What make is this horn? - UK Vintage Radio Repair and Restoration Discussion Forum

PJL · 18th Oct 2007, 5:31 pm

This is part of my £17 win at the local auction.

The horn speaker just has the marking H H A stamped on the rubber insert that fits under the base. Anybody know who made it? It has a mark where I suspect there was a label and it would be nice to replace it. There is a handle on the base that appears to adjust spacing.

Included in the haul was a BBC stamped Marconi DE5 with good filament but it is a pipless version along with numerous other 20's parts.

mickjjo · 18th Oct 2007, 7:11 pm

I don't know if this site will help, but there are quite a few horn designs here:-

http://www.sparkmuseum.com/HORNS.HTM

Regards, Mick.

PJL · 18th Oct 2007, 8:07 pm

Thanks Mick, sent him an email...

Anyone know if 110K ohms is OK for this - seems very high.

chipp1968 · 18th Oct 2007, 9:13 pm

it may be a Fellows Volutone

PJL · 18th Oct 2007, 9:18 pm

Mmmm - I suspect it should read about 4K as per headphones and the two halves of the coils are different - looks like it needs a rewind!

PJL · 20th Oct 2007, 8:21 pm

Thanks chipp1968 - any idea where I could find a picture? John Jenkins suggested a Brown but didn't think they made a straight neck version. I have a couple of other questions...

Does anyone know what the resistance of a horn should be? I have seen 2K mentioned.

What are the rubbers that apparantly people seem to replace?

Are they all made the same? This one is essentially an oversized headphone driver mounted in a cup which (now) can be moved up and down to adjust the distance to the diagphram (took me two hours to free the sliding cup from the bore in the cast iron base - blowtorched it in the end).

Now I've started I'm going to get this thing going again...Peter

mickjjo · 20th Oct 2007, 8:33 pm

Hi Peter, I have an Ultra horn speaker here and that measures 2K ohms with a digital meter across the terminals so I guess that is typical. If only one of your windings is O/C you could measure the resistance of the good one and double it for the total. I think some horns had rubber couplings to connect the bits together

.

Regards, Mick.

chipp1968 · 20th Oct 2007, 11:48 pm

in the book RADIO RADIO there is a selection of speakers in the back and there was a horn that looked similar base etc . but the pic is small so its only a maybe and it was showing front on so it wsnt clear if the thing was straight or swan neck . I assumed straight as on some of the others they were described as swan neck , but not for that one .

KeithsTV · 21st Oct 2007, 9:29 am

Quote:

Originally Posted by PJL

Does anyone know what the resistance of a horn should be? I have seen 2K mentioned.

I have an Amplion speaker from about 1925 which has a value of 2000ohms stamped on the case. Internally there are 2 series connected coils with a measured resistance of about 2.5k.

Keith

PJL · 22nd Oct 2007, 1:41 pm

Below is a picture of the imprint left by the label. A crest with a seperate small oval - any help in identification?

This is a very substantial speaker with 14 inch horn, cast iron base with adjustable piston mounted coil assembly and heavy chrome plated cast brass cover plate, 3 inch diagphram, aluminium horn, steel vertical. If I can get it going it may sound quite good (well loud anyway).

I have unwound half of one of the spools and now have 4 lengths of wire and a remaining 500 ohms so 1K per spool sounds about right. It appears the former has leaked a substance that has caused a corrosion spot and I guess the other spool is the same.

Next I need to estimate the wire gauge - initial inspection says its bigger than human hair so maybe 44SWG will do? I suspect the existing wire is a copper alloy for strength as pure copper would not be as resistive but I don't think the reduced resistance will be a problem.

If all else fails I may try using wire from faulty headphones, and least favourite, I could fit an entire headphone assemble but performance will not be as good as the current unit has a large magnet and laminated cores.

Station X · 22nd Oct 2007, 1:45 pm

There are several forum members including myself who could "mike up" a sample of the wire and tell you what gauge it is.

If you measure the resistance of a given length of wire and compare the reading with wire tables you'll be able to tell whether it's resistance wire or not.

PJL · 22nd Oct 2007, 10:37 pm

Thanks for the offer Graham...

I wound 50 turns on a screwdriver shaft and it averages out at .070mm. According to langford 45 SWG enamelled is .078mm and 46 SWG is .067mm. 1m of wire measured 6.3 ohms and Langford lists 46 SWG as 5.75 ohms/m so I shall order some 46 SWG from wires.co.uk.

Each turn looks to be around 35mm so I will need to wind 4,500 turns. Whilst the wire is on order I will construct a simple jig and counter.

It is of interest that Langford lists 42AWG (larger than 46SWG) at 8.9mA max. when wound. This might have been OK for pre-1925 valves but later 1920's home constructors valves would readily exceed this, a PM202 up to 20mA. High DC current would of course have other adverse effects on efficiency and I beleive there were high impedance output transformers to overcome this problem...Peter

PJL · 25th Oct 2007, 11:34 pm

Below is a picture of the jig I constructed from parts I had lying around. The counter is a Walkers crisps pedometer and a house alarm magnetic switch serves to record rotations.

I successfully completed the first coil of 5000 turns 46SWG. This is a little more than my estimated 4500 and measures 1.13K. Having wound the extra turns I decided I would leave them. Tensioning was by friction on the spool and I used my finger wrapped in tape as a guide.

I had planned to put in some gearing with a rubber band drive but without a decent bearing for the spool and a method of tensioning with some give, the 46SWG would certainly break. It took around an hour and my arm needs a rest before I tackle the second.

I am now quite confident that the horn will work again...Peter

Nickthedentist · 26th Oct 2007, 6:32 pm

Quote:

Originally Posted by PJL

The counter is a Walkers crisps pedometer...

What a good idea!

I bet that's the only one that's going to be used for something useful (rather than played with for 10 minutes, left in a drawer until the batteries go flat, then chucked in the bin).

Nick.

PJL · 26th Oct 2007, 10:36 pm

Nick...If you told an engineer back in the 50's that a crisp manufacturer would be giving away 5 digit counters they would think you were mad!

I started on the 2nd coil and after 200 turns found the break so rather than unwind I made a join and added back the missing 200 and a further 500 to match the newly wound one. The initial results were a little dissapointing with sound output without the horn no better than a 4K headphone. I tried driving the coils independently and both are working. Closer inspection shows a 0.5mm difference in spacing from the coil to the diaphragm. The coils are screwed to the base on a thin layer of bitumen which I did not disturb but I will now have to reseat them.

Once I have the coils realigned I will finish off with a new coat of paint and post a picture.

peter_scott · 30th Nov 2007, 1:01 pm

I wonder if this is the same make as your horn?

http://cgi.ebay.co.uk/Sparta-Fuller-...QQcmdZViewItem

Peter

PJL · 30th Nov 2007, 1:33 pm

Peter, brilliant detective work - that's exactly the model I have and I will email the seller to see if they will send me a photo of the label...Peter

peter_scott · 30th Nov 2007, 1:54 pm

Hi Peter,

Having established the manufacturer here's an advert from Modern Wireless in March and again in May 1924.

Regards,

Peter

PJL · 30th Nov 2007, 3:30 pm

That even explains the H.A stamped in the bottom...

18th Oct 2007, 5:31 pm	#1
PJL Dekatron Join Date: Sep 2005 Location: Seaford, East Sussex, UK. Posts: 5,997	What make is this horn? This is part of my £17 win at the local auction. The horn speaker just has the marking H H A stamped on the rubber insert that fits under the base. Anybody know who made it? It has a mark where I suspect there was a label and it would be nice to replace it. There is a handle on the base that appears to adjust spacing. Included in the haul was a BBC stamped Marconi DE5 with good filament but it is a pipless version along with numerous other 20's parts. Attached Thumbnails

18th Oct 2007, 7:11 pm	#2
mickjjo Rest in Peace Join Date: Jul 2004 Location: Dartford, Kent, UK. Posts: 1,661	Re: What make is this horn? I don't know if this site will help, but there are quite a few horn designs here:- http://www.sparkmuseum.com/HORNS.HTM Regards, Mick.

18th Oct 2007, 8:07 pm	#3
PJL Dekatron Join Date: Sep 2005 Location: Seaford, East Sussex, UK. Posts: 5,997	Re: What make is this horn? Thanks Mick, sent him an email... Anyone know if 110K ohms is OK for this - seems very high.

18th Oct 2007, 9:13 pm	#4
chipp1968 Rest in Peace Join Date: Jul 2006 Location: Somerset, UK. Posts: 2,356	Re: What make is this horn? it may be a Fellows Volutone

18th Oct 2007, 9:18 pm	#5
PJL Dekatron Join Date: Sep 2005 Location: Seaford, East Sussex, UK. Posts: 5,997	Re: What make is this horn? Mmmm - I suspect it should read about 4K as per headphones and the two halves of the coils are different - looks like it needs a rewind!

20th Oct 2007, 8:21 pm	#6
PJL Dekatron Join Date: Sep 2005 Location: Seaford, East Sussex, UK. Posts: 5,997	Re: What make is this horn? Thanks chipp1968 - any idea where I could find a picture? John Jenkins suggested a Brown but didn't think they made a straight neck version. I have a couple of other questions... Does anyone know what the resistance of a horn should be? I have seen 2K mentioned. What are the rubbers that apparantly people seem to replace? Are they all made the same? This one is essentially an oversized headphone driver mounted in a cup which (now) can be moved up and down to adjust the distance to the diagphram (took me two hours to free the sliding cup from the bore in the cast iron base - blowtorched it in the end). Now I've started I'm going to get this thing going again...Peter

20th Oct 2007, 8:33 pm	#7
mickjjo Rest in Peace Join Date: Jul 2004 Location: Dartford, Kent, UK. Posts: 1,661	Re: What make is this horn? Hi Peter, I have an Ultra horn speaker here and that measures 2K ohms with a digital meter across the terminals so I guess that is typical. If only one of your windings is O/C you could measure the resistance of the good one and double it for the total. I think some horns had rubber couplings to connect the bits together . Regards, Mick.

20th Oct 2007, 11:48 pm	#8
chipp1968 Rest in Peace Join Date: Jul 2006 Location: Somerset, UK. Posts: 2,356	Re: What make is this horn? in the book RADIO RADIO there is a selection of speakers in the back and there was a horn that looked similar base etc . but the pic is small so its only a maybe and it was showing front on so it wsnt clear if the thing was straight or swan neck . I assumed straight as on some of the others they were described as swan neck , but not for that one .

22nd Oct 2007, 1:41 pm	#10
PJL Dekatron Join Date: Sep 2005 Location: Seaford, East Sussex, UK. Posts: 5,997	Re: What make is this horn? Below is a picture of the imprint left by the label. A crest with a seperate small oval - any help in identification? This is a very substantial speaker with 14 inch horn, cast iron base with adjustable piston mounted coil assembly and heavy chrome plated cast brass cover plate, 3 inch diagphram, aluminium horn, steel vertical. If I can get it going it may sound quite good (well loud anyway). I have unwound half of one of the spools and now have 4 lengths of wire and a remaining 500 ohms so 1K per spool sounds about right. It appears the former has leaked a substance that has caused a corrosion spot and I guess the other spool is the same. Next I need to estimate the wire gauge - initial inspection says its bigger than human hair so maybe 44SWG will do? I suspect the existing wire is a copper alloy for strength as pure copper would not be as resistive but I don't think the reduced resistance will be a problem. If all else fails I may try using wire from faulty headphones, and least favourite, I could fit an entire headphone assemble but performance will not be as good as the current unit has a large magnet and laminated cores. Attached Thumbnails

22nd Oct 2007, 1:45 pm	#11
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,289	Re: What make is this horn? There are several forum members including myself who could "mike up" a sample of the wire and tell you what gauge it is. If you measure the resistance of a given length of wire and compare the reading with wire tables you'll be able to tell whether it's resistance wire or not. __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

22nd Oct 2007, 10:37 pm	#12
PJL Dekatron Join Date: Sep 2005 Location: Seaford, East Sussex, UK. Posts: 5,997	Re: What make is this horn? Thanks for the offer Graham... I wound 50 turns on a screwdriver shaft and it averages out at .070mm. According to langford 45 SWG enamelled is .078mm and 46 SWG is .067mm. 1m of wire measured 6.3 ohms and Langford lists 46 SWG as 5.75 ohms/m so I shall order some 46 SWG from wires.co.uk. Each turn looks to be around 35mm so I will need to wind 4,500 turns. Whilst the wire is on order I will construct a simple jig and counter. It is of interest that Langford lists 42AWG (larger than 46SWG) at 8.9mA max. when wound. This might have been OK for pre-1925 valves but later 1920's home constructors valves would readily exceed this, a PM202 up to 20mA. High DC current would of course have other adverse effects on efficiency and I beleive there were high impedance output transformers to overcome this problem...Peter

25th Oct 2007, 11:34 pm	#13
PJL Dekatron Join Date: Sep 2005 Location: Seaford, East Sussex, UK. Posts: 5,997	Re: What make is this horn? Below is a picture of the jig I constructed from parts I had lying around. The counter is a Walkers crisps pedometer and a house alarm magnetic switch serves to record rotations. I successfully completed the first coil of 5000 turns 46SWG. This is a little more than my estimated 4500 and measures 1.13K. Having wound the extra turns I decided I would leave them. Tensioning was by friction on the spool and I used my finger wrapped in tape as a guide. I had planned to put in some gearing with a rubber band drive but without a decent bearing for the spool and a method of tensioning with some give, the 46SWG would certainly break. It took around an hour and my arm needs a rest before I tackle the second. I am now quite confident that the horn will work again...Peter Attached Thumbnails

26th Oct 2007, 10:36 pm	#15
PJL Dekatron Join Date: Sep 2005 Location: Seaford, East Sussex, UK. Posts: 5,997	Re: What make is this horn? Nick...If you told an engineer back in the 50's that a crisp manufacturer would be giving away 5 digit counters they would think you were mad! I started on the 2nd coil and after 200 turns found the break so rather than unwind I made a join and added back the missing 200 and a further 500 to match the newly wound one. The initial results were a little dissapointing with sound output without the horn no better than a 4K headphone. I tried driving the coils independently and both are working. Closer inspection shows a 0.5mm difference in spacing from the coil to the diaphragm. The coils are screwed to the base on a thin layer of bitumen which I did not disturb but I will now have to reseat them. Once I have the coils realigned I will finish off with a new coat of paint and post a picture.

30th Nov 2007, 1:01 pm	#16
peter_scott Dekatron Join Date: May 2003 Location: Edinburgh, UK. Posts: 3,274	Re: What make is this horn? I wonder if this is the same make as your horn? http://cgi.ebay.co.uk/Sparta-Fuller-...QQcmdZViewItem Peter

30th Nov 2007, 1:33 pm	#17
PJL Dekatron Join Date: Sep 2005 Location: Seaford, East Sussex, UK. Posts: 5,997	Re: What make is this horn? Peter, brilliant detective work - that's exactly the model I have and I will email the seller to see if they will send me a photo of the label...Peter

30th Nov 2007, 1:54 pm	#18
peter_scott Dekatron Join Date: May 2003 Location: Edinburgh, UK. Posts: 3,274	Re: What make is this horn? Hi Peter, Having established the manufacturer here's an advert from Modern Wireless in March and again in May 1924. Regards, Peter Attached Thumbnails Last edited by peter_scott; 30th Nov 2007 at 2:07 pm.

30th Nov 2007, 3:30 pm	#19
PJL Dekatron Join Date: Sep 2005 Location: Seaford, East Sussex, UK. Posts: 5,997	Re: What make is this horn? That even explains the H.A stamped in the bottom...