A modern interpretation of la Revue de l’Audiophile… Part 1 – Western Electric 755A

I do remember quite well my first encounter with Jacques Ledauphin in February 2013. He is some kind of tutelar figure in the pantheon of French audiophilia.

For those who do not know him, Jacques is a well known French audiophile who developed among other things horns, multi amp with analog and digital crossovers speakers and of course electronics. He also explained his personal building in La Revue de l’Audiophile. I could not believe that I would meet him in person and that I would listen to his incredible set-up using six active channels per speakers which has been reviewed Jean Hiraga with highest regards.

But… (there is always a caveat) when I first visited him in February 2013, his big set-up had not been working for a few years. In fact he had issues with the Western Electric 437A tube that was used in eight out of twelve of his power amps and in his preamp. After measuring and testing with a Metrix LX109A tube analyser over twenty NOS of these tubes coming from different batches : the Metrix revealed that there was major vacuum inconsistencies in  all of his tubes. For Jacques, more than vacuum issue, the WE 437A must have a polluted cathode induced by there long term storage. As these tubes are of small dimensions : the heating filament as alas not enough energy to unpollute the cathode. So he decided that he would go for some other tubes. Telefunken YL-1350 and Mullard / Philips/ RTC E55L valves for instance… (tubes for the American valves and valves for the English tubes…)

In the meantime… Something else had replaced the gigantic speaker set-up… Something quite the opposite :  Western Electric 755A speakers in bass-reflex wood enclosures designed and built by Jacques Ledauphin himself. These enclosures are made of thick marine plywood with no parallel sides and a vent on the bottom. Jacques also designed a an  exponential horn embryo to the WE 755A in order to cancel some frequency response issues in the lower mid.

This new speaker project was also a good way to work on the new amps of the big (or should I say HUGE) set-up… Jacques has been using SPUD amps for over 25 years now. SPUD amps are designed to work with only one tube on the signal path. No drivers, no splitters… just one tube. As said before, first iterations were using Western Electric 437A tubes and designed to have the incredible output power of 0.8W. In fact these amps were used only on eight of the twelve channels of the set-up. We will come back on this topic with the second part of these visits.

In replacement of the faulty WE 437A tubes, Jacques designed a brand new SPUD amp around the E55L valves. As with all his power amps, Jacques prefer to use tubes at reasonable specs. In this case : the E55L has only 125V on its plates and thus produces a hefty 0.6W. The E55L is used in triode connected mode with fixed bias  and is :
– driven by a Lundhal 7902 (600 ohm / 10 ohm) transformer which increases the signal ratio by 1 : 4.
– feeds a Tamura F-5002 output transformer (amorphous core sadly not available anymore).
The heater filament power supply is two stages regulated, high tension power supply stabilized and fixed bias power supply (used on the cold spot/point of the secondary windings of the input transformer) is  a two   stages regulated split with a three Farad capacitor (!!!)…

Would this be enough to control the WE 755A ?

We started by listening to records on the Brinkmann Balance turntable with an Ikeda IT-407 gold tonearm, RS-1 headshell and REX cartridge. There was also a Micro Seiki step-up transformer and a lightly tweaked Counterpoint SA-9 as well as a home made preamp (we will talk about it later on in part 2…).

First record? French music of course with Barbara chante Barbara. A few notes and Barbara starts singing. Imaging is pinpoint, laser cut in fact : she is there in front of us a tad behind the speakers and it leads me to immediate goose bumps syndrome. I think that I actually forgot to breathe for a few seconds. This is definitely one of the best vocal rendition I have ever listened to. We then listened to a record of Areski with Brigitte Fontaine on the Saravah label and here again the magic happens : the level of details, the precision of the rendition is astonishing and still this incredible soundstage.

So what about these impressive 0.6W power amps? Was it sufficient to drive the WE 755A to realistic levels? Yes and no. In fact these speakers were not designed to be played at high levels but to suit the specification of low power tubes amps and in this particular case the E55L is particularly well suited for this application. Was it able to produce the lower octave of music ? Yes and no : bass extension is rolled of at around 60Hz due to the nature of the transducer and the enclosure used. The exponential horn embryo reinforce the lower mid and thus allow a good rendition of the upper bass registers.

After all : let us keep in mind that we are listening to an old 8″ wide band speaker from the 50’s. Nether the less this is quite a listening experience and it is not so much different from my 15A, 16A, 12A  or 22A Western Electric horn experiences. In fact the 755A (being designed for the subway trains of New York and by extension for smaller rooms) do share some common points with is bigger counterparts. One of them is that these are all designed to reproduce a large bandwidth with no or very little electrical crossovers. In a way we could say they perform ” raw” sound, signal freshly cooked out from the amp with no spices and thus the TFK E55L SPUD amp is truly complementary to these and allows us to hear, to apprehend the sound of these rare equipments. With these kind of equipment : I am always astonished by the ease with which the music flows, fills the room.

Some would speak of shear musicality, I would state more the quest for the owner/designer/dreamer, Jacques, of some kind of ataraxia, of Zen gestures which put back in main focus the musical content more than the inherent technical aspects that underly such a complicate set-up as a a six way active speaker.None of the less : there was still something (slightly) hidden behind the Western Electric 755A speakers… And I knew that one day I would listen to these…See you in part 2 !