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OK Maggie 3.7 crossover sleuths. Look what I stumbled upon today. Maybe someone will step up and buy them, or can someone figure it out from the photos. No affiliation, just interested to see the crossover mystery solved!
Jim
Bring Dynamics Back to Music
http://turnmeup.org/
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The question(s) is......why would anyone want to be buy these crossovers? What use would they be to anyone? Cut 'em up for parts to build something else? Possibly frankenstein them into a 3.6 system?
And, why would the seller want to sell them? If the speakers are ultimately sold, they'll be worth more if the "original" crossovers go with them.
Obviously the seller's objective here is to make a few bucks on the "mystery" (which isn't really much of a mystery) of the new Magnepan 3.7 series crossover. :)
This is actually just about as irritating as Magnepan's zipped-lipped comments regarding the new crossovers.
Dave.
"And, why would the seller want to sell them? If the speakers are ultimately sold, they'll be worth more if the "original" crossovers go with them."
Perhaps the speakers were severely damaged plus being too costly for Magnepan for repair/restore them. So the seller is salvaging parts and trying to sell them off to minimize his/her loss. I think it's unlikely that he/she knows anything about any 'mystery' and wouldn't give a care if they did.
It's unlikely the speakers are damaged. The statement "These were replaced with external custom built crossovers" in the Ebay ad seems to indicate they're probably working fine.
But who knows??? :)
Dave.
I was wrong in my assumption and humbly apologize. You are absolutely correct, it was an oversight on my part having forgotten: "These were replaced with external custom built crossovers" ....
(Sorry, yet another one of my 'senior moments'.)
I think I have seniority on you. :)
Regardless, if I were the owner, I'd hang on to them.
Dave.
He now has a pair of external XOs which must deliver better SQ because:
a) they are mounted off the panel, and
b) use better-quality parts (parts that Magnepan couldn't afford to use bcoz doing so would price the 3.7s out of being an economic buy).
So selling them will recoup something to put against the cost of the new external XOs.
But I sure would like to know what that schematic looks like. :-)) I wonder if it was anyone here who bought those XOs?
Andy
The reserve was not met and the highest bid was $1.50. What does that say to you? :)
Dave.
These factory X-overs are now listed on Canuck Audio Mart.
http://www.canuckaudiomart.com/details/649177076-magnepan-37-oem-passive-crossover-network-pair-with-schematic-crossover-frequencies-amp-roll-off-rat/
There seems be be a rather large discrepancy between what the seller is asking and what the market is willing to pay, at least based on the E-Bay offers.
He's essentially selling the design I guess. I'm not sure why it took "a considerable amount of time to measure the response to each of the elements." That's about a five minute job for me once my laptop is setup next to the exposed crossover on a speaker.
I still don't understand what a prospective buyer would have in mind for these other than possibly transplanting into a 3.6.
Oh well.
Dave.
"This is actually just about as irritating as Magnepan's zipped-lipped comments regarding the new crossovers."
Greater than their zipped-lippedness as to how a 3.7 is turned into a 3.7i?
I had exactly the same thoughts.
In any case, it looks like the crossover is just a standard 3-way 1st order series. It would be nice to know the impedances of the drivers. (I suspect the standard 3, 3.3, 4.0 for the tweeter, mid and woofer) and the inductance of the coils. Perhaps someone with a 3.7 would be willing to measure the resistance across the mid and woofer --no surgery needed other than opening the access panel.
Edits: 02/06/15
You can't measure the midrange driver without a wire disconnection or two since the large inductor shunts it. The woofer can be measured pretty much directly via the positive and negative terminals. (One inductor in series which can be subtracted.)
Regardless, without the L value of the inductors, it's difficult to determine the exact alignment.
Did you determine the capacitor values by sleuthing that photograph?Dave.
Edits: 02/06/15
I think the mids are about 6 ohms. The foil is 0.001" x 0.1" and about 48 feet long.
here is a link to the crossover schematic on the ad. I couldn't read the component values.
looking for some jazz and a little libations - joe strummer
Inmates are cartwheels all over the world...
FYI...My brothers and sisters call my Spark or Sparky...to nieces and nephews calling me Uncle Sparky...
thanks again
Mark
The implications of this auction are far more interesting. Someone already went to line-level on the 3.7, YEAH!
Rats! Just when Mark Man was beginning to consider surgery on his 3.7i. LOL
Unlike yourself Dr. Strangelove, where you dream of tweaking...Marcus Welby M. D., (that's me), does not like being a "chest cutter" and reaching for his bone saw as he is pulling it out of the box...
The extent of my surgery is going to be fuse by-pass and possibly attenuator hard wire with new binding posts...even that I am going to bring in a specialist...
When I did the Ed Hsu 1.6 crossover and did soldering myself...I am guessing that I may be the ONLY one to have FLAMES shooting out of both sides of his Maggies...(they are di-poles)...this nightmarish event left me with serious Maggie PTSD...
That being said, my friend who is going to do the surgery, is an anal-attentive engineer, (is there any other kind??!!??), depending on how much we open them up, if we got to the x-over I was going to take pics of heart of the i's so 3.7 owners could see what was different...(Waz)...
thanks
Mark
Perhaps you can get Dr. McCoy, aka Bones, to scan your 3.7i with his tricorder.
BTW does your family call you Sparky because of your attempts to solder on your Maggies?
Edits: 02/06/15
E L E C T R I C I A N...
Thanks for lobbing that in there...too easy...
The 1.6 "tragedy" was witnessed by my friend the engineer, who will do the 3.7 surgery, to this day he laughs out loud every time we talk about it...
It was the bridge cap, (?), at the inductor...I had cranked the volume, showing off, when all of sudden there was weird burning smell...then this very black smoke...followed by FLAMES out of both sides...I ran across the room, dropped to my knees, clapped my hands together, with the 1.6 in-between...it did NOT stop burning right away...in fact at that point the speaker fabric started to burn...it was about a 20-30 second "event", but it felt like time stood still...
As far as the Spark (y), nickname goes...I had allot of energy as a kid...duh...some might even say I was the poster child for ADHD...back in the 70's it was known as hyper...add a little dyslexia...I was pretty much a hot mess...
When I graduated from college and I did graduate, my Mother said..."I did not expect this to happen"...with tears in her eyes...my response was..."thanks Ma, for that vote of confidence"...when I was in high school, she kept pushing the army for me..."I think the army would you some good"...
Thanks again Neo...
Mark
And the fun continues! So Sparky Mark it is? LOL, you are going to kill me for what follows (though Neo is really the one to blame, always is : - ))
I just got home and , surprise, the Chinese-built filters I ordered for the "low pass" circuits on the "other project" had arrived! They look as basic and as useful as I hoped. Furthermore, they should be quite "tweakable". This, even for many a non-experienced "ELECTRICIAN", if one ever gets interested, LOL!
Well, as I thought about this, something else came to mind. As we progress with the experimental project -- and determine what others could do -- you Mark could contribute with an "index of ease" or "Sparky Index"?
Some examples:
-- Sparky Index 0: Easy, just plug in or install batteries
-- Sparky Index 1: Easy, just raise the volume, slowly
-- Sparky Index 5: Caution, pull the Op-amp from socket but DISCHARGE STATIC first!
-- Sparky index 9: Caution, call 911 before pluging in solder gun!
-- Sparky Index 10: Crap, I told ya', FLAME THROWER ALERT!
Anyway, this stuff arrived now but I'll be traveling most of this weekend and all of next one. I'll have very little time to fool around with the "new toys".
Which is safer for my Maggies. In fact...had they had ribbon tweeters, my experimental blunders would have blown them every other week. So, you don't really have the exclusive...just a really nice new brand for the ability, Sparky Index!
Your killing me Dr. Strange-tweak...
I am more of digital guy so on the Sparky index...I am going to stick to 1's and 0's...
5's...what is an op-amp?
My soldering gun was confiscated by President W. Diller of the Maggie nation...
One more flame thrower story...early 90's helping a friend do some roofing...got some tar on my pants, so I soaked them in gas, through them in the laundry tub, ran the hot water...added some Tide and bleach...so lets recap...
Gas + Bleach + Tide = 911
After I added the bleach, the suds disappeared and it all started to bubble...the hot water was still running, so when the very close gas hot heater kicked in it went WHOOOOMMMMPPPHHH...the flames shot across the floor, up the side of laundry tub...(as I was standing in my undies and saw the flame shoot across the floor...I was heading for the door)...when it blew, it singed all the hair off the back of my legs and a pretty good patch on the back of my head...I dialed 911...
By the time the fire truck got there...the plastic laundry tub had melted and black smoke was coming out of the 3rd story window of this townhome...the tub fire had gotten hot enough to melt the solder on the copper pipes, so the whole basement was flooded and seeped into the neighbors basement...
The real rub of this tale...it was my COUSINS townhouse and he was renting to me a very discounted rate...it is an Italian thing...I had no renters insurance and my cousin is a lawyer...well...I bought new carpeting for the neighbors and paid for all painting and carpeting in my cousins townhome...we are still good friends and his kids love that story...
So now I walk around like Buddhist Monk...
"Tell us what you have learned Dorothy"...Uncle Sparky does not play with electricity or fire...I won't even light a fart...(yes that does work)...
It will be interesting when your 10" woofers are up and running...you make tweaking fun...as Maggie owners, the challenges of adding bass that blends is something that I personally have not been able to achieve as of yet...I am currently not interested in the DWM's, I want low bass where the 3.7i's don't go...
Thanks again Jben...
Mark
The belly aches from laughing, LOL.
Also, you seem to have read my (or our collective?) mind about the opportunity to compare, for what may have changed in the xover. If you stay short of getting that far, pehaps a few camera flashes from angles may reveal enough. I'll stay tuned for when that surgery happens.
It doesn't say anything about a line-level crossover. It says ".....replaced with external custom built crossovers."
I assume that means (alternative/audiophile) high-level crossovers and not a multi-amp, line-level setup.
You know something that we don't know?
Dave.
LOL! Nahw, I am just day dreaming. You and I have to replace our MMGs down the line. I think it will be 3.7i for me...no regular xover is going to stay there for long, nor a similar one take its place.
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