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104/2 info, advice and opinions

 
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MartinW
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Joined: 12 Jun 2011
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PostPosted: Fri Jun 17, 2011 3:04 pm    Post subject: 104/2 info, advice and opinions Reply with quote

Hi all,

First I'd like to briefly introduce myself as a new member of the forum. I've been pretty keen on music and hifi over the years, and as a result of various moments of weakness I've currently got a PC server storing flac and mp3 files, a Logitech squeezebox, a CA DacMagic, a homebuilt buffered pre-amp, Rotel 200Wpc power amp, REL Storm 3 sub and the most recent acqusition of 104/2s.

The 104/2s are a later bi-wire SP3128 version in great condition, with the foam LF surrounds and doughnuts intact (for now at least). I used to have a pair of Reference 102s many years ago, which I partly regret selling, and the urge to get back to a KEF presentation became irresistable Very Happy.

Anyway, on to a couple of questions that I'm hoping you folks can help with.

1. Does anyone have copies of any documents or reviews for the 104/2s that could be emailed? User/operating manual, maintenance manual, crossover schematics and any specs on the drive units (especially the SP1191 HF unit) etc. would be great.

2. The T33B SP1191s both work OK, but I suspect that they may lave lost some of their output over the years, and being critical they do have a slightly 'tizzy' nature (which seems to match some other comments I've read). So, I'd be prepared to try some replacements but options seem very limited and most of the ones suggested over the years are discontinued.

The main ones I've read of/had suggested/spotted are:
- KEF R1548X, fits but apparently too 'hot', has a different sound, and expensive
- Morel CAT298 - an 8 ohm unit and sensitivity probably too low, might need a bit of work to make fit if too deep
- Vifa MG27TG-29/04 - apparently fits and sounds great, but discontinued (not sure how long ago) and not sure if I could get hold of any
- Audax TW025A2 - don't know anything about this one.
- Morel MDT29-4 - a 4 ohm version of the MDT29 that Madisound have had made, but needs some unknown surgery to make fit into 104/2s. Madisound have said that second hand feedback on this rated it higher than the Audax above

So... has anyone tried any of the above (especially the Morel MDT29-4), or any other current candidates, and have any info on how they sound and what mods were needed to make them fit?

3. Has anyone tried bi-amping 104/2s and using something like the Behringer DEQ2496 on the LF end to extend the LF response like a KUBE200 would?


Thanks for reading this far! Any help/opinions/info/whatever would be much appreciated.

Best regards,
Martin
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proffski
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PostPosted: Fri Jun 17, 2011 6:43 pm    Post subject: Re: 104/2 info, advice and opinions Reply with quote

Nice one, I have a small review here ready to post if you wish.
The other reviews I cannot find.

Another item is my missing blueprint sized schematic for the 104/2.
How I fiot that onto my scanner IF I can find it will bea problem.

Anyway, review available if you so desire.
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MartinW
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Joined: 12 Jun 2011
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PostPosted: Fri Jun 17, 2011 8:35 pm    Post subject: Reply with quote

Hi Proffski,
Yes, that would be great please. If you find the blueprint it might be easier to pin it to the wall and use a camera .
Cheers,
Martin
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proffski
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PostPosted: Fri Jun 17, 2011 9:35 pm    Post subject: Reply with quote

MartinW wrote:
Hi Proffski,
Yes, that would be great please. If you find the blueprint it might be easier to pin it to the wall and use a camera.
Cheers, Martin


This implies me getting a tidy mind and a working memory!

You have a PM regarding this subject.
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ColinR
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Location: Staffordshire

PostPosted: Sat Jun 18, 2011 11:18 am    Post subject: Reply with quote

Once you've safely removed the ~50lb front baffle you'll have to be prepared to do some engineering with a Dremel or such like.

Don't restrict yourself to "modern" units if you can find a suitable 4 Ohm Peerless or Isophon unit.

The following describes the installation of a 4 Ohm Isophon KK unit which has similar efficiency, polar and frequency responses to the original.


"Quite proud of myself...tweeters fitted and working perfectly!

Not quite as straightforward as I had hoped, but the end result is that I cannot personally detect any significant sonic difference between the T33's and the Isophons, so all is well that ends well!

Just for the record and in case you come across another novice 104/2 repairer, I took your advice concerning the removal of the front enclosures...they weigh a ton!. On inspecting the recessed mounting space for the T33's, it appeared quite a straightforward task to remove them and secure the Isophons in place. However, the Isophons were just a little too big to fit into the existing circular recess which I carefully routed-out using a small rotary drill normally used by modelling enthusiasts.

As you are doubtless aware, the T33's are held in place by a single screw threaded through a piece of wood and tightened directly onto the centre rear of the T33. Undoing the screw allows the piece of wood to slide to one side within the retaining slots in which it is located.

On mounting the Isophons, it became apparent that (a) the connections on the rear of the speaker were in the centre...exactly where the securing screw would foul them and (b) the connections would not clear the piece of wood, preventing it from sliding into place.

Fortunately, I managed to sufficiently flatten the connections on the Isophons to clear the sliding wood panel without breaking them and solved the problem of securing the units by carefully drilling two holes in each of the the wood panels (in line with the original centre hole) each aligned with the left and right sides of the Isophon and fitted metal-threaded screw guides that have a pointed claw on their underside which is drawn tightly into the wood panel as the securing screws are tightened onto the rear of each tweeter. After a fair bit of fiddling about I managed to accurately locate the Isophons in place , with the bonus result that from the front their appearance is identical to the original T33's.

Having first double-checked all my re-connections and re-mounted the front enclosures, I connected up to my Audiolab 8000, put on a favourite Decca Phase Four recording and prayed! Brilliant clear sound....job done!!

So it seems I must thank you once again for your invaluable advice and expertise without which I would doubtless still be mourning the passing of my 104/2's!"


Very Happy
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MartinW
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PostPosted: Mon Jun 20, 2011 1:54 pm    Post subject: Reply with quote

Hi Colin, thanks for the reply and thoughts re older units - I'll keep my eyes open for 4 ohm Isophon KKs. Have you any suggestions on which peerless models I should look out for?

Over the weekend I removed the MHM units to have a first-hand look at how the T33s are mounted. They aren't 50lbs (the whole speaker is apparently 70lbs) but are still quite a weight! From what I'd read I had presumed that the wooden slider would be tight up against the back of the tweeter giving a depth limit (without surgery) of about 26mm. On my pair built in mid 1994 the slider seems to be set further back, with the securing bolt protruding by about 8mm to press against the tweeter. In other words I've got about 34mm to play with, which might open up some options. I'm fairly practical and able to wield a dremel but would obviously rather not make mods unless I had to.

Still happy with the 104/2s, and listening to music more than normal which is a good sign. They can really highlight the difference between good and bad recordings/productions, which is a bit of a mixed blessing.

In addition to proffski's contributions, KEF have kindly emailed me some further bedtime reading in the form of a sales brochure, installation instructions and some maintenance notes.
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proffski
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PostPosted: Mon Jun 20, 2011 2:17 pm    Post subject: Reply with quote

My old 104/2s are now living elsewhere but still in the family.

I used to drive them with either an Audiolab MkII or via an Adcom power amplifier using the Audiolab as pre-amp.

Recently the 104/2s were unplugged from the Adcom and introduced to a much higher rated AV Amplifier. Mistake! I am now repairing the output stage on the AV amplifier, the loudspeakers are fine!

The surrounds are now becoming tacky to the touch but not rotting as yet.
One repair I am dreading should the day arrive!
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ColinR
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PostPosted: Tue Jun 21, 2011 11:02 am    Post subject: Reply with quote

Quote:
you any suggestions on which peerless models I should look out for


Animals like this a revamp of the SK/LK10 http://www.parts-express.com/pe/showdetl.cfm?Partnumber=279-050 which will operate without a faceplate, some Audax and SEAS units also unscrew in a similar manner so you just need to play with a Dremel, silicone sealant and a resistive attenuator Smile .
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MartinW
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PostPosted: Sun Jun 26, 2011 2:59 pm    Post subject: Reply with quote

Well, curiosity got the better of me, and I have tried an experiment with a pair of Morel CAT298s which were the easiest candidates to get hold of. The helpful chap I spoke with at Wilmslow Audio reckoned they were a good match for the 104/2s even though they are 8 ohms, and I thought that if it seemed worthwhile then I could get a pair of the 4 ohm voice coils from Madisound.

Fitting them wasn't quite as straightforward as I had hoped (maybe my 104/2s are different to earlier versions?). Behind the removeable face plate of the Morels is the plastic of the voice coil assembly which extends to the diameter of the magnet. The inside of the MHM module is machined to the profile of the T33B and so the extra plastic on the Morels prevents them sitting forward enough. The choice was either to remove the extra plastic, or significant surgery to the MHM modules, and I chose the former. I can post some photos and more details if anyone wants it, but briefly it involved removing the voice coil assembly and carefully removing the plastic beyond the edge of the foam gasket.

How does it sound? Well, it's early days, and if tweeters do need running in then they won't have yet, and also it's not easy to do a A/B comparison. But I'd sum it up so far as 'pretty good with reservations'.

To my ears with the original T33 SP1191 the 104/2s have a slightly strident edge and treble is a touch 'tizzy'. With the CAT298s it definitely sounds smoother and has tamed the stridency, but it has gone too far. Probably because of the impedance and sensitivity there's just not quite enough HF output at the very top end.

Anyway, I'll leave then in place for a bit and see how it goes. Apart from the cost of the Morels (which was a calculated risk) there's nothing lost as I can easily swap back to the T33s again.

Hope this is of some interest and helps someone looking to replace their T33Bs.
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ColinR
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PostPosted: Sun Jun 26, 2011 8:31 pm    Post subject: Reply with quote

Quote:
Well, curiosity got the better of me


That's why I've got about 70 KEF based designs lurking in and around my place Very Happy .

Joking aside, as you're using an 8 Ohm unit the crossover point will be 3.5kHz/2=1750Hz which is about twice the 900Hz Fs of the 89dB CAT298 so it'll work but trials with trimmed MTD29 4 Ohm unit would prove more fruitful.

I suspect you have to "dremel" off all the raised plastic mountings of the annular ring and use silicone as a fixative.
https://www.madisound.com/store/product_info.php?products_id=9063
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Last edited by ColinR on Sun Jun 26, 2011 9:06 pm; edited 1 time in total
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MartinW
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PostPosted: Sun Jun 26, 2011 9:04 pm    Post subject: Reply with quote

ColinR wrote:
That's why I've got about 70 KEF based designs lurking in and around my place Very Happy .


Shocked I don't think I'd get away with that... fortunately computer bits like hard disks are quite small items to sneak into the home.

Anyway, thanks, yes - I had reaslised that the impedance would seriously mess up the crossover point, and I was hopeful that the output level would be high enough to use some shunt resistors to bring the impedance back down. I might still have a go, even if it will end up too quiet, but will probably just try to get hold of the 4 ohm voice coils as being a better starting point.
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MartinW
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PostPosted: Wed Apr 24, 2013 12:14 pm    Post subject: Reply with quote

Was it really mid 2011 when I was asking for advice and info on the 104/2s and the SP1191s?

Anyway, with my usual sense of urgency I've ordered the 4 ohm voice coils from Madisound to fit the Morels I bought.

I'll try to post a few opinions once I've got them cut down to size and installed. Probably this year Wink
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