Isophon tweeter orientation

[BTH K10A]

I wanted a small pair of high sensitivity speakers for some 45 triode amps and these Isophons seemed to fit the bill.

All I need now is some cabinets and I'm wondering whether the mid/tweeter unit might give better imaging if mounted vertically rather than horizontally as per the original 30/70's.

[Rare Bird]

Nice Andy
Don't you have the original corner cabs?

[Jonboy]

To my mind horizontally to form an arc or else one will be pointing skywards and the other towards the floor

[BTH K10A]

Nice Andy
Don't you have the original corner cabs?

Unfortunately not Andre. The person I bought them from had binned them as they were "big & heavy". They did come with the brochure though which has plans for a number of cabinet options. Still, I can't complain as they were cheap at just over £100 for the set.

They are very flexible in that they can be configured to be driven straight off the outputs of a pair of PP valves as they have 3000-4000 Ohm & and 7000-8000 Ohm taps as well as 4-6 Ohm, 10-15 Ohm, 200 Ohm & 850 Ohm 100V taps.

I might try them straight off the outputs of the 45's

As for a cabinet, I was thinking along the lines of an Onken Bass cabinet with the mid/highs in their own enclosure on top

[BTH K10A]

To my mind horizontally to form an arc or else one will be pointing skywards and the other towards the floor

True but they will still be forming an arc and having the tweeter pointing at the ceiling doesn't seem to have too much detrimental impact on a number of speakers I've hear such as the Wilson WATTS, and they have the mid pointing there too.

If I go down the bass cabinet - mid/high satellite route I suppose I could then try both options.

[walpurgis]

Isophon speakers are superb quality and were (and are) expensive, do not underestimate these, they may look strange and old fashioned but they should sound very good (they all have good Alnico magnets assemblies). I'd suggest trying them as they are, Isophon knew what they were doing.

I think I may have the original product brochure for them, it may be the same as you already have, but if you're interested (if I can find it) I can scan the relevant pages and forward them to you, I believe cabinet diagrams may be included.

If I'm not mistaken Rehdeko have used Isophon drivers in some of their extremely expensive speakers.

Oh, and if you decide you won't keep them, let me know, I'd be interested.


Geoff.

[southall-1998]

Isophon speakers are superb quality and were (and are) expensive, do not underestimate these, they may look strange and old fashioned but they should sound very good.

I think I may have the original product brochure for them and if you're interested (if I can find it) I can scan the relevant pages and forward them to you, I believe cabinet diagrams may be included.

If I'm not mistaken Rehdeko have used Isophon drivers in some of their extremely expensive speakers.

Oh, and if you decide you won't keep them, let me know, I'd be interested.


Geoff.

A project in mind Geoff?

[walpurgis]

A project in mind Geoff?

Usually several, always!

I've been pencilling out a very unusual design for a pickup arm for the last few weeks. Glass ball bearing, fluid damped, unipivot! Made from hardwood, acrylic and paxolin.

[BTH K10A]

Isophon speakers are superb quality and were (and are) expensive, do not underestimate these, they may look strange and old fashioned but they should sound very good (they all have good Alnico magnets assemblies). I'd suggest trying them as they are, Isophon knew what they were doing.

I think I may have the original product brochure for them, it may be the same as you already have, but if you're interested (if I can find it) I can scan the relevant pages and forward them to you, I believe cabinet diagrams may be included.

If I'm not mistaken Rehdeko have used Isophon drivers in some of their extremely expensive speakers.

Oh, and if you decide you won't keep them, let me know, I'd be interested.


Geoff.

Yes, the build quality is not too bad, not in the same league as my BTH & Westrex speakers but that's not surprising given the price differential when new.

The brochure I have is an eight page document that has plans for a number of different cabinets on the last couple of pages and is probably the same as yours. Andre gave me a link to a site that has details of the frequency curves and I found the TSP figures on a French site.

I think I may still go for the separate enclosures for the drivers as it was quite common for German manufactures in the 60's to aim for as wide a treble dispersion as possible, sacrificing some of the imaging as a trade off. The separate box route will give me the chance to experiment and as you know, the mid/hi is a self contained unit.

These are only a bit of fun to go with some triode amps I found but at present are not high priority as I want to add a second tonearm to my EMT 930 first. I have a spare 929 that can be converted into a 997 and the mounting plate is available in Germany.

[walpurgis]

Well have fun with them Andy. I'd be interested to see what you end up doing with them.

I don't know if you have any dates stamped on those, but my guess would be that they were made in the late sixties.

I still have one pair of hefty Isophon DKT11/C110/8 horn tweeters left and I'm hanging onto those, as they sound superb.


Geoff.