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The lord of the tubes. Now we finally get to the Erato. This grandiose setup of preamp, two monos plus a pair of huge output transformers had as many similarities with the Ligeia as there were differences. The similarities didn’t end in appearance, size and colossal weight (Erato is substantially heavier however) and the differences transcended names and specs (power, tube types). Both of these objects of the audio arts can be called ‘made in Russia’ but with some qualifications. A lot of components and several important schematic elements are actually not of Russian origin.

Alexei Syomin finished this amplifying quintet just in time for the 2012 Moscow Hi-End Show (MHES). It was here that I first saw and listened to what then didn’t even have a name yet. As you remember, Ligeia borrowed its name from a nymph. To support his tradition of naming components after mythological heroines, I suggested to Alexei a lady from Apollo’s retinue: Erato the muse. Without hesitation Syomin approved this spontaneous birth certificate on the spot.

Explaining the idea behind Erato, he stated his aspiration to create a single-ended filamentary amplifier with higher output power than Ligeia and other models. Erato’s output power thus became a chunky 100 watts into 8 ohms. Prior to it Syomin used to construct amplifiers of low output power, as a rule no more than 10 watts. This he viewed as sufficient for most applications. But predictably the pendulum swung to the other side. As he put it, "as soon as you finish something, the idea to create an ideologically different concept grips you. A lot of modern speakers represent a complex load for an amplifier to need higher power to work properly. That’s why I decided to construct a more versatile machine."

Erato inherited Ligeia's design philosophy of sectioned transformers, divided cathode heating and stabilized DC voltage by means of chokes. "I tried voltage stabilization with transistors but didn’t like the results. The sound shifted to an undesirable side." In his other products Syomin followed the unwritten audiophile law of pure filamentary tubes and valve rectifiers. Wherever possible he used vintage components and special iron cores for his transformers. For Erato he decided to give up on valve rectifiers. Instead he went after Schottky diodes and Germanium diodes for the preamp. As a result the sound became sharper and quicker. Talking to Alexei I mentioned that the power increase itself played an important role in the end result.

"But you can hear how the amplifier's sound is different at the same power level" he objected. I still think that one can’t brush away the sum of several factors and also—this may well be the main reason—the character of the output tube. "This time I wasn’t going to use only non-Russian or old tubes. There are many Soviet tubes in the Erato. But I decided to install samples from before 1970 only in extreme cases due to physical degradation." The powerful output pentode working as a triode—the first fiddle in Erato's tube ensemble—was manufactured in 1962. This tube is a copy of a Telefunken model and was mass-produced in the USSR under the ГУ-80 designation by means of repair equipment from Nazi Germany. This equipment was no doubt subject to old age and wear.

"The ГУ-80 working as triode reminds me of my favorite 300B. The sound of the ГУ-80 can be rightly called proper and neutral whilst most of the high-voltage tubes with high inner resistance are pretty specific i.e. not neutral. This time I paid attention not so much to the sound character and year of the tube manufacture as to harmonizing the entire valve set and finding parts that collaborated perfectly. Some driver tubes will work with three or four different followers but these combinations will all affect the sound differently and sometimes gravely so. It’s important to also by ear and perhaps primarily so find the preferred combination. My winning candidate as ГУ-80 driver was the 300B which opened up the output tube completely and created high amplification at the expense of the previous stage with very good linearity. I could have installed a 2A3 or other valve but the 300B performed well above these other options.

Output transformers

"I didn’t aim to drive the output tube with just a single stage as popular notions would like to enforce. It's impossible if one considers the 520V peak-to-peak voltages. Besides I think it's crucially important to remain within the maximum linearity zone of a given tube. Bearing in mind that whilst recording the signal is being subjected to multi-stage transformations, we have to admit that it doesn’t matter whether in an amplifier we have one stage more or less. The main thing is to make the devices perform linear and without distortion."