Tuesday, 13 November 2018

Field Coil Power Supply

There are a wide variety of opinions about speaker field coil power supplies.

Some believe any lab supply will do - switching or linear. Others insists only Selenium rectification is best while others insist that Tungar is the only way for the best of true field coil sound. The focus is on rectification in these last two cases. It is entirely possible that batteries were originally used and so the 7 volt specification of the WECO 555's, Tungar battery chargers were used to recharge them and then only later employed directly.

A supply's performance relies on much more than the rectification type. If a supply is well designed rectification influence is lessened. 

After listening to many types it seems that choke loading makes the most noticable improvement and Schottky diodes work very well in this application. The sound is only slightly different from Tungar being a little less "you are there" and a little more "they are here".

I prefer listening more in person rather than going to an event in my mind.

Then there is the connector, something which is rated for the amperage and easy and sure to connect. Avoiding the any possibility of cooking a voice coil while connecting in the dark or under other handicaps which can occur during listening sessions.

These snap in with a noticeable click so that they communicate when they are connected. Turn it on and that is that. The they are set for each speaker type in its application and we provide these with our field coil equipped speakers to ensure the correct type supply and to avoid having to worry about such things.

Outside right now there is another story...

It has begun to end once again... the the lovely, and grave, deciduous cycle...

Monday, 5 November 2018

VinylSavor and Thomas Mayer

Last month we had the pleasure to visit Thomas Mayer at his Company VinylSavor

Located in lovely Lindau, which my family used to visit for holiday from the time before I was born!

Inside its all business...

Unless you have a passion for tubes, transformers and the like....

then it might seem more like Ali Baba's Cave...

With treasure in every corner...

Stocks of NOS and Elrog tubes.

Lundhal Transformers.

Upstairs is the assembly...

and testing areas.

Racks and racks of parts and hardware.

Some hand selected NOS globe tubes... 

and a lovely, unique 78 RPM player.

We were lucky enough to be able to hear some amplifiers in testing. 
46 drives 46 Differential and 46 drives 46 SE Silver on our Mojo speakers that Thomas tests with.

Herr Mayer at work. He builds them all, by hand, one at a time, point to point, bench tested and then run in and listened to for many hours. Dedication, passion and discipline provide music lovers with...

a combination of personal, professional and uniquely excellent sounding amplification.

It is a privilege to have an insight into an endeavour of this level.

Thank You Thomas.

Thursday, 1 November 2018

Hadron Production Part II

Hadron Production Part II

The next steps in production...

After the external milling in complete it is possible to see the annealed curved shape...

 combining with the internal structure.

The rear panel location in recess.

Driver aperture.

Front panel overview.

Internal chamber.

Construction details.

Rear panel aperture.

Cut away overview.

Next will  be the finishing process .

Until then...

Friday, 26 October 2018

Hadron Production Part I

Hadron Speaker Production details. Part I

Here is the block before external sculpting for perspective.

The interior is already in place with braces,

antireflective surface and harmonic proportioning shape.

Now it will go into the milling machine.

All external shaping occurs here...

...from this solid block.

Quality assurance is a constant process.

and occurs during each step.

It is a pleasure to build something the way it should be built.

Video of the milling...

Once completed, inspected and tested it will get one of these....

More to follow.

Now accepting orders. Just send us an email.

Monday, 22 October 2018

Field Coil Broad Range Drivers

The next step for the Sfera Loudspeaker was to bring field coil drivers into the horn loaded design.
Horns amplify the colours, shadings and nuance which field coil speakers bring to the enterprise and so this is a natural evolvement for the Sfera as a horn loaded system.

A high tension design was selected to run between 75 and 125 volts.

Kapton Tape isolation.

Hammertone paint was selected for its vintage aspect.

Baskets mounted.

Here a stock phase plug is attached for the pictures.

However this will change to a bronze unit later...

 which significantly changes performance.

These assorted pictures scale the 5" basket to the magnet assembly.

After break-in and testing the brand is applied.

More to follow on the 15" bass field coil and power supplies...

as well as testing and listening impressions.