[xk] Horns

XK
21

The “spiral” I was referring to is not under the dome of the assembly.
It is the shape of the "horn"part of it ending in the “bell” where the
sound comes out. You can see the spiral shape going from the center of
the round base to the bell of the “horn”. The diaphragm vibrates the air
entering the narrow center hole - the beginning of the column of
vibrating air that is twisted into a spiral shape just like a French horn.

Bagpipes use a reed in the chanter that vibrates at a constant high
frequency. (If you listen for it, you can hear it as part of the bagpipe
sound. It sounds kind of like a mosquito’s buzz.) The effective length
of the vibrating column of air is changed by opening and closing holes
along its length just like in an oboe. Every one of the nine notes
produced by the chanter is driven by a reed vibrating at one constant
frequency.

A brass wind instrument can produce different notes with one column
length. Consider the bugle with no valves to alter the length. Different
notes can be produced by changing the frequency of the trigger
(vibrating lips) to get the column of air to vibrate at multiples of its
primary resonant frequency. This may be how the Jaguar horns produce
different notes - or they might use one frequency for the trigger and
different column lengths. It might also be two combinations of trigger
frequencies and horn lengths - i.e. high trigger with short spiral and
low trigger for long spiral. If the spirals are different lengths, they
would likely have different numbers for that part.

Our 120 only had one working horn when we got it and the other one
failed after a couple of years. On removing the domes, I discovered that
the works had both been destroyed by fire. Good thing the fire was
contained by the domes. I bought a pair of after-market horns which look
and sound perfect.

Bruce

22

Bruce,

Yes, all true for the type of horn that has this method of construction and
there are many versions out there. But the HF1748 isn’t one of them. It is
very flat, no spiral air passage but has a metal diaphragm which is vibrated
by what is effectively a buzzer. This is connected by a small rod to flat
disc of what appears to be 1/8" thick aluminium. This is what Lucas call the
tone disc in their parts list but there is no diifference between these in
either high or low tone. The diaphragm has a circumferential curved set in
it and has a number of radial slots running from its outer edge. My
suspicion was that the length of the slots is how the diaphragm is tuned but
now I have looked at mine in more detail I can see that this isn’t the case.
The slots merely accommodate the fixing screws.

It appears that the diaphragm is tuned by the size and the depth of the
circumferential set. The three low tone diaphragms appear much flatter than
the one high tone that I have.

I could have a low tone diaphragm available to swap for a high tone one
later when I come to refurbish these horns.

Eric
Church Stretton, UK----- Original Message -----
From: “Bruce Cunningham” bcunning@gmavt.net
To: xk@jag-lovers.org
Sent: Monday, May 23, 2011 3:34 PM
Subject: Re: [xk] Horns

The “spiral” I was referring to is not under the dome of the assembly. It
is the shape of the "horn"part of it ending in the “bell” where the sound
comes out. You can see the spiral shape going from the center of the round
base to the bell of the “horn”. The diaphragm vibrates the air entering
the narrow center hole - the beginning of the column of vibrating air that
is twisted into a spiral shape just like a French horn.

Bagpipes use a reed in the chanter that vibrates at a constant high
frequency. (If you listen for it, you can hear it as part of the bagpipe
sound. It sounds kind of like a mosquito’s buzz.) The effective length of
the vibrating column of air is changed by opening and closing holes along
its length just like in an oboe. Every one of the nine notes produced by
the chanter is driven by a reed vibrating at one constant frequency.

A brass wind instrument can produce different notes with one column
length. Consider the bugle with no valves to alter the length. Different
notes can be produced by changing the frequency of the trigger (vibrating
lips) to get the column of air to vibrate at multiples of its primary
resonant frequency. This may be how the Jaguar horns produce different
notes - or they might use one frequency for the trigger and different
column lengths. It might also be two combinations of trigger frequencies
and horn lengths - i.e. high trigger with short spiral and low trigger for
long spiral. If the spirals are different lengths, they would likely have
different numbers for that part.

Our 120 only had one working horn when we got it and the other one failed
after a couple of years. On removing the domes, I discovered that the
works had both been destroyed by fire. Good thing the fire was contained
by the domes. I bought a pair of after-market horns which look and sound
perfect.

Bruce

23

I searched in vain for my original horns with the crispy insides. I may
have discarded them. (I can’t believe I did that - maybe they will turn up.)

I did, however, find a picture (#3) of the horn on page 169 of Urs
Schmid’s r*****-covered book (The anatomy of a Cult Object - Volume 1)
clearly showing the spiral path for the air from the center of the
underside to the bell of the horn. Urs described it as "… black,
snail-shaped horn housings with their oval megaphones … ".

I do remember comparing the replacement horns with the originals and
noting that they both had spiral horns but with quite different castings
to produce the similar sounds.

Bruce

24

Eric
When do you want to swap?
Best
Klaus-----Original Message-----
From: owner-xk@jag-lovers.org [mailto:owner-xk@jag-lovers.org] On Behalf Of
Eric Capron
Sent: Monday, May 23, 2011 11:20 AM
To: xk@jag-lovers.org
Subject: Re: [xk] Horns

Bruce,

Yes, all true for the type of horn that has this method of construction and
there are many versions out there. But the HF1748 isn’t one of them. It is
very flat, no spiral air passage but has a metal diaphragm which is vibrated

by what is effectively a buzzer. This is connected by a small rod to flat
disc of what appears to be 1/8" thick aluminium. This is what Lucas call the

tone disc in their parts list but there is no diifference between these in
either high or low tone. The diaphragm has a circumferential curved set in
it and has a number of radial slots running from its outer edge. My
suspicion was that the length of the slots is how the diaphragm is tuned but

now I have looked at mine in more detail I can see that this isn’t the case.

The slots merely accommodate the fixing screws.

It appears that the diaphragm is tuned by the size and the depth of the
circumferential set. The three low tone diaphragms appear much flatter than
the one high tone that I have.

I could have a low tone diaphragm available to swap for a high tone one
later when I come to refurbish these horns.

Eric
Church Stretton, UK

----- Original Message -----
From: “Bruce Cunningham” bcunning@gmavt.net
To: xk@jag-lovers.org
Sent: Monday, May 23, 2011 3:34 PM
Subject: Re: [xk] Horns

The “spiral” I was referring to is not under the dome of the assembly. It
is the shape of the "horn"part of it ending in the “bell” where the sound
comes out. You can see the spiral shape going from the center of the round

base to the bell of the “horn”. The diaphragm vibrates the air entering
the narrow center hole - the beginning of the column of vibrating air that

is twisted into a spiral shape just like a French horn.

Bagpipes use a reed in the chanter that vibrates at a constant high
frequency. (If you listen for it, you can hear it as part of the bagpipe
sound. It sounds kind of like a mosquito’s buzz.) The effective length of
the vibrating column of air is changed by opening and closing holes along
its length just like in an oboe. Every one of the nine notes produced by
the chanter is driven by a reed vibrating at one constant frequency.

A brass wind instrument can produce different notes with one column
length. Consider the bugle with no valves to alter the length. Different
notes can be produced by changing the frequency of the trigger (vibrating
lips) to get the column of air to vibrate at multiples of its primary
resonant frequency. This may be how the Jaguar horns produce different
notes - or they might use one frequency for the trigger and different
column lengths. It might also be two combinations of trigger frequencies
and horn lengths - i.e. high trigger with short spiral and low trigger for

long spiral. If the spirals are different lengths, they would likely have
different numbers for that part.

Our 120 only had one working horn when we got it and the other one failed
after a couple of years. On removing the domes, I discovered that the
works had both been destroyed by fire. Good thing the fire was contained
by the domes. I bought a pair of after-market horns which look and sound
perfect.

Bruce

25

OK - now I get it.

I thought we were talking about horns similar to the 120’s. I didn’t
realize that the part number being discussed was for a quite different
design that was not used for the 120. The 140 must have a significantly
different sound for the horn that I either haven’t heard or haven’t
noticed. Sorry about my confusion.

Bruce

26

Actually Bruce it’s kind of interesting because I looked up the horns Lucas
supplied for XK120. My 1954 parts list indicates all home market cars had
WT614 horns - the type you described with the spiral - but export dhcs and
fhcs had HF1748s. So according to this your OTS had the correct horns but if
you’d had one of the other two models you’d have got the rather less refined
HF1748.

Eric----- Original Message -----
From: “Bruce Cunningham” bcunning@gmavt.net
To: xk@jag-lovers.org
Sent: Monday, May 23, 2011 6:46 PM
Subject: Re: [xk] Horns

OK - now I get it.

I thought we were talking about horns similar to the 120’s. I didn’t
realize that the part number being discussed was for a quite different
design that was not used for the 120. The 140 must have a significantly
different sound for the horn that I either haven’t heard or haven’t
noticed. Sorry about my confusion.

Bruce

27

Thanks, Eric.

I like “refined” - also “elegant”.

Almost every time I drive the 120, early in the journey I select an
appropriate time when there are no cars or pedestrians near that might
be alarmed and sound the horn just for the pleasure of hearing it.

Donna used to look around and ask why I honked the horn. She seldom asks
any more. Sometimes I claim that I am just testing it to make sure it
still works.

Modern horns are probably more effective as warning devices but not as
much fun.

BTW - my original V regulator was restored by British Vehicle Electric
and is on the way back from Ontario. I tried to contact BVE about a week
ago but their web site was not functional and their phone was
disconnected. I did a little detective work and found the owner’s name -
Mike and Sue Hildrey - and home phone and left a message. Their home
address is the same as the business.

Got an accidental call back from them on Saturday - Sue intended to call
someone else and called our number by mistake. They assured me the
regulator had been sent by post two weeks ago and would arrive shortly -
to call back in a week if it was not here yet.

Now I’m wondering whether they had shut down their business in
anticipation of the rapture and were just making some farewell phone
calls before 6 pm arrived.

Bruce

28

Bruce,

Well some people will believe anything.

Say hi to Donna for me.

All the best,

Eric----- Original Message -----
From: “Bruce Cunningham” bcunning@gmavt.net
To: xk@jag-lovers.org
Sent: Monday, May 23, 2011 7:53 PM
Subject: Re: [xk] Horns - and the rapture (not)

Thanks, Eric.

I like “refined” - also “elegant”.

Almost every time I drive the 120, early in the journey I select an
appropriate time when there are no cars or pedestrians near that might
be alarmed and sound the horn just for the pleasure of hearing it.

Donna used to look around and ask why I honked the horn. She seldom asks
any more. Sometimes I claim that I am just testing it to make sure it
still works.

Modern horns are probably more effective as warning devices but not as
much fun.

BTW - my original V regulator was restored by British Vehicle Electric
and is on the way back from Ontario. I tried to contact BVE about a week
ago but their web site was not functional and their phone was
disconnected. I did a little detective work and found the owner’s name -
Mike and Sue Hildrey - and home phone and left a message. Their home
address is the same as the business.

Got an accidental call back from them on Saturday - Sue intended to call
someone else and called our number by mistake. They assured me the
regulator had been sent by post two weeks ago and would arrive shortly -
to call back in a week if it was not here yet.

Now I’m wondering whether they had shut down their business in
anticipation of the rapture and were just making some farewell phone
calls before 6 pm arrived.

Bruce

29

There is quite a bit of cross-purposes now dominating this thread.

The original thread was to do with XK140 horns - a Lucas Model HF.1748 which
came in two variations - the “High Note” (Lucas part no. 70071D) and the
“Low Note” (Lucas part no. 70063D). These are the FLAT appearance horns
Eric has been commenting about - and are illustrated/detailed within XK140
EXPLORED in Plate 7-e6. No detail provided of the internals however, and
short of pulling a couple apart, I cannot answer question asked, never
really looking for difference as my originals and a couple spares I have are
all intact and working, with identification tags still in place. Other than
the tag, there is no obvious difference on outside between High Note and Low
Note versions

The so called “SPIRAL” horns were not used in XK140 - but were used in both
XK120 and XK150. These are extremely common horns to find being used by
all manner of English vehicles throughout the 1950s. These are a Lucas
“Windtone” horn, or WT.29, with several minor variations including both Low
Tone and High Tone over the years. Urs Schmid’s book is on XK120 only,
thus the pictured horns are WT.29. These are slightly different on outside
and I seem to recall whether High Tone or Low Tone is cast on the inside
edge of the trumpet, but would have to dig out my stock of many spares to be
sure.

Roger Payne - XK140MC OTS; E-Type 4.2 S.1 OTS; DSV8.
Canberra.-----Original Message-----
From: owner-xk@jag-lovers.org [mailto:owner-xk@jag-lovers.org] On Behalf Of
Bruce Cunningham
Sent: Tuesday, 24 May 2011 2:21 AM
To: xk@jag-lovers.org
Subject: Re: [xk] Horns

I searched in vain for my original horns with the crispy insides. I may
have discarded them. (I can’t believe I did that - maybe they will turn up.)

I did, however, find a picture (#3) of the horn on page 169 of Urs
Schmid’s r*****-covered book (The anatomy of a Cult Object - Volume 1)
clearly showing the spiral path for the air from the center of the
underside to the bell of the horn. Urs described it as "… black,
snail-shaped horn housings with their oval megaphones … ".

I do remember comparing the replacement horns with the originals and
noting that they both had spiral horns but with quite different castings
to produce the similar sounds.

Bruce

30

Klaus,

Bagpipes aside, the 140 horns have no “trumpet” of any shape either
spiral or straight. There is no apparent air column to resonate. Their
diaphragms are “naked” save for a thick alloy washer fastened to the
diaphragm’s center. I suspect the mass of this “washer” alters the
vibrating frequency as it does not seem logical to punch out diaphragms
and the internal armature parts with different tolerances.

They look pretty much like a flat faced motorcycle horn that is
occasionally protected with a shallow grille or screen.

I also suspect the different Hi/Lo part number stamping refers to the
assembly as a whole (mass) and not the separate pieces, but I don’t know
for sure. I do think you can alter the sound (frequency) by changing the
mass of the fitted washer.

I think the adjuster screw is to optimize the output volume at the units
designed frequency and current limit, although playing with it will no
doubt change its sound.
Regards,

Rick____________________________________________________________
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31

Over to the trusty LUCAS Master Spare-Parts Catalogue - 400E (1945-1960)

HF.1748 is the MODEL of horn, but this model came in a number of variations,
as indicated by exact PART NUMBER.

70063 was available in A to F suffix variations, but suffix variations are
not functionally relevant.
A 70063 is described as 12 volt, and “Low Tone”, and finished in
Polychromatic Grey (whereas other HF.1748 were available in BLACK)
A 70071 (also available in A to F suffix variations) was the matching 12v
“High Tone” horn, again in Polychromatic Grey.

The Spare-Parts-Catalogue then provides individual part numbers of every
separate component of each Horn Assembly:-

Bracket, Tone Disc (flat or dished), Nut for Tone Disc, Washer cover and
diaphragm packing, Nut for diaphragm locking, Contact Set, Terminal Block,
Rubber Seal for Terminal Plate, and Sundry parts set - are all identical.

The only difference between a 70063 and a 70071 is the:-
DIAPHRAGM and ARMATURE assembly - part number 703726 (for Low Tone) and
703727 (for High Tone).

The 400E catalogue also includes detail photos, showing detailed photos of
every actual component, but there is only ONE photo - and this one photo is
labelled as being a 703726, 703727 or 690813 - so this tells you that the
actual difference between these three different DIAPRAGMS is not apparent in
a photograph.

The 690813 is actually the same diaphragm as used in a number of different
model WINDTONE horns, interestingly in both Low and High Tone pairs (thus
TONE variation is achieved some other way in Windtone Horns)

Back to the XK140 HF.1748 High and Low Tone horns - clearly the ONLY
difference is with the DIAPHRAGM - but given difference is not discernable
in a photo, then you need to have actual diaphragms in your hand to closely
examine to see what difference is, so OK if you are disassembling known High
or Low tone horns, but if you have a box of disassembled bits - GOOD LUCK.

Alternatively, you can always drop down to your local 1950s Lucas Spare
Parts outlet and order a new 703726 and a new 703727 to assist your 2011
rebuild!

Roger Payne - XK140MC OTS; E-Type 4.2 S.1 OTS; DSV8.
Canberra.-----Original Message-----
From: Roger Payne [mailto:@Roger_Payne2]
Sent: Tuesday, 24 May 2011 9:14 AM
To: ‘xk@jag-lovers.org’
Subject: RE: [xk] Horns

There is quite a bit of cross-purposes now dominating this thread.

The original thread was to do with XK140 horns - a Lucas Model HF.1748 which
came in two variations - the “High Note” (Lucas part no. 70071D) and the
“Low Note” (Lucas part no. 70063D). These are the FLAT appearance horns
Eric has been commenting about - and are illustrated/detailed within XK140
EXPLORED in Plate 7-e6. No detail provided of the internals however, and
short of pulling a couple apart, I cannot answer question asked, never
really looking for difference as my originals and a couple spares I have are
all intact and working, with identification tags still in place. Other than
the tag, there is no obvious difference on outside between High Note and Low
Note versions

The so called “SPIRAL” horns were not used in XK140 - but were used in both
XK120 and XK150. These are extremely common horns to find being used by
all manner of English vehicles throughout the 1950s. These are a Lucas
“Windtone” horn, or WT.29, with several minor variations including both Low
Tone and High Tone over the years. Urs Schmid’s book is on XK120 only,
thus the pictured horns are WT.29. These are slightly different on outside
and I seem to recall whether High Tone or Low Tone is cast on the inside
edge of the trumpet, but would have to dig out my stock of many spares to be
sure.

Roger Payne - XK140MC OTS; E-Type 4.2 S.1 OTS; DSV8.
Canberra.

-----Original Message-----
From: owner-xk@jag-lovers.org [mailto:owner-xk@jag-lovers.org] On Behalf Of
Bruce Cunningham
Sent: Tuesday, 24 May 2011 2:21 AM
To: xk@jag-lovers.org
Subject: Re: [xk] Horns

I searched in vain for my original horns with the crispy insides. I may
have discarded them. (I can’t believe I did that - maybe they will turn up.)

I did, however, find a picture (#3) of the horn on page 169 of Urs
Schmid’s r*****-covered book (The anatomy of a Cult Object - Volume 1)
clearly showing the spiral path for the air from the center of the
underside to the bell of the horn. Urs described it as "… black,
snail-shaped horn housings with their oval megaphones … ".

I do remember comparing the replacement horns with the originals and
noting that they both had spiral horns but with quite different castings
to produce the similar sounds.

Bruce

32

Actually, when I was a teen and had just acquired my first British
“drug of choice” - a Bugeye Sprite, I started noticing that ‘complete
disassembly’ aspect of their cars. I then acquired a Healey 100-4 and
cemented my love. That ‘to the last nut or bolt’’ concept is what I
really loved.

'Merican cars at that time had many crimped and welded together parts
which forbad arcane inspection and it seemed like the “chuck it away
and buy a new one” was the automobile’s answer to planned
obsolescence. I hated it. Being the stingy bastard that I was/am, I
hated spending for a new part when the only thing often wrong was a
five-cent thingy in the guts of it. So, I took them apart, of course,
and tried (and often did) fix them, but that only made the enmity worse.

Now, of course, you can’t escape it. I still pry and un-crimp and cut
them apart and fix them if I can. Nowadays, the exorbitant prices of
the whole part is the driving force creating a whole 'nother enmity.
And, more then ever, I am interested in ways to fix a part, rather
than contribute to the growing and expensive heap of detritus that is
our lives.

Brian

When one considers just how many hundreds of thousands of individual
parts
Lucas made and the fact that you could toddle of to your local Lucas
parts
counter and buy the smallest part to fix whatever it was that was
broken at
the time, they had a really astonishing operation going. None of this
“chuck it away and buy a new one sir” they supplied parts for
practically
everything they made.

33

In reply to a message from Brian Ternamian sent Tue 24 May 2011:

Bryan, this is venturing off topic a bit, but I once had an '82
Mercury that the dimmer switch for the headlights failed. $40 for
a combination dimmer/turn signal/horn (yes, the horn button was in
the turn signal stalk).

I paid $8 for a headlight dimmer switch alone (gave the parts store
monkey the part number for the same part on my '78 Mercury), pulled
the headlight wires out of the old switch, wired 'em up to the new
switch, and bolted it to the dashboard. With a little ingenuity, I
saved $32, fixed my headlights, and figuratively flipped Ford Motor
Company the finger for not making the car easier to fix, all in one
operation.–
Robert Allen
Huntsville, TX, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
–Support Jag-lovers - Donate at http://www.jag-lovers.org/donate04.php –

34

Brian,

That philosophy and curiosity is what put my DHC back on the road today.
I bought it used in 1960 and was “too poor” to pay someone to fix “what
broke”. If I couldn’t fix it, I couldn’t drive it, and because of that
practise, I still drive it today, however it was “asleep” for 38 years or
so.

It took a bit out of me to wake it up! I was about 20 when I bought it,
am a rung above 70 (but still climbing)

I also hold Lucas in high regard for its(their) “fixability” component
assortment. Damn good stuff on the whole!

Regards,

Rick

Brian writes:> 'Merican cars at that time had many crimped and welded together

parts
which forbad arcane inspection and it seemed like the "chuck it away

and buy a new one" was the automobile’s answer to planned
obsolescence. I hated it. Being the stingy bastard that I was/am, I

hated spending for a new part when the only thing often wrong was a

five-cent thingy in the guts of it. So, I took them apart, of
course,
and tried (and often did) fix them, but that only made the enmity
worse.

Now, of course, you can’t escape it. I still pry and un-crimp and
cut
them apart and fix them if I can. Nowadays, the exorbitant prices of

the whole part is the driving force creating a whole 'nother enmity.

And, more then ever, I am interested in ways to fix a part, rather

than contribute to the growing and expensive heap of detritus that
is
our lives.

Brian

When one considers just how many hundreds of thousands of individual

parts
Lucas made and the fact that you could toddle of to your local Lucas

parts
counter and buy the smallest part to fix whatever it was that was
broken at
the time, they had a really astonishing operation going. None of
this
“chuck it away and buy a new one sir” they supplied parts for
practically
everything they made.

Penny Stock Jumping 3000%
Sign up to the #1 voted penny stock newsletter for free today!
http://thirdpartyoffers.juno.com/TGL3141/4ddc49904012ffb48fst02vuc

35

One of my favourite pieces of XK trivia (and apologies if someone has
already recently said this) is to note that the high and low horns WT29U
were separated by a musical note interval of a minor third (i.e. 3 notes).
One is marked H the other L. Kind regards, John Elmgreen
www.jtpublications.com.au

36

One of my favourite pieces of XK trivia (and apologies if someone has
already recently said this) is to note that the high and low horns WT29U
were separated by a musical note interval of a minor third (i.e. 3 notes).
One is marked H the other L. Kind regards, John Elmgreen
www.jtpublications.com.au

John,

Thanks for that info. I was looking into this. Do you also know which
notes they are?

BruceOn 5/25/2011 8:48 AM, John Elmgreen wrote:

37

My 120 horns play E flat and G, a major third. They are also slightly sharp.
Maybe they need a tune up? :wink:
Rob>the high and low horns WT29U were separated by a musical note interval of a

minor third (i.e. 3 notes). One is marked H the other L.
Do you also know which notes they are?

38

I am missing a cover “dome” for one of the horns (on my XK120) and I wondered if anyone might have a spare. Thank you.

john