SpeakerTalk

essence · Introductory Contributor Joined: 29 Jan 2007 Posts: 6

I have three B139 6171's. I have one B139B 1044 Constructor seris.

In my first rebuild pair, I was using one 6171 and one 1044. The bass on the 1044 sucked. I replaced it with a 6171 and got some bass again.

To be even more technical, the 6171 'flapped' as it should when the bass drum was rolling.

So my B139B 1044 constructor series is destined for scrap heap. I could find nothing wrong with it, but it did feel significantly stiffer.

Now here is the question. Did I just get a duff unit (I bought it in the ?late 70's from a shop up Tottenham High Court Rd) , or is there a difference between the 6171 and 1044? I need to know the answer, as I need to purchase another pair, and I don't know which to go for on ebay.

I seem to remember some message about how constructor series units were the rejects.

ColinR · Posted: Sun Feb 04, 2007 2:21 pm Post subject:

Quoting from a reliable source, a former manufacturer of transmission lines, "B139A's were terrible things, we used to get them 100 at a time and each one measured differently."

Laurie Fincham once (~1988) stated "you can take any two drivers off the production lines and they'll measure within +/-0.5dB."

When the 6171 evolved into the SP1044 the equivalent volume and lower frequency response limit were reduced somewhat, so you do get less boom for you buck, but it's more consistent.

The best drivers btw, are the least desirable, rebuilds from the mid 80's to the early 90's.

Regarding Constructor Series they're very variable from pair to pair, some are +/-0.25dB others are dogs, never buy a single.

Your SP1044 appears to have canine qualites, although it would be ideal in an isobaric configuration.

Tread carefully with ePrey.
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proffski · Posted: Sun Feb 04, 2007 2:43 pm Post subject: B139

Colin I was aware of the facts stated, but I have never been happy with my lack of knowledge regarding the motor design and power handling.
Was there much difference between the versions?
_________________
I contend that for a nation to try to tax itself into prosperity is like a
man standing in a bucket and trying to lift himself up by the handle.
-Winston Churchill

ColinR · Posted: Sun Feb 04, 2007 4:15 pm Post subject:

proffski · Posted: Sun Feb 04, 2007 4:43 pm Post subject:

You missed the double sided sticky tape! Very Happy

_________________
I contend that for a nation to try to tax itself into prosperity is like a
man standing in a bucket and trying to lift himself up by the handle.
-Winston Churchill

essence · Introductory Contributor Joined: 29 Jan 2007 Posts: 6

Thanks for the feedback. I got outbid in the last 30 secs on a pair of 6171's which were being sold 10 minutes away from me, which was a pity, but I have bid again on a single 6171 and will pay postage. But I did pick up a pair of Tannoy 603's which will replace the TDL cheap things for the kitchen for the wife. They sound good for £27.

I think I will go for 6171's, and just mix and match if I find a poor unit.

I should have explained at the start - I am renovating a old pair of HiFi Answers TL speakers, and building a new pair, using units from a Concerto I picked up for £80 at a school fete.

The removated pair is complete, apart from front grill, installed in their old place, and sound wonderful. I can listen to first movement of Mahler's 8th properly again.

Also my gangster rap shakes the house again - I have to wait until the neighbours have gone out.

Possibly my replacement for the T27's, the vifa XT25TG-30-04, needs toning down slightly, or else the grill will help a little.

The new pair I am doing more carefully, just finished veneering cabinets and about to start electrics and front panel.

ColinR · Posted: Sun Feb 04, 2007 9:55 pm Post subject:

essence · Introductory Contributor Joined: 29 Jan 2007 Posts: 6

Out of interest, I have basically completed my renovation of a pair, and new build of a pair, of hi Fi Answers TL's (cambridge R50 look alikes).

They are superb.

But having slightly less luck getting an ebayer to actually send me the single B139 6171 i have paid by paypal for. So I am one B139 short of a house warming. Neighbours have already complained.

Interestingly enough, I realised the monitors are too big physically for my bedroom (which is a good size, 18' by maybe 12'), so got a pair of Monitor Audio Monitor 3 speakers, second hand for 150 GBP, which are tall but narrow, good looking and fit the room well.

But in comparison with my TL's, they simply do not fill the room. No warmth. Loud, yes, but impact, no.

suffolk2 · Posted: Sat Jun 23, 2007 9:00 pm Post subject:

I have a pair of B139 [ not radiators ] with stickers SP1044.
Can anyone tell me what speakers they come out off, or are
they from the constructor series ?

ColinR · Posted: Sat Jun 23, 2007 10:59 pm Post subject:

suffolk2 · Posted: Sun Jun 24, 2007 8:32 am Post subject:

it is not from constructor series, as there are no labels.

i have kept these units from the 1980s as i got them off a hi-fi mate
who had celestions 66 but modified them to have B139s' in them.
so they must be originals from any of those kef speakers, as they
were definately not from ebay.

if i were to use them in the calinda[ replacing the ABR ], would i be
able to use concerto / cantata / cs7 / xovers ?

ColinR · Posted: Sun Jun 24, 2007 10:10 am Post subject:

A very, very bad idea.

suffolk2 · Posted: Tue Jun 26, 2007 12:18 am Post subject:

yes i agree the B139 will need a bigger box Very Happy

i still like the idea of the isobarik, but that would mean buying
another pair of B139s, and sourcing the other mid and tweeters
and xovers, which is not cost effective when they go for about
£400 on eprey Very Happy