First Thoughts on the New Stellavox IDEM Monoblock Amplifiers

[MylesBAstor]

Part of continuing to improve as a reviewer is staying abreast of new developments and taking every opportunity to audition to innovative products. Preferably, but not always possible, in your own reference audio system. Thus one, in combination with a steady diet of live music (thanks to living in New York City the opportunity is boundless), gets a better benchmark and picture of just exactly where we lie in audio reproduction.

Enter an opportunity to audition (and hopefully review down the road for Positive-Feedback) the new IDEM monoblock amplifiers from the legendary and newly resurrected Stellavox company. Let’s face it. There’s nothing super sexy about solid-state amplifiers. No glow of tubes, just a metal box with the guts inside. On the other hand, there is a beauty in simplicity and how the manufacturer uses CNC machining to make everything fit together oh so perfectly.

Setting the amplifiers up was pretty simple. The IDEMs are no lightweights and definitely require two people to lift them out of the box and then place in position. (Here they were set up on some Symposium Ultra platforms.) Connect the interconnects and the speaker cables. Select single-ended or biwired input, adjust for the needed gain. I’m not familiar with these binding posts but they provided a very tight and secure connection. Take care there’s a firm and tight contact with thicker, heavier spade lugs. Connect the power cord and then it’s time to power the amplifiers up.

A few other useful observations about the amplifier. First, leave the IDEMs turned on all the time for the best possible sound (as I recommend for all solid-state amplifiers and digital products). The IDEMs take a good two hours after coming out of standby to sound their best. Next, these amplifiers run hot! But they are equipped with a sizeable amount of heat sinking on the back of the amplifiers to deal with heat issues.

The system surrounding the Stellavox IDEM amplifiers consisted of:

Speakers: Zellaton Plural Evo;

Sources (LP): VPI Avenger Statement direct-drive turntable with outboard Vanquish power supply; SAT LM-12 tonearm; HyperAnalogue Hypersonic X4 cartridge; (Tape) Technics RS1506 reel-to-reel with very low (80 mH) inductance FM heads, redone tape path, heads wired balanced out;

Electronics: Soulution 326 preamplifier; Doshi Audio EVO phonostage with NOS cryo’d Mullard CV4024s, Phillips 12DW7s and new Genelex ECC83s tubes; Doshi Audio EVO tapestage with NOS Tele ECC801s (phase splitter) and Mullard 4024 (EQ section) tubes;

Cabling: Kubala-Sosna Ovation speaker cables; Audience Front Row Reserve ICs; Audience Front Row power cords.

So I thought I would start out with a couple of pictures of the setup as well as some teaser videos of some LPs and 15-ips tapes played back through the reference system.

 

[nc42acc]

Impressive engineering and design.

 

[MylesBAstor]

First a couple of vocals on LP.

Mel Torme at Shorty’s

Shirley Horn Softly from 2XHD

[

One of my favorite artists Fink from Low Swing Records

 

[MylesBAstor]

Some jazz beginning with the recent terric AP reissue of the Pablo recording of Joe Pass and Zoot Sims

For percussion freaks like me, Carlos Chavez from SuperPercussion, SuperAnalogue Records

Lastly from the new reissue cut by BG of the TBB Orang-Utan. Among the best sounding TBMs! Don't get the recent French reissue.

 

[MylesBAstor]

Finally a little tape. Suzanne Vega from An Evening of New York Songs and Stories at the Carlyle Hotel in NY. Horch House.

Next a little fusion from George Duke Feel with Frank Zappa on guitar.

Another new Artist Reema from Low Swing Records/Horch House.

For Yello fans! Oh Yeah from Stella.

Lastly, Makaya McCraven Quartet from Int. Phonograph.

 

[MylesBAstor]

Being a reviewer isn’t all the glitz and glamor it’s made out to be! No one mentions the deep sadness experienced after packing up a great piece of gear and returning it to the manufacturer. That goes double here in the case of the Stellavox amplifiers (though, hopefully at some point a new pair will return for a full, in depth review for PF!)

So how to characterize the overall sound of the IDEM amplifiers without getting too bogged down into audiophile minutiae? How to describe the product’s overall “gestalt” and its ability to faithfully reproduce the sound of music? It came down in the end to two words: Realism vs. accuracy. It’s clear that designers of both tube and solid-state electronics have made impressive inroads into reducing the colorations of their products by various means including reducing distortions, decreasing the noise floor of their units, increasing overall transparency and allowing more information to flow through. Yet with all those improvements, there was still something missing.

That missing element was realism. That indescribable ingredient that bridges the gap (gulf if you may) between reproduced and real music. It’s sometimes hard to describe but you know it when you hear it. That panache that the best tube electronics possess. In this case, it’s the IDEM’s lack of artificiality coupled with their ability to resolve the finest musical nuances on recordings (especially tape) that gives them an incredible sense of ease. It's also—thanks in part to the new Kubala-Sosna Ovation speaker cables—the amplifier’s ability to get the proper relationship between instruments’ fundamentals and overtones. As a result, you don’t have to concentrate on the music; instead, the music just flows and engulfs you. Just like when you hear live music.

Realism aside, there were several areas where the IDEMs really set benchmarks especially when it came to soundstaging, transparency and the recreation of palpable, visceral images. No doubt some of the soundstaging was due to the monoblock design (as was the low end); but the amplifier’s sense of depth and ability to resolve layering in the back of the stage—such as on the Fink album—was exceptional. No less impressive were the amplifier’s ability to produce a palpable, realistic, three-dimensional image of performers. Beyond what I’ve experienced with the best of tubes or solid-state.

Then there’s the amplifiers low end extension, speed, control and authority. Nothing fazes them whether it be the ability to move air on the huge Taiko drums on Ondekoza’s Fujiyama, the beguiling tone and detail of the cello on the Makaya McCraven Quartet IPI tape or the sheer speed and impact of drums on SuperPercussion. It’s just a thrill a minute and bass freaks will go to town here.

Last but not least is the amplifier’s remarkable midrange. The individuality of different voices are brought to the fore along with the subtlest bits of information. The singer’s breathing, the pauses, the phrasing, the intelligibility. It’s all there in spades. That ranges from the incredible delicacy of Shirley Horn on the Pierre Sprey recorded Softly, the mellowness and emotion of Dean Martin on Dream with Dean, the darkness of Reema on Low Swing Sessions or the magic of Fink’s cover of Soundgarden’s “Black Hole Sun” on Low Swing Sessions!

That’s just a smattering of what the Stellavox amplifiers are capable of and I encourage people to hear these amplifiers to hear them for themselves with their own favorite music. I predict it will be a real treat all around!

 

[Rob181]

One of my favorite artists Fink from Low Swing Records

Like this & the presentation is VERY good.
Been a fan of the Plural Evo's for a while now - never heard them sound better...

 

[vinyl_mike]

Being a reviewer isn’t all the glitz and glamor it’s made out to be! No one mentions the deep sadness experienced after packing up a great piece of gear and returning it to the manufacturer. That goes double here in the case of the Stellavox amplifiers (though, hopefully at some point a new pair will return for a full, in depth review for PF!)

So how to characterize the overall sound of the IDEM amplifiers without getting too bogged down into audiophile minutiae? How to describe the product’s overall “gestalt” and its ability to faithfully reproduce the sound of music? It came down in the end to two words: Realism vs. accuracy. It’s clear that designers of both tube and solid-state electronics have made impressive inroads into reducing the colorations of their products by various means including reducing distortions, decreasing the noise floor of their units, increasing overall transparency and allowing more information to flow through. Yet with all those improvements, there was still something missing.

That missing element was realism. That indescribable ingredient that bridges the gap (gulf if you may) between reproduced and real music. It’s sometimes hard to describe but you know it when you hear it. That panache that the best tube electronics possess. In this case, it’s the IDEM’s lack of artificiality coupled with their ability to resolve the finest musical nuances on recordings (especially tape) that gives them an incredible sense of ease. It's also—thanks in part to the new Kubala-Sosna Ovation speaker cables—the amplifier’s ability to get the proper relationship between instruments’ fundamentals and overtones. As a result, you don’t have to concentrate on the music; instead, the music just flows and engulfs you. Just like when you hear live music.

Realism aside, there were several areas where the IDEMs really set benchmarks especially when it came to soundstaging, transparency and the recreation of palpable, visceral images. No doubt some of the soundstaging was due to the monoblock design (as was the low end); but the amplifier’s sense of depth and ability to resolve layering in the back of the stage—such as on the Fink album—was exceptional. No less impressive were the amplifier’s ability to produce a palpable, realistic, three-dimensional image of performers. Beyond what I’ve experienced with the best of tubes or solid-state.

Then there’s the amplifiers low end extension, speed, control and authority. Nothing fazes them whether it be the ability to move air on the huge Taiko drums on Ondekoza’s Fujiyama, the beguiling tone and detail of the cello on the Makaya McCraven Quartet IPI tape or the sheer speed and impact of drums on SuperPercussion. It’s just a thrill a minute and bass freaks will go to town here.

Last but not least is the amplifier’s remarkable midrange. The individuality of different voices are brought to the fore along with the subtlest bits of information. The singer’s breathing, the pauses, the phrasing, the intelligibility. It’s all there in spades. That ranges from the incredible delicacy of Shirley Horn on the Pierre Sprey recorded Softly, the mellowness and emotion of Dean Martin on Dream with Dean, the darkness of Reema on Low Swing Sessions or the magic of Fink’s cover of Soundgarden’s “Black Hole Sun” on Low Swing Sessions!

That’s just a smattering of what the Stellavox amplifiers are capable of and I encourage people to hear these amplifiers to hear them for themselves with their own favorite music. I predict it will be a real treat all around!

Having heard the Stellavox amps in my system, I can say that Myles' eloquent review is spot on. These are indeed special. More comments will follow.

 

[matthias]

I am really curious what a complete Stellavox set-up with the upcoming DAC, preamp and the IDEMs will bring to the party

 

[Audioarts]

Hi Matthias

I heard the prototype DAC at the Stellavox factory, having compared it with the legendary TD9 reel to reel. We listened to an original master of Max Bruch on tape, then streamed through the DAC. I was in shock how the tape quality was essentially preserved in the proto, meaning that the Stellavox analog midrange magic, sweetness and immediacy all came through well preserved by the DAC. There’s so much digital that I respect, but this digital I loved because of the way it got its claws into my soul. Stellavox focuses on time delay elements in music and much has carried over from the pro audio side, so I’ll be sure to update once available and ready to demo.

Gideon

 

[Iamrael]

How did you guys “stream” through the DAC?
The file was sampled from the TD9?
What rate were you using for conversion and which server?

 

[LL21]

Hi Matthias

I heard the prototype DAC at the Stellavox factory, having compared it with the legendary TD9 reel to reel. We listened to an original master of Max Bruch on tape, then streamed through the DAC. I was in shock how the tape quality was essentially preserved in the proto, meaning that the Stellavox analog midrange magic, sweetness and immediacy all came through well preserved by the DAC. There’s so much digital that I respect, but this digital I loved because of the way it got its claws into my soul. Stellavox focuses on time delay elements in music and much has carried over from the pro audio side, so I’ll be sure to update once available and ready to demo.

Gideon

Fascinating. Look forward to hearing more about this. When is the prototype coming to the market formally? Price expectations?

 

[matthias]

Hi Matthias

I heard the prototype DAC at the Stellavox factory, having compared it with the legendary TD9 reel to reel. We listened to an original master of Max Bruch on tape, then streamed through the DAC. I was in shock how the tape quality was essentially preserved in the proto, meaning that the Stellavox analog midrange magic, sweetness and immediacy all came through well preserved by the DAC. There’s so much digital that I respect, but this digital I loved because of the way it got its claws into my soul. Stellavox focuses on time delay elements in music and much has carried over from the pro audio side, so I’ll be sure to update once available and ready to demo.

Gideon

Hi Gideon,
thank you, I am also like @Iamrael very interested what the hardware and software was upstream to the DAC at the Stellavox factory

 

[Audioarts]

Matthias -

Here’s some background on that listening session which I hope you find useful.

We listened to: Max Bruch: Scottish Fantasia; David Oistrach / Jascha Horenstein ( DECCA RECORD CO. 1962).

We heard the first piece: Op. 46: 1. Adagio cantabile. Joseph Sabaini concert master under Karajan, a student of Ostraich (and close friend to Stellavox), copied on 1/2” tape (15”/s) from the DECCA production tape Nr. SD2713 recorded on AMPEX.
The tape was produced on 13th Feb. 1963 for RCA New York (see attached a photo of the tape label). We played it back on a beautifully restored TD9, equipped with a new 1/2” headblock.
The piece is actually mentioned often as one of Oistrach’s masterpieces.

And to your question specifically:

The digital file is originally from DECCA MUSIC GROUP, released in 2022 and mastered from the original master tape. Data: 176.4kHz / 24bit. (Producer: Erik Smith, recording Engineer: Alan Reeve).

The DAC prototype, which I listened to is a discrete R2R DAC without oversampling and no digital filtering or similar applied.

In this case, the file was reproduced from a PC using as player FOOBA 2000.

Gideon

 

[LL21]

Matthias -

Here’s some background on that listening session which I hope you find useful.

We listened to: Max Bruch: Scottish Fantasia; David Oistrach / Jascha Horenstein ( DECCA RECORD CO. 1962).

We heard the first piece: Op. 46: 1. Adagio cantabile. Joseph Sabaini concert master under Karajan, a student of Ostraich (and close friend to Stellavox), copied on 1/2” tape (15”/s) from the DECCA production tape Nr. SD2713 recorded on AMPEX.
The tape was produced on 13th Feb. 1963 for RCA New York (see attached a photo of the tape label). We played it back on a beautifully restored TD9, equipped with a new 1/2” headblock.
The piece is actually mentioned often as one of Oistrach’s masterpieces.

And to your question specifically:

The digital file is originally from DECCA MUSIC GROUP, released in 2022 and mastered from the original master tape. Data: 176.4kHz / 24bit. (Producer: Erik Smith, recording Engineer: Alan Reeve).

The DAC prototype, which I listened to is a discrete R2R DAC without oversampling and no digital filtering or similar applied.

In this case, the file was reproduced from a PC using as player FOOBA 2000.

Gideon


View attachment 160445View attachment 160445

Fantastic! I certainly am further intrigued by the description, discrete R2R, no digital filtering or oversampling. Timing of release and anticipated price?

 

[Audioarts]

TBD although we’re anticipating early Spring.
Once I have a more accurate time frame and details, will certainly revert.

Gideon

 

[LL21]

TBD although we’re anticipating early Spring.
Once I have a more accurate time frame and details, will certainly revert.

Gideon

Thank you!

 

[matthias]

The DAC prototype, which I listened to is a discrete R2R DAC without oversampling and no digital filtering or similar applied.
In this case, the file was reproduced from a PC using as player FOOBA 2000.

Thanks Gideon,
I am very pleased to get this info.
IIUC, it is not necessary to use a sophisticated server to get the listening experience you reported.