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本帖最后由 子弹飞 于 2013-2-5 23:44 编辑
Buy a used pair. Some tips.
So you want to buy a used pair of LS3/5As?
Like antiques or secondhand cars there are good used LS3/5As and dodgy LS3/5As around. Here I offer some tips for prospective buyers of a pair of used LS3/5As.
Organ Donation.
It is important to understand the professional and industrial context in which the LS3/5A was used. When used by the BBC or in another professional monitoring environment the LS3/5A was a tool. All LS3/5As were considered equal and so "organ donation" was considered entirely acceptable towards the end of the speakers in-service life and as spares became difficult to obtain. Parts from two or more damaged LS3/5As would be combined to make a single, in specification, working unit. So an LS3/5A from an industrial background might well have, for example, a Chartwell cabinet with a Rogers' crossover.
Cut and Shut
By Cut and Shut I mean any LS3/5A which is described as being made of original parts but which actually contains non-specification components with the intention of misleading the buyer.
The most common example of this is where a SP1003 B110 drive unit in a 15 ohm LS3/5A has been replaced by one which falls outside the BBC specification. The replacement B110 drive unit may have been pulled from another speaker which used them or may be new old stock. Unfortunately the LS3/5A design called for the use of B110 SP1003 units that fell right at one end of their manufacturing spread. This caused the manufacturers considerable problems and there was a high reject rate of units that were perfectly OK in other speakers. This is described well in the Rogers History section of this web site. So a replacement B110 might be OK if you are lucky, or more likely it may fall a little or even a lot outside the LS3/5A specification.
In some cases this may have been done in all innocence. For example by a technician or private owner who repaired a LS3/5A without understanding the need for a selected drive unit. Or it may have been done with the deliberate intention of obtaining a high price. It isn't difficult to imagine the temptation faced by someone selling, say, a pair of Chartwells with one damaged B110. Unfortunately this is impossible to detect visually. In the early days of manufacture Rogers had to build a LS3/5A, measure it, and if the drive unit fell outside the specification, unscrew the cabinet and try another one!
Copy LS3/5As.
There are several examples of speakers that have used the designation LS3/5A but are not licenced by the BBC, or have been marketed as a clone. For more information please see the Inspired Designs section of theis web site.
Fake LS3/5As
The most serious problem facing a buyer of a pair of used LS3/5As is the out and out fake where a pair are built from parts, sometimes genuine or sometimes copies and intentionally offered for sale as something they are not! They can look very convincing and even can sound very good if well made. This isn't of course a new problem. In the Rogers' History on this web site Brian Pook describes how back in 1976 it was necessary to take legal action in Hong Kong to stop the production of fakes.
Spare parts, both genuine and copies, are easily available online. This is good news for genuine DIYers who want to try to build a pair of small speakers like the LS3/5A for themselves and in the case of genuine spare parts, for anyone wanting to do a proper repair. Unfortunately it is also good news for fakers. As I write this, listed on the internet are cabinets, drive units pulled from other speakers, badges, copy 15 ohm crossovers, copy terminals and even copy Rogers' sticky rear cabinet labels. Put them together and the result is a convincing fake pair LS3/5As.
Gordon's Story describes someone who believes he nearly bought a fake pair.
Some tips to avoid a fake.
- Know your subject before parting with your money. Think like both a buyer of a used car and an antique.
- Read my pages about the history of the LS3/5A and also the sections on Support.
- Does the speaker have any provenance? Does any documentation make sense? Do any instruction brochures or receipts the seller has tie up with the serial numbers and the history of that manufacturer? Does the documentation contain any spelling mistakes?
- Does the speaker look right? Are the drive units, felt surrounds, grille, badges, labels, terminals etc all correct for the manufacturer and time? Does the cabinet wear and tear match the history? It is easy to buy copies of all these parts on the internet.
- Ask to see inside. Faking the outside is easy. Faking the crossover using the correct PCB and components the original manufacturer used is less easy. But even copy 15 ohm crossovers are available on the internet. In the Gallery section are several examples of genuine LS3/5A crossovers for you to compare.
- Check the date stickers on the drive units. See my support pages for how to decode a KEF date sticker
- Consider how rare the pair you are considering buying is likely to be. Rogers made a lot of units. Some versions like Rogers Gold Badge or those from other manufacturers like RAM or Chartwell are rarer. Rare and limited edition LS3/5As are more tempting to fake because there are less genuine ones for comparison, and they fetch higher prices.
- If in doubt ask the members of the LS3/5A yahoogroup. There are 1500+ members with a vast range of experience and knowledge. Between them they own every LS3/5A ever manufactured including some really rare units. If anyone can spot a fake they can!
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发表于 2013-2-5 18:12
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