Introducing My System

[morricab]

Really enjoying this discussion as Nat Magma Ms are on order for my system.
So, in addition to now wondering about these NAT Symbiosis New - first I've heard of these, gotta ask Mike, I'm also a bit concerned/quesitoning the approach that Nat uses to bias and manage tube life in his amps.

To be specific, the Nat amps auto bias, which I imagine is a fine approach (I'm no electrical engineer so can't comment on the pros nor cons of auto biasing vs the simpler resister and manual adjust approach). However, per a rather extensive email exchange with Dejan and discussions with Mike, the Nat amps do not indicate when the tube can no longer be biased within the target range. Of "concern" is that Dejan says the amp will continue to operate when the tube can no longer be biased within the target range.

Unlike many other tube amp mfgrs, Nat does not provide a ready means for measuring the bias voltage, nor an idiot light (eg red led) indicating the tube needs to be replaced - think the oil low light in a car. Experience with many tubes over the years clearly demonstrates that tubes do indeed age out and good new tubes can be a rather pleasant surprise.

Dejan's response to my concerns is that (1) the tubes have a long life because the design does not work the tubes hard at all, and (2) worn out tubes sound like crap. Well, while both statements are true, my rebuttal is (1) most tubes have a long life, some don't, and (2) I don't want to wait until I realize the system is sounding like crap. Importantly, tube "wear" is gradual, it is not a binary affair (barring failure of course). So, like the frog in boiling water or tire wear on your car (yup, another automotive analogy) we, or at least me, get accustumed to the gradual performance decline until....

Given all the time and money and emotion in this nutty hobby, I'd much rather know the status of the tubes in play. A means to measure voltage or an idiot light would alleviate that nagging wonder if the tubes are toast.

So, while I remain quite excited to put the Magma M into my system, its also frustrating to now learn that there is literally no way to know if the Nat tubes are operating at optimum - I'm begining to quesiton my decision and call off the purchase.

Thoughts? What am I missing here?

My experience with SETs is that when the power tubes start to go bad they start making strange noise on start up or start making a higher noise level. I have never had a “tube ready to change light” on an amp…never needed it. On amps where the bias coukd be measured/adjusted, I found that as long as the amp biased ok the sound did not change significantly. This gradual decline in performance is a bit of a myth I think. Used tubes that measure fine sound as good (or better) than new ones.

 

[Thundersnow]

Here’s the skinny from NAT on the new amp that Dejan shared with me just now:

“Symbiosis New - Single Stage Single-Ended Hybrid Mono Block Power Amplifier

Some twelve years ago NAT announced the first OTL and OCL - direct coupled hybrid integrated amplifier – Symbiosis Se! Now it is NATSymbiosis New - power amplifier that is completely different indesign!

There is a time now to promote again totally new approach in hybrid amplification!

The unit we called NAT Symbiosis New.

Symbiosis New is an unique mono power (up to 150W) hybridamplifier made by NAT, based on scientific grade single gold platedFET and single nuvistor triode tube that operate in pure class A aspure single-ended device!

Symbiosis New represent true OTL (output transformer less) and true OCL (output capacitor less) mono block power amplifier! There are no capacitors in the signal path. There is only single input hand coiled silver-ofc PTFE (teflon) isolated nano - crystalline core transformer with bandwidth over 1MHz ! Ref. to mention facts Symbiosis New is fully compatible with true balanced (XLR) or single - ended (RCA) type of operation!

Symbiosis New is unique as there is no input, no driver stage, only one single ultra high power gold plated FET with one tube (best - nuvistor triode tube type that is immune to external vibration- zero microphonic device)! Moreover there is “only” a SINGLE power transistor (no parallel connection of many transistors)!

Together there is totally new - unique combination - NuFET(Nuvistor-FET) that act as high current “triode” with very low distortion and excellent behavior ref. to speakers load ! In Symbiosis New nuvistor triode tube that is connected in special manner between two electrode of the FET act as linearization device to the whole “system” (new device) - NuFET !

Energy storage is over 600J as indicated approx. 500.000uF of capacity! For single-ended unit it is incredible amount of capacity that is used!

Inside unit there is also “gigantic” hand coiled ultra low resistance magnetic inductor that additionally increase quality of power supply! Weight of mention magnetic inductor inside Symbiosis New is incredible 35 lbs (approx.16kg)!

In mechanically domain Symbiosis New is also unique ref. to thefact that whole heat sink (with all main electronics) is connected to the main chassis with special damping high quality silicone parts!There is no any “hard” connection between them!

Main facts of Symbiosis New:

• Unique device - High power single NuFET self amplification(single) stage amplifier
• One of (if not) the most compact in class (pure single-ended 150W) (19"x19"x15")
• One of (if not) the most efficiency in class (320W of power consumption for up to 150W of pure single-ended class A)”

 

[poonbean]

My experience with SETs is that when the power tubes start to go bad they start making strange noise on start up or start making a higher noise level. I have never had a “tube ready to change light” on an amp…never needed it. On amps where the bias coukd be measured/adjusted, I found that as long as the amp biased ok the sound did not change significantly. This gradual decline in performance is a bit of a myth I think. Used tubes that measure fine sound as good (or better) than new

My experience with SETs is that when the power tubes start to go bad they start making strange noise on start up or start making a higher noise level. I have never had a “tube ready to change light” on an amp…never needed it. On amps where the bias coukd be measured/adjusted, I found that as long as the amp biased ok the sound did not change significantly. This gradual decline in performance is a bit of a myth I think. Used tubes that measure fine sound as good (or better) than new ones.

Thanks, but I think your response makes my point.

Because the Nat does not indicate if the tube is out of bias, the user can't measure bias, and the amp continues operate when the tube cannot be auto biased, the notion "as long as the amp biased ok" remains a mystery. So, one must wait until the tube is bad enough to "start making strange noise on start up or start making a higher noise level".

I've never seen a tube ready light either. Re never needing one, is that because your amps had a means to measure bias or you simply waited for the tube to start making noises? I definitely recall occaisions (Lamm for example) when changing out the tubes simply because they had many hours on them (who knows how many) but were not noisy, yet new tubes sounded much better.

In my experience with amps that have bias adjustment, I definitely recall seeing that the max voltage a tube could be baised to decreases over time. This suggests gradual tube decay until the tube can no longer be biased within the desired range. After that, I suspect it will continue to degrade until it becomes noisy. This is the domain - between not biasing within goal and noise - that I wish Nat would address in a more meaningful way.

 

[morricab]

Thanks, but I think your response makes my point.

Because the Nat does not indicate if the tube is out of bias, the user can't measure bias, and the amp continues operate when the tube cannot be auto biased, the notion "as long as the amp biased ok" remains a mystery. So, one must wait until the tube is bad enough to "start making strange noise on start up or start making a higher noise level".

I've never seen a tube ready light either. Re never needing one, is that because your amps had a means to measure bias or you simply waited for the tube to start making noises? I definitely recall occaisions (Lamm for example) when changing out the tubes simply because they had many hours on them (who knows how many) but were not noisy, yet new tubes sounded much better.

In my experience with amps that have bias adjustment, I definitely recall seeing that the max voltage a tube could be baised to decreases over time. This suggests gradual tube decay until the tube can no longer be biased within the desired range. After that, I suspect it will continue to degrade until it becomes noisy. This is the domain - between not biasing within goal and noise - that I wish Nat would address in a more meaningful way.

You kind of missed my point, which was simply, you worry too much about something that isn’t a big problem. If you are really that worried just replace the tubes every year and enjoy the good sound they make.

 

[Argonaut]

I've never seen a tube ready light either. Re never needing one, is that because your amps had a means to measure bias or you simply waited for the tube to start making noises? I definitely recall occaisions (Lamm for example) when changing out the tubes simply because they had many hours on them (who knows how many) but were not noisy, yet new tubes sounded much better.

In my experience with amps that have bias adjustment, I definitely recall seeing that the max voltage a tube could be baised to decreases over time. This suggests gradual tube decay until the tube can no longer be biased within the desired range. After that, I suspect it will continue to degrade until it becomes noisy. This is the domain - between not biasing within goal and noise - that I wish Nat would address in a more meaningful way.

I understand your point and might empathise as to your concerns , However It appears obvious that NAT do not have any plans to implement a significant addition to their circuit and design to accommodate either a bias meter or bias warning light . The only other option being for NAT to issue instructions on how to perform bias reading monitoring manually , which for obvious reasons they may not do so ( unless that is part of their product manual already ? )

It seems to me that should your concerns regarding this product be of such paramount importance to you that you might be best off looking elsewhere for your amplification.

 

[poonbean]

I agree that your advice to not worry about something one has no control over makes a lot of sense. Surely there's some profound philosophical theme buried in there somewhere. If I was whining about not knowing if the capacitors were still storing and discharging maximum farads, then yes it would be reasonable to advise me not to worry if not label me nuts.

OTOH, assuming that the primary ingredients to tube equipment are the transformers and the tube(s), and the predominant issues with tube gear are tube degradation/noise (which affects SQ) and heat (which affects comfort), tube equipment should allow the user to assess tube status in order to keep the equipment optimally operating before tube failure (noise). We can mitigate excess heat by opening a window, turning up the AC, or enjoying another beer while naked.

I'll close with hoping there would be a more technical discussion that would show me where my thinking is wrong, or because WBF has some influence and is perused by dealers and manufactures, that we would collectively agree that this is an improvement Nat (and other tube manufactures for that matter) ought to consider. Because this is such a small marketplace, I suggest that we can be proactive, rather than passive, consumers of audiophile equipment.

 

[morricab]

I agree that your advice to not worry about something one has no control over makes a lot of sense. Surely there's some profound philosophical theme buried in there somewhere. If I was whining about not knowing if the capacitors were still storing and discharging maximum farads, then yes it would be reasonable to advise me not to worry if not label me nuts.

OTOH, assuming that the primary ingredients to tube equipment are the transformers and the tube(s), and the predominant issues with tube gear are tube degradation/noise (which affects SQ) and heat (which affects comfort), tube equipment should allow the user to assess tube status in order to keep the equipment optimally operating before tube failure (noise). We can mitigate excess heat by opening a window, turning up the AC, or enjoying another beer while naked.

I'll close with hoping there would be a more technical discussion that would show me where my thinking is wrong, or because WBF has some influence and is perused by dealers and manufactures, that we would collectively agree that this is an improvement Nat (and other tube manufactures for that matter) ought to consider. Because this is such a small marketplace, I suggest that we can be proactive, rather than passive, consumers of audiophile equipment.

Look, just because a tube has a lot of hours doesn’t mean it has an issue. If a tube with 5000 hours still tests fine it will not sound worse than a new one . LAMM might drive their tubes very hard but NAT says they are very easy on them. This whole tube degradation is way at overblown. This is coming from someone who has had a whole bunch of tube gear over the years…most of which had no way to check where it’s at. As I said, when they start to go out you will know.

 

[poonbean]

Got it. Really appreciate the advice. Thank you.

 

[cjfrbw]

I stopped worrying about tubes when I started worrying about transistors.

 

[poonbean]

Touché

 

[Thundersnow]

If someone had told me I’d had the privilege of being an audiophile in Serbia some 30 odd years ago, I’d probably buy that person some cake. Meaning I’d probably think he’s so far gone, meds won’t help so might as well have some cake.

Anyway, fast forward to today and I have the pleasure of sampling and acquiring fantastic gear from folks like Dejan of NAT and Sasa of Trafomatic.

Anyway, in a quest for a preamp that was a little less “out there” and complicated, as well as more visually appealing and ergonomic, I have been paying close attention to Trafomatic’s work. To be honest, they blew me away in Munich for two consecutive years in 2022 and 2023 (skipped 2024), so I knew I was going to pull the trigger at some point.

I gave the Trafomatic guys a call and ended up speaking with Sasa. The guy happens to be a very down to earth and extremely smart and approachable dude, so we had a very easy going and engaging conversation as he delivered the Lara preamp to me.

I already thought I was hitting the pinnacle with NAT, but oh boy, does Trafomatic know what the hell they’re doing! The elegant and relatively speaking simplistic design of the Lara pre translates wonderfully into its sound signature. It’s like peeling off lairs of excess electronics to hear the very essence of the recording. So, in terms of sound philosophy of preamps a different approach from NAT. While the NAT preamp takes over the sound signature, the Trafomatic Lara pre politely gets out of the way while unassumingly so making everything sound bigger, cleaner and more beautiful. So there you go.

Having a lot of experience now with NAT and various other preamps, I suspect the culprit in NAT’s design is the battery power supply. As much as it drives some aspects of the sound forward, it veils the presentation to an extent — I guess due to the inherent drawbacks of battery power supplies. If you want analogies, think about listening to music from a laptop powered by battery power versus quality AC power.

How impressed am I with Lara and Trafomatic’s sound? I’ve ordered Tara 30A… which Sasa tells me is a serious leap forward. It also has 25ohm output impedance which will work a lot better with my NAT Symbiosis New.

And in case you plan to ask… no I’m not looking to try Trafomatic power amps. I’m done with tiny supernovas sitting in my living room for now

 

[Thundersnow]

Paid a visit to NAT’s listening room a few days ago. Read my description in the video for the impressions:

 

[Kingrex]

Non of my tube gear has a bios now. If I wanted, I could get a tube tester and check them periodically. I heard my mercury rectifier starting to go. Actually saw it first. The color got a little out of balance on the plates. Then it became noisy in an odd way. I replaced the tube and all good again.

 

[Chrispb1]

Hey guys, a quick update on my slow-rolling evolution of the system. I was previously testing with Magma M’s from NAT to see if they’re up my alley. I saw huge potential in the sound and decided to take the plunge. However, I was testing previously with what I believe are the standard GM30 tubes. For my own pair, I managed to procure a pair of Eimac 450TL tubes.

The difference in sound is substantial in favor of the US tubes. Less heat emission (which is a big thing for me) — not to mention the added clarity in the sound, control and tighter bass. As it is, the 450TL is a higher power tube than the GM30 and with that comes a higher damping factor. This controls the Coltrane 3’s in such a way that I don’t see a need for bi-amping that I was experimenting with previously.

I have only spent a couple of hours with the amp, but those are the quick first impressions.

Also, as another update, I ended up with using the KR PX25 Anni tubes in the GG3 Lampi DAC, to go along with the NOS WE 274A tube (use it with an adapter). As compared to the stock 45’s (which in retrospect and having tried a few different tube setups are the worst I’ve heard), and comparing to new WE 300B the PX25’s are clearly better in every way than the 45’s and maybe only lack a touch of tube magic/warmth on the 300Bs, but improve on dynamics, sound stage and bass considerably.

View attachment 104270

Hi, I’m considering a pair of Magma SE, the main tube is an Eamac 450TH not the TL that you mention. Do you know if they are effectively the same tube or why it changed from the TH to the TL. Thank you

 

[poonbean]

Prior to ordering the Magma M, I had an email discussion with Dejan regarding tubes. I'll leave out most of the discussion about bias, for obvious reasons given prior support from this WBF group .

Here it is:
-------------------
My Questions:
The website lists the "6C21 (or equivalent)" tube for this amplifier.
Do you provide the Eimac tube?
Which version?
What other equivalents do you provide or offer?

Dejan's Responses:
Standard, it is GMI30 tube from soviet era, but we have on stock Eimac equivalent or Machlett US made as well!
The best will be 450TL Eimac at additional cost, please contact our distributor on the ground for the info!
Amplifier has automatic bias and it is set the same from the new tube to the near end point of life (dymanic control,not with simple cathode resistor)!

My follow up questions:
Thank you for the information.
Are the standard GMI30 and 450TL equivalent?
If I order with the 450TL, will you need to modify the amp for the GMI30?
I'm not familiar with Machlett, is it the 450TL also?
Please know that I'm working with Mike Powell, I have the Wolf Von Langa Chicago loudspeakers.

Dejan's Responses:
We produce Magma M to be compatible with next type of tubes:
-6C21
-450TL
-450TH
-GMI-30 (soviet era tube)
Remember,all type of tubes should be checked (aging(degassing) and matched)!
[thus my questions/concerns about bias etc, which I explored further with Dejan (to no avail) as I'm unable to check aging /degassing nor matched]
Machlett is 6C21 tube type that we have some in stock!
Speaker that you have is very good to match!
---------------------
Is anyone familiar with the Machlett 6C21 vs Eimac 450TL ?

Based on the above, I ordered the Nat Magma Ms with Eimac and a back up pair of the standard GM130 - should be here in a couple weeks.

Thundersnow - I thought you bailed on the big tubes in favor of the hybrid...?

 

[Thundersnow]

Prior to ordering the Magma M, I had an email discussion with Dejan regarding tubes. I'll leave out most of the discussion about bias, for obvious reasons given prior support from this WBF group .

Here it is:
-------------------
My Questions:
The website lists the "6C21 (or equivalent)" tube for this amplifier.
Do you provide the Eimac tube?
Which version?
What other equivalents do you provide or offer?

Dejan's Responses:
Standard, it is GMI30 tube from soviet era, but we have on stock Eimac equivalent or Machlett US made as well!
The best will be 450TL Eimac at additional cost, please contact our distributor on the ground for the info!
Amplifier has automatic bias and it is set the same from the new tube to the near end point of life (dymanic control,not with simple cathode resistor)!

My follow up questions:
Thank you for the information.
Are the standard GMI30 and 450TL equivalent?
If I order with the 450TL, will you need to modify the amp for the GMI30?
I'm not familiar with Machlett, is it the 450TL also?
Please know that I'm working with Mike Powell, I have the Wolf Von Langa Chicago loudspeakers.

Dejan's Responses:
We produce Magma M to be compatible with next type of tubes:
-6C21
-450TL
-450TH
-GMI-30 (soviet era tube)
Remember,all type of tubes should be checked (aging(degassing) and matched)!
[thus my questions/concerns about bias etc, which I explored further with Dejan (to no avail) as I'm unable to check aging /degassing nor matched]
Machlett is 6C21 tube type that we have some in stock!
Speaker that you have is very good to match!
---------------------
Is anyone familiar with the Machlett 6C21 vs Eimac 450TL ?

Based on the above, I ordered the Nat Magma Ms with Eimac and a back up pair of the standard GM130 - should be here in a couple weeks.

Thundersnow - I thought you bailed on the big tubes in favor of the hybrid...?

I did. In terms of sound, the magic you get with those big tubes, is — in my experience — undeniably the most “there” sound I’ve heard in a hi fi system. BUT I couldn’t live with GM100’s heat — and that one to me at least sounded better — more linear, neutral and dynamic — than the Eimac 450TL or the GM30. The GM30 was by far the worst of the three, Eimac was incredibly romantic and had most of that tube glory as people perceive it. I was simply in the more linear, neutral camp — that’s my general preference in hi-fi (as long as the sound’s got meat on the bones). One big advantage of the Eimac 450TL is that I could fairly easily live with its heat dissipation — so in the sense of sound vs ergonomics it’s quite possible that that one is the best choice. But in terms of the sheer power dynamics, linearity and very low distortion (as I heard it) — the GM100 is king.

Yes, I am living with the hybrid amps now — they are very easy on the ergonomics. In terms of that magic in the sound, they have the “thereness” — the illusion of physical performance taking place. They have incredible dynamics and bass control, but they do miss some of that elusive magic of the Magma Evo with the GM100.

So in short the hybrids to me are a great compromise and the perfect match for my taste/heat tolerance.

IF I had smaller speakers, Magma Evo with GM100s in low power mode and sound-wise things CAN’T get better. Yet to hear anything better.

So if we turn a blind eye on the comfort aspect of it and discuss sound alone — GM100 is king. Sorry @Ron Resnick