Deaf-Aid Receiver: How Old?

[russell_w_b]

I have four of these, acquired from a car-boot sale. 'Ardente' of Oxford Street, London. I have found a bit about 'Ardente' on t'internet, but nothing so far on this particular receiver.

They're bakelite, with a volume control in the end and a one-bobbin coaxial magnet headphone receiver at the other.

I'm guessing 1930s / 1940s, but not really sure. Any advice welcomed.

[Darren-UK]

Pardon?

There's some info here, including dates, if that isn't the page you've already found.

[russell_w_b]

Darren,

Thanks. I'd found this page, but couldn't see my particular handset / earpiece. There's a receiver earpiece similar, but it's on a headband rather than a Bakelite handle.

[Ed_Dinning]

Hi Russell, there were some of these installed in the local curch for deaf parishoners in the 60's, fed from a small PA amp that also fed 2 speakers.

Ed

[russell_w_b]

Ed,

Thanks for that. I read that such things were available when Googling 'Ardente'. Interesting about the period though: the overall construction and style suggests 1930s, but the wiring and potentiometer look, upon closer inspection, like 1950s. I would have said, initially, 1920s / '30s for the receiver, but the wiring insulation and improvement (presumably) on the two-bobbin arrangement look newer than this. I would have thought that if such a device were installed new in the '60s, then rocking-armature receivers would have been used. Perhaps your church system was originally from an earlier time?

Or maybe a classical unobtrusive style of listening-aid was maintained, appropriate to the surroundings, with electrical improvements? I'll open one up fully tomorrow and measure coil resistance, etc...

[russell_w_b]

Sorted! Church receiver it is. Details on a sub-section of Darren's link here.

[bobsterkent]

I've got a couple of these somewhere myself, and the amplifier as well, they came out of a theatre and the wiring was strung along the walls with plugs for the aids to be plugged into.

[Dave Moll]

I must say that my immediate reaction on seeing the pictures was that it resembled an earlier version of the "lorgnette" hand-held receivers that we used to use with the audio frequency induction loop system (AFILS) in the local meetinghouse - before the now almost universal availability of AFILS-compatible hearing aids. Interesting to learn that these are an earlier method of achieving the same result, but hard-wired rather than using an induction loop.

[russell_w_b]

Opened up and investigated. Incoming pair to each end of a 66k pot, with receiver (1k) between one leg and the wiper. Pot so arranged so that there is a 700R limit at one end and a 1k5 limit at the other.

Sound quality is good, peaking slightly (audibility) around 760Hz. Response flat-ish otherwise from 70Hz to 9.5kHz.

[Ed_Dinning]

Hi Russell, possibly installed late 40's/early 50's. They were connected via 2 pin 2A plugs and sockets. The amp was of a similar vintage and it was probably a home installation.

Ed

[russell_w_b]

The two-pin plugs on the receivers fit nicely into the half-inch spaced PO231 (GPO-type) test-tablets we use at work! I'll keep one to hand as a useful monitor.

[chipp1968]

I came across a similar if not identical unit at an antique fair last Sunday to the one in Darrens first link ! Hearing aid with battery compartment etc .
How does it amplify the mic to the earpiece ? It cant be better that an ear trumpet ...Smaller i suppose

[russell_w_b]

The carbon mic probably points in the direction of the speaker, and / or may be discreetly spoken into directly. I see no particular advantage either, unless the casing contains some sort of telephone-type induction coil.

Perhaps the user has more control over where the mic is pointed?

[Herald1360]

A carbon mike properly matched to an earpiece has a fair amount of gain. Even without any matching transformer (induction coil in phone speak) a simple series mike, earpiece battery circuit will oscillate (screech) if the mike and earpiece are close enough.

[Peter.N.]

I would have said immediatly 30s/40s until I saw the plastic insulation on the earpiece wires.

Peter

[russell_w_b]

Originally Posted by Herald1360

'a simple series mike, earpiece battery circuit will oscillate (screech) if the mike and earpiece are close enough.'

I suppose modern hearing-aids had to have an inbuilt oscillatory feature to maintain the tradition (my mother's whistles like crazy, as did our late neighbour's)

I've sent a carbon mic'd telephone handset into hoot mode more than once, simply by putting it down heavy-handedly. I guess deaf-aid mics were more sensitive than those used in telephone instruments as well.

[Lucien Nunes]

A couple of days ago, a friend discovered some sockets and their labels still extant in a church in Farnham, Suffolk. I had a search through my public-address literature and to my surprise found it listed in the Ardente PA brochures for 1935-36. At least, I presume the paperwork is all from that year based on other items found with it. The lorgnette receiver shown in the theatre application looks much older and more elaborate. Mobile phone pics of same attached.

The Group Hearing System is an interesting crossover product between hearing-aids and public address, presumably a good foot in the door of premises that didn't realise they were in the market for sound-reinforcement, and individuals who didn't realise they needed hearing aids!

Lucien

[MichaelR]

This looks like your example:

http://en.wikipedia.org/wiki/File:Ar...earing_aid.JPG

Mike

[russell_w_b]

Because I have four of them, all from the same source, I would reckon they were part of a hard-of-hearing church / theatre installation (I'm guessing part of a job-lot). The plugs would certainly fit the sockets in Lucien's pics.

Mine have volume controls on them as well, but my examples look newer than Lucien's illustrations. Of course, perhaps the same receiver was used for sound reinforcement and personal hearing aids. Keep the info coming!

[Cobaltblue]

Whilst trying to sort out my service info I came accross this.
There is a higher definition pic here
Enjoy
Mike T