Isophon HSB 35

[numba1killa]

I found a pair of Isophon HSB 35 speakers at my local Habitat for Humanity store and have no idea what they are... they are rated at 4ohms and are 35 watts each.

There is also this little black switch on both speakers that I am unsure does anything.... I did search AK and it turned up results but nothing I can go on.

Any info guys? I got these with a "The Fisher" 400-T which does do 4ohms.

Any help would be great!

Thank you!

I tested them out with the Fisher and they sounded pretty good on FM radio.

 

[numba1killa]

Not sure if I can give you guys anymore info to go on! Still trying to find anything.... very little info.

 

[Rolf Zetterberg]

Can't find anything on those boxes-not even in Isophon's own archive!
But there was a kit called BS35/8.Perhaps similar?
http://kaizerpowerelectronics.dk/audio/isophon-bs35-loudspeakers/

 

[PastTechFan]

Not sure if I can give you guys anymore info to go on! Still trying to find anything.... very little info.

By googling, I can (only) find info on HSB (Hi-Fi Speaker Box) 30 and HSB 45. The last model is said to be 1966. It has a switch on the back to change from 4 ohm to 16. I'm a big fan of the Isophon drivers from this era. Of course, most of the info is in German.

Are you able to open the cabinets and give us a peek?

 

[numba1killa]

By googling, I can (only) find info on HSB (Hi-Fi Speaker Box) 30 and HSB 45. The last model is said to be 1966. It has a switch on the back to change from 4 ohm to 16. I'm a big fan of the Isophon drivers from this era. Of course, most of the info is in German.

Are you able to open the cabinets and give us a peek?

Yes, I can do that and will post them soon. I have them hooked up to a Marantz 2285... even though the speakers are rated at 4ohms... is it bad to have them on there????

 

[numba1killa]

By googling, I can (only) find info on HSB (Hi-Fi Speaker Box) 30 and HSB 45. The last model is said to be 1966. It has a switch on the back to change from 4 ohm to 16. I'm a big fan of the Isophon drivers from this era. Of course, most of the info is in German.

Are you able to open the cabinets and give us a peek?

The back doesn't appear to come off... i took out about 12 screws and the back still won't budge... i even took off the connection screws and the ohm changer screws too... nothing. No more screws left!

 

[PastTechFan]

Yes, I can do that and will post them soon. I have them hooked up to a Marantz 2285... even though the speakers are rated at 4ohms... is it bad to have them on there????

I'm not familiar with your Marantz but, according to this AK thread:
http://audiokarma.org/forums/index.php?threads/marantz-2270-vs-2275-and-2285.81895/

it appears to be very conservatively rated at 100/8 ohm or 140/4 Ohm. Thread also says, "The 2270 is known for a weak power supply and doesn't do well with lower impedances. The 2275 corrected the problem. The 2285 is minimally more powerful."

I expect those Isophons are pretty efficient. They were built to sing with fairly low wattage. I don't think you'll have any problem with your set up (at any reasonable volume). That receiver might barely notice the speaks are there.

 

[PastTechFan]

The back doesn't appear to come off... i took out about 12 screws and the back still won't budge... i even took off the connection screws and the ohm changer screws too... nothing. No more screws left!

I think it's just very tight. Try to put a bigger (thicker) wood screw into one or two of the holes in the back (near a corner), just far enough to bite into the back panel, and tug a bit (pliers help). Those German cabinets have some really precise (tight) tolerances. You can also try to pry with a thin shim, maybe after you get the back to release a bit. This trick has worked for me.

Might help if you let the cabs warm in the sunlight for a bit. They might expand just enough to free the edges against the inset back.

 

[numba1killa]

I'm not familiar with your Marantz but, according to this AK thread:
http://audiokarma.org/forums/index.php?threads/marantz-2270-vs-2275-and-2285.81895/

it appears to be very conservatively rated at 100/8 ohm or 140/4 Ohm. Thread also says, "The 2270 is known for a weak power supply and doesn't do well with lower impedances. The 2275 corrected the problem. The 2285 is minimally more powerful."

I expect those Isophons are pretty efficient. They were built to sing with fairly low wattage. I don't think you'll have any problem with your set up (at any reasonable volume). That receiver might barely notice the speaks are there.

They sang quite well on the Marantz 2285, although with my Cornwalls, it gets loud with just a few turns of the volume knob, these require a few more yet are still very very loud and clear. I will try your suggestion about thr screws into the wood with some pliers... thanks for the suggestions. Will report back tomorrw when I am off work!

 

[kj2005]

I found a pair of Isophon HSB 35 speakers at my local Habitat for Humanity store and have no idea what they are... they are rated at 4ohms and are 35 watts each.

There is also this little black switch on both speakers that I am unsure does anything.... I did search AK and it turned up results but nothing I can go on.

Any info guys? I got these with a "The Fisher" 400-T which does do 4ohms.

Any help would be great!

Thank you!

I tested them out with the Fisher and they sounded pretty good on FM radio.

Hi,
First , please find Isophon S5004/BS35 DIY kit from 1969 at "Lup Berlin" : http://www.lup-berlin.de/archiv/Katalog/index.html

...and then download the Isophon 1969 catalog ....Isophon speaker catalog including hippie-girls from that period

Secondly I have redrawn the actual crossover for the S5004/BS35 kit of mine : http://vintagehifi.dk/forum/viewtopic.php?f=557&t=2242&start=45

Rgds. Kim