Magnepan MG-12 Crossover upgrade

[waynebosz]

I'm upgrading the crossovers in my Magnepan MG-12QR's. Can a 47uf 250V Mundorf MKP replace the stock 50uf 150V capacitor without a problem or should it be an exact match? The 33uf tweeter will be replaced with
a 20 & 12uf V-Cap OIMP and 1uf Mundorf Silver & Oil. A distributor's suggestion for my upgrade. Or are there any other suggestions out there.
Thank you.

[gootee]

It's only 6% different.

If in doubt, I'd check out the posts on that subject at The Planar Speaker Asylum

There are also some articles on upgrading the MG12/QR (and other Magnepan) crossovers, at MUG Tweaks .

I did buy 50 uF polypropylene caps for my MG-12/QR's crossovers. But you could also just add a 3 uF in parallel with your 47 uF.

Did you also buy copper foil inductors?

I haven't had time to assemble my new crossovers, yet, unfortunately. But I can't wait to hear what difference they might make.

[waynebosz]

Yes. I will be replacing with 2.70MH 16GA FOILQ- COPPER FOIL AIR CORE INDUCTORS. My concern was reading post referencing Magnepan's careful decision on using single caps instead of multiple caps in parallel. I ask Chris, president of Parts Connnexion to help in my decision which resulted in using caps in parallel for the 33uf cap for the tweeter crossover. Which 50uf cap did you decide on? This is what Chris has to say about MG12's crossovers:

The only sonically critical part is the 33uf cap on the tweeter (with the 0.1uf bypass)....everything else is shunted to ground, or after the drivers.

And the 50uf low end cap: It's far less critical......as it shunts around the driver, to ground.

[gootee]

I ended up with 50 uF Solen Châteauroux Fast Cap PB-MKP-FC 400VDC with 5% tolerance, for which I paid $16.10 each. I also got a pair of 30 uF and a pair of 3 uF of the same Solen model line, for $11.25 and $2.65 per cap. And I got two Erse copper foil 16AWG 2.7mH air core inductors for $33.50 each. Shipping for the lot was $12.65. It was March 21, 2011 but I now have forgotten the name of the place from which I ordered them! (And it's not on the receipt.) [Edit: Found it. It was Madisound.]

Here is some info about the caps (and about many different types of caps, but mostly from a subjective audio perspective), that I just now stumbled across: Humble Homemade Hifi

Not sure I can agree with Chris's reasoning about why the 50 uF would be far less critical.

Cheers,

Tom

[andyr]

Originally Posted by waynebosz

Yes. I will be replacing with 2.70MH 16GA FOILQ- COPPER FOIL AIR CORE INDUCTORS. My concern was reading post referencing Magnepan's careful decision on using single caps instead of multiple caps in parallel. I ask Chris, president of Parts Connnexion to help in my decision which resulted in using caps in parallel for the 33uf cap for the tweeter crossover. Which 50uf cap did you decide on? This is what Chris has to say about MG12's crossovers:

The only sonically critical part is the 33uf cap on the tweeter (with the 0.1uf bypass)....everything else is shunted to ground, or after the drivers.

And the 50uf low end cap: It's far less critical......as it shunts around the driver, to ground.

I have to disagree with Chris in the sense that, even though the sonic quality of a shunt cap shouldn't have too much effect on the sound ... IME, it does. So, if you can afford it, buy just as good caps for that as for series caps.

And IMO whether it's "after" the driver or "before" is irrelevant.

Re. "Magnepan's careful decision on using single caps instead of multiple caps in parallel" - in other speakers, Magnepan uses multiple caps (like, I think, 8x25uF instead of a 200uF in the 3.6). So don't stress about using several smaller ones - however, AIUI, for signal caps it is best to use multiple caps of the same value (so the signal doesn't get "smeared" by passing through caps of different physical size, which have different path lengths).

Finally, you are suboptimising by using 16g ribbon inductors. Use 12g.

Good luck,

Andy

[a.wayne]

Be very careful changing inductors and resistors , the drivers are sensitive to inductance and dcr not so much with capacitance. highly recommend the shunting caps or multiple caps ..


regards,

[waynebosz]

My 2.7mH 16ga FoilQ ERSE inductor arrived Tuesday. Andyr replied with a post expressing that 16ga is sub-optimizing...12ga would be better choice. You ordered the 16ga also, so what's your take on Andyr?

[waynebosz]

So many opinions. 12ga in what mH? My 16ga arrived Tuesday. These were recommended.There are many arguments on inductors and I have limited knowledge on the subject so I thank you for responding.

[waynebosz]

So a.wayne what is your opinion with the 2.7 mH 16ga ERSE FoilQ inductors for Maggie MG12?

[a.wayne]

Not familiar with the Brand...


It will change the sound for sure as foil coils have a different DCR and magnitude vs freq....compared to normal wire aircore for eg..A 2 mh foil coil will tend to be more linear in it's rating and will be closer to it's 2 mh rating vs frequency compared to a normal aircore.


regards,