nice unit and quite versatile. I'm a fan of Wyred gear. Well built. No nonsense. Very high bang for the buck. Their customer service is also great. The F7 has a somewhat low input impedance of 10k ohms and gain is 14db at 2.5V. Shouldn't be an issue for most modern preamps. My "Mutant Ninja Tortuga" has a pretty low output impedance (I    ,             ) though output voltage is only about 1.5V. I don't have enough output voltage to reach full output of the F7, BUT the caveat is that I have Omegas. They're super easy to drive and have high sensitivity. Unless I want to blow my eardrums, 1.5V is PLENTY.

I am using a Tortuga Audio LDR volume control unit ahead of my tube preamp to give me remote control. It is a great unit with a lot of features. My preamp uses 301A(01A) directly heated triodes with Coleman regulators for the heaters and Lundahl OPT's. It only has 3db of gain which is what I wanted due to my DACs high output. Works very well into my SIT2 amp which is driving my Omega Super Alnico High Output speakers. My SIT2 has a choice of 100K or 10K inputs. The 100K inputs add input buffer circuitry but they sound much better to me.

[RDavidson]

I am using a Tortuga Audio LDR volume control unit ahead of my tube preamp to give me remote control. It is a great unit with a lot of features. My preamp uses 301A(01A) directly heated triodes with Coleman regulators for the heaters and Lundahl OPT's. It only has 3db of gain which is what I wanted due to my DACs high output. Works very well into my SIT2 amp which is driving my Omega Super Alnico High Output speakers. My SIT2 has a choice of 100K or 10K inputs. The 100K inputs add input buffer circuitry but they sound much better to me.

You might try the Tortuga after your tube preamp. Turn your tube pre's attenuator all the way open. Use the Tortuga's impedance adjustment settings and set the SIT at it's purer 10k ohm input setting. In my mind, simpler is better and I think Nelson recommends the 10k setting (if possible). Might be worthwhile. Wouldn't cost you anything but time and a little bit of trial and error (with the Tortuga's settings).

[doggie]

You might try the Tortuga after your tube preamp. Turn your tube pre's attenuator all the way open. Use the Tortuga's impedance adjustment settings and set the SIT at it's purer 10k ohm input setting. In my mind, simpler is better and I think Nelson recommends the 10k setting (if possible). Might be worthwhile. Wouldn't cost you anything but time and a little bit of trial and error (with the Tortuga's settings).

Good idea.

Now why didn't I think of that?

[RDavidson]

Good idea.

Now why didn't I think of that?

It might not work out better for you / your system, but experimenting is a big part of the fun in this hobby (for me anyway). If I don't like the result of an experiment, no big deal. At least I learned something. Omegas are very revealing, as you know, which can make even subtle changes more profound.

[mrvco]

Great to hear your experiences with the Tortuga.  I can probably wait for the V3 update, but it's hard not seeing one in my future.  What are your thoughts on unbalanced versus balanced inputs on the J2 and SIT-2?  My DAC doesn't have a balanced output, but the mPRE and J2 have them.  I'll probably buy a set of balanced interconnects, but wasn't if it was worth spending any real money on them.

And my J2 has been delivered!

[RDavidson]

It doesn't make sense to go with balanced cables unless your system is balanced throughout. There's really no benefit to doing so, unless you need the added gain from preamp to amp. The benefit of balanced connection in home audio is debatable in general....but experiment for yourself.

[doggie]

Great to hear your experiences with the Tortuga.  I can probably wait for the V3 update, but it's hard not seeing one in my future.  What are your thoughts on unbalanced versus balanced inputs on the J2 and SIT-2?  My DAC doesn't have a balanced output, but the mPRE and J2 have them.  I'll probably buy a set of balanced interconnects, but wasn't if it was worth spending any real money on them.

And my J2 has been delivered!

The SIT2 does not have balanced inputs as the J2 did but I built a cable to go from the balanced outputs on my Schiit Ygdrasil to my SIT2's SE inputs. I had heard that the balanced outputs were better than the SE outputs even when just using one leg. It seems to be true

[mrvco]

This is nice.  My deepOmega8 is far less necessary with this amp.  It really gets the RS7s moving.  Looking forward to some uninterrupted listening.

I am going to need an easier way to turn it off.  The power switch in the middle of the back is not ideal, even in my open rack.

[doggie]

I received my new Super Alnico High Outputs last week and sold my old Super 6's yesterday.

I hope to offer a mini-review soon as it seems that there are few of these out in the wild.

[mrvco]

Congratulations, I'm looking forward to hearing about the SAHOs.

[doggie]

Congratulations, I'm looking forward to hearing about the SAHOs.

I have lived with these for a few weeks now and feel very comfortable about recommending them.

Two things to note. I bought these used from another member here. They were originally crossed over at 500hz. Although I liked them I felt that they lost a bit of the Alnico clarity. I asked Louis about this and he said that his original design cut off the lower driver at 200hz. He decided to send me a new pair of inductors and I installed then. I also rewired them with Duelund DGA16 wire which I heard about from Jeff Day's audio blog.

It took a bit for it all to break in but now they sound much better than my previous Super 6 Alnicos. They have a broad, deep soundstage with excellent imaging and tonal accuracy. They also have a more dynamic and fuller sound.

Based upon feedback Louis has decided to sell this model with the lower driver cut off at 200hz.