I just purchased a used OTL Atma-Sphere M-60 mono blocks that I have sent to Atma-Sphere to be upgraded to the current model 3.3 and I also added the option of a higher quality power supply and V caps.
I have sold my old trusted Eggleston Andra 2’s speakers and have built some monitors using Aurum Cantus ribbons (102db) and Aurum Cantus midwoofers (90db) that are both rated as 8 ohm nominal. I have a DEQX Premate and will be crossing over to (2) JL Audio F-113 subs at 80hz.
Currently I am using a solid state high power stereo amp (Pass Labs) that I used with the Andra 2’s.
The Atma-Sphere M-60 is rated at 60 watts class A and is said to work better with higher impedance loads.
It will probably be a few weeks until I get the M-60 and was hoping someone could provide opinions of what to expect.
I listen to late 60 early 70’s classic rock music mostly. Sometimes loud.
I have tried many tubes including some NOS RCA's from the 50's. To me the Sophia's are the best in sound quality. You can buy them direct from Sophia. They go about $100 each. But the Full Music looks and sounds just as good at 1/2 the price of the Sophia's.
What were they replacing? This thread is getting pretty long. If I recall, they were pretty old. And, where did you buy them? I am using the stock tubes from Atma-of which, I have no complaints, but am always interested in 'upgrades'. Bob
Dragonvibe...I noticed you referred to your "New" Atma-sphere Nirvana amps. They are not yet listed on Ralphs website. Would love to hear more about them, as well as your impressions, and comparison to your M60's.
It seems my post was a bit too much ( I can't type outre with the Accent Grave on my keyboard). Gee, I thought if the President said it, it was okay. B
I am glad to hear you find the Zero’s benefit your system. I have to say that I am surprised that they would make such a difference, considering that you have very efficient speakers to begin with. Bob
Ozzy, Your results make sense, the OTL reveals more of its ultimate sonic performance driving the higher/easier impedance load. I bet your system sounds terrific, Congratulations. Charles
Well, I just removed the Zero’s from the M-60’s after about 10 days connected and once again used the amps solo. After listening to a few tracks I then replaced the Zero’s with the 2X connection.
In the end, I’ve got to admit the Zero’s are a needed complement to my DIY speakers. There is a wider soundstage along with much better dynamics.
So Ralph and others the Zero’s are keepers with my Atmasphere M-60's and my DIY speakers.
I also found that the Full Music 6SN7 tubes are the same as the Sophia tubes and at much lower price!
Ozzy, I don't have the Zero's. I only mentioned it because when I changed the crossover settings of the M5-HP, things sounded grainy/shrill. John Rutan said it was that the circuit needed to settle in for about 60 hours or so. Hence, I was wondering that if you changed the Zero settings, it, too, might need to 'burn in' in order for you to gauge the differences in sound quality. As I said, it may not be the same thing, but I thought I would mention it. Glad to hear the Atma's living up to your wishes. Bob
Phil, That's a tough one. First off are you sure you want to stay in the low power arena? I guess it depends on your speakers. Now, I had the X series Pass Labs and you are talking about the XA so its hard to compare. I like the Atmasphere because of its purity of natural sound. ozzy
Ozzy, I've been considering a Pass xa30.5 vs Atma-Sphere S-30, which I assume is pretty similar to your amp comparison....just lower power. How would you describe the sonic differences? I prefer a full-bodied, dense tonality, but with bottom end slam....not looking for a lean, highly detailed presentation. Thanks, Phil
Ozzy, When you described the Atma-Sphere as more natural sounding than the Pass Labs, case closed IMO. What's more desirable than improving that elusive characteristic? Natural = organic= realism. Charles
Oh, by the way. I like the Atmasphere M-60's so much that I did sell my Pass Labs X350.5 amp. It was a good sounding reliable amp but I won't miss the weight...
Thank you for your post. Did you find the higher multiples better? What did you finally end up preferring?
I am pretty sure that the 2X is better with my amps and speakers. To me it was quickly apparent. The 3X setting increased the sense of more dynamics but the soundstage was not as open sounding. So, for now I will leave the 2X setting attached for maybe about a week .The only question is whether the system will sound better without it.
Not to be a pain, but I wonder if you should leave the transformers set at a connection for a period of time. I only say this because, when I adjusted my Vandy M5-HP crossovers, Johnny Rutan said they need to settle in for a few days before they exhibit their true character. This situation may be different, but I thought I would post my thoughts with the hope of having you make the best informed decision. (BTW- I recall reading that Steve McCormack felt that the Zero Transformers made a significant difference even with his SS amps). Bob
IMO there's no specific areas to really analyze. I'd just listen to a variety of music you enjoy. Your ears and spontaneous response to what you hear will determine the best combination for your listening.
ozzy between this and your graphene contact stuff experiment I think we need to dub you "The Tinkerer"! Not sure I've ever seen someone do so much to their system in such a short period of time ;-) glad you're having fun and keep keeping us posted!
I have received the Zero Transformer. I have tried the 2x and now the 3x connection. There seems to be an improvement with both but there is no way to do a quick A/B comparison.
What should I listen for that would help me decide which is the best multiplier?
Ozzy, I'm interested in your findings with the Zeros due to mixed results I've read about. Your easily driven speakers could sound better without the transformers. Charles
I just found a used set of the Zero-Autoformers for a good price. Perhaps next week I will be able to try them with the M-60's to see if they provide any benefits with my DIY speakers.
Too bad more Maggie lovers who want to drive them with M-60's aren't aware of the Eminent Technology LFT-8b loudspeaker. It like Maggies is an inefficient planar-magnetic design, but the LFT-8's impedance is nominally 8 ohms, and if bi-amped the m/t panel (frequencies below 180Hz are handled by a sealed-enclosure dynamic woofer) has an impedance of 12 ohms, much better for a tube amp than the 4 ohm Maggies.
Doesn't using zero transformers defeat the whole point of an OTL amp?
It's putting a transformer in and makes it similar to a non OTL push
pull tube amp.
'Defeat' as used in the question above suggests that an OTL is trying to do something that is somehow in opposition to a normal amp with a transformer?
It isn't. What we are trying to do is get as close to the music as we can.
The fact is that the ZERO has a very low turns ratio. Because of this it has very wide bandwidth- wider than almost any amplifier made, tube or solid state. You can't do that with a regular tube amp with an output transformer. You need to start with an amp that already has a fairly low output impedance, and a circuit that is not putting DC through the transformer winding.
The ZERO is really a problem solver- for example, here in Minnesota a lot of people want to use the M-60 with Magnaplanars. Usually they have smaller Maggies, but the M-60 is usually challenged when presented with a 4-ohm load. The ZEROs fix that and you don't loose the transparency of the amp. My rule of thumb is that when using the ZEROs you don't encounter any serious sonic tradeoffs. If the amp sounds better without the ZEROs then you just don't need them.
I think its better if the amp doesn't need the ZEROs. That usually means the speaker load is 8 ohms or more as in the case of ozzy's speakers.
Doesn’t using zero transformers defeat the whole point of an OTL amp? It’s putting a transformer in and makes it similar to a non OTL push pull tube amp.
That’s a logical question, which has been stated here in a number of other threads in the past, but basically the answer is "no." From a technical standpoint the following statements quoted from the FAQ at the zeroimpedance.com site are good ones IMO:
12) What is the difference between the ZEROs autoformer and a typical tube amplifier’s transformer?
The ZEROs have a few advantages over "typical" tube amp transformers:
A) The music comes out on the same winding wire that it goes in on so the music does not have to pass from a primary winding to a secondary winding.
B) There is no DC current to contend with. When a transformer is made to accommodate a DC field, its audio transparence is compromised.
C) The impedance ratio is very small (16 ohms to 4 ohms, compared to a few thousand ohms to 4 ohms). This simply means that it is much easier to achieve things like, frequency response extremes, than with a "typical" tube amp transformer. The ZEROs sport a frequency response of 2 Hz to 2 MHz.
13) Doesn’t adding the ZEROs to my Output-Transformer-Less (OTL) Amplifier defeat the benefits of the OTL design?
The ZEROs were originally designed to maximize the full benefits of the OTL amplifier by changing the speaker’s load impedance to the Maximum Power Transfer Region of the amplifier being used.
The ZEROs are not an amplifier fix, they are a speaker fix. It is a great disfunction to music loving audiophiles for speaker manufactures to be making 4 ohm speakers with 3 or 2 ohm impedance dips, and then expect amplifiers and speaker cables to be able to transfer music into a load approaching a dead short. The ZEROs simply multiply the impedance of the speaker in use, and do it so transparently they provide greater benefits than the "penalty" of an added component.
As I said, from a technical standpoint that all makes sense to me. Basically, all transformers and autoformers are not created equal :-)
Doesn't using zero transformers defeat the whole point of an OTL amp? It's putting a transformer in and makes it similar to a non OTL push pull tube amp.
ozzy glad to hear you're enjoying the amps and not already thinking about your next amp, at Audiogon we call that progress :-p. Seriously though have fun roll tubes and just settle into that sound for a while I am sure its going to continue to improve for you. Happy listening!
We are on the same page. But, you've got to give Atma-Sphere and Ralph credit for allowing an ongoing upgrade path for his components. So that in itself will mean long term enjoyment with the latest and greatest version of his equipment.
Ozzy, Thanks and I sure you understand my observatIonal comment. Read the threads on Audiogon and many other audio forums and they're full of people discussing their various journeys through the maze of audio equipment over the years.
At some point some do finally find what they've been looking for. Relatively few build their first system and retain all the initial components for life. That's all I am pointing out. A friend of mine has the same Audio Research power amplifier he bought new in the 1980s. He's the exception rather than the rule. Charles
I went from Krell (KSA250) to Pass Labs (X350.5) to now the Atmasphere M-60's.To my ears each change has brought significant improvements in sound quality enjoyment.
That's not to say that sometime in the future, something better may come my way, but I am really digging the M-60's.
I understand their are people who hang on to their components/speakers for life. in addition to yours there are "lifer' ARC,CJ, Krell, McIntosh etc. They exist but don't make up the majority of the audiophile community. I suspect many more of them over their life rotate through much equipment.
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