Don't worry on my account Alan. I wasn't really making a point, just sharing a few impressions of drivers.
Celestion HF1300 versions ?
Hi eanee and Toaster,
about the Celestion HF1300 -there has been several versions.
The original had an Alnico magnet, then next was the Ceramic magnet version.
The Ceramic magnet version was available in three different Impedance voice-coil versions:
4 ohm; 8 ohm; 15ohm.
The 15 ohm version was used in Spendor's BC1, but I'm not sure if it was the Alnico or Ceramic or both for the different production eras.
By "stronger magnet version" were you refering to the Alnico versus Ceramic magnet versions only,
OR, to the later HF1300 Mk2 ?
Mk2 ... about which I cannot find any information except that it was used by B&W in their DM4
- which was basically B&W's commercial version of a BC1.
{It had a different bass/mid driver, but HF1300 and Coles 4001 tweeters.}
With some drivers when different thicknesses and/or different lengths of wire is used for the voice-coil for the different Impedance versions
the high-treble extension is different, thus the 15kHz extension samples you mention, are those of a particular Impedance only ?
Apart from samples that sometimes are offered on ebay, do either of you know of any sellers of NOS originals, eg: in Australia ? ,
or is the Coles' version the only new stock available ?
Hi eanee and Toaster,
about the Celestion HF1300 -there has been several versions.
The original had an Alnico magnet, then next was the Ceramic magnet version.
The Ceramic magnet version was available in three different Impedance voice-coil versions:
4 ohm; 8 ohm; 15ohm.
The 15 ohm version was used in Spendor's BC1, but I'm not sure if it was the Alnico or Ceramic or both for the different production eras.
By "stronger magnet version" were you refering to the Alnico versus Ceramic magnet versions only,
OR, to the later HF1300 Mk2 ?
Mk2 ... about which I cannot find any information except that it was used by B&W in their DM4
- which was basically B&W's commercial version of a BC1.
{It had a different bass/mid driver, but HF1300 and Coles 4001 tweeters.}
With some drivers when different thicknesses and/or different lengths of wire is used for the voice-coil for the different Impedance versions
the high-treble extension is different, thus the 15kHz extension samples you mention, are those of a particular Impedance only ?
Apart from samples that sometimes are offered on ebay, do either of you know of any sellers of NOS originals, eg: in Australia ? ,
or is the Coles' version the only new stock available ?
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Hi Alan,
I've got a stash of HF1300s squirelled away.This includes a pair from some early Celestion Dittons.These have smaller magnets and appear less sensitive as well as sounding less satisfactory than the "larger"(normal) magnet units.
Most of my samples are of 15 ohm impedance.I think the issue of 15khz extension was more related to Celestion quality control problems.There appears to have been some variability depending on the particular grade of phenolic impregnated fabric used.Acording to M. Colloms even the spacing wrt the phasing plate was critical to performance.Historically Spendor received mild censure of their BC1 due to colouration issues with less than perfect samples of the HF1300 exhibiting a 12khz peak.Apparently this was resolved with tighter selection process(more rejects).Spendor used to stock replacement diaphrams,not sure if this still applies?
Ebay shows matched pair HF1300 supposedly NOS available at "Hi Fi Classics-de".
The best sounding units are undoubtedly the Spendor "selected" ones.
See pic L-R Early Ditton unit,Spendor selected(red dot),HF1300 Mk2 with plastic pot and screw terminals.
Attachments
more about HF1300
Hi eanee,
thankyou for posting the above - there is some there that I did not know.
If you have not seen, then go to:
Click below to go to
and to his Spendor BC1 page in "Vintage" at the top-right of the screen.
There you will see photos of a dis-assembled HF1300, and having seen those I can easily understand the points Martin Colloms made about "tolerances".
Also, TG has posted measurements he made of his 15 ohm sample, and additional for reducing the baffle-caused anommolies in its frequency response.
He shows the BC1 crossover schematic also.
TG quotes another Australian - J. Bright - who I think is likely the Jonathan Bright who is member of this forum,
as he has posted about other Celestion drivers in other threads here.
Do you know him ?
I can hear clearly to 16kHz {measured}, but immediately above that my hearing drops off sharply.
I would hear any 12kHz annomolies, and in general any prominent resonance in the 12k <---> 16k region causes what I describe as a wirey sound
{as in a resonating set of thin metal wires all together in a mixture of pitches} superimposed on a violin's harmonics, or on a cymbal causing its sound to be a bit prominent and of thinner tone.
I was thinking I might obtain a pair of HF1300 and use in a 2-way with a 6.5" bass/mid driver that plays no lower than about 80Hz, because when reduced bass extension sometimes full 16kHz treble extension seems to unbalance the sound, thus to about 13kHz may be audibly OK ...
however I have not yet decided.
"Coles" make what looks like a HF1300, thus I suppose those are for Spendor and other users' replacements.
I could not find a web-site named "Hi Fi Classics-de", but there are at least 3 web-sites in German with similar names,
however I have not found the HF1300 on any yet.
I have found the pair on ebay.
Given all the HF1300 samples you have, I suppose you can pick the best ones by ear !
Hi eanee,
thankyou for posting the above - there is some there that I did not know.
If you have not seen, then go to:
Click below to go to
and to his Spendor BC1 page in "Vintage" at the top-right of the screen.
There you will see photos of a dis-assembled HF1300, and having seen those I can easily understand the points Martin Colloms made about "tolerances".
Also, TG has posted measurements he made of his 15 ohm sample, and additional for reducing the baffle-caused anommolies in its frequency response.
He shows the BC1 crossover schematic also.
TG quotes another Australian - J. Bright - who I think is likely the Jonathan Bright who is member of this forum,
as he has posted about other Celestion drivers in other threads here.
Do you know him ?
I can hear clearly to 16kHz {measured}, but immediately above that my hearing drops off sharply.
I would hear any 12kHz annomolies, and in general any prominent resonance in the 12k <---> 16k region causes what I describe as a wirey sound
{as in a resonating set of thin metal wires all together in a mixture of pitches} superimposed on a violin's harmonics, or on a cymbal causing its sound to be a bit prominent and of thinner tone.
I was thinking I might obtain a pair of HF1300 and use in a 2-way with a 6.5" bass/mid driver that plays no lower than about 80Hz, because when reduced bass extension sometimes full 16kHz treble extension seems to unbalance the sound, thus to about 13kHz may be audibly OK ...
however I have not yet decided.
"Coles" make what looks like a HF1300, thus I suppose those are for Spendor and other users' replacements.
I could not find a web-site named "Hi Fi Classics-de", but there are at least 3 web-sites in German with similar names,
however I have not found the HF1300 on any yet.
I have found the pair on ebay.
Given all the HF1300 samples you have, I suppose you can pick the best ones by ear !
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I've only just joined so I'm late to the discussion, but as an owner for many years of a pair of modified MC-4s I can help.
I was dissatisfied with the original tweeter. To me it sounded dull and hard. After much experimenting I settled on using the Morel MDT-30. With some changes to the crossover in place the sound opened up completely. A smooth, spacious, crisp and airy treble replaced what I had before.
The crossover is changed to:- a RC impedance correction, values 10R and 3.3mfd, across the tweeter input terminals and before the input resistor. Input resistor changed from 2.7R to 3.9R. The third order high pass is 3.0mfd (1.5 + 1.5), 0.42mH, 6.2mfd (4.0 + 2.2).
It's awkward to fit due to the screw holes being close to the opening, and you must fill the gap around the faceplate to prevent odd diffraction effects, but the sound is worth it.
I was dissatisfied with the original tweeter. To me it sounded dull and hard. After much experimenting I settled on using the Morel MDT-30. With some changes to the crossover in place the sound opened up completely. A smooth, spacious, crisp and airy treble replaced what I had before.
The crossover is changed to:- a RC impedance correction, values 10R and 3.3mfd, across the tweeter input terminals and before the input resistor. Input resistor changed from 2.7R to 3.9R. The third order high pass is 3.0mfd (1.5 + 1.5), 0.42mH, 6.2mfd (4.0 + 2.2).
It's awkward to fit due to the screw holes being close to the opening, and you must fill the gap around the faceplate to prevent odd diffraction effects, but the sound is worth it.
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