If you have a question that is not here, please contact us. What is Atma-Sphere Music Systems, Inc. all about? Atma-Sphere was started in 1978 and is the oldest manufacturer consistently producing OTL (Output TransformerLess) and triode amplifiers. Ralph Karsten designed and patented the music producing circuit which makes our products the best in the world. Atma-Sphere's claims to fame are: the world's first reliable and practical OTL! the world's first fully balanced OTL. the first all triode fully differential zero feedback tube amplifier. the first commercial tube amplifier with only one stage of gain. -and all in the same place at the same time. We also make unique preamps: the world's first fully differential zero feedback all tube preamp. the world's first all-tube preamp with a direct-coupled balanced output. the world's only all-tube preamp to support the 600 Ohm balanced standard. Are there any reviews on Atma-Sphere products? Yes, see our Reviews Page. What is the most powerful OTL made? The Atma-Sphere MA-3 makes slightly over 500 watts into 3 ohms. So far it it the most powerful OTL in production. Why don't you make a phono stage? We do. Both of our preamps are designed as stand-alone phono reproducers. Since we developed and patented our line stage technology, it happens to be a fact that they do sound better than any other line stage available at this writing. This has been true since the inception of the preamps in 1989. So if you want to hear the best that phono can offer, it is best done through our preamps. By incorporating the phono into the preamp, we eliminate the variables of interconnection between the phono section and the line stage and we offer one of the best volume controls available in the industry. Our patent allows for performance in the line stage that is obviously superior to any line stage available elsewhere even when price is no object. Are Atma-Sphere products Futterman OTLs? No. Our gear employs our patented Circlotronic® design which is not only much simpler, but side-steps the problems of the Futterman, making OTLs available to a much wider audience. Are OTLs unreliable? Again, no. The Futterman and New York Audio Lab amplifiers (sold by Harvey Rosenburg) created this reputation. A properly designed OTL such as an Atma-Sphere OTL is very reliable and are proven to run for decades without service other than tubes. How does Atma-Sphere's patented design work? In each audio channel, there are two single-ended triode amps running 180 degrees out-of-phase with each other (differentially). So distortion is cancelled at every point throughout the amp (without feedback), leaving only the music. Thus, Atma-Sphere combines the power of push-pull with the musicality of single-ended, but with better sound than either, because the output is direct coupled (no output transformer). Thus, our gear is wide bandwidth, very dynamic, extremely neutral, and virtually distortion-free. What is the function of the meter? On our older amps: The bias is set using the meter and the appropriate controls located on each chassis. The procedure (outlined in the owner's manual), is simple and requires less than one minute per chassis to complete. On the new MkIIIs: the meter allows you to monitor output power and is also used to set DC Offset. The bias is automatic on the MkIII amplifiers. What do I need to know about the tubes? Not a lot. Atma-Sphere equipment is designed to work with commonly available tubes, making our products easy to live with. The 6SN7 tubes we use are produced in China but there are many aftermarket versions available. The output tubes are Sovtek, Svetlana or Chinese. The miniature triodes used in the preamps such as the 12AT7 and the 12AU7 are usually Chinese. Other types of tubes may be available on request. Below are the tube types and quantities needed per chassis: Equipment Output Tubes Qty Driver Tubes Qty S-30 Mk III Stereo Power Amp 6AS7G 10 (for stereo) 6SN7 6 M60 Mk III Power Amp 6AS7G 8 6SN7 4 MA-1 Mk III Power Amp 6AS7G 14 6SN7 5 MA-2 Mk III Power Amp 6AS7G 20 6SN7 6 MA-3 Power Amp 6AS7G 42 6SN7 12 MP-1 MkIII Preamp 6SN7 10 12AT7 8 MP-3 Preamp 6SN7 2 12AT7 7 12AU7 2 Will the new amp/preamp work with my current preamp/amp? Yes. Atma-Sphere equipment can be run either Balanced or Single-Ended. There is no need to modify your system to use our preamps or power amps. In fact, most of the reveiws on the power amplifiers were written with single-ended preamps. How Many watts are produced into 4, 8, 16 ohm loads? S-30 Mk III M-60 Mk III MA-1 Mk III MA-2 Mk III MA-3 20, 30w, 45w 45w, 65w, 80w 135w, 140w, 160w 220w, 220w, 218 w 500w, 495w, 490 w Will the amp be comfortable with my loudspeaker? As with all tube amps, 8 ohms or more is preferred for best results. The MA-1 and MA-2 are quite comfortable on 4 ohm speakers. For lower impedances that don't need a lot of power, there is an outboard device called the ZERO that is surprizingly effective. If fact so much so that for 4 ohm speakers Atma-Sphere and a set of ZEROs is often one of the best choices available. Does the amp produce a lot of heat? All Atma-Sphere amplifiers operate Class "A". They run about 10% hotter than an equivalent power Class A transistor amps, but produce a remarkably greater depth of sound for that slight increase in heat. A switch allowing the amplifier to run Class AB is optionally available. If a tube goes down will it damage my speaker? No. The amplifier itself will be undamaged as well. Additional information The power tubes have built in fuses that limit their current capacity. Is the amp stable? Under what conditions might it oscillate? Our amplifiers are unconditionally stable. They will not oscillate with any load or input condition. Can the equipment be built for 235 volt operation? Yes. Atma-Sphere products are silent with 50 Hz operation, making for especially quiet transformers. Please notify your dealer if you need overseas voltages. Will the preamp work with my low output cartridge? Yes. Any cartridge of .2 mV or more will work. An optional stepup transformer for ultra low output moving coil cartidges is available too. What is the break-in period for my new equipment? About 2-6 weeks depending on use. What options are available? Caddock resistor package (standard on MA-2 and MA-3), Teflon coupling caps, power supply capacitance boost (for M-60 and MA-1). STANDARD features include HEXFRED rectifiers, our own custom wire and Cardas connectors. Options are listed on each of our products pages. Is the price stated for a single chassis or for a pair? Except for the S-30, Atma-Sphere power amps are monoblocks, which means there is a single channel per chassis. Therefore, all power amp pricing is for a pair of chassis. What are the shipping dimensions? What does it look like? On the products page are links to individual data sheets, where the shipping dimensions can be found toward the bottom. The equipment is also pictured. How long after I order can I expect to receive my equipment? If there is a dealer in your area, you may be able to pick one up at the time of purchase if s/he has one in stock. Otherwise, delivery varies from immediate to up to 6 weeks on optioned equipment. How is payment made? We accept credit cards, check, and wire transfer. Please contact us for details and arrangements.