Tannoy M20 Gold crossover

[musicalaudiofan]

Hi all - I'm a total newbie here


I have recently got a pair of Tannoy M20 Gold (1986) that I'm planning to refurbish.


I'm not sure my M20s still have the original crossover, as the number on the board suggests they may have been worked on in 1997.



My question is, does anyone have the schematic of the original crossover? I contacted Tannoy directly, but they don't have the data in their archive.


Cheers

 

[Sonce]

This seems to be an "upgraded" crossover, as the original one has a cored inductor for the woofer, if my hazy memory is right.
Schematic is simple: just an inductor in series with the woofer, and a second-order high-pass filter for the tweeter, consisting of one capacitor and one inductor, plus resistor for tweeter attenuation.

 

[musicalaudiofan]

Thanks Sonce, I thought this didn't look like an original crossover. So was the cored inductor the only difference compared to the original?



It would be interesting to know the components and their values in the original crossover, to see if this 'upgraded' version uses the same.


But if no information is available I should probably just refoam the woofers, refurbish the cabinets and leave the crossovers as they are?

 

[drewan]

Hi, I took apart the crossovers from a pair of Mk2 M20s, and the values were
1.4mH on the woofer, and 3ohm resistor 6.8 cap and 0.6mh on the tweeter. The parts were all glued to the plastic panel with the binding posts, and the cables were 3 different colours. I think black for -ve and two different for the +ves. Hope that helps.

 

[musicalaudiofan]

Thanks for this information drewan. I might rebuild the crossover using the values of the Mk2 M20s, it could be fun to listen to the different crossovers and see which one sounds better.