The Xaudia Blog

12-08-2013

Ervox R58 – French ribbon mic

Today on the bench we have an unusual microphone from France. I have never heard of this brand!

Ervox R58 ribbon mic

The Ervox R58 is a high impedance ribbon microphone designed for public address or home taping to a reel-to-reel recorder. It is made from a two part cast body, perhaps inspired by the RCA Varacoustic, and is nicely finished in hammertone paint. Paint still covers two of the screws, so I can see that I am the first person to look inside this one, which is always a nice feeling, like unwrapping a present!

Ervox R58, rear

Inside the mic everything looks nice and clean. The motor is built around a sturdy block of clear plastic with a large horseshoe magnet to the rear, and the ribbon itself is a piston-style design similar to those found in B&O and Altec microphones.

Inside the Ervox R58

Unfortunately the transformer is not working properly – the inductance measures only 14 microhenries, which for an (estimated) 0.2 ohm ribbon would make a HPF filter at around 2KHz… I’m sure it can’t have been designed like that, so one suspects either insulation breakdown and a short, or the laminations have deteriorated with age and lost some permeability.

Ervox ribbon motor assembly

I’m not sure if it is worth the effort of re-winding this one, particularly if the lams are below spec. Luckily we can make a new low impedance tranny for it and bring it back to life.

The previous owner kindly included this scan of a wiring diagram for the mic.

09-08-2013

Beebs to Belgium!

We have just shipped this rather lovely set of Reslo microphones to Thomas at Le Lupanar Studios in Belgium. He will be recording a brass section with two of our ‘Beeb’ Reslos, and a pair of upgraded cardioid Reslo CR mics on goosenecks.

His studio is still under construction but Thomas has been making a photo diary of the project – from the pictures so far it will be an amazing facility in a great location! How’s this for soundproofing…

Good luck with the building, and we will watch with interest as it all comes together.
🙂

08-08-2013

Reslo Beebs in Organ Action

Organist Andy Wright used a pair of our Xaudia Reslo ‘Beeb’ ribbon microphones to record his organ playing at St Peter and St Paul Church, Kimpton, Hertfordshire.

Reslos at St Peter and St Paul Church, Kimpton

He kindly sent in this brilliant photo, and an .mp3 file too so that we can hear how it sounds! 

Organ recording with Beeb Reslos – Andy Wright.

(Or download the file)

The recording was made with the mics plugged straight into a Tascam DR100 mk 2 and recorded in wav mode, then compressed to mp3 in Soundforge.

In the eighties and early nineties Hyperion Records used the organ to record classical music, including string quartets, piano solo and the Kings Consort doing The Four Seasons. Eventually Luton Airport, about 8 miles away, got too busy!

The Reslo RB mics are perhaps most famous for being used by the Beatles in their Cavern Club days. As a young photographer, Andy was assigned to one of their early gigs, and here are some of those photos at the Daily Mail website.

One of Andy’s photos of the Beatles

You can see more of Andy’s photos at his website.

07-08-2013

Stereo guitar switching box

Carrying on from my previous post….

Matt from Bobby and Jemima, had one of our stereo pickups fitted to his guitar. For stage use, we made him one of these….
3 channel guitar switch box

 It’s a very simple custom 3 channel foot-switch box, which lets him control each of the bass, treble and rhythm channels separately. I was pleased with how it came out. Hammertone paint always gives things a 1950s industrial look.

The battery just lights the three LEDs, and should last for ages, so long as the cables are unplugged when not in use.
06-08-2013

Pickup fitting with Bobby and Jemima

I recently installed one of our hexaphonic pickup systems into a a guitar for Matt Shaw, who is one half of Bobby and Jemima.

Bobby and Jemima… AKA Charlese and Matt (not sure who is who!)

Matt provides a large chunk of the music for the act, playing guitar and drums – often at the same time – and he wanted to be able to send bass runs on the lower strings to a bass amp whilst simultaneously playing the melody and lead from the top strings out through a guitar amp. No problem at all!

I fitted a hexapup to the bridge position, wired out to a pair of output jacks, and an additional toggle switch gave the option of sending the G-string to either the bass or treble output. And we put one of our new P90 pickups in the neck position, with its own output for a third amplifier. Now Matt can make a lot of noise with one guitar!

Many thanks to Karen Duckworth who hung out with us for the afternoon and took these marvellous photos.

Lots of mess during the pickup transplant.

All stripped down and ready for the new pickups

Xaudia’s Meteor coil winder, and lots of wire!

Some fine tuning of the setup
All done!
31-07-2013

Inside the Beyer M360 (again) …

Beyer M360 cardioid ribbon mic
Back in May I posted about the Beyer M320 and M360 directional ribbon mics and mentioned that they used acoustic labyrinths to provide damping to the ribbon, adding omnidirectional character to the ribbon’s native figure-8 pattern, to give, hopefully, an overall cardioid behaviour.
Since then I have had the opportunity to peek deeper inside the M360, and below is a picture showing the labyrinth. It is not a great photo as the shiny varnish on the top confused my autofocus, but we can see what is going on.
Beyer M360 labyrinth (left) and motor.

The magnet assembly is larger than the standard Beyer motor, in order to accommodate a smooth curved cavity at the rear of the ribbon. This tube curves through 90 degrees and out through a hole in the aluminium base plate. This connects to the inlet of the acoustic chamber, which consists of 25 interconnected tubes that go up and down through the block. There does not appear to be any kind of outlet at the far end, and the tubes are stuffed with string to damp internal reflections.

The mic is really directional, with relatively little pickup from the rear of the ribbon. The back pressure from the sealed rear chamber also has the consequence of making the output brighter and lower than it would otherwise be. These are really very bright sounding for ribbon mics.

SJT 31 July 2013
23-07-2013

Reslo MR1 ribbon mic (MOTM)

The MR1 was an attempt by Reslosound to re-invigorate the classic RB model for a 1970s market, whilst trimming down the cost of manufacturing parts and assembly.

Reslo MR1 and RB models

The MR1 (left) has the same format as the RB, with the ribbon element and magnets housed in a tilting head attached to a cylindrical body that contains the transformer. The grills are now flat, rather than domed, and the custom pivot screw is replaced with a standard hex socket bolt.

Reslo MR1 and RB

The MR1 still usesd Reslo’s custom 3-pin connector, and still makes ground contact through the body only. One assumes that this was to ensure backward compatibility with their older mics and cables, but it seems like madness  that they did not take the opportunity to switch to using XLR connectors, which were very well established by this time.

The classic stamped brass badge on the RB is replaced by a printed foil sticker that hides the join between the barrel of the mic and the cast base of the pivoting head. The sticker shouts ‘Reslo MR1’ – note that it no longer says ‘Reslosound’ – in a very trendy 1970’s style font, with fattened letters typical of the era. I am also 1970s vintage, and the label reminds me of watching programmes like Magpie on TV in my childhood!

Magpie – classic 70s font!

The ribbon and motor assembly (top in the picture below) is exactly the same as the RB, but the transformer is smaller. Over time, better understanding gave rise to alloys with higher magnetic permeability, enabling smaller transformers to be made with the same inductance properties.  The RB mics used a EE24/25 size core (pictured below the motor). The MR1 has a narrower body and a smaller transformer marked 4414.

Top to bottom… Reslo MR1 motor,  transformers from RB, MR1 and Xaudia

Xaudia, as you might expect, make a suitable replacement transformer (bottom) for upgrade and impedance matching duties. 😉

Compared to the RB, I see very few MR1s, and can only conclude that they were not a great success. By the 1970s, good dynamic mics were becoming the first choice for home recording, and professional recording studios would probably favour condenser microphones for many applications. Reslosound Ltd. disappeared sometime in the 1970s, and this must have been one of the last models that they produced.

17-07-2013

Lustraphone microphone catalogue

Here is a scanned product sheet from Lustraphone, which includes the VR53 and VR64 ribbon microphones, along with dynamic microphones and accessories. Like many other manufacturers, they supplied stands and impedance matching transformers to use with their mics.

With a typically British quirkiness, the price of the VR65 stereo ribbon is given as 30 Guineas rather than pounds, shillings and pence. A guinea was equivalent to one pound and one shilling, so at about 4 times the cost of the mono VR64, the stereo VR65 was a very expensive mic!

In other Lustraphone related news, I have commissioned a batch of replacement enamel badges for Lustraphone VR53 and other microphones. They will be available through the Xaudia website very soon.

16-07-2013

Electro-Voice Microphone Catalogue

Here is a scan of an old Electro-Voice catalogue, probably from the 1950s or early 60s, featuring a wide range of microphones. It includes the multi-pattern Cardak, which appears to have been the flagship model, and the V-series ribbon mics. There is no date on the document, but at this point in time the V1 would set you back US$27.50, and the multi-impedance V3 was $50. The Cardak II would set you back a whopping $75!

In the velocity microphone description I was amused to read that “the woven housing allows the sound to pass through without reflection”. This neglects to mention the whopping magnet located at the rear of the ribbon! All of the dynamic ribbon mics were available in 50, 200, 500 ohm and high impedance models, which reflects the plethora of input types around at that time.

The second page deals with carbon and crystal microphones and accessories. The bottom of the page was uppermost in the box, and consequently is somewhat grubby.
14-07-2013

Cadenza Crystal Mics – a mystery solved!

This Ebay auction has solved a little mystery for me!

Cadenza Crystal Microphone

Cadenza was a British brand remembered primarily for their ‘Rocket’ ribbon microphones. They are still quite common, and I have repaired many of them in the course of my work.

Cadenza microphone with ribbon element

Most of the Cadenza mics are grey or pale blue in colour, and have a removable stand. However, I have come across three or four of these mics with black bases and a fixed stand. These often have a crystal element rather than a ribbon motor, and I and speculated on their origins in a previous blog entry. When I first encountered one of these, I had thought that it was some kind of DIY ‘repair’ job, but having seen more than one, it seemed more likely that they came out of the factory this way.

Crystal element in a Cadenza body

Until now I had never seen an advertisement, manual or box that could confirm the existence of a Cadenza Crystal microphone. The photos in the auction show the original packaging, marked ‘Cadenza Crystal. So this was indeed a Cadenza product, using the same body as the ribbon microphones.

I like the triangular box!

Thanks to Benchmark Collectibles for permission to use this photo.