Rogers BBC LS3/5a?

[pdm4606]

harbeths

If you read Stereophile it seems that the harbeths are like the best speaker ever made.
I have been reading about them for years but never heard them.

Paul

 

[kyle]

I've heard Spendor, Rogers and Harbeth versions and never really been able to tell the difference. Same drivers and the spec was set by the BBC not the manufacturers so a major difference would be unusual.
One thing that does seem to matter is what you use to power them. They're low sensitivity and low power handling as well so the amp choice is narrower.

 

[RJee]

If you're into the ls3/5a you should look into the kef reference 101. Same drivers, slightly bigger box. I heard them head to head with some rogers recently and I preferred the kefs, a little mor low end.

And at half the price you can't argue value. (Bought mine for €120.)

 

[bobschneider]

I have one bought new early 90s. Never intend to sell it, now it stays in my office room. Unfortunately my baby boy blew one tweeter and i replace it with modern tweeter.

It sounds really great, and still sounds great though I replace the tweeter with non original one.

The correct tweeter is the KEF T27 SP1032. They aren't that hard to find on the auction site or other audio sites. Or Falcon Acoustics in the UK has announced they will begin making new replacements later this year. They already make an excellent replacement B110 woofer for the LS3/5a.

 

[mech986]

This is from the LS3/5a Wiki:

Rogers Audio was the earliest licensee, but went broke before ever producing one unit. The name was bought by Swisstone, who started manufacturing the Rogers 3/5A under licence in 1975.[21] Rogers' production accounted for the lion's share, of around 43,000 pairs by 1988, and 50,000 pairs all told.[9] Spendor's production amounted to about 22,000 pairs, Audiomaster 10,000. Dudley Harwood, the BBC engineer instrumental in the creation of the 3/5A, starts Harbeth. Although licensed since 1977, the company produced no LS3/5A for a decade.[21] Eventually, Harbeth accounted for 7,000 pairs.[8] KEF, who obtained its licence in 1993, claims approximately 4,000 pairs made.[13] Other licensees included Chartwell, RAM, Goodmans and Stirling Broadcast.[9]

Rogers Developments, run by Jim Rogers and others had the original license for the LS3/5 but was not able to get them into production (possibly save for some prototypes) before the BBC began a redesign due to the original 1970-esque drivers having evolved into newer forms by 1975. The resulting LS3/5a revision came just as Rogers went into bankruptcy. Malcolm Sced, then engineering director (and I believe designer of a number of Rogers tube electronics of the era) had been working with the BBC design team to perfect Rogers prototypes and production techniques during the end of Rogers Developments.

Brian Pook was brought in to try to rescue the company and found it floundering. While the bank and other factors put the company into receivership, Pook found help from Michael O'Brien, owner of a small chain of stereo stores, and O'Brien's solicitor who helped immensely with the winding down of Rogers, it's asset sale and repurchase of assets by this new team, and resurrection of Rogers via Swisstone Electronics, a holding company purchased and created to oversee the new Rogers.

It is my understanding that during this time, Mr. Sced had transferred all of the LS3/5a prototypes and most of the engineering materials and parts to his home before the original company failed, saving much of it from being potentially lost. Rogers as a new company rehired all of their staff including Sced, and was able to renegotiate a new license for the LS3/5a and quickly recover and commence production of the LS3/5a thanks to Sced, Pook, and the help of KEF's Raymond Cooke - Cooke was instrumental in identifying the parameters of the BBC selected spec of the KEF B110 SP1003 used and then computer grade and select units (a first in the industry) from SP1003 production units to sell to Rogers for their production, greatly simplifying this task for Rogers and making volume production more economical and efficient.

If you're into the ls3/5a you should look into the kef reference 101. Same drivers, slightly bigger box. I heard them head to head with some rogers recently and I preferred the kefs, a little mor low end.

And at half the price you can't argue value. (Bought mine for €120.)

Contrary to some popular belief, the KEF R101 has the similar T27 tweeter but a DIFFERENT midbass driver, the later KEF B110 SP1057, sometimes referred to as the B110B. This driver has a different surround made from PVC instead of neoprene rubber, and with a different profile. The Plastiflex coating used to damp the Bextrene cone is applied to the back of the cone instead of the front, and has a different voice coil construction and parameters. It is certainly a very good driver, and was used in KEF's flagship R105 or 105.1. The R101 is certainly a very good speaker and has its fans. However, IMHO, it is let down by an overly complex crossover with its built-in S-STOP overload protection system which some felt compromised its sonics. Also, IMHO, the cabinet is not as well built as it could have been, being somewhat flexible and having a cavity in the bottom where the crossover was housed.

The R101 is a very good speaker, but the market for it isn't as fanatical, typically running around $300-$600 depending on condition and veneer type, the teaks being common, and the Rosewood being the most rare and sought after. As most know, the LS3/5a in any decent condition now starts around $700-800 and has recently sold much higher over the last 4-6 years due to the internet and Ebay bringing the LS3/5a much more visibilty to a world wide audience.

The correct tweeter is the KEF T27 SP1032. They aren't that hard to find on the auction site or other audio sites. Or Falcon Acoustics in the UK has announced they will begin making new replacements later this year. They already make an excellent replacement B110 woofer for the LS3/5a.

Yes, very true. Falcon also has been making LS3/5a type speakers using other drivers, and has a current kit with their Falcon FB110 KEF replacements so, in all respects a kit version of the LS3/5a at full BBC specification, crossover included.

Most recently, Falcon has announced they will be commencing production of fully built BBC licensed LS3/5a's in late summer 2014. Since they are the only ones producing a true bextrene B110 and T27's to original specification (Malcolm Jones, original owner of Falcon Acoustics was KEF's first employee and designed these two and other drivers whilst at KEF), it will now be possible to hear and buy NEW production LS3/5a to the original 15 ohm specification and be able to compare them to vintage LS3/5a, and now older vintage 11 ohm specification LS3/5a's coming from a BBC and KEF revision in 1987. The revision was needed due to problems with the original B110 SP1003 drivers becoming harder to make consistently to spec, and drivers in use drifting in frequency response due to aging and weather/atmospheric effects.

The KEF B110C SP1228 driver was created along with a new crossover and using the existing T27 to form the 11 ohm revision. The revision was described to be more "on center" to the LS3/5a spec. and voiced to be back at the original specification. During a large "shootout" by HiFi News via Ken Kessler, the 15 and 11 ohm units were tested and found interspersed among the ratings. All versions were eclipsed rather convincingly by the original BBC 001/002 prototype reference pair. That pair was built slightly differently and of course uber tweaked by BBC design engineers. What was interesting is that none of the LS3/5a used in the shootout was checked, tested or tweaked prior to use, they were selected from private and studio owners and used as is.

There are a number of important checks and maintenance items to do with any LS3/5a before one can be more sure its close to spec, and many 15 ohm units should (if possible) be checked for B110 drift which can be compensated somewhat through the crossover. However, the testing isn't easy to do reliably in the home setting.

 

[mech986]

LS3/5a shootout:
http://www.g4dcv.co.uk/ls35a/shootout.html

Falcon Acoustic announcement for LS3/5a production:
http://www.falconacoustics.co.uk/ls3-5a/ls3-5a-full-bbc-specification.html

 

[tube-a-lou]

I still would love to get a pair, but at prices there going for (ebay) and elsewhere.
but the Gini's look good, but we'll wait and see.

Tube