DIY TA-7331-A here we go...

Do It Yourself

MrEd

Senior Nobody
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I hope this will be a fun adventure.
Today I have two 12" field coil drivers in hand. One arrived yesterday, one today, I need to measure their coils, but if the sellers measured correctly I have a pretty good match.
These are Rola drivers from Hammond organ Tone Cabinets.
I will blame this on @Tsingtao_1903 for now.... for stirring up my interest in this concept again. 😊
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Ooh, this should be fun. Curious to see where you go with these. Haven’t played with field coils yet myself.
 
I took measurement and the voice coils are both 6.7 ohm, the field coils are 658 and 669 ohm.
The date codes are 1 year apart.
I have not been able find any info on what years the were used, I am going to assume they are from the 50's.
The 4th digit is the year but it is 0 through 9 the the next two digits are the week of the year. 285 is Rola, 280 is Jensen. I have 285225 and 285125.
 
This will be a slow project.
I need to design a power both supply first. Then make a couple quick n dirty open baffles to try them with.
I am going finish my 2a3 amps first.
 
Ah, so check back in another couple years, then? :)

(Y’all know how quickly my projects move... I’m allowed to say this!)

Hey... what are insiniuating here Nate ?
That I might see some shiney object and get off track... 🤣
 
The photo Joe83 just posted is helpful, and it’s consistent with a comment Joe Roberts made somewhere a few years ago. Charles Michlin also has some info on the cabinet in his blog.
 
Saw the same post. Poster said he used fabric. I am asking him what kind of fabric as the original drawing calls for "Soundtex".
 
I found a couple more cabinet photos also.
I have the drawings from Charles blog, but it is very hard to read and doesn't enlarge well.
 
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