Hi,

I have a complete Rotosonic unit that came from a Concorde I've scrapped last year. As I intend to mate it with a AO-68 that I've converted into a (fine sounding, btw) guitar amplifier, I need to know the speaker's power rating. Can anybody help me, please?

Best regards!

开云体育

The power amplifiers used in the Concorde were rated at 35 watts. One other point to consider, rotosonic units in organs were generally, either used with a crossover to feed bass notes to a separate bass speaker, or only for manual keyboard notes. Bass pedal notes were never fed to rotosonic speakers.

Hi,

I have a complete Rotosonic unit that came from a Concorde I've scrapped last year. As I intend to mate it with a AO-68 that I've converted into a (fine sounding, btw) guitar amplifier, I need to know the speaker's power rating. Can anybody help me, please?

Best regards!

Thanks, Chris!

Concorde and similar power amplifier modules were rated at 35 watts @ 8 ohms. I do know that. But what I don't know is the actual impedance of a Rotosonic 9" x 6 ". If it is 16 ohms as with the reverb speakers in, say, a 251, output power is halved at about 18 watts. If it is 8 ohms, they might cope with 35 watts indeed (besides for lower frequencies, as you mentioned).

Best regards!

开云体育

You can get a reasonable idea of a speaker's nominal impedance by measuring it's resistance with a meter. DC resistance as measured by a meter will usually be a little lower than the impedance (about 10~20% lower). I believe that the rotosonic used as an internal Leslie in the Concorde was 8 ohms.

Thanks, Chris!

Concorde and similar power amplifier modules were rated at 35 watts @ 8 ohms. I do know that. But what I don't know is the actual impedance of a Rotosonic 9" x 6 ". If it is 16 ohms as with the reverb speakers in, say, a 251, output power is halved at about 18 watts. If it is 8 ohms, they might cope with 35 watts indeed (besides for lower frequencies, as you mentioned).

Best regards!