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I got this old Kent A45 amp which has one of those 6 X 9 speakers which seems to fart out.

What would someone recommend as a replacement.

I have no idea of the ohm requirement

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That looks like a car speaker.
 

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I'd try it into some test speaker first, before going to any trouble with a baffle or anything else. If it still sounds poor you haven't wasted any time on it. :)
You can measure the impedance with a multimeter once the speaker is disconnected.
 

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I'd try it into some test speaker first, before going to any trouble with a baffle or anything else. If it still sounds poor you haven't wasted any time on it. :)
You can measure the impedance with a multimeter once the speaker is disconnected.

Yes ... Set your multimeter to 1 K ohm range and measure
If its 8 ohm speaker you will get a reading of 6 or 7 ohms . If its 16 ohms your reading should be 13-15 and so on.
Some old radio consoles used similar speakers and they have a very special grit to them when driven in a guitar amp
 

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Some meters have a 200 Ohm range - basically the lowest range setting on a given meter.

Anywho, just to be clear, the farting out of the current speaker is not due to it being a bad speaker of the oval shape; it is fatigued out and in need of a recone (except it is hardly worth the cost). You can get a replacement for 20-40 bux on ebay any day of the week (vs 100+ for a recone). They were very common in hifi consoles in the 60s (either paired with a supertweeter, or alone - either way run 'full range' as they have a very similar response to a guitar speaker) - I have such a console and it sounds great. I am a little surprised that the shape did not catch on for instrument speakers; many advantages (smaller baffle sizes with higher piston moving mass are possible - a 6x9 takes less space than an 8, but moves as much air) and no real disadvantages. There were even some legendary hifi woofers of that type (e.g. by Kef) that are very sought after and worth a lot of money in audiophile circles these days.

Here is an IMF monitor speaker exploded component view showing an ovular Kef B139 woofer in a transmission line type enclosure (my favorite, and IMHO best sounding enclosure type - I made some TL guitar cabs and they are great). A very sought after classic for those in the know.

 

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Slightly off topic, but that amp may not have a power transformer. The original ran right off the line.
If that's the case you have more to worry about than a speaker.
Thats what it looked like to me from the pics but wasnt sure.

What would you do for that - add a simple 1:1 iso transformer at he end of the cord before the circuit?
 
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