[service_guy]

Hi all.
Going to make the move to a passive pre, and I am looking for some input.
What are you guys using, or have used?
Transformer based, or shunt type?
I am looking at two different ones................
http://www.akustyk.com/stereo_selector.html
or
http://www.promitheusaudio.com/tvc.htm
Just looking for some feedback before I make a purchase, hate buying a piece to find out it will not do the job for me.
Thanks.
Dave.

[paul79]

My experience with passive type preamps is good, but I found that the source needs allot of drive current, and the amp needs to be an easy load (high input impedance). Even in this scenario, the music could sound amazing at one point of the volume, and completely lifeless at another.

I would go for a TVC type but it must be very high quality to retain transparency. This way you will not have the impedance issues associated with passive pre's.

[glynnw]

Look within the AudioCircle.  See Tortuga Audio.  Best passive I have ever had.

[rikhav]

I was using promethius passive pre with my stratos extreme stereo for about 2 and a half years. It was sounding good. Decent frequency extension, decent stage.  Oohing much to complain about until I tried DIY pass b1 in my setup

There was lack of bass in sound which I always thought was the sound of the DIY transmission line bookshelf speakers. I actually did not feel the lack of bass as I listen more to vocals but few people told me so.

But after connecting b1 the resolution, the tone, bass and details improved immensely in comparison to what I was getting with the Prometheus passive pre in the chain

I have a standard edition Prometheus pre which is not at all bad but when I compare it to the pass b1 it just pales out in all departments

If you can manage to build one you will surely be very happy with the pairing of b1 and khartago

Also my b1 does not use any exotic parts as they are not so easily available in my country

[Randy]

I now use a TVC Prometheus balanced version. It's good. I auditioned the Tortuga which blew it away. It's simply a no-brainer as to which way to go. The Tortuga is outstanding. Check out the user reviews at this link:http://www.audiocircle.com/index.php?topic=119915.0

[RDavidson]

I've become a big fan of the "passive" preamp with output buffer design. I think the Pass B1 is such?
This scenario seems to be the best of both worlds. You get most of transparency of a true passive, but you don't have the electrical issues to deal with because the output buffer basically neutralizes mismatches.

I know there are other preamps of this type out there, but one that I know for sure is the Wyred 4 Sound STP SE. Additionally, it is the least expensive and most fully featured preamp of its type that I have come across. I'd put it against anything below the now rare Bent Audio Tap. I think Music First is one of the few brands licensed to use Bent modules now, and those are like $6000 for a Baby Reference I believe?

[RDavidson]

I now use a TVC Prometheus balanced version. It's good. I auditioned the Tortuga which blew it away. It's simply a no-brainer as to which way to go. The Tortuga is outstanding. Check out the user reviews at this link:http://www.audiocircle.com/index.php?topic=119915.0

I'd love to see Tortuga create a buffered output version. The type of passive circuitry they use is second to none and built to about the most exacting tolerances possible, but there's no getting around possible electrical (impedance) issues with any passive. If they offered a buffered version, it'd be more universal.....though perhaps not as absolutely transparent as their pure passive line. They should offer both, or a version where the output can be switched from buffered to pure passive.

[rikhav]

I've become a big fan of the "passive" preamp with output buffer design. I think the Pass B1 is such?
This scenario seems to be the best of both worlds. You get most of transparency of a true passive, but you don't have the electrical issues to deal with because the output buffer basically neutralizes mismatches.

Very true

Sure other TVC based passive pre could be better then promethius standard edition but the price I paid to build the b1 (approx USD 200), it surely performs something worth 10 to 15 times more

[RDavidson]

Very true

Sure other TVC based passive pre could be better then promethius standard edition but the price I paid to build the b1 (approx USD 200), it surely performs something worth 10 to 15 times more

I'm sure it does. Pass is the real deal.