Exact Speaker Impedance

[Neddy]

 

Found an old 70's Carlsbro speaker (think originally PA) with 2 celestion speakers, with an impedance at 8.3ohms.

Would a speaker like this work with an amp head even if it might have originally been for PA and would the 8.3ohms work fine with an 8phm head?

Thanks for the help.

[Dad3353]

Impedance is a rather nominal notion, and 'exact' figures are fairly meaningless, really. The actual impedance is only for a specific frequency and power input. There is no noticeable difference between 8 and 8.3; treat is as 8 and you'll be fine. Would it be suitable for guitar..? The answer, I'm afraid, is 'a lemon; suck it and see'. If it sounds OK, it's OK. Be aware, however, that typical PA stuff, 'back in the day', was not rated highly for power handling, as only vocals from a modest amp were expected. Don't connect a 100W Marshall amp turned up to 11, as it won't last long, I'd say. Vintage gear can be nice, if played in vintage manner. Watkins Westminster amps from that period are now collector pieces, but their 17 watts won't fill a stadium..! Go easy on your find and enjoy it for what it does, not what you think it should do. 

[Neddy]

Thanks for the help, planning on putting a 50watt marshal head into it that won't be put past 5. Hopefully get to something close to a decent sound out of it, cheers.

[Dad3353]

1 hour ago, Neddy said:

Thanks for the help, planning on putting a 50watt marshal head into it that won't be put past 5. Hopefully get to something close to a decent sound out of it, cheers.

 

See my reply to the other question, then. Good luck with the project. 

[randythoades]

As @Dad3353 says, just because you can, doesn't mean you should. The speakers may or not cope with the power going through it (and I also remember old Carlsbro PAs being basic workhorses rather than particularly good), but it might not sound very good. You might just get the sound of your power amp coming through, rather than the Marshall sound which relies on the speaker to impart some colouration or break up. As @Dad3353 says. Try it and see, but start looking out for some nice Celestion speaker to replace them in the future.