Anyone Clone The Spendor Bc1?

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qwad

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Joined 2003
#1
:idea:Hi all, while sitting on the "throne" earlier this AM AND MULLING OVER what to do next Inspired by the recent PROac 2.5 Clone thread, :bulb: I had an idea, why not clone the venerable BC1?, anyone try this?, the idea progressed to almost fruitition as I have a pair of grotty spendor PREludes with the vinyl peeling off I picked up in a hock shop for next to peanuts then it all started to germinate since I also have COLES VERSION OF THE CELESTION HF1300 AND A PAIR OF 8 ohm 4001 k super tweeters to do the job with, until this idea came up I was always goiung to build new and better boxes for the Preludes, FOR MY VERsion of the BC1 I want to do a series x-over, as I HAve had good success using this type of network on 2 ways and 2.5 ways , any comments, suggestions? of course one of the most important ingrediants of the BC1 was the enclosure material itself, BIrch ply, looks as though I will have to hunt around for that at timber suppliers, cheers to all, TJB, NEXT PROJECT AFTER THAT IS THE FET VERSION OF THE JLH SE, YOU THERE GEOFF?, 😉 :Popworm: may need your assistance or suggestions about this too , later... TJB
 
#2
Looking at the title, i was going to suggest that finding the 2 tweeters might be difficult, but you seem to have that covered 🙂

Finding a good 8" to sub-in shouldn't be too much of a challenge.

I have a friend with BC1s (i sold him in 1977) -- they are quite an excellent speaker.

dave
 
#3
:bigeyes: EEEKKKK! sub, why would you wanna do that? huh?, I hate subs, I listen to my preludes at my mid level and I hear all the bass I want to thanks very much!, I"m not a head banger, ANd I have had speakers with plenty of bottom end velly, which tire me very quickly, and I don't need to watch the furniture rearrange itself in front of my eyes. if I need to do that I can do that myself in an orderly fashion the way I want to, which is what I prefer, I'm still trying to come to grips with this almost universal obsession with subwoofers😕 which seems to be of manic proprtions on the eastern shore of the pacific,:goodbad: anyhow you of all people from t/line org should be satisfied with a decent t/l which is usually not wanting in the bottom end:nod: CHEERS and thanks for your input:devily: TJB
 
#6
🙂 well I GUESS I did not make myself very clear, in case you don't know it the PRELUDE has an updated version of the 8" bextrene coned bass unit used in the BC1, it has a 40mm kapton voice coil former and does not suffer from the sagging/scraping malaise of the BC1 driver, so I was going to use that with the tweeters through a series network, one of the real secrets of the BC1 sound quality is due to the type of cabinet cunstruction and material used as you will find on the link I gave the other day to our friend who was trying to work out his sub woofer enclosure to stop it ringing at 200hz, I've lost the scrap of paper I had it written on otherwise I would give it again:nod: 😉 cheers, tjb, I'll catch up with my old mate 'mefinnis' mark later
 
#7
Ahhh BC1s, one of the best speakers ever for listening to FM speech radio!

I have a pair with rebuilt/upgraded crossovers on semi perminant loan to a friend, because she needed sounds and I had no room for them. I still miss them...
 
#8
: :xeye: She must be a GOOD FRIEND, if I had a pair I wouldn't let them out of my sight, or earshot.... so you see I understand where you are coming from:nod: IT is hard to beleive how old the design is, yet apart from the quad 57, nothing to date has managed to come near it, despite all the hi tech hype from various mfctr'rs a true classic that has stood the test of time and fashion... You say the xover was modded in what way, may I ask?:scratch: in mine I am planning on using the simple series xover...
cheers, TJB:devily:
 
#9
qwad said:
: :xeye: She must be a GOOD FRIEND, if I had a pair I wouldn't let them out of my sight, or earshot.... so you see I understand where you are coming from:nod: IT is hard to beleive how old the design is, yet apart from the quad 57, nothing to date has managed to come near it, despite all the hi tech hype from various mfctr'rs a true classic that has stood the test of time and fashion...
Click to expand...

As I said, it was a great speaker for voice, but it didn't quite have the dynamics and range needed for brilliant music reproduction, but I have certainly heard much worse comparable modern speakers. I would imagine with an old Troughline tuner and a Quad valve amp they couldn't be beaten as a system for listening to BBC Radio 4😎

You say the xover was modded in what way, may I ask?:scratch: in mine I am planning on using the simple series xover...
Click to expand...

A simple rebuild with Solens and air cored inductors, and now I think of it I also put spacers behind the front baffle, so it mounted flush with the box sides with the grill removed. I would be interested to hear your results with the series XO, I'm fairly sure mine had a conventional one, but it was about 7 years ago I made the mods, so I can't be certain.
 
#10
:scratch: how did you detrmine the inductor values? at one time I HAD a book by martin colloms called "high performance speakers" the basic circuit was shown in there ... very complex part section /part series cascaded into each other with the ubiqtous auto transformer to match levels
when I've got the series x-over sorted, I might post it on the forum for others to see :bigeyes: Though bear in mind the main drivers will be different to the BC1, the bass unit although superficially identical would have different electrical characteristics and therefore different parameters and more than likely response as well, also the mid tweeter will be different a COLES HF 3000 WHICH WAS SUPPOSED TO COMPETE WITH the celestion HF 1300, unsuccesfully it appears as almost everybody has forgoten this unit now due to a lack of use in systam on ac of it's unfortunate characteristics.....CHEERS TJB
 
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