November 1999

The Svetlana 300B Legacy Amplifiers...

Review By Thorsten Loesch
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Thoughts behind a city window

Through the windows and the slight haze of October London fog I see the twinkling of streetlights.

(Cue in Tori Amos “Twinkle” - Boys for Pele)

  The glow from Valves warms the soul and so does the Music playing. The summer is over; the leaves are turning colour. I have just come back from covering yet another “HiFi” Show where in most exhibiting rooms the main purpose for a HiFi, namely music was completely AWOL. A few rooms had music. Dimly lit by the glow of emitters, there was music. The last HiFi Show in this century, little real music and plenty of the artifice that the “High Fidelity” Industry has been substituting for music for many decades now.

We are nearing the end of the century, the century of the valve, the transistor and finally the computer chip. The Century of the Nuclear War that was not (yet?) and of conventional war that was plenty. The end of a century that has irrevocably changed our lives, so that those who lived in the years of it’s beginning hardly would recognise it’s end.  A Century whose Rallying- and Battle- cry seems to have been: “Progress, Progress, Progress!”, ever without asking “Where are we going to?”, ever without asking “What will this Progress cost us?”. A century that has turned art into industry. A century that has seen the most amazing feats performed to better communicate Music to people of all sorts. A century that has also seen the most amazing feats to turn this “great music for all” into “fat profits for a few”.

I guess it is time to make another Amplifier.

(Cue in an old mono recording of Toscanini directing Tschaikowsky’s “Pathetique” Symphony)

An Amplifier that will be the last for me, in this fast-moving century. What Amplifier shall it be to greet the Brave New World that is descending upon us? The Brave New World of DVD Audio and Super Audio CD. The brave new world of supposedly “CD-Quality” MP3 (which upon investigation turns out to be more like telephone quality most of the time). And the Brave New World of supposedly inaudible and indelible (do not these two never go hand in hand?) watermarking to preserve the obscene profits raked in by the Music Industries Fat Cat’s.

What Amplifier shall it be to greet the first glow of dawn in the Millennium with its own warm glow from its emitters?

Part 1: The Remembrance of Sounds Past

The title for this section is borrowed from Susumu Sakuma’s Book. I have thought long and hard but could not find a better title. So I bow in reverence to those who before me have remembered the sounds past and have bought them alive again. Names like Nobu Shishido, Anzaï Zaïka, Jean Hiraga, Herb Reichert, JC Morrison, Arthur Loesch, Hiroyasu Kondo, Susumo Sakuma, Ken Shindo, Mr. Atarashi and many others come to mind as those who have travelled here before. To them do we owe both the opportunity for and the existence of a forum for such ancient crafts and they provide the inspiration for many of us.

(We are still listening to Tschaikowsky)

If we look back, some names, some companies in Audio stand so huge; they are hard to avoid. Equipment made by these Companies has attained almost cult status in many countries. Be it the Marantz Model Seven Preamplifier (which launched many an Audio-Designer into starting their career) or the MacIntosh 275 Amplifier or an EMT 927 Turntable or the Goodmans Axiom 80 Fullrange Speaker. Many Companies and their designers have left indelible marks in the books of Audio History. Yet in the grey mists of time, in the beginning, the huge, hulking dark shape with the unmistakable yellow flash is where it all really started.

Western Electrics

Making Loudspeakers and Amplifiers for the early “Sound Film” Theatres from the 1920’s onwards they as much as anyone started the high quality reproduction of sound. Not in the aid of music, but rather in the aid of satin wearing Blonde Bombshells, of Humphrey Bogart and Valentino. And the Audience was listening!

Introduced in 1936 (or even earlier, records are somewhat unreliable) the WECO 91 Amplifier was a Milestone. Using all the latest in Audio it combined for the first time a number of interesting features. Not only was the 300A (and a little later the 300B) Output Valve used, the amplifier also used the then brand-new indirectly heated Penthode. My schematic marks out a 6C6 but the WE310A was also used as Driver for lower hum and fewer gainstages.

The 300B has already been declared to be the Valve of the Century by Jean Hiraga of the late French review l’Audiophile. If we count in the 1935 Production of 300A Valves, the 300B is one of the longest serving Valves in History. By now continuously in production for the better part of 65 Years, the 300B is still going strong. So, the “Amplifier for the next Century” should of course use the valve of the Century. But what about the rest?

The WECO 91 Amplifier did not become an instant classic. It was not even available to buy for a long time. It was leased out to movie theatres. Indeed, many of these Amplifiers where scrapped in the 1950’s and 1960’s “Watt Race” when finally massively powered Penthode or Tetrode Amplifiers took over.

The remaining examples have however been acquiring a loyal following of devoted music Lovers. There is something about the Sound, about the way the music is presented by the WECO 91 Amplifier that is hypnotic. Sure, in many ways the Frequency Extremes are a little soft, but the magic of the Midrange is something else. Many of the Amplifiers that have set off the Directly Heated Single Ended Triode Amplifier Craze that is still sweeping the Far East, Europe and America where adaptations or even unashamed copies of the WECO 91. Hence, if the 300B is the “Valve of the Century”, then surely the WECO 91 must be the Amplifier of the Century.

(Time to turn over the record, really great, majestic music this is)

So it should surely be one of this centuries greatest to greet the new century's dawn with a glow from the heaters. It should be one of this centuries greatest amplifiers to carry on the LEGACY and the Remembrance of Sounds past. One of this centuries greatest amplifiers to carry on the thermionic fire into a whole new century, YES into a whole new millennium. The Amplifier to Remember the Sounds Past should be no other as a close descendant of the WECO 91.

Why do I say a close descendent? Why not the original WECO 91? Why not indeed? These questions will be answered in another, less philosophical, more technical Instalment next month. For this Month I believe I shall just whet your appetite.

The “Son of the WECO 91” will be in many ways based on the crowning achievements of Valve Technology. It will feature not a SINGLE Solid State component. The Unit will also eschew the use of electrolytic Capacitors entirely. Only high quality Film or Paper/Oil Capacitors are to be used.

The Powersupply will feature Valve Rectification and Valve Regulation, using even gas discharge Voltage Stabilisers as reference. Using the 300B with AC Filaments will require the revival of some of the Hum cancellation tricks invented for the WECO 91. The Driverstage will remain an indirectly heated Penthode. However, the driverstage will be much higher powered. We now have such high power Pentodes readily available, while in the Days of the WECO 91 they needed yet to be made. All this will be in order to somewhat firm up the Performance of the Amplifier at the Frequency Extremes.

I have kept one “ace” up my sleeve. With only one flick of a switch the Amplifier can be adjusted from 420V or 295V HT. Then simply plug in a 2A3 and you have a 2A3 Amplifier with the 295V Supply. Or crank it up to 420V and plug in a 300B play Hawkwind and rock out. Do some very minor modifications and you can plug in a 45, or a 50 or maybe even a 71. Fit new Sockets and try a PX25.

So, what kind of Amplifier would you like today, Sir? Shall it be the 3,500 milliWatt 2A3 Amplifier? Or maybe the diminutive 1,500 milliWatt 45 Amplifier? How about the amazing wonder 71A Amplifier with a whopping 800 milliWatt? No, Sir!? The Big Bruiser 9,000 milliWatt 300B Amplifier for you, Sir? Suits you, Sir.

I do not know yet how exactly the Amplifier will shape up soundwise. Some details about the circuit are unclear yet. I do however know how it will look like. PRETTY. I will be using the Chassis and Transformers from a commercially available Amplifier Kit (the Edison 60). That means that it will be possible to get a PARTIAL kit that offers good looking casework, decent quality transformers and hence will allow almost anyone to build the Amplifer.

Click here for larger photo.

So the Amplifier will be handsome and actually affordable to make. All valves used will be of types that are still readily available as “New Old Stock” Valves, but which are also in current Production. Indeed, with a working title like “Svetlana 300B Legacy Amplifier” most of the Valves in my Amplifier will be Svetlana Valves. To buy a complete set of all Chassis Parts, Polypropylen Capacitors and all Transformers needed will no more than $ 800 and postage....

At the current prices it should be possible to assemble a complete set of Valves for the Amp (2 X 300B, 2 X EL84 or SV83, 2 X 6AS7, 2 X GZ34, 1 X EF86 and 1 X 0A2) from mostly current production for about $ 450. Add an handfull of resistors and a few high quality coupling Capacitors for another $ 50. Here you have a $ 1,300 or so “semi Kit” that will allow you to build what is likely to be one of the best 300B Amplifiers available.

Yes, you can buy finished Amplifiers for that kind of money. Yes, you can buy Kit’s for less. However, here I aim at creating a “new classic”. An amplifier that decades from now someone finds, puts some Valves into in and is as blown away as we where in the late 70’s when the old WECO 91’s where staring their second coming. So if you are interested, stay tuned to this channel and wish me luck.

Now first let Tschaikowsky and Toscanini finish. Now, just for kicks and old time's sake play Queen “Radio GaGa”. Then tune in into some cool funky Jazz from Andy Shepard and finally anoint your soul with the Chorus from Haendels Messiah.

Or play whatever Music you like.

And don’t forget - Enjoy the Music