Thrax Libra - A Statement Preamplifier and A Game Changer

dcc

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Yesterday, I had the visit of François from Ana Mighty Sound who came along with Rumen Artarski, the founder of Thrax Audio.

The purpose of their visit was to present me the new flagship preamplifier from Thrax.



Libra employs two 300B tubes per channel in true dual mono differential pure class A triode operation. Not only all inputs are adjustable but also Libra features two independent outputs that can be offset from each other to allow for bi-amplification with different amplifiers for mid/hi and bass. This is particularly interesting for me as I have a pair of Krell Evolution One and a Tenor Audio 175S in my system. I am swapping between both according to my mood or the type of music I am listening to.



Rumen is a tape aficionado and his preamp comprises another interesting feature: a fully balanced tape loop. This is important to me as I have two tape decks (a fully refurbished Studer A80 RC MK II and a Nagra IVS with the QGB extension module).

We first tested the Libra preamp with the Krell mono blocks only and then we switched to the Tenor Audio. In both cases, the improvements were substantial compared to my current Krell Evo 202 which is a little bit dry and analytical. The combination with Tenor Audio was pure audio bliss.

But the best was yet to come. After lunch, we bi-amped the system. Rumen adjusted the output gains (there is difference of 5.5 dB between the Tenor Audio and the Krell). What I heard was beyond my wildest dream: more space, more depth, more authority and ease with a sense of natural beauty. I had a real game changer in my listening room.



After a full day of listening a variety of LPs and tapes, I placed an order for a unit in black, which should be delivered within a month.

The Krell Evo 202 will move to my secondary system.

I want to thank François and Rumen for their visit and the wonderful discovery of this superlative product.
 
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Petou

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Congratulations !
 

ashandger

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Congrats. Would it be possible for you to share info on your full system? Looks like Peak Consult speakers, Brinkman Balance/SAT etc? Many thanks
 

Vienna

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Wonderful Denis! I am very happy for you !
 
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RdW

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Apr 8, 2018
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Yesterday, I had the visit of François from Ana Mighty Sound who came along with Rumen Artarski, the founder of Thrax Audio.

The purpose of their visit was to present me the new flagship preamplifier from Thrax.



Libra employs two 300B tubes per channel in true dual mono differential pure class A triode operation. Not only all inputs are adjustable but also Libra features two independent outputs that can be offset from each other to allow for bi-amplification with different amplifiers for mid/hi and bass. This is particularly interesting for me as I have a pair of Krell Evolution One and a Tenor Audio 175S in my system. I am swapping between both according to my mood or the type of music I am listening to.



Rumen is a tape aficionado and his preamp comprises another interesting feature: a fully balanced tape loop. This is important to me as I have two tape decks (a fully refurbished Studer A80 RC MK II and a Nagra IVS with the QGB extension module).

We first tested the Libra preamp with the Krell mono blocks only and then we switched to the Tenor Audio. In both cases, the improvements were substantial compared to my current Krell Evo 202 which is a little bit dry and analytical. The combination with Tenor Audio was pure audio bliss.

But the best was yet to come. After lunch, we bi-amped the system. Rumen adjusted the output gains (there is difference of 5.5 dB between the Tenor Audio and the Krell). What I heard was beyond my wildest dream: more space, more depth, more authority and ease with a sense of natural beauty. I had a real game changer in my listening room.



After a full day of listening a variety of LPs and tapes, I placed an order for a unit in black, which should be delivered within a month.

The Krell Evo 202 will move to my secondary system.

I want to thank François and Rumen for their visit and the wonderful discovery of this superlative product.

Congrats!!

Considering the Dionysos. Any thought?
 

dcc

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Nov 4, 2012
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Congrats!!

Considering the Dionysos. Any thought?
I never had the chance to listen to the Dionysos as due to the current Covid 19 circumstances I have not been able to visit François’ show room in Paris where he is using a Dionysos. During their visit at my place last Saturday, Rumen and François had a long conversation about the Dionysos and its features for avoiding ground loops.
 

RdW

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Apr 8, 2018
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I never had the chance to listen to the Dionysos as due to the current Covid 19 circumstances I have not been able to visit François’ show room in Paris where he is using a Dionysos. During their visit at my place last Saturday, Rumen and François had a long conversation about the Dionysos and its features for avoiding ground loops.
Interesting indeed. I had an conversation with a local dealer who compared the Dionysos V3 with preamps like Dan' D'agostino Progression and Soulution 325. This Dionysos might outperform the two competitors in terms of transparency and soundstage.

Any feedback views on on the ground loop ?
 
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Cala

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May 2, 2018
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anamightysound.com
Hi There, just sent you a PM.

The Dionysos is a wonderful preamp. Perfectly transparent and yet not boring. Very natural and spontaneous with one of the best soundstage I know (super low background noise). No ground loop issues with multiple ground array possible, two outputs either in symetrical or asymetrical....

As a professional user : it is just the perfect Swiss knife and allows us to play with multiple sources and exhibit the best of all of them.

In our Parisian showroom you can also compare it to the darTZeel NHB-18NS which is quite something too but way more expensive too ;) and of course the Thrax Libra 300B.
 

Hieukm

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Oct 2, 2016
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I am interested in the Libra as i have the Thrax 300b mono. How big of a step up the Libra compared to the Dyonisos?
 

Cala

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Significant. Everything is fine until you compare the Libra 300B to the Dionysos.
 
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RdW

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Apr 8, 2018
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Hi There, just sent you a PM.

The Dionysos is a wonderful preamp. Perfectly transparent and yet not boring. Very natural and spontaneous with one of the best soundstage I know (super low background noise). No ground loop issues with multiple ground array possible, two outputs either in symetrical or asymetrical....

As a professional user : it is just the perfect Swiss knife and allows us to play with multiple sources and exhibit the best of all of them.

In our Parisian showroom you can also compare it to the darTZeel NHB-18NS which is quite something too but way more expensive too ;) and of course the Thrax Libra 300B.
Hello François,

The Libra would indeed be an interesting choice and am looking forward to hear from fellow WBF members what experiences will be going forward. I might drop by one day in your showroom if I’m around.

Thank you for your PM. Appreciated.
 

ashandger

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Jun 15, 2013
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258
Hi There, just sent you a PM.

The Dionysos is a wonderful preamp. Perfectly transparent and yet not boring. Very natural and spontaneous with one of the best soundstage I know (super low background noise). No ground loop issues with multiple ground array possible, two outputs either in symetrical or asymetrical....

As a professional user : it is just the perfect Swiss knife and allows us to play with multiple sources and exhibit the best of all of them.

In our Parisian showroom you can also compare it to the darTZeel NHB-18NS which is quite something too but way more expensive too ;) and of course the Thrax Libra 300B.
Hello François,
it possible for you to share your thoughts on the most noticeable differences between the Dartzeel NHB-18NS and the Libra, especially in terms of transparency, bass definition and microdynamics? Many thanks
 

Cala

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May 2, 2018
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17
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Paris
anamightysound.com
Hi Ashandger,

Comparing Thrax and darTZeel electronics is quite a tough exercise. In our Parisian showroom we have customers who are pro darTZeel and others pro Thrax and it is always interesting to make them meet with one another as you see two sets of really different approaches to what can be musical reproduction. Clearly darTZeel is most of the time more spectacular, more demonstrative than Thrax. Thrax offers another display of music reproduction being more relaxed and less in your face, more natural.

In the end there is a singular point of junction in between those two tribes when you combine the darTZeel CTH-8550 mk2 or LHC-208 with Thrax Lyra or Lyra SE speakers. This combination is absolutely amazing and some of my customers in small (Parisian) environments have even pushed the experience by using NHB-18NS preamp with NHB-108 model two stereo amp....

But getting back to the topic : the NHB-18NS is a preamp that can also can contain two excellent phonostages. It is also designed to work with 50 ohm Zeel outputs that are the ideal outputs for .... darTZeel power amps. From a personal point of view : I prefer the Dionysos as a preamp to the NHB-18NS as it sounds more natural, with more bandwidth, more liquid sound and a better soundstage when not used with darTZeel amps. I must precise that I also use mostly symmetrical outputs and this "symmetrical output thing" is something Hervé Delétraz is not really fond of. The Zeel way is indeed the darTZeel way and it is hard to do outperform the NHB-18NS in combination with a darTZeel power amp.

Thrax Libra 300B is something else than both the Thrax Dionysos and darTZeel NHB-18NS. It is better to have a true symmetrical input on your power amp in order for it to work to its best potential, especially in passive bi-amplification. There is indeed some kind of limitation here but if you have an amp with a true symmetrical input than you are in for a ride (and yes it works super well on the darTZeel amps too). The Libra 300B has the all the DHT triode flavors but with none of the usual negative things about It (microphonic issues, background noise, bandwidth issues, etc...).

I do not want to say too much about what I feel about this preamplifier as I do believe that the best way to know what it does is to listen to It and that is exactly how I proceeded with Denis. For instance I made him listened to the Thrax Libra 300B and after that I sent him the French review about it that was just published about it in Haute-Fidélité. If I do recall well, Denis told me that the reviewer had written exactly what he had experienced and told me while our listening session.
 
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ashandger

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Jun 15, 2013
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Hi Ashandger,

Comparing Thrax and darTZeel electronics is quite a tuff exercise. In our Parisian showroom we have customers which are pro darTZeel and others pro Thrax and it is always interesting to make them meet with one another as you see two really different approach to what can be musical reproduction. Clearly darTZeel is most of the time more spectacular, more demonstrative than Thrax. Thrax offers another display of music reproduction being more relaxed and less in your face, more natural.

In the end there is a singular point of junction in between those two tribes when you combine the darTZeel CTH-8550 mk2 or LHC-208 with Thrax Lyra or Lyra SE speakers. This combination is absolutely amazing and some of my customers in small (Parisian) environments have even pushed the experience by using NHB-18NS preamp with NHB-108 model two stereo amp....

But getting back to the topic : the NHB-18NS is a preamp that can also can contain two excellent phonostages. It is also designed to work with 50 ohm Zeel outputs that are the ideal outputs for .... darTZeel power amps. From a personal point of view : I prefer the Dionysos as a preamp to the NHB-18NS as it sounds more natural, with more bandwidth, more liquid sound and a better soundstage when not used with darTZeel amps. I must precise that I also use mostly symmetrical outputs and this "symmetrical output thing" is something Hervé Delétraz is not really fond of. The Zeel way is indeed the darTZeel way and it is hard to do outperform the NHB-18NS in combination with a darTZeel amp.

Thrax Libra 300B is something else than both the Thrax Dionysos and darTZeel NHB-18NS but it does not like any asymmetrical power amplifiers. You need a true symmetrical input in order for it to work to its best potential. There is indeed some kind of limitation here but if you have an amp with a true symmetrical input than you are in for a ride (and yes it works super well on the darTZeel amps too). The Libra 300B as the DHT triode sound but with none of the usual negative things about It (microphonic issues, background noise, bandwidth issues, etc...).

I do not want to say too much about what I feel about this preamplifier as I do believe that the best way to know what it does is to listen to It and that is exactly how I proceeded with Denis. For instance I made him listened to the Thrax Libra 300B and after that I sent him the French review about it that was just published about it in Haute-Fidélité. If I do recall well, Denis told me that the reviewer had written exactly what he had experienced and told me while our listening session.

Hello François, I really appreciate you taking the time to provide such detailed and helpful feedback. I am sure the Libra will sound incredible when used with the Spartacus 300B power amp just as the Dart pre sounds amazing when used with the Dart 108 or the 468 power amps. Thanks again for the feedback.
 

Cala

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May 2, 2018
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That is exactly my point : if you want the full darTZeel experience than stick to the a complete darTZeel line. It is a very unique and astonishing performance.
 

dcc

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Nov 4, 2012
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I do not want to say too much about what I feel about this preamplifier as I do believe that the best way to know what it does is to listen to It and that is exactly how I proceeded with Denis. For instance I made him listened to the Thrax Libra 300B and after that I sent him the French review about it that was just published about it in Haute-Fidélité. If I do recall well, Denis told me that the reviewer had written exactly what he had experienced and told me while our listening session.

I confirm the approach adopted by François. I had been looking at replacing my Krell preamp for a while but all the preamps I had the chance to listen to or that I had on my list for consideration did not offer all the functionalities I was looking to: fully balanced design, balanced tape loop, input and output gains individually adjustable , volume control with steps of 0;5 dB.

I actually never told François about this project. He called me several weeks ago asking me whether he could come to my place. He explained me that he had a preamp that could allow to passively bi-amp my system by using both the Krell Evolution One mono blocks and the Tenor Audio 175S. He told me that he had just made a test of passive bi-amplification that had blown him away and be believed that he could replicate the same experience in my system. I was not aware that the test was actually the review that was about to be published in Haute-Fidelité. I am not a subscriber anyway.

Basically I could have the best of both worlds: the iron fist of the Krell as well as the smooth and silky but still authoritative feel of the Tenor. Don’t get me wrong. Both amps are strong performers but they have their own idiosyncrasies.

I told him that indeed I would be interested. I informed him that I had been considering a new preamp but I had very high expectations and so far none of the preamps I had listened to had made the cut.

In short, I was seriously shaken by the test in my system. I just need to be patient before the unit I ordered gets delivered.
 

gian60

Well-Known Member
Apr 17, 2016
2,182
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Hi Ashandger,

Comparing Thrax and darTZeel electronics is quite a tough exercise. In our Parisian showroom we have customers who are pro darTZeel and others pro Thrax and it is always interesting to make them meet with one another as you see two sets of really different approaches to what can be musical reproduction. Clearly darTZeel is most of the time more spectacular, more demonstrative than Thrax. Thrax offers another display of music reproduction being more relaxed and less in your face, more natural.

In the end there is a singular point of junction in between those two tribes when you combine the darTZeel CTH-8550 mk2 or LHC-208 with Thrax Lyra or Lyra SE speakers. This combination is absolutely amazing and some of my customers in small (Parisian) environments have even pushed the experience by using NHB-18NS preamp with NHB-108 model two stereo amp....

But getting back to the topic : the NHB-18NS is a preamp that can also can contain two excellent phonostages. It is also designed to work with 50 ohm Zeel outputs that are the ideal outputs for .... darTZeel power amps. From a personal point of view : I prefer the Dionysos as a preamp to the NHB-18NS as it sounds more natural, with more bandwidth, more liquid sound and a better soundstage when not used with darTZeel amps. I must precise that I also use mostly symmetrical outputs and this "symmetrical output thing" is something Hervé Delétraz is not really fond of. The Zeel way is indeed the darTZeel way and it is hard to do outperform the NHB-18NS in combination with a darTZeel power amp.

Thrax Libra 300B is something else than both the Thrax Dionysos and darTZeel NHB-18NS. It is better to have a true symmetrical input on your power amp in order for it to work to its best potential, especially in passive bi-amplification. There is indeed some kind of limitation here but if you have an amp with a true symmetrical input than you are in for a ride (and yes it works super well on the darTZeel amps too). The Libra 300B has the all the DHT triode flavors but with none of the usual negative things about It (microphonic issues, background noise, bandwidth issues, etc...).

I do not want to say too much about what I feel about this preamplifier as I do believe that the best way to know what it does is to listen to It and that is exactly how I proceeded with Denis. For instance I made him listened to the Thrax Libra 300B and after that I sent him the French review about it that was just published about it in Haute-Fidélité. If I do recall well, Denis told me that the reviewer had written exactly what he had experienced and told me while our listening session.
I have Lyra in my second system and is the best stand speaker I listen in my life and I am very happy,but what is Lyra SE?
Thanks
 

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