Amps Atma-Sphere M-60 Mono blocks OTL design

atmashere,

Does the usage of the Zero’s draw more AC current? That is in monthly energy cost?

I ask this because the M-60's meters move a little now.

ozzy

atmasphere,

I just posted some pictures under "ozzy system" page.

gdnrbob,

I was wondering why there are not any used Zero's for sale. They are a real plus.

charles1dad,

The amps seem like they are now more powerful.

ozzy

Well I just placed the 2nd pair of Zero's into position.

Wow! what an improvement! 

Now, with biwiring and the dual Zero's there is much more detail in the bass, mid, treble along with better dynamics.

Ralph and others this is truly the best I have heard thus far with the M-60's.

ozzy

Ralph,

Thanks again for the help.

At this point, I have spent a great deal of time, effort and $$$ to get speakers and the proper crossovers for an 8 ohm load.

But, that being said the M-60's still sound very good without the Zero's.

ozzy

Atmasphere,

So, should I place the Zero’s before or after the crossovers?

ozzy

jond,

Just a crazy ole' audiogonner gone wild!

ozzy

Tinkerer? I think I am way beyond that!

ozzy

As I noted in this thread I am using a pair of the Zero Autoformers with my M-60’s. The M-60’s were made with dual binding posts for bi-wiring.

Since my DIY speakers and external crossovers were also built with bi-wiring in mind, I am going to try a second set of the Zero’s to complete the Biwire set up.

Has anyone tried this? Will a pair of the Zero's on each speaker change the impedance?

ozzy

Early on I did have a couple of the power tubes blow that took out the fuses. So I’m reluctant to put a $100 fuse there. But, I have coated the fuses with graphene.

Now that the tubes and other changes have settled down someday I will probably try the SR black fuse.

Ralph, What value is that first fuse? I think it was a 3 amp slow blow, is that correct?

ozzy

gdnrbob,

Well since they are currently in production you can buy them new from the Vendors charles1dad mentioned. Buying through EBay is a little more risky but like on Audiogon you check the sellers reviews and take a chance. I have not had a single Sophia or Full Music tube fail thus far. But, I have had a NOS vintage RCA fail.

almarg,

You always post such great information and I thank you. Perhaps with other tube amps the Sophia/Full Music tubes would be a problem but with the M-60's they are good.

ozzy

I bought mine off EBay.

ozzy

almarg,

I have noticed a very low level hum when I place my ear up to the speakers with no music playing. But, it is minimal and I overall prefer the sound quality over that minor annoyance. Perhaps if they are installed in a preamp it may cause more problems downstream.

charles1dad,

How does Sophia get there brand on the tubes if they select the best ones? I think they just purchase a lot of the tubes from TJ and have them branded "Sophia" then they grade them A-C. I think the grade A ones are used in the USA market and sold direct from within the USA.

ozzy

Charles,

I don't think that's quite right.

I think the manufacturer in China is called TJ or something like that. Then they are different branded. I think Sophia's claim to fame is they select the higher quality tubes and then put there brand on them. At least that is my understanding.

ozzy

gdnrbob,

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.

ozzy

Sure impressed with the Sophia / Full Music tubes with my M-60's.

ozzy

Naw, I'm a gentleman.

But the Zero's are recommended.

ozzy

gdnrbob,

Bob, I think its a matter of impedance more so than sensitivity. The 16 ohm connection just sounds better than the 8 ohm.

ozzy

dragon_vibe,

In essence that is what I'm doing, but for the low bass I am using 2 JL Audio F-113's subs.

ozzy

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.

Bob,

Thanks for that info.

ozzy 

Charles,

Yes, it is a pleasure to listen to it.

ozzy

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...

ozzy

gdnrbob,

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.

ozzy

jond,

Yeah I never should have retired. Too much time on my hands... but I'm really enjoying myself.

charles1dad,

Thanks, so far it seems that as I increase the multiplier the music comes  forward. But I need to investigate further.

ozzy

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.

gdnrbob,

Thanks I will. They won’t be shipped until Monday from Ca. so I might not get them next week.

atmasphere,

Thanks for your reply. I just gotta know. And if the Zero’s are not needed for my speakers I will sell them.

ozzy

armasphere,

I didn't quite mean rock concert levels.

charles1dad,

Yeah, I concur, but this will complete the process of trying to get the best out of the M-60's.

ozzy

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.

ozzy

Yes, but can the M-60 power these to rock music levels?

ozzy

Charles,

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

Atmasphere, charles1dad,

I think you are both right.

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.

ozzy

Thanks, Ralph! You the man!

ozzy

I picked up a couple used Sophie 6SN7 tubes. I think Ralph suggested that the center back would be the best placement. A few moments of listening and they do sound more lively than my previous NOS RCA's.

So, I also just bought another 2 more (used on line) Sophie's. I think Ralph said to place them in position 1 and 3. Is that the opposite back corners?

Can someone explain the tube numbering scheme on the M-60's 6SN7 tubes.

Starting with the front, then left back, middle , then right back.

ozzy

atmasphere,

Thanks. I kind of suspected it. It just seems due to the price point there should be some on line reviews comparing the two products.

charles1dad,

Are you aware of any on line comparison of the 805ia with the M-60’s?

mac4845,

You could always do what I did, find good used units and have them upgraded at Atma-Sphere.

ozzy

atmasphere,

Can you share your comparison? Ralph, I know you are the owner of Atmasphere but I would really like to hear your opinion. And Is there an on line comparison?

I am only asking because I really do love the M-60’s amps. But, the Prima Luna gets more press coverage and is only single ended.

I think it would be very interesting for a head to head comparison sound quality wise. I did hear the Prima Luna at a Dealers showroom a few years back and I was not impressed. At the time I was using Pass Labs amp and the Eggleston Andra 2 speakers and the dealer was using Sonus Faber speakers with the Prima Luna.

My bet would be on the Atmasphere stomping the Prima Luna.

ozzy

Has anyone ever compared the Atmasphere amp to the Prima Luna?

ozzy

atmasphere,

I know many that I have were listed as GTB but the writing on the glass tube is gone.

Any way to physically check it ?

ozzy

gdnrbob,

Yes, I do have (2) JL Audio F-113 subwoofers. With the DEQX  I am crossing over at 100hz. And yes, this combo far exceeds my Egglestons. I sold them.

Well my 72 hour abstinence is complete! I just turned back on the Atma-Sphere M-60's with the NOS 1970's era Russian 6H13C output tubes and the RCA 1950's era  6SN7GT driver tubes.

ozzy

gdnrbob,

The rated FR is 37 to 4000hz. But that is probably with a ported design and to me would be very subjective anyway. I would say reasonable / usable low end and a non ported design would be about 50-60hz.

ozzy

steakster,

Thanks for your info. The Grand Prix amp stands that I am using have little pads that go between the acrylic 3/4" shelf and the carbon fiber stand. They are available in different "squishy" pads for different weight loads. I did try Stillpoints Ultra SS under my Pass labs amp and I did not like the sound with them with my Grand Prix amp stand.

o_holter,

Thanks for your post. My DIY speakers have a very flat 8 ohm load and a high sensitivity rating. Couple that with the high crossover setting , I think they are easy to drive.

ozzy

steakster,

First off I am getting older and my Eggleston Andra 2 speakers were 215lbs each. Moving them around the room is no fun. I always wanted to try tube amps but I knew that my Andra’s required a fairly hefty amp to drive them properly.

Once I got the DEQX Premate with its built in subwoofer crossover, my brain juices started to flow. BTW, I also retired 2 years ago so I now have extra tinkering time available.

Anyway, I wanted to make a very easy to drive stand mounted speakers to use with my JL Audio subs. I made a prototype with some drivers I bought on EBay. They actually sounded pretty good but the cabinets still looked very DIY (I own a jig saw and a circular saw and haven’t changed the blade in 30 years)!

I then found on Parts Express some really nice Hi Gloss cabinets with the internal volume and size I was looking for. So keeping with Parts Express, they sell the Aurum Cantus G1 ribbon tweeters that can handle 100 watts rms. (I have always loved the sound of ribbon tweeters). I then thought keeping within that family line was the top of the line Arum Cantus 6.5 mid woofer. It had the specs that I was looking for. Well, the 6.5 mid woofer really turned out to be a 7" size and the High Gloss cabinets were a pain to cut. The front baffles are 1 1/2" thick !

But I did it, and they look great. I stuffed them with " acousta stuff". I wanted to be able to experiment with different crossover settings so I built an external crossover box. Well as I started trying more and larger caps and inductors that box became too small and I made a larger one with spikes! ( BTW, I ended up with all Mundorf silver, Gold, Oil caps).

Anyway, it has been a fun challenging project that I am really proud of. I have listened to many systems and I think I have a winning combination! Total cost about $2600.

Thank you for asking...

ozzy

charles1dad,

Thanks!. I finally received my 1970's new Russian output tubes. With these tubes and my newer 1950's RCA driver tubes, I think I can finally be ready for the final voyage.

But, Ralph says for tube longevity to put these new tubes on standby for 72 hours before using them. That means no music until Tuesday night! Yikes!

gdnrbob,

Yes, I have done probably a dozen or more calibrations. But I guarantee no matter how many times you read the manual the first time you try it you will be going back and forth through the instructions mumbling words that you won't be proud of.

I still have a problem interpreting the impulse response graph and the corrections settings. But most everything else I could help you with. Al is also very knowledgeable about the DEQX and its settings.

ozzy

charles1dad,

I say its the purity of the sound.

ozzy

gdnbob,

I can’t really comment about DEQX support. ( I hope I don’t have to find out). In actuality the DEQX is more complicated than the on line info shows. But, many of us are now mastering all the quirks and can help you. I must say the finished calibration does not sound in any way digital or with the negatives I have experienced with previous room correction devices. (The current one that comes to mind is the DSPeaker).  The DEQX is the real thing!

bugredmachine,

Now that I’m getting more time with my Atma-Spheres I am so impressed that I can’t imagine anything sounding better!

The heat in my audio room will increase about 4 degrees, IF I have the amps on all day.(12+ hours). This amount is probably not much more than when I used the Pass Labs the same amount of time.

I must add that Ralph at Atma-Sphere is a A+ dealer and will provide help when needed. Highly recommended!

ozzy

atmasphere,

Thank you for the tips. Yes, I am using Grand Prix amp stands.

I got my Chinese output tubes , but I'm still waiting for the Russian tubes.

ozzy