Friday night listening

[Carlos269]

Unfortunately they are local pick up only in Melbourne. I'm in Hobart. Bass Strait is in the middle. And unfortunately my friend who died didn't keep the packaging.

Sorry to say my health isn't up to more than having a shower and walking out to the lounge at the moment. Let alone organizing a freight company to go pick them up, pack them and get them to me. And then hoping they arrive undamaged.

In any event - these photo's were from the Estate sale: the seller hasn't posted any recent photos. You will be able to tell me if they are original Stamm's. They have the whizzer, so I expect they are.

View attachment 79958

View attachment 79959



Re Open Baffles

Ahhh - that all makes sense. The ones I had in 2008 were a pair of the now defunct Hawthorne Audio 15 inch coaxial sterling drivers with bass 15 inches drivers, in tall not very wide baffles, and then in 2009 single drivers (by memory some form of Lowthers) in much the same.

The OB's I came up with sounded not bad - especially with certain music - but not in the same league as the Troubadours, or ESL's or a good box speaker - at least for classical which is what I listen to. Fun experiments though. I am quite sure what you are making would sound sublime.

I shall follow your adventures with much interest! A great pity I cannot snap my fingers and come over for a listen. Your type of systems interest me. Something away from the usual.

Speaking of Single Drivers - the Eclipse TD 712.
View attachment 79960
This was a speaker I owned in 2015/2016 that was very special. It is a single driver sealed unit. I would own another pair of those is a jiffy - they were my wife's favourite speakers - high WAF. That said - SETS need not apply - well they would work with 8 watts of 300B, but you wouldn't want to. I found them monsterously difficult to partner well. The better you feed them the better they sounded.


Thank you again for posting.

Andrew, the Stamm drivers in your late friend’s Troubadours are the second version of Stamm drivers and not the original version, but nonetheless great drivers based on my research and understanding. I have not heard the second, and last, version of the Stamm driver myself, but someone who has and who has great knowledge of all things Loth-X/Stamm summarized the differences as follows:

the Mk1 have more separation and extended highs whereas the Mk2 extended the bass a little lower, had less separation, rolled off earlier, but also had no peak.

I have Heard good things about the Hawthornes OB speakers. And also hear that the Fujitsu Eclipse series has very precise imaging. Lots of very different paths lead to audio nirvana. Keep enjoying your music in good health.

 

[Andrew S.]

Keep enjoying your music in good health

Thank you very much Carlos. Most kind.

 

[Carlos269]

I have spent the better part of the afternoon listening to my latest system, based on an OTL amplifier driving a full-range single field-coil driver in an Open Baffle affair:





This has been a system in the making for some time now as it has experienced a number of delays including the mounting of the drivers to the Open Baffles, which was originally meant to be front mounted but ended up being rear mounted, a bad Harrison DC power supply and locating and procuring the appropriate amplifier……but as they say “good things come to those who wait!”.

The new system shares the same Tidal streaming to the dCS Elgar Plus DAC as a source with a few of the other systems in the room:



The preamplifier is a Transcendent Sound Grounded Grid which has been upgraded with Paper In Oil (PIO) capacitors:



For the amplifier I had intended to use a Single Ended OTL amplifier but the more I thought about it the more I realized that 1 Watt, 1.5 Watts or even 4 Watts (from monoblocks) was not going to be enough to drive the Supravox 215 2000-EXC drivers because part of the trade off of increasing the Qts factor to 0.71, by lowering the field-coil voltage to 6Vdc, to make them suitable for Open Baffle installation/implementation is that the efficiency drops from 102dB down to 97dB. So I set my sights on a conventional OTL and looked at the usual suspects: Atma~Sphere, Joule~Electra, Tenor, Einstein, Graaf and others. I then realized that those OTL designs perform optimally with 8 Ohm loads and higher and I did not want to resort to sticking a Paul Speltz Zero transformer at the output of an OTL amp as that seems to me to negate the whole concept of an output transformer-less topology. I was fortunate to find an OTL design that is suitable for 4 Ohm loads. In enters the 6C19Pi based Transcendent Sound T16 OTL amplifier, which is rated at 15 Watts at 16 Ohms and delivers between 7 to 9 Watts into the Supravox’s 4 to 6 Ohm load:



The drivers are the aforementioned Supravox 215 2000-EXC original version. The original version is key as the MkII revision is not as extended or efficient as the original version:

 

[Carlos269]

For relative comparison purposes, and in “Dark” mode, here are the same two songs for which I have previously posted videos, on page 8 of this thread, for the:

1) One-of-a-kind LampizatOr DSD-Only DAC —>>Thomas Mayer 10Y Silver preamplifier—>> Custom Sayes 46 amplifier —>> Loth-X Troubadours speakers with the original version of the full-range Stamm drivers

2) dCS Elgar Plus DAC —>> custom Telefunken RE084K DHT preamplifier —>> custom Bavera JE Labs 45 SET DHT dual-monoblock amplifier with Telefunken output transformers—>> Altier-Rullit Silver Labs 10 AlNico full-Range drivers mounted on JE Labs style Open Baffles

Here are the field-coil system’s videos in “Dark“ mode for impressions and relative comparison purposes::

 

[Carlos269]

I have been listening to my Supravox 215 2000-EXC field-coil drivers mounted on Open Baffles and driven by the Transcendent Sound T16 OTL amplifier based system for enough time to formulate an impression. I have experienced much of what Ralph Karsten, of Atma-Sphere fame, and others have previously described of similar combinations, a quickness, directness, electrostatic type transparency but with meat on the bones. Because of the Supravox’s limited high frequency extension there is a chesty quality to the tone that makes for life-like reproduction of human voices, in particular male voices.

The presentation of the system is very interesting as it relates to the current discussions on the forum regarding vintage versus modern speakers. I noted on Peter’s system thread that the difference in presentation between “Natural” sounding systems versus modern “Hi-Fi” bells, whistles and fireworks sounding systems revolves around the high frequencies contour, detail/resolution, and extension. This single full-range field-coil driver mounted on OB and driven by OTL amplification reinforces my conjecture.

I have not performed any measurements of the high frequency extension of the system but if it reaches 12KHz I would be very surprised, it probable goes -10dB closer to 10KHz. Wow that’s not very high in the context of the 21st century. On the low frequency side, it would be interesting to see if the response gets to the 40’s Hertz region before it gets down to -10dB and goes silent.

With those deficiencies in mind and clearly outlined, I’m here to state that my single-full range-field-coil-driver/OB/OTL system is an extremely “Natural” sounding system. Even my wife commented, unsolicited, about how nice the “new“ system sounded. The vocals in particular are chesty and for lack of a better word organic or 3-dimensional as you get the sound of the chest cavity and lips & tongue movement and not just the sound of the voices.

Of interesting note is that similarly to the Loth-X Troubadours with the original version of the Stamm drivers, the Supravox field-coil driver system is truncated at the frequencies extremes but do not want for reinforcement. In other words, just as the Stamm driver based system does not make me long to complement it with subwoofers, neither does the Supravox field-coil driver make me want to the go to the room next door for a set of capacitors & tweeters or super-tweeters. I accept both systems for what they are, warts & limitations and all, because what each system brings to the table to me resembles what I hear in real life when I interact with others and listen to un-amplified music. If you look at the frequency chart you will notice that no instrument has a range of 20Hz to 20KHz, they are all segmented about the frequency scale with only a few producing sound below 30Hz or above 16KHz, most music lives in the 40Hz to 14KHz region, like it or not. Now this is not a call for compromised frequency response or mediocrity, it is just simply reality, real life and the way it is.

So what do I think and how do I feel about the Supravox field-coil driven by the Transcendent sound OTL system? I like it, actually I like it a lot, because it brings a presentation that is different to what I hear with my other S.E.T. DHT amplified horn or single driver based systems. For one I hear the quickness, speed, directness and the bass snap attack that Ralph and others have attributed to the FC & OTL combination and then you add to that the chesty, for lack of a better word, full bloomed midrange, and you get what I would describe as an organic or “Natural” sounding system that you can listen to for days.

So I asked myself, is this the product of the field-coil drivers or the OTL amplifier or the combination of both, well obviously it is the combination of both but they are not equal contributors. How do I know this? Well the story continues……..

 

[Carlos269]

The Supravox field-coil drivers are extremely neutral and thus what you ultimately end up hearing and listening to is the dominant character, tone and sound of the amplifier. And while the 15 Watts into a 16 Ohm load Transcendent Sound T16 OTL can drive all my speakers currently driven by my various Type 45, 46, 10/10Y/801/801A, AD1, 2A3, 300B, and 211/845 DHT Single Ended amplifiers the same cannot be said of going the other way, with the exception of my 300B and 211/845 S.E.T. DHT amps.

Playing around with my various amps and speakers yielded some first hand experience on the the strength of the OTL amplifier. My OTL amp sounds quicker, clearer, more direct and perhaps more honest than my SET DHT amps but it lacks the romantic tone and euphoric sweetness of the flea powered transformer coupled DHT amps. My massive 801A amplifier comes the closest but its Type 26 drivers add that beautiful tone, akin to the ever so slightly softness of viewing video on film.

As I listen the OTL amp through the field-coil drivers, I struggle with the balance of the extra cost and complexity, with the external DC power supplies, compare to AlNico drivers from both Stefan Stamm and Oleg Rullit. I have a mint pair of the original Supravox Bicone T-215-SRTF drivers that would provide more insight into the gains, or losses, between similar field-coil and AlNico drivers. I do not feel like disassembling the FC drivers from the OB and the results would not be conclusive to compel me to swap the drivers at this time. I will wait to see what Audiophile Bill concludes with his similar experimentations.

But what I have done, is paired my new Single-Ended OTL amplifier with the Stamm drivers to see if they can beat the Supravox FC/Transcendent Sound OTL system at their own game: quickness, directness, honesty of tone and so on. What happens next……………

 

[Addicted to hifi]

I have spent the better part of the afternoon listening to my latest system, based on an OTL amplifier driving a full-range single field-coil driver in an Open Baffle affair:

View attachment 81728

View attachment 81730

This has been a system in the making for some time now as it has experienced a number of delays including the mounting of the drivers to the Open Baffles, which was originally meant to be front mounted but ended up being rear mounted, a bad Harrison DC power supply and locating and procuring the appropriate amplifier……but as they say “good things come to those who wait!”.

The new system shares the same Tidal streaming to the dCS Elgar Plus DAC as a source with a few of the other systems in the room:

View attachment 81731

The preamplifier is a Transcendent Sound Grounded Grid which has been upgraded with Paper In Oil (PIO) capacitors:

View attachment 81732

For the amplifier I had intended to use a Single Ended OTL amplifier but the more I thought about it the more I realized that 1 Watt, 1.5 Watts or even 4 Watts (from monoblocks) was not going to be enough to drive the Supravox 215 2000-EXC drivers because part of the trade off of increasing the Qts factor to 0.71, by lowering the field-coil voltage to 6Vdc, to make them suitable for Open Baffle installation/implementation is that the efficiency drops from 102dB down to 97dB. So I set my sights on a conventional OTL and looked at the usual suspects: Atma~Sphere, Joule~Electra, Tenor, Einstein, Graaf and others. I then realized that those OTL designs perform optimally with 8 Ohm loads and higher and I did not want to resort to sticking a Paul Speltz Zero transformer at the output of an OTL amp as that seems to me to negate the whole concept of an output transformer-less topology. I was fortunate to find an OTL design that is suitable for 4 Ohm loads. In enters the 6C19Pi based Transcendent Sound T16 OTL amplifier, which is rated at 15 Watts at 16 Ohms and delivers between 7 to 9 Watts into the Supravox’s 4 to 6 Ohm load:

View attachment 81733

The drivers are the aforementioned Supravox 215 2000-EXC original version. The original version is key as the MkII revision is not as extended or efficient as the original version:

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View attachment 81736

Beautiful setup I love it .congratulations

 

[Carlos269]

Into my main listening room entered the rarest of amplifiers in terms of circuit topology and implementation. Single-Ended OTL amplifiers are a rare breed and usually implemented with a number of parallel output tubes, typically 6C19PI’s (like in the original Transcendent SE-OTL), with pairs of 300B’s as also done by Transcendent Sound or with EL-509’s as done in the upcomingTranscendent Sound new version of the Mini-Beast SE-OTL amplifier. The topology requires multiple parallel output tubes to be able to get the output impedance low enough to be useful with high-efficiency speakers. To achieve a low enough output impedance from just a single output tube is nearly impossible to do with any type of useable wattage/power to the loudspeaker/driver load. But some very clever DIY’ers have designed SE-OTL circuits with a single 6C33C output tube. The problem is that due to its plate resistance the lowest impedance matching driver that can be used with the 6C33C SE-OTL amplifiers is 16-Ohms. There are many 16-Ohm full-range single speaker drivers out there but my full range Stamm and Supravox drivers are not one of them. The Stamm has a nominal 8-Ohm resistance and the Supravox a nominal 4-Ohm resistance; so 6C33C tubes will not work, same with the mighty 7242 tube.

From my research below are the only tubes that can be implemented as “Single” output tubes in Single-Ended Output Transformerless amplifiers with any kind of useful power output for typical speaker loads:



From left to right: 6336A?6C33C?13E1?and 7242.

In enters the beautiful and massive 13E1 tube, the only tube from the above that can be used with single high-efficiency 8-Ohm drivers, like the original Stamm drivers in my Loth-X Troubadours speaker cabinets.

Is this the ultimate match? A match made in heaven? Will have to continue listening but the early first impressions are extremely promising. More to follow……….

 

[Carlos269]

It is my understanding that only two 13E1 SE-OTL amplifiers have been built
by two DIY’ers. The original:





The original amp has, per the builder, been dismantled and it’s parts repurposed for a different project.

Which left only the second built, and only other 13E1 SE-OTL amplifier. This amplifier now resides in my main listening room and it’s the latest addition to my stable of ultra-rare, unique and one-of-a-kind amplifiers:





The 13E1 SE-OTL amplifier has been partner with my mighty and massive one-of-a-kind Thomas Mayer 10Y Silver preamplifier:



The 13E1 SE-OTL amplifier steps in for my custom Sayes 46 amplifier in driving the Loth-X Troubadours speakers with the original version of the Stefan Stamm full-range 104dB efficiency AlNico drivers:





The built quality and attention to detail is spectacular for such a custom built amplifier. I’m very happy to welcome this amplifier home, where it is here to stay.

 

[Carlos269]

The 13E1 SE-OTL is able to drive the Stamm drivers with authority and imparts its sonic signature on the presentation. It shares the forceful bass control of the Transcendent Sound T16 OTL amplifier and its directness in the midrange.

Before fully expounding on my assessment, of the amplifier thus far, as it could bias the listeners’ thoughts, I like to share the following two videos, which will allow for direct relative comparison to some of my other most recent systems and to generate a general impression of this rarest of amps:

Based on the sound in the room, it is safe to say that its sound aligns itself with the T16 OTL amplifier compared to the signature sound of my flea power S.E.T. DHT amplifiers. My overall feelings, more comparisons, and further thoughts on this special amp to come………..

 

[the sound of Tao]

It is my understanding that only two 13E1 SE-OTL amplifiers have been built
by two DIY’ers. The original:

View attachment 82132

View attachment 82133

The original amp has, per the builder, been dismantled and it’s parts repurposed for a different project.

Which left only the second built, and only other 13E1 SE-OTL amplifier. This amplifier now resides in my main listening room and it’s the latest addition to my stable of ultra-rare, unique and one-of-a-kind amplifiers:

View attachment 82134

View attachment 82135

The 13E1 SE-OTL amplifier has been partner with my mighty and massive one-of-a-kind Thomas Mayer 10Y Silver preamplifier:

View attachment 82136

The 13E1 SE-OTL amplifier steps in for my custom Sayes 46 amplifier in driving the Loth-X Troubadours speakers with the original version of the Stefan Stamm full-range 104dB efficiency AlNico drivers:

View attachment 82137

View attachment 82138

The built quality and attention to detail is spectacular for such a custom built amplifier. I’m very happy to welcome this amplifier home, where it is here to stay.

They are lovely Carlos (especially the silver 10y Thomas Mayer)… they definitely deserve their own space. Enjoy

 

[cjfrbw]

Intriguing as usual, Carlos. Those last two vids sounded great on headphones.

 

[Carlos269]

Intriguing as usual, Carlos. Those last two vids sounded great on headphones.

Thank you, yes agree that the 13E1 SE-OTL amplifier/Thomas Mayer 10Y Silver preamplifier combo driving the Loth-X Troubadours with the original version of the Stefan Stamm full range driver sounds great in the room and part of that magic translates in the videos.

The last few weeks I have been enjoying the Transcendent Sound T16 OTL amp driving the field-coil Supravox 215 2000-EXC drivers in the OB and the 13E1 SE-OTL amplifier so much that I have become very impressed with the OTL circuit topology. I can hear the speed and bass articulation that getting rid of the output transformers allows. As I mentioned previously, I do believe that these OTL amps provide a more neutral and honest presentation of the recordings.

My OTL amplifiers provide that snap and crisp electrostatic-like presentation but with meat on the bones. The 13E1 SE-OTL is very special as it delivers a sense of realism that is very organic and non-fatiguing. Both OTL amplifiers are hard to fault with their speed, direct and neutral sound.

As you can tell, I have been very, very impressed with both OTL amps that in many way have overshadowed the field-coil driver investigation. I can now state that based on my limited experience, the OTL topology brings more to the table than the field-coil drivers. Of course the combination of both is extremely good as they buildup on their strengths of speed, direct, neutral presentation, and electrostatic-like transparency but with heft, or for lack of a better descriptor, meat on the bones. Really enjoy the chesty male vocals and detail without harshness.

 

[Carlos269]

Being the relentless obsessive person that I am, I decided to further explore if the one thing missing from my OTL amps’ presentation could be had. The one aspect that I miss is that romantic euphoric midrange and treble that the best flea power SET DHT amplifiers can deliver.

Although I own a number of fantastic 845, 211, 300B and 2A3 amplifiers, I find that the best magic is with the lower power tubes, the 10/10Y/801/801A, 46, AD1 and Type 45 flea power tube SET DHT amplifiers.

Since I’m using the Thomas Mayer 10Y Silver preamplifier with the 13E1 SE-OTL amplifier it is a perfect combination for the resultant neutrality and directness, which I respect for its honest and sublime presentation. Rather than muddying that signal chain, I set it to the side and decided to put together a new contender system.

A new system that will carry the flag of the SET DHT faction forward into battle with the invading dominance of my two new OTL amplifiers and related systems.

In looking at my favorite SET DHT amplifiers in house the two amplifiers that immediately came to mind are my massive dual chassis monster interstage transformer coupled 801A amplifier and my boutique AD1 stereo amplifier. But then I started thinking, as I always do, and said to myself “why would I use any other tube than my all-around favorite of the SET DHT power tubes?” I like them all but overall the Type 45 is to me the best all-around tube. While I did have two separate set of 45 monoblocks already in house, they are being used in two of my other systems and were not built to the highest degree of refinement and execution. Lucky for me after more than a year in design, development and assembly I recently took delivery of my statement level 45 SET DHT monoblocks, which I had planned to partner with the Stamm drivers. The timing was perfect for continuing my audio explorations………

 

[cjfrbw]

45 amplifier is really special for raw elegance, willowy imaging, and the best upper midrange that makes you forget about the rest of the frequency spectrum as long as you can just keep that upper midrange going. If you think you have heard everything in your signal, listen to it with a 45 amp on a compatible speaker and be surprised.
I suppose what the 45 lacks is pleasurable intensity (at least with my ribbons) that you can get with excellent SS. However, that may be compensated by a highly efficient horn setup (which I don't have but have heard with 45).

 

[Carlos269]

45 amplifier is really special for raw elegance, willowy imaging, and the best upper midrange that makes you forget about the rest of the frequency spectrum as long as you can just keep that upper midrange going. If you think you have heard everything in your signal, listen to it with a 45 amp on a compatible speaker and be surprised.
I suppose what the 45 lacks is pleasurable intensity (at least with my ribbons) that you can get with excellent SS. However, that may be compensated by a highly efficient horn setup (which I don't have but have heard with 45).

I agree. Each tube has its strengths: the 10/10Y/801/801A is the king of clarity. As I said, the best of these low power tubes to me is the 45 as it does it all well and gives me the best overall sound.

At this stage in my audio life I’m exploring and experiencing what others in small factions in the hobby have proclaimed as possessing special qualities and that is just what the 45 delivers.

I enjoy walking around my house and looking at all the special and unique pieces of audio equipment that I have aquired over the years. Most of the pieces are on the massive heavy end of the spectrum as I have always preferred the most robust and extreme built pieces, but I can also appreciate the more elegant and sophisticated of audio jewelry like the Goldmund Gold Cubes and Dalby preamplifier amongst others. One of my pieces that always catches my eye is the boutique style and crafted AD1 amplifier:







When it came time to build my reference Type 45 monoblock amplifiers, I wanted my statement pieces to also be as visually engaging as they are sonically. I’m extremely satisfied with how they turned out:







With Emission Labs EML-45’s with solid plate:





These little guys are still burning-in but they already sound as good as they look. Pure audio jewelry and eye candy for sure but also valuable tools for my audio explorations going forward.

Next, another very unique preamplifier enters the listening room……..

 

[Carlos269]

Once one has been exposed to and has heard a Directly Heated Triode (DHT) preamplifier there is simply no going back to a conventional preamp in my opinion. The intimacy and detail presented by DHT preamps is intoxicating. There is a community of DIY’ers who have been refining and experimenting with DHT preamps for quiet a long time now. Within this faction of the hobby some favorite designs and concepts have emerged.

The tubes most favored for the DHT preamps are the 01A, the Type 26, and the 10Y series and all with good reason as they sound fantastic. Outside of these core DHT preamps you will find other less common designs, such as my Transcendent Sound Masterpiece 300B and my ultra-rare one-of-a-kind exotic Telefunken RE-084K DHT preamp. Other DHT preamps have been built with 4P1L, 71A, EML 20A/20B tubes and also a number of other more nonstandard tubes. One of the leaders in the DHT preamp community is Ale Bartola in the UK who is constantly experimenting and prototyping new DHT circuits.

One of the rare unicorn DHT preamp that myself and others have inquired about numerous times for years and which is rarely executed is a DHT 45 preamp. I had only seen maybe one examples of a 45 DHT preamp and after I saw Thomas Mayer comment that he had experimented with both 45’s and 2A3’s in DHT preamps but was not satisfied with them in the DHT preamp implementation; as he favors others such as the mighty 10Y tube instead, I kind of stop inquiring about them.

Within the DIY community there are many builders that recycle tried and proven circuit designs and just a few on the periphery that push the envelope and build with more exotic tubes, rare parts and unconventional circuits, design concepts and implementations. One of these builders is the great Radu Tarta with his Shiny Eyes designs. Radu designed and built my Type 01A/26 switchable DHT preamp that I use in one of my other systems; the Yuichi Aria A-290/ TAD TD-4001 horn/basshorns based system.

Recently I had the very fortunate opportunity to acquire an extremely rare one-of-a-kind 45 DHT preamp designed and built by Radu “without compromises”, his words. This is a rare find and you never see a 45 DHT preamp, let alone one built to this extreme level:





The massive Thomas Mayer 10Y Silver DHT preamplifier now has a new neighbor:







And my new SET DHT custom one-of-a-kind statement 45 monoblocks have a new companion to provide them drive and control





The last two nights I have had two 7 plus hours listening sessions lasting past 2 AM and that is a very good indication of how much I’m enjoying this new combination.

This 45 DHT amplification chain combination exemplifies the best that this niche of our audio hobby has to offer.

More fun times ahead and more listening impressions to come……..

 

[Tango]

It is a pretty good indication when the sun rising tells you that your listening session must come to an end and that you have to go to bed. Another nice listening session last night.

Started with listening to the powerhouse system that is the one of a kind LampizatOr DSD-Only DAC, massive Thomas Mayer 10Y Silver preamplifier, custom 46 amp and Loth-X Troubadours with the original version of the Stefan Stamm ultra high sensitivity Alnico full range drivers.

Ended the night/morning listening to my newest system streaming Tidal HiFi to a dCS Elgar Plus DAC as source for my new custom Telefunken RE084K DHT preamplifier, which controls the new JE Labs inspired dual-monoblock Type 45 amplifier with vintage Telefunken irons that drive the Atelier-Rullit Silver Lab 10 Alnico full range drivers in the JE Labs style Open Baffles, augmented by the Radu Tarta super-tweeters.

For those wondering how the sound of these two very different systems compares to each other, here are a couple tracks on each system for your dicernment:

Thank you for posting videos. Without them there is no glimpse of how each system sounds. They certainly sound very different to one another. I enjoy your Lampi/TM/45 more than the DCS/TeleF/JE Lab. How a person prefers which is meaningless. The difference you show through videos is a great data point to further explore. I admire the way you have fun with this hobby. To me it is not just music or how reproduced sound should be, it is about exploration and fun learning different gears too.

 

[cjfrbw]

I use a Manley Neo 300b preamp as a driver stage for the Wisdom/Bohlender 75 inch ribbon to great effect. I got the circuit diagram, and it accommodates 183, 182b (both ancient 5V versions of 45), 6a5g (indirectly heated version of 2a3 with 6v cathode), 6b4g (directly heated version of 2a3 with directly heated 6v cathode). Along with several types of 300b. these all sound great and all have a different flavor. The 183,182b tubes do manage to convey a slice of the 45 type sound to the amp, though 45 amp itself is best overall for the 45 mystique.

 

[KostasP.]

Thank you, yes agree that the 13E1 SE-OTL amplifier/Thomas Mayer 10Y Silver preamplifier combo driving the Loth-X Troubadours with the original version of the Stefan Stamm full range driver sounds great in the room and part of that magic translates in the videos.

The last few weeks I have been enjoying the Transcendent Sound T16 OTL amp driving the field-coil Supravox 215 2000-EXC drivers in the OB and the 13E1 SE-OTL amplifier so much that I have become very impressed with the OTL circuit topology. I can hear the speed and bass articulation that getting rid of the output transformers allows. As I mentioned previously, I do believe that these OTL amps provide a more neutral and honest presentation of the recordings.

My OTL amplifiers provide that snap and crisp electrostatic-like presentation but with meat on the bones. The 13E1 SE-OTL is very special as it delivers a sense of realism that is very organic and non-fatiguing. Both OTL amplifiers are hard to fault with their speed, direct and neutral sound.

As you can tell, I have been very, very impressed with both OTL amps that in many way have overshadowed the field-coil driver investigation. I can now state that based on my limited experience, the OTL topology brings more to the table than the field-coil drivers. Of course the combination of both is extremely good as they buildup on their strengths of speed, direct, neutral presentation, and electrostatic-like transparency but with heft, or for lack of a better descriptor, meat on the bones. Really enjoy the chesty male vocals and detail without harshness.

Hello Carlos,

I admire your exuberant passion and meticulous and incessant pursuit for maximising your pleasure that you derive from your multiple systems. Your knowledge in the domain of valve equipment and exotic speaker drivers is well-documented and acknowledged and I would never dare "step on your toes" in these matters.

However, I would like to make a corrective comment about the fleeting references to electrostatic speakers and the much abused and misguided comment that is nonchalantly thrown about by a number of basically conventional box speaker owners. As an owner of them for well over twenty years and having critically listened to a plethora of box speakers, I think that my comments have some validity.

Firstly, may I remind you that, just like you rightly consider OTL topologies to be more NEUTRAL and LINEAR ( I agree as I had done some direct comparisons with mic preamps, choosing Millennia as a result ), SO ARE electrostatics ( in my case Martin Logan CLXs ) compared to box speakers. The "meat on the bone" is a colouration, mostly in the mid bass. Of course you have every right to prefer it but it does NOT cease to be an induced artefact imposed by the speaker. Your inference implies that it is a negative trait of the electrostatics ; and by the way, they do much, much more than "snap and crisp" as you claim. On the other hand, the fact that you used them as a reference to exalt the virtues of your electronics is indeed an endorsement!

You spend so much effort, time, mind and heart optimising your own set-ups. I can assure you that if you did the same with electrostatic speakers, in terms of micro and macro amplification ( and not only ), these misconceptions \ presumptions will cease to exist, especially in view of your OTL observations. In a sense, there is a bit of a contradiction here; I'm sure you can detect it!

By no means do I intend to be antagonistic or aphoristic. In this hobby, we all choose imperfections in the false belief that we are attaining a non-existent perfection. I had long concluded that I would rather live with the imperfect "perfections" of the CLXs rather than the perfect "imperfections" of box speakers, to put it rather provocatively!

Finally, none of what I have said negates your right to like or dislike anything at all. I was compelled to make these comments because I sensed a void of rationality in your fleeting references to electrostatics which you may have made inadvertently and most likely in good faith......but we all know that faith is usually blind.

Be always well and enjoy your systems. Cheers, Kostas.