14 less connections: bypassed with a midrange fuse bypass

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Elizabeth

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Looking at the back of the 20.7 plate holding the fuses..
The wire from ?crossover? to the plate (1) crimped to a zinc plated steel FastOn
Fast on slipped on the FastOn male (2) also zinc plated steel
FastOn male zinc plated steel specially made? capture fit (3) under unknown metal rivet (could be aluminum, stainless, or steel???)
Unknown metal rivet capture fit holding (4) '? plating to look like gold' fuse clip
Fuse clip holding (5) end of fuse body cap gold plated
Fuse body cap gold plated to (6) fuse element ? unknown metal
Fuse element to (7) other end fuse body cap gold plated
Fuse body cap to (8 ..) other fuse holder clip ((Funny the 8)  8 and ) ... automatically turnes into a emoji ))
Fuse holder clip capture fit (9) under unknown metal rivet
rivet from fuse holder capture fit (10) clip zinc plated steel
Clip zinc plated steel to (11) soldered on solid core nickle plated copper wire
Solid core nickle plated wire soldered (12) to plated clip to look like gold
Plated clip compression fit (13) to Maggie pin #1 plated to look like gold
***************************************
Maggie pin #2 plated to look like gold to (14) compression fi clip plated to look like gold
Clip platd to look like gold to (15) FastOn steel with zinc plating
FastOn crimp fit (16) to exiting from area wire to crossover....

Wow. all that stuff to add in a fuse. (and allow user gizmos in between the  Maggie pin sets)

Skipping the fuse means the wiring goes:
The wire from ?crossover? to the plate soldered (1) to wire exiting Maggie pin #1
Wire entering Maggie pin #2 soldered (2) to wire exiting area to crossover.
(if no resistor, then those two wires would be one wire connected, but still two solder connections.)

Amazing how MANY connections Magnepan uses to add in a fuse.
If they used a few less connections?? particularly getting rid of the zinc/steel. (I understand ease of assembly. is the primary reason for the FastOn use.)

Anyway, after looking at the number of connections, I can understand how bypassing the midrange fuse can have such a big effect.

I still am not sure I will bypass.If I did not bypass, I still could remove 4 of the connections...

More if the wires were slipped into the fuse clip so the fuse was a compression hold to the actual wire instead of other connections. This would mean drilling small holes to allow the wire to pass through the plastic fuse holder shell. I had a jumper in my 3.6 which was held just by the spring tension of the fuse holder clips. worked fine.
Added: the least with fuse is four connections. It would mean trying to get the wire from crossover into the fuseholder and pressed between the fuse and clip. This particular connection would be hard to maintain unless the wire was glued to the fuseholder? Ditto the wire from between fuse and clip out. would need some way to keep it from being pulled loose.
 But might be a compromise worth investigating..

Elizabeth

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Re: 14 less connections: bypassed with a midrange fuse bypass
« Reply #1 on: 2 Feb 2019, 03:26 pm »
I finally did a preliminary experiment. I bypassed the fuse at the fuse clips, with a bit of silver plated 20 gauge wire.
The immediate result seems to be slightly more 'sparkle' from piano notes. (Currently playing Beethoven piano sonatas.) Plus low level info is better.

Added... I am also making little 5" dowels, to  take the wire out the 3/4" wide back panel, and ?? maybe do a choke to the ends so the wires go down straight to the 5" long Duelund resistors. instead of stressing the wires out of the Duelund at a hard angle. I have NO IDEA if the choke will do anything good. The same sort of home made choke with the same wire did good on the tweeter line. I will want four dowels, one for each Duelund. If the choke idea fails, unwinding the wire and using the dowels to just widen the wire span, without added choke will work anyway.
« Last Edit: 2 Feb 2019, 05:46 pm by Elizabeth »

Elizabeth

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Re: 14 less connections: bypassed with a midrange fuse bypass
« Reply #2 on: 4 Feb 2019, 06:27 pm »
I finally assembled one of the four dowels.
Six inch lead (to go into the rear panel and to be eventually soldered inside For now on outside as normal
About 27 wraps of Kimber 18 gauge wire to the left of one lead, 27 to the right of other. The wires start and end going through holes in 1/4" dowel. The point of the length is to protect the Duelund CAST resistors. So far I have broken off two resistor leads. (seems the tension of the leads rather taunt at an angle. plus the weight, plus the speaker vibrations.. bad combination) making the resistors useless. Both broke off right in the resistor. ARRRGH!
Good thing I got them at half price.
Anyway the idea of the choke windings is the same as the tweeter. kill HF junk. Yeah so what if it is theory of nonsense. It does make the sound seem smooth.. hard to exactly describe.
Anyway the second reason to wrap around the dowel is to get the end wire lined up straight with the Duelund resistor leads. I also made a little card 'carry device' with some Teflon plumber's tape. So that, with a 1/4" spacer holds the Duelund UP instead of the Duelund weight all on the resistor leads. Now all the weight is carried by the resistor body... (and the 18 gauge Kimber wire!) And hopefully no more leads breaking off.
The downside is way harder to change reisitance. So I Chose 1.05 ohms.
With one gizmo made I stuck it on the right speaker.

Differences? small warmth added. (also the wire is new, Teflon. so it will take a day or so to settle. fuller, Like I again am listening to Joni Mitchell. and her voice is a little fuller, more natural than after just adding two more PS Audio Noise Harvesters when playing with a noise sniffer this weekend. Again those added Noise Harvesters brought the system back to clarity slight lean condition, over warm. Which is always my experience. then getting the warmth back with no loss of clarity.. Bingo!)
I am not making a second until I feel the first is exactly what I want.
I was going to make four, one for each resistor. But decided not to. This way I have two dowels premade in case I want to alter the ohms.
As is I could fairly easily add a 10 ohm to the current device and reduce the impedance from 1.05 to 0.95 ohms. But so far I am happy with the immediate sound.
I am going to wait a few days before making the second one. I hope the leads do not break off on any more resistors until then.

Elizabeth

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Re: 14 less connections: bypassed with a midrange fuse bypass
« Reply #3 on: 4 Feb 2019, 10:10 pm »
Duelund CAST resistors silver leads break off way too easy. I wish I knew what I NOW know. Do NOT move the base of the leads ever. zero. the moment you get them use some sort of polyurethane to glue the resistor lead junction.
That point can be bent five six times TOPS then it will just fall off. No fixing it.
The tendency I had was to straighten them out to look at them. Then bend them back to put away until I used them straight. then angled for use without any extra lead(means the resistor leads are tensioned a bit holding up the resistor.
Lucky for me I bought extras.
If you pay full price I tell you DO NOT EVER bend the base of the lead from where it is when you get them.
I would now Teflon tape the lead past the joint as the come, with the lead touching the resistor body, plus urethane the joint. Then make a longer lead if I had to.
I am assuming there is no warranty for breaking off the leads.
I have three useless resistors.
First one I tore the lead off screwing a insulation thing on it. My bad.
Second one just fell off when I took them off speaker.
Third one was weak. and all it took was one touch. plop. fell off. It had been on tte speaker
I finished the second dowel and resistor device and it is on the speaker.
I hope both will last. I may get some urethane goop to seal the lead junction of the resistors in the gizmos just to be sure.

Added: also the sound was messed up a bit with one gizmo and the other speaker had just the resistors. Got me motivated to do the second one. Now listening all is back to normal... So the coils do something. but I can't really put my finger on what exactly was different (except the two speakers were not behaving the same...)