Stellavox Introduces a New State of the Art Amplifier IDEM Monoblocks

[Mike Lavigne]

Namaste! I tip my hat to you, sir.

I have felt that there is a concerted effort to promote certain brands on WBF. With that said, I also believe that most people who have posted on these products speak truthfully of their experience. That they did not work for you doesn't say to me that these amps aren't great. It reinforces (to me) that many of the outspoken audiophiles here speak genuinely of their experience (despite any promotional advantages that hang in the balance).

Thank you for your comments. In addition to being a leader in the community you are also a great educator.

thank you Pat, for the kind words.

 

[microstrip]

(...) current USA retail pricing of the 468's is not clear; so i use $225k in my mind. just as a reference number. and i've seen $240k too. could be currency fluctuations. the $225k number is where i get the 50% more than the $149k of the IDEM's. just trying to avoid hyperbole for effect. in any case 468's retail is not $300K USD.

Thanks for correcting me - my net sources had pointed me to 265k for the NH 468 and around 135 for the IDEM. I must say I deeply dislike the practice of “by request only” pricing and the omission of prices when reviewing or commenting gear - for most of us choice is also an affair of value for money. IMO the RRP should be public and easily accessible.

 

[Mike Lavigne]

Thanks for correcting me - my net sources had pointed me to 265k for the NH 468 and around 135 for the IDEM. I must say I deeply dislike the practice of “by request only” pricing and the omission of prices when reviewing or commenting gear - for most of us choice is also an affair of value for money. IMO the RRP should be public and easily accessible.

totally agree. i do see that in Europe or the UK posting prices including VAT is more common, than the USA.

in 2022 Absolute Sound on a recognition award page listed the 468's at $235,000. on this thread Gideon was clear about the USA price for the IDEM's at $149,995. and darTZeel's low profile lately leads to less clarity too.

on this topic of price, thinking further about my earlier mention of the Berning 211/845 mono blocks as a reference for the sound of the IDEM's, and that i viewed that OTL as similar to the darts other than in power, i realized that i had the earlier 458's back then. which was a less expensive amplifier than the 468's. that would be an interesting compare, the IDEM's to the very awesome sounding 458's. the 468's are a different beast.

 

[exupgh12]

Thank you for the thorough and honest review, @Mike Lavigne. It's valuable feedback highlighting the IDEM's qualities versus the DarTZeel amplifiers you currently own.
Indeed, it might be, as you write, that if you had other speakers, your preference might have been different.

 

[Ron Resnick]

Dear Mike,

Thank you for taking us on this comparative audition journey with you! It was very fun!

Anyone who knows you well would know that under no circumstances would you ever put into your system a new component that was not at least on the same indifference curve as the incumbent component.

 

[microstrip]

(...) on the same indifference curve as the incumbent component.

What are the two variables you are considering in such reasoning?

 

[Mike Lavigne]

Dear Mike,

Thank you for taking us on this comparative audition journey with you! It was very fun!

Anyone who knows you well would know that under no circumstances would you ever put into your system a new component that was not at least on the same indifference curve as the incumbent component.

this ain't economics. it's levels of art and not broken down so cold heartedly.

but generally i do get your drift.

 

[vinyl_mike]

first off, thank you to Gideon for the opportunity to spend time listening to the Stellavox IDEM amplifiers. he sent these beauties to me to get my thoughts and feedback, not necessarily as a shootout. I cannot help myself as my own way is to consider gear for keeping. the idea of new amps is exciting. so i seriously did that. the dart 468's being 50% more costly, ought to be a great barometer for these new amps.

With that said, and after an incredible 11 day demo and 250 hours. in my system to my ears with my music i prefer my darTZeel 468 mono blocks. a longer time period might have changed things incrementally but IMHO not the result. i have spent lots of time on this and (somewhat reluctantly) time to move on.

all the positives represented by Gideon, Mike Malinowski and Myles Astor about the IDEM amplifiers are objectively true as far as i could determine. it certainly has a special purity and unprocessed character unique in solid state amplifiers (i have heard) outside my darts and does have an SET like feel. it's liquid, agile and with beauty of tone (NEVER sterile!) while likely the bass is not all the way in at 250+ hours, the bass was very good (and true to life) while adjustable based on the gain setting which adds a great deal of flexibility for system matching. it's dynamic, fast and soundstages wonderfully, incredibly organic and nuanced. and as it breaks in all those attributes likely will continue to incrementally improve. build quality is superb and it's logistically an easy amp to like. i love the look.

in my first compare a week ago the IDEM's were not anywhere near where they were yesterday when my local friend @jazdoc arrived for our 2nd head to head. yesterday morning first with the IDEM's we did an hour of digital, then another hour of vinyl; switched the amps to the darts, then 30 minutes of digital and 30 minutes of vinyl. Break in for the IDEM yielded night/day differences.

the previous week i was using the 22db gain setting, and it had 75 hours on it, and it was not ready. @2fastdriving's comments last week were on point. while it showed signs of nice things to come, it was not the amp we heard yesterday at the 18db gain setting fully singing. i already described the results of the gain setting process here and here and won't repeat it.

i think @jazdoc might add more comments, so i am just speaking for myself as far as how the darTZeel 468's were preferred; the darts were more present and real, it was not mainly to do with tonality, more a matter of organic rightness and completeness. more information. the bass was more controlled and defined. both amps were natural and balanced.

keep in mind things we do not know. how is the match with my speakers verses Zellatons? do my MM7 ceramic drivers favor the darts? i have powered bass towers below 40hz; might the Stellavox distinguished itself more with full range speakers? what effect would the new coming Stellavox preamp have with it's DC adjustment synergy and ability to use the ideal 14db gain setting? more break-in? maybe even the 20 amp IEC to 15 amp IEC adapter? cases can be made.

i think we have lots of feedback on how many great amps have been documented in compares to the big dart 468's by Fremer and Heilbrunn. and those guys continue to use their 468's. it's as much of a gold standard as can be in such a subjective arena as high end audio. i view the Stellavox as a stone cold bargain of a high level solid state amplifier especially if you value the purity and unprocessed side of things. it has zero niggles. i could live with this amp forever if i did not already own my 50% higher cost darts.

Gideon has been a joy to interact with and he allowed me to enjoy them in my own way with my own journey. I really look forward to exploring further Stellavox products as they become available (especially the pre and dac!), and even with the hope to hear them in the future with Zellaton.

My audio journey continues.....

First, you did an outstanding job meticulously analyzing and parsing the differences between two SOTA contenders. Your summary is clear, concise, and well thought out. Absolutely fantastic.

I do have a question. You touched on the bass response and delineation between the two amps. As you indicated, overall, the Stellavox is very resolving, and you noted a significant improvement with a small with small changes to the Input gain. Additionally, one of the strengths of Stellavox is their resolution and definition in the deepest bass. I never owned a speaker with a self-powered woofer. It is my understanding (and correct me if I am wrong) that the amps driving your woofers are fed by your primary amplifier either darTZeel or Stellavox - not your preamp. Finally, to the question. How do you account for the bass in your system when it is being changed to some degree via its internal amp since every electronic device imparts its own signature? Stated another way, how are you able to determine the true bass characteristics of either the darTZeel or another amp?

 

[Mike Lavigne]

First, you did an outstanding job meticulously analyzing and parsing the differences between two SOTA contenders. Your summary is clear, concise, and well thought out. Absolutely fantastic.

thanks Mike.

I do have a question. You touched on the bass response and delineation between the two amps. As you indicated, overall, the Stellavox is very resolving, and you noted a significant improvement with a small with small changes to the Input gain. Additionally, one of the strengths of Stellavox is their resolution and definition in the deepest bass.

true. as i said i enjoyed the bass on the Stellavox. and noted at 250 hours my expectation is that there was more to come with more break-in.

I never owned a speaker with a self-powered woofer. It is my understanding (and correct me if I am wrong) that the amps driving your woofers are fed by your primary amplifier either darTZeel or Stellavox - not your preamp.

correct. but it's not so simple. the main passive towers descend to the upper 20hz range, and then the active bass towers can get as high as 50hz. there is a crossover range. i have the bass towers coming in at 37hz. the passive main towers have a considerable amount of bass by them selves, with -4- 11" ceramic matrix mid-woofers which cover from 25hz-250hz. these do the heavy lifting for the bass. lots of driver surface. minimal excursion. 97db, 6 ohm.

then the active bass towers use -4- class D 1000 watt amplifiers and get their signal from the passive tower speaker terminal. so the main amplifier character is passed on to the very neutral class d amps to have an 'of-a-piece' coherent overall bass integration. the character of the bass seems to be properly respected in my experience.

Finally, to the question. How do you account for the bass in your system when it is being changed to some degree via its internal amp since every electronic device imparts its own signature?

since i've had the MM7's i've had multiple different main amplifiers in my system and each one seemed to retain their own distinct bass character, particularly the Lamm ML3's, VAC Signature 450's and Berning 211/845's. each one were coherent in the bass. only the deepest bass below 37hz is powered by the bass towers. it's also possible that those amps were less stressed by not doing the lowest octave and performed better than typical too. that is one advantage of active bass, it opens up more amplifier possibilities while still plumbing the depths of the music.

it's also possible that with the Stellavox if i played around with the bass tower adjustments that some further bass performance could be found. it's possible. my viewpoint is that those adjustments are 'room adjustments' not amplifier relevant. and so far my experience has reinforced that.

Stated another way, how are you able to determine the true bass characteristics of either the darTZeel or another amp?

it's an open question, which i noted.

>>>>>keep in mind things we do not know. how is the match with my speakers verses Zellatons? do my MM7 ceramic drivers favor the darts? i have powered bass towers below 40hz; might the Stellavox distinguished itself more with full range speakers? what effect would the new coming Stellavox preamp have with it's DC adjustment synergy and ability to use the ideal 14db gain setting? more break-in? maybe even the 20 amp IEC to 15 amp IEC adapter? cases can be made.<<<<<

and we have no answers. does my system give advantage to the dart 468's? we do know that in other systems the 468 seems to do a fine job in the bass, and in your system, and mine, so does the Stellavox. both these amps have excellent bass performance objectively.

Fremer does not use subwoofers in his system with the 468's, Heilbrunn has generally run subwoofers with his 468's. one friend of mine with 468's does run subwoofers.

i can only judge the end result in my particular system. the result in your system with the beautiful big Zellaton's might be different.

 

[vinyl_mike]

thanks Mike.

true. as i said i enjoyed the bass on the Stellavox. and noted at 250 hours my expectation is that there was more to come with more break-in.

correct. but it's not so simple. the main passive towers descend to the upper 20hz range, and then the active bass towers can get as high as 50hz. there is a crossover range. i have the bass towers coming in at 37hz. the passive main towers have a considerable amount of bass by them selves, with -4- 11" ceramic matrix mid-woofers which cover from 25hz-250hz. these do the heavy lifting for the bass. lots of driver surface. minimal excursion. 97db, 6 ohm.

then the active bass towers use -4- class D 1000 watt amplifiers and get their signal from the passive tower speaker terminal. so the main amplifier character is passed on to the very neutral class d amps to have an 'of-a-piece' coherent overall bass integration. the character of the bass seems to be properly respected in my experience.

since i've had the MM7's i've had multiple different main amplifiers in my system and each one seemed to retain their own distinct bass character, particularly the Lamm ML3's, VAC Signature 450's and Berning 211/845's. each one were coherent in the bass. only the deepest bass below 37hz is powered by the bass towers. it's also possible that those amps were less stressed by not doing the lowest octave and performed better than typical too. that is one advantage of active bass, it opens up more amplifier possibilities while still plumbing the depths of the music.

it's also possible that with the Stellavox if i played around with the bass tower adjustments that some further bass performance could be found. it's possible. my viewpoint is that those adjustments are 'room adjustments' not amplifier relevant. and so far my experience has reinforced that.

it's an open question, which i noted.

>>>>>keep in mind things we do not know. how is the match with my speakers verses Zellatons? do my MM7 ceramic drivers favor the darts? i have powered bass towers below 40hz; might the Stellavox distinguished itself more with full range speakers? what effect would the new coming Stellavox preamp have with it's DC adjustment synergy and ability to use the ideal 14db gain setting? more break-in? maybe even the 20 amp IEC to 15 amp IEC adapter? cases can be made.<<<<<

and we have no answers. does my system give advantage to the dart 468's? we do know that in other systems the 468 seems to do a fine job in the bass, and in your system, and mine, so does the Stellavox. both these amps have excellent bass performance objectively.

Fremer does not use subwoofers in his system with the 468's, Heilbrunn has generally run subwoofers with his 468's. one friend of mine with 468's does run subwoofers.

i can only judge the end result in my particular system. the result in your system with the beautiful big Zellaton's might be different.

Things are always more complex than they appear on the surface. Once again, great response!

 

[jazdoc]

first off, thank you to Gideon for the opportunity to spend time listening to the Stellavox IDEM amplifiers. he sent these beauties to me to get my thoughts and feedback, not necessarily as a shootout. I cannot help myself as my own way is to consider gear for keeping. the idea of new amps is exciting. so i seriously did that. the dart 468's being 50% more costly, ought to be a great barometer for these new amps.

With that said, and after an incredible 11 day demo and 250 hours. in my system to my ears with my music i prefer my darTZeel 468 mono blocks. a longer time period might have changed things incrementally but IMHO not the result. i have spent lots of time on this and (somewhat reluctantly) time to move on.

all the positives represented by Gideon, Mike Malinowski and Myles Astor about the IDEM amplifiers are objectively true as far as i could determine. it certainly has a special purity and unprocessed character unique in solid state amplifiers (i have heard) outside my darts and does have an SET like feel. it's liquid, agile and with beauty of tone (NEVER sterile!) while likely the bass is not all the way in at 250+ hours, the bass was very good (and true to life) while adjustable based on the gain setting which adds a great deal of flexibility for system matching. it's dynamic, fast and soundstages wonderfully, incredibly organic and nuanced. and as it breaks in all those attributes likely will continue to incrementally improve. build quality is superb and it's logistically an easy amp to like. i love the look.

in my first compare a week ago the IDEM's were not anywhere near where they were yesterday when my local friend @jazdoc arrived for our 2nd head to head. yesterday morning first with the IDEM's we did an hour of digital, then another hour of vinyl; switched the amps to the darts, then 30 minutes of digital and 30 minutes of vinyl. Break in for the IDEM yielded night/day differences.

the previous week i was using the 22db gain setting, and it had 75 hours on it, and it was not ready. @2fastdriving's comments last week were on point. while it showed signs of nice things to come, it was not the amp we heard yesterday at the 18db gain setting fully singing. i already described the results of the gain setting process here and here and won't repeat it.

i think @jazdoc might add more comments, so i am just speaking for myself as far as how the darTZeel 468's were preferred; the darts were more present and real, it was not mainly to do with tonality, more a matter of organic rightness and completeness. more information. the bass was more controlled and defined. both amps were natural and balanced.

keep in mind things we do not know. how is the match with my speakers verses Zellatons? do my MM7 ceramic drivers favor the darts? i have powered bass towers below 40hz; might the Stellavox distinguished itself more with full range speakers? what effect would the new coming Stellavox preamp have with it's DC adjustment synergy and ability to use the ideal 14db gain setting? more break-in? maybe even the 20 amp IEC to 15 amp IEC adapter? cases can be made.

i think we have lots of feedback on how many great amps have been documented in compares to the big dart 468's by Fremer and Heilbrunn. and those guys continue to use their 468's. it's as much of a gold standard as can be in such a subjective arena as high end audio. i view the Stellavox as a stone cold bargain of a high level solid state amplifier especially if you value the purity and unprocessed side of things. it has zero niggles. i could live with this amp forever if i did not already own my 50% higher cost darts.

Gideon has been a joy to interact with and he allowed me to enjoy them in my own way with my own journey. I really look forward to exploring further Stellavox products as they become available (especially the pre and dac!), and even with the hope to hear them in the future with Zellaton.

My audio journey continues.....

That was a fun experience! Mike's post summarized my impressions perfectly....

 

[vinyl_mike]

Other amplifiers had such feature since decades - e.g. Krell amplifiers. DC entering a DC coupled amplifier is not a 2025 problem. The question only shows to me because it seems Stellavox is not allowing the DC mode for a peamplfier that seems certified to have zero DC at the output. BTW, IMO technical questions deserve technical answers ...

Based on my own curiosity and forum questions that have been raised, I contacted Stephan at Stellavox - Head of R&D and designer of the IDEM, to obtain a technical explanation regarding the AC/DC switch when used with my 727 preamplifier. Stephan subsequently reached out to Cyrill Hammer at Soulution for additional confirmation.

The consolidated findings from several discussions are as follows:

• The Soulution 727 employs no capacitors in the signal path at its outputs. Instead, it uses DC servos to maintain output DC at ground potential (i.e., zero volts).

• Stellavox also uses servo control, but their reference point is a –8 V coupling (Not 0 V). Therefore their DC coupling is not compatible with the 727. The rationale, according to Stephan, is straightforward:-8V delivers the best sonic performance, and that is all that matters.

• Practically speaking, the AC/DC switch on the IDEM should not be over-interpreted. One position is intended for all standard commercial source equipment, while the other is a proprietary Stellavox configuration.

• This is conceptually similar to the darTZeel “Zeel” interface. Hervé Delétraz engineered a proprietary impedance-matched connection between his components and optimized his designs around that interface. I evaluated the darTZeel preamp, Zeel connection, and amplifier over several months, and the sonic advantages were clear. It was widely praised. Functionally, it was implemented via a simple switch, no different from the IDEM.

Given the liquidity, coherence, and full-range resolution I am hearing in the AC setting today, I can’t wait to hear the upcoming Stellavox preamplifier paired with the amplifiers with DC coupling. Based on my current experience, the results should be exceptional.

If anyone has additional technical questions, reach out to Stephan Schertler at Stellavox, he was very responsive. schertler@stellavox.swiss

 

[microstrip]

Based on my own curiosity and forum questions that have been raised, I contacted Stephan at Stellavox - Head of R&D and designer of the IDEM, to obtain a technical explanation regarding the AC/DC switch when used with my 727 preamplifier. Stephan subsequently reached out to Cyrill Hammer at Soulution for additional confirmation.

The consolidated findings from several discussions are as follows:

• The Soulution 727 employs no capacitors in the signal path at its outputs. Instead, it uses DC servos to maintain output DC at ground potential (i.e., zero volts).

• Stellavox also uses servo control, but their reference point is a –8 V coupling (Not 0 V). Therefore their DC coupling is not compatible with the 727. The rationale, according to Stephan, is straightforward:-8V delivers the best sonic performance, and that is all that matters.

• Practically speaking, the AC/DC switch on the IDEM should not be over-interpreted. One position is intended for all standard commercial source equipment, while the other is a proprietary Stellavox configuration.

Thank for the detailed answer - we can now see the DC mode is biased at -8V. As you say It is a proprietary custom mode, not standard and IMO should be labeled accordingly. Did Stephan tell you what would happen if users used the DC mode inadequately? Fried woofers?

• This is conceptually similar to the darTZeel “Zeel” interface. Hervé Delétraz engineered a proprietary impedance-matched connection between his components and optimized his designs around that interface. I evaluated the darTZeel preamp, Zeel connection, and amplifier over several months, and the sonic advantages were clear. It was widely praised. Functionally, it was implemented via a simple switch, no different from the IDEM.

Sorry, but in fact is not exactly "conceptually similar to the Zeel interface". The 50 ohm standard is an old standard in instrumentation - I used it for decades and its is part of any course in basic electronics instrumentation. It had also been applied before in audio by Meridiam in the early 80's. It is simply a standard audio interface with specific output and input impedance, and became a marketing point of DartZeel. Surely outputs have to deliver the needed current to drive the low impedance.

BTW, early broadcast and studio devices supported the 50 Ω line interfaces before 600 Ω became dominant.

 

[vinyl_mike]

Thank for the detailed answer - we can now see the DC mode is biased at -8V. As you say It is a proprietary custom mode, not standard and IMO should be labeled accordingly. Did Stephan tell you what would happen if users used the DC mode inadequately? Fried woofers?




Sorry, but in fact is not exactly "conceptually similar to the Zeel interface". The 50 ohm standard is an old standard in instrumentation - I used it for decades and its is part of any course in basic electronics instrumentation. It had also been applied before in audio by Meridiam in the early 80's. It is simply a standard audio interface with specific output and input impedance, and became a marketing point of DartZeel. Surely outputs have to deliver the needed current to drive the low impedance.

BTW, early broadcast and studio devices supported the 50 Ω line interfaces before 600 Ω became dominant.

I was fortunate to spend a day with Hervé Delétraz at his home in Switzerland when he was developing the original 108 and Zeel interface. I was aware of the previous existence of 50-ohm connections and asked Hervé about using standard off the shelf cables. This was a long time ago, and if memory serves me correct, he said that while they might work, his specific Zeel cable was optimized for the darts electrical characteristics. I don't know if that has changed over the years or what other option are available.

I I realized that high-end DACs are connected with proprietary cables (Wadax, DCS...) but I’m not aware of any mainstream manufacturer with unique connections between their source components and their amplifiers – except for darTZeel and Stellavox. I could be wrong and if so, I stand corrected.

A follow-up question about using the 727 with the IDEM in the DC mode Stephan said: “In order to refer all devices to ground, we would have had to install a second voltage amplifier on the output, which would damage sound more than a capacitor would do. Not a good idea!”

During the installation Gideon clearly and unambiguously stated that the AC switch was for all non-Stellavox equipment, and the DC switch was for future connections to Stellavox source equipment. As to the dangers, I'm clearly aware that DC to speakers will fry them.

My point in the larger picture is that we have two manufacturers thinking a little bit outside the box for the purpose of improving sound quality. I applaud the efforts of both.

 

[Ron Resnick]

Sorry, but in fact is not exactly "conceptually similar to the Zeel interface". The 50 ohm standard is an old standard in instrumentation - I used it for decades and its is part of any course in basic electronics instrumentation. . . . It is simply a standard audio interface with specific output and input impedance, and became a marketing point of DartZeel.

+1

And the BNC connector -- which looks exotic to audiophiles -- is a quick disconnect interface completely ubiquitous in radio in the VHF range.

 

[exupgh12]

I I realized that high-end DACs are connected with proprietary cables (Wadax, DCS...) but I’m not aware of any mainstream manufacturer with unique connections between their source components and their amplifiers – except for darTZeel and Stellavox. I could be wrong and if so, I stand corrected.

Pilium preamps such as Ares, Alexander and Olympus list two sets of XLR outputs: a “standard” XLR out for use with any power amp, and a second XLR output labeled P-LINK. The P-LINK output is electrically optimized (impedance‑matched and voice‑tuned) for Pilium’s own power amplifiers. I guess more companies employ electricallly optimized output\input connections.

 

[vinyl_mike]

Pilium preamps such as Ares, Alexander and Olympus list two sets of XLR outputs: a “standard” XLR out for use with any power amp, and a second XLR output labeled P-LINK. The P-LINK output is electrically optimized (impedance‑matched and voice‑tuned) for Pilium’s own power amplifiers. I guess more companies employ electricallly optimized output\input connections.

Interesting. Did not know that about Pilium.

 

[wil]

Interesting. Did not know that about Pilium.

Aries Cerat AC LINK

 

[Mike Lavigne]

I was fortunate to spend a day with Hervé Delétraz at his home in Switzerland when he was developing the original 108 and Zeel interface. I was aware of the previous existence of 50-ohm connections and asked Hervé about using standard off the shelf cables. This was a long time ago, and if memory serves me correct, he said that while they might work, his specific Zeel cable was optimized for the darts electrical characteristics. I don't know if that has changed over the years or what other option are available.

I I realized that high-end DACs are connected with proprietary cables (Wadax, DCS...) but I’m not aware of any mainstream manufacturer with unique connections between their source components and their amplifiers – except for darTZeel and Stellavox. I could be wrong and if so, I stand corrected.

A follow-up question about using the 727 with the IDEM in the DC mode Stephan said: “In order to refer all devices to ground, we would have had to install a second voltage amplifier on the output, which would damage sound more than a capacitor would do. Not a good idea!”

During the installation Gideon clearly and unambiguously stated that the AC switch was for all non-Stellavox equipment, and the DC switch was for future connections to Stellavox source equipment. As to the dangers, I'm clearly aware that DC to speakers will fry them.

My point in the larger picture is that we have two manufacturers thinking a little bit outside the box for the purpose of improving sound quality. I applaud the efforts of both.

i have a little 'zeel' experience. tried a few different generic BNC cables which are labeled 50 ohm and they suck on the darTZeel. tried broadcast 50 ohm cables. still suck. conventional quality cables are better.

tried Herve's own earlier version of the 50 ohm cable with the plug install optimized for the 'zeel' application and they are very good and take things to that special place. still own some of it. my own Evolution Acoustics BNC's are the best 'zeel' i have heard, not cheap, and i'm told better than Herve's newest 'zeel' cable versions (Fremer commented on the newest 'zeel' cable in his 468 review). my EA 'zeel' is quite heavy and stiff and the connectors are special. the Evolution Acoustics cable builder also did warranty repair work for darTZeel for years.

can't speak to any technical things about the 'zeel' interface, or the 50 ohm advantage. when done right it just sounds less there regardless of length. Herve wrote an article for Stereophile in the September 2001 edition which was about conventional cable reflections (Impedance Matching in Cables; Myth or Reality?). this was before there was any darTZeel the company or any mention of the concept of the 'zeel' interface. Herve was an engineer working on a DIY amplifier project documented in Stereophile. here is part one, from August of 2000. there are 6 parts. it is fun to see how an amplifier company begins before it does.

connecting dots the 'zeel' was the answer to Herve's viewpoint on conventional cables.

 

[microstrip]

I was fortunate to spend a day with Hervé Delétraz at his home in Switzerland when he was developing the original 108 and Zeel interface. I was aware of the previous existence of 50-ohm connections and asked Hervé about using standard off the shelf cables. This was a long time ago, and if memory serves me correct, he said that while they might work, his specific Zeel cable was optimized for the darts electrical characteristics. I don't know if that has changed over the years or what other option are available.

It seems you are missing the point that DartZeel marketing claims - using a 50 ohm interface the sound would not depend in a meaning way on the cable, as long as it was exactly matched in impedance. As far as I remember Herve used a standard 50 ohm cable also used in CERN - I used a very similar one in very long lengths to delay analog detector signals, a standard technique that probably some high-end manufacturers would inappropriately call "feed forward" or some other nice sounding technical derivative ...

The reality is that sound still depends on IC cables, as Mike Lavigne referred several times.

No need to look far to read similar claims - Ralf Karsten makes the same claim for the 600 termination in WBF.

BTW, I discussed the subject with Herve in a copious lunch in Estoril about twenty years ago, but is was a private talk - at that time I owned DatZeel,

I I realized that high-end DACs are connected with proprietary cables (Wadax, DCS...) but I’m not aware of any mainstream manufacturer with unique connections between their source components and their amplifiers – except for darTZeel and Stellavox. I could be wrong and if so, I stand corrected.

BNCs have been used by several manufacturers, Levinson and others used specific LEMO connectors and made similar claims on them.

A follow-up question about using the 727 with the IDEM in the DC mode Stephan said: “In order to refer all devices to ground, we would have had to install a second voltage amplifier on the output, which would damage sound more than a capacitor would do. Not a good idea!”

During the installation Gideon clearly and unambiguously stated that the AC switch was for all non-Stellavox equipment, and the DC switch was for future connections to Stellavox source equipment. As to the dangers, I'm clearly aware that DC to speakers will fry them.

Ok, I was just referring to pictures shown in WBF.

My point in the larger picture is that we have two manufacturers thinking a little bit outside the box for the purpose of improving sound quality. I applaud the efforts of both.

I have been admiring manufacturers able to think inside and outside the box for decades, I reserve my applaud to those I find really innovative. Maybe I will applaud the Stellavox designer after I know more details about the IDEM technical features, but IMO we have not been told enough to carry a judgement on it. Surely MHO, YMMV.