Help for IMF RSPM MKIV/IMF SACM

[saba777]

Hi, my problem: In my RSPM MK.IV the bass is an IMF 128/20 instead of the KEF B139. I just want to bring the bass crossover to the modified state of the SACM from 1982. In the circuit diagram from August 18, 1982 of the IMF SACM (imf-electronics.com/Home/imf/cross) I see only two capacitors for the bass. Are they really only (C1 = 1x 100 microF) and (C2 = 1x 2.2 microF) and not several in parallel as in the RSPM? And I can't see any series resistors for the bass in the schematic.
The best of all worlds for us
saba777

 

[Jan-Helge]

Then you have the improved-version of RSPM, also this (wich is better than version with Kef B139).


I have that version myself!

Same driver is used in IMF's best speakers, the SACM.

Bouth seen here

Last thing you should tink about is the Kef B139 driver, if you should change you end with ordenary (not improved) version of speaker.

 

[Tor-S]

Hi, my problem: In my RSPM MK.IV the bass is an IMF 128/20 instead of the KEF B139. I just want to bring the bass crossover to the modified state of the SACM from 1982. In the circuit diagram from August 18, 1982 of the IMF SACM (imf-electronics.com/Home/imf/cross) I see only two capacitors for the bass. Are they really only (C1 = 1x 100 microF) and (C2 = 1x 2.2 microF) and not several in parallel as in the RSPM? And I can't see any series resistors for the bass in the schematic.
The best of all worlds for us
saba777

Can you post a pic of your crossover?

Yes, the later crossovers had only one 100uF + 2,2uF in paralell in Bass section. And yes there are no Resistors on the bass circut because theres one less switch on the crossover.