How I rescued my 25-year old Spendor BC1 loudspeakers when the bass drivers failed

Summary for those who don't want to read this longish story:

  • BC1 bass drivers can be replaced with a modern alternative for about £40 UK each. The sound from the drivers I used is acceptable but not comparable to the original drivers.
  • There are at least two specialists (details below) who will re-cone and re-coil your driver at a cost in the range £50 - £80 UK. I would recommend this course of action.

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I have owned a pair of Spendor BC1 loudspeakers for more than 25 years and have been extremely satisfied with the sound they deliver - especially their legendary mid-range sweetness and the great clarity of voice reproduction that results from it.

My BC1's have serial numbers 14600 & 14601 and they were secondhand when I bought them in 1983, then about 4 years old.

In about 1993 the bass drive unit in one of them failed, due to an apparent failure in the voice coil continuity. I contacted Spendor and they offered to send me a new replacement unit for about £100. I ordered it and fitted it relatively easily. The new unit was clearly more modern and had a slightly different shape. (The reason is probably that the early drivers had iron magnets whereas the later ones had ferrite. This results in a shorter, wider magnet.) The new unit gave a sound that was indistinguishable from the original, at least to my ears.

Ten years of satisfactory listening later (December 2003) the bass driver in the other speaker failed in a similar manner. I contacted Spendor again, but this time the news was not good. This is what they said:

BC1 Bass units: The BC1 was an extremely successful speaker which
commenced production in 1969.  The BC1 has been out of production
since 1989, and regrettably we are no longer able to supply new replacement
bass units, nor repair/recone the customer's BC1 bass units manufactured
prior to 1982 (serial numbers 1 to 25099).
We are able to rebuild the customer's  BC1 bass units if they were
manufactured after 1982 (from loudspeaker serial no.25100).  The cost per
unit is £180.00 plus p&p of £14.10 (within the UK).  Prices include VAT.
Celestion HF1300:  We can no longer supply new replacement HF1300's as
Celestion ceased production of these many years ago, but we can still supply
HF1300 diaphragms to enable the customer to repair his existing units. 
The cost per diaphragm is £30.25 inclusive of VAT + postage and packing
within the UK of £5.87.
Coles 4001G: We are no longer able to supply this tweeter.

Since the failed bass unit that I had on my hands was one of the original pre-1983 ones, it seemed that I had a problem.

This bad news was confirmed in a phone call in which the phrase "reached the end of their useful life" was used. They did offer me a trade-in deal of £125 for my speakers against any speakers of their current production, but I decided not to adopt that option.

Getting a recommendation

After fruitlessly disassembling and examining the failed unit, I began a web search for solutions. I found nothing specific to repairing BC1's - hence this page. But a Google search for 'loudspeaker repair' turned up Wilmslow Audio as a likely prospect:

Wilmslow Audio Limited, 50 Main Street, Broughton Astley,
Leicester, LE9 6RD. Telephone- 01455 286603 Fax- 01455 286605 email- sales@wilmslowaudio.com

At the other end of the phone I found a friendly Neil Smith, who had a recommendation at his fingertips. He recommended:

VIFA C20WJ-19-08 polymer cone Bass £36 + delivery (here's a spec sheet: pdf)

He told me that other customers had successfully installed them in BC1s.

Although I am not in the habit of throwing £80 down the drain, I concluded that this was a sum well worth risking in order to test Neil's recommendation. My view was reinforced by Neil's offer to accept the return of the speakers after a couple of weeks if I was not satisfied. So an order for two of them was duly placed and the speakers were despatched by Wilmslow Audio the same day.

Installing the new units

Issues and solutions:

Removing the front panel
Opening the back of the speaker cabinet is straightforward but removing the front panel without damaging it is trickier and this is necessary in order to reveal the fixing screws that have to be removed and repositioned. I found that the best way to remove the front was to open the back and remove the old bass unit, then to introduce a thin tool into the hole and slide it under the frame of the front panel in order to lever it away from the cabinet. Once you get the panel off one of its studs, you can pull it away from the rest of them by grasping it from the front.

Repositioning the bolts
The VIFA speaker units have 4 fixing holes whereas the Spendor ones have 5, so the fixing bolts in the cabinet have to be repositioned. This necessitates removing the existing bolts, drilling 3 new holes (leaving one bolt in situ), re-fitting the bolts in the new holes and filling in the old holes. The bolts holding the bass units in place are actually a weird hybrid of a wood screw and a bolt. The upper portion is shaped as a wood screw with reverse thread! I discovered this only after applying considerable force to get the first two out of the wood in a rather crude fashion, whereas they come out rather easily if you screw them clockwise a few turns.

Adjusting the hole
Although the diameter of the VIFA units is the same as the Spendor ones, the roll foam surround supporting the cone is closer to the edge and this results in it just touching the edge of the hole in the cabinet when it is offered up to it. Two possible solutions - widen the hole or fit a narrow circular spacer between the speaker and the cabinet. The latter would be a neater solution, but I didn't have any spacer material to hand so I chose the former - I bevelled the inside edge of the hole just enough to clear the speaker surround.

Wiring
I took the opportunity to fit some multi-strand QED speaker cable in place of the very spindly original wires. I soldered the new wires directly to the tabs on the VIFA speakers and to the pins on the crossover unit. I also replace the cable connecting the crossover unit to the external terminal posts with the heavier cable, soldering to the pins on the crossover.

The results

I was rather sceptical about the likely quality to be expected from the VIFA units given their price and their generally mass-produced appearance. But their dimensions and the appearance of the cones and magnets are very similar to those of the late-model Spendor bass unit.

I am writing this one day after completing the conversion, so I can't yet give a definitive assessment. I haven't yet listened to a wide-enough range of material and I am told that new speakers require quite a few hours of use before they yield their best. I will update this page with further comments in due course.

My initial impressions of the converted speakers are good. The quality of the bass frequencies is, if anything more open than with the original drivers. I'm not yet sure about the mid-range. It is good, but I haven't reached a conclusion about whether it matches the superlative mid-range quality that BC1 users are used to. A final opinion should be based on at least a couple of weeks of listening, and if possible a side-by-side comparison with a pair of BC1s with the original drivers. Watch this space for a further assessment ...

Certainly the resulting 'hybrid' BC1's are very listenable and are, I'm sure of comparable quality to most other modern high-quality speakers.

Further experience

26 January 2004

After 10 days, I am happy with the sound - perhaps because I have grown accustomed to it! I have been offered the loan of a pair of unmodified BC1's, but haven't yet got around to doing a side-by-side test - more news when I get the chance to do so.

17 February 2004

After offering my working Spendor drive unit for sale on eBay I received several messages of advice including pointers to the Spendor owners Yahoo news group. This led me to withdraw the working drive unit from ebay and I am now investigating methods for getting it restored.

22 March 2004

My BC1's are restored to their original state! Via the above-mentioned Spendor owners Yahoo news group I discovered Terry Miles, ex-Spendor engineer, email: and he has fully restored my faulty base unit, including new cone, surround, etc, in addition to repairing the broken voice coil, all for the very reasonable sum of £79 including UK postage.

So what are my conclusions on quality?

The refurbished speaker produces a sound that matches the other one well (although there is some difference in the sound off white noise).
Overall what I'm getting now is the original BC1 sound that I have grown used to. I can tell the difference from the substitute Vifa drivers - the mid-range clarity is better - it's noticeable in music (classical is my taste) and even more so in speech - the Vifas had a slightly 'boxy' sound in speech.

The Vifa alternative is a viable option for those who can't get their original drivers restored, the resulting sound is of good quality, comparable to many current mid-price speakers (I haven't heard many high-end ones).

But I'm glad that I've ended up with a properly-restored original pair of BC1's.

December 2006

December 2008

I'm now driving the BC1's with a refurbished Quad 303 power amp in a hybrid role; they are used as a stereo pair for music and as the front speakers in a surround system for a computer-based home cinema system. The Quad 303 seems excellently matched to the BC1's. I noticed a major improvement when it was installed in place of my previous Denon ADV 1000 surround receiver/amp. More details at:


If others have useful information to pass on about the maintenance of BC1's, please add a comment using the commenting facility below.

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George Coulouris