- Posted by pictureguy (A) on October 12, 2010 at 22:17:42
In Reply to: RE: Can I suggest you try replacing the 6g Cu wire with 24g Cu wire ... posted by thetintdoctor on October 12, 2010 at 18:34:05
With my cheap-o RS DVM, I've never measured above about 20vac....on peaks. The numbers jump around quite a bit. That was louder as I ever normally go. I'd be surprised if that was more than maybe 50 watts total...on the peaks to both panels added up. Based on those numbers, I wonder why my Rotel RB1070 was unable to cut it? I'm guessing it simply didn't like a steady 4 ohm diet. The specs do not list a 4 ohm power, though they DO list a 8 ohm bridged output.
couple of questions, though. Why junk out the fuse? That's just another 1" piece of very tiny wire, isnt' it? To be honest, I'm struggling with the magnet wire as internal wiring. For ICs, no problem....and it's on the list to test. Dawn even posted a pic of his 'winding' on a core.
Among the changes I know I'll make is to remove all the jumper associated wire and go to a simple set up with just 'ins' and 'outs' from the crossover. The aim will be to reduce the number of connections and the amount of wire. Fuse and those extra connections goes away at that time, too.
Speaking of wire, what do you all use in the crossovers? I even saw an example over on MUG of someone making double runs of like 18 or 20. Just for giggles, what does Magnepan use? 16 or 18 of just plain 'wire' would be my guess.....solid or stranded?
Anyway, I've started a big list. Everything is being recorded to be sifted thru later. Notes on who/what also. Some suggestions don't jive with others, so choices have to be made about what to do. Some, like the razor mods seem like lots of work and are difficult to undo perfectly. Crossover mods and various wiring schemes can be changed with a simple soldering iron, some solder wick and a little time.
By the time I'm done with wood shop, I'll start on x-over boxes and start accumulating the stuff.
The panels will be reframed, hopefully working it by this time next year. I can't afford the woodshop to do what I want, so off to school I go....and I'll learn from top people.
This is a longer range project than first I anticipated, but it can't be helped. For the first time in years I've got time for an ambitious project and I'll just take my time.
Don't think I'm shining anybody on or being ignorant. I'm a little ....obsessive.....and won't do anything on impulse that is not reversible. Those 'Big' jumpers I made? Obvious overkill but certainly not bad. Good therapy, too. STEEL? who'd a thunk it? Gives me the willies.
I plan an entire project like this. did it at work, too, and drove my boss nuts. Sometimes I'd think about a project for a day or so, trying to decide on the most bang/buck way to get the task done. That's the mode I'm now in.
Does anyone own an inductance meter? I'm a couple months away from trying my hand at winding inductors.
Jumper recipe:: per jumper:: 2" of #6 copper solid. Hand finish the ends with a file than some sandpaper. #6 has a nominal diameter of 0.162" and the magnepan jumpers are smaller.....and a tight fit. I put the wire in a vise with exactly 5/8" protruding an bent it over 90degrees. Repeat for the other side. I spun the ends in sand paper to reduce the diameter and than polished with 400 and oil. Rinsed the oil with acetone than water. No residue was left. A few minor tweeks and they fit fine. Wire was about .39$ per foot....
Too much is never enough
Follow Ups:
- RE: Can I suggest you try replacing the 6g Cu wire with 24g Cu wire ... - Dawnrazor 21:26:09 10/13/10
(5)
- In Reply to: RE: Can I suggest you try replacing the 6g Cu wire with 24g Cu wire ... posted by pictureguy on October 12, 2010 at 22:17:42
Pict,
couple of questions, though. Why junk out the fuse? That's just another 1" piece of very tiny wire, isnt' it? To be honest, I'm struggling with the magnet wire as internal wiring. For ICs, no problem....and it's on the list to test. Dawn even posted a pic of his 'winding' on a core.
HUH?? Arent you the one that was talking about the thin wire making the amp a current source???? Why would it matter for internal wiring.
Some, like the razor mods seem like lots of work and are difficult to undo perfectly.
Yes and no. Sure it IS work, but well worth it, and if you can make frames this is childs play, and FWIW you can completely reverse it.
Anyhow I get I think what you are talking about in regards to the whole project. It sounds like you have a good general strategy.
Do take picts and document things.
No one here remembers the bending of our minds
- RE: Can I suggest you try replacing the 6g Cu wire with 24g Cu wire ... - pictureguy 23:35:25 10/13/10
(4)
- In Reply to: RE: Can I suggest you try replacing the 6g Cu wire with 24g Cu wire ... posted by Dawnrazor on October 13, 2010 at 21:26:09
Never mentioned that as an issue with internal wire. But, did mention that with longer runs of real thin wire for entire system. 6" of higher resistance wire is noise compared to 10 feet of same.
Total resistance matters, of course.
What is internal wiring of the panels as they come from Magnepan? 16? 18? thinner?
I'm almost scared to look. but not quite!
Too much is never enough
- RE: Maggie Wire Size... - thetintdoctor 16:48:03 10/14/10
(1)
- In Reply to: RE: Can I suggest you try replacing the 6g Cu wire with 24g Cu wire ... posted by pictureguy on October 13, 2010 at 23:35:25
Just measured the bass panel wires on the 1.5QR... My digital dial caliper shows .60~61mm wire diameter. Twenty-eight(28) vertical strands for the bass panel. Actual height of the bass panel wire wrap is appx 50.5 inches.
So; 28vertical runs of wire X 50.5" x .60mm diameter.
I was too lazy to go get the Fluke and measure the actual DCR. Had the dial caliper upstairs for a non-audio project. If I get a chance I'll measure the DCR tomorrow.
Cheers, Jeff.
- RE: Maggie Wire Size... - pictureguy 19:18:20 10/14/10
(0)
- In Reply to: RE: Maggie Wire Size... posted by thetintdoctor on October 14, 2010 at 16:48:03
good. IF you can calculate a good number for length, and get a DCR reading, it is a simple matter of a lookup table for the wire gauge.
I suspect this is one of the things Magnepan is REAL touchy about. Too much/ little or wrong gauge wire results in disaster.
This kind of stuff is ALL good information.
This is also why I'm picky about inductors. Magnepan, for the 1.6 says the DCR of the inductor is 0.4 ohms. If you reduce this to 0.2 ohms, proportionally more power will go to the woofer and perhaps change the frequency balance. I was shown a calculation using log of the resistance, which I don't offhand remember. It was EASY with a hand calculator or spreadsheet.
I'm reluctant to change this balance so my inductor studies hinged on NOT changing the DCR more than 10%, up OR down. I have a design which is 5% low and should make an imperceptible change upward in bass response. All other things being equal. The DCR of the LF part of the panel itself is 4 ohms.
Too much is never enough
- RE: Maggie Wire Size... - pictureguy 19:18:20 10/14/10
(0)
- RE: Can I suggest you try replacing the 6g Cu wire with 24g Cu wire ... - Dawnrazor 23:48:56 10/13/10
(1)
- In Reply to: RE: Can I suggest you try replacing the 6g Cu wire with 24g Cu wire ... posted by pictureguy on October 13, 2010 at 23:35:25
Yes!!! This is my point about the magwire. Everyone freaks out about 10ft of runs from the amp to the speaker but neglects the 100ft or more runs of thin aluminum wire that makes up the actual driver.
From the looks of it the driver wire is 28-30g.
on my mmg bass panel, I count 38 runs of 38" so roughly about 114ft. That is on MMGs. If you have the bigger models you have tons of thin wire in there already....
No one here remembers the bending of our minds
- RE: Can I suggest you try replacing the 6g Cu wire with 24g Cu wire ... - pictureguy 09:24:04 10/14/10
(0)
- In Reply to: RE: Can I suggest you try replacing the 6g Cu wire with 24g Cu wire ... posted by Dawnrazor on October 13, 2010 at 23:48:56
It should be possible to calculate wire size. Measure length of 1 run of wire. Multiply by number of turns. Measure resistance. consult chart and do math. You should be able to by a good estimate of length and resistance, come up with wire size, at least on the driver itself. As for the REST in the panel? Well, that's probably no better than those steel jumpers (still can't get over STEEL) I removed the other day.
Just an example from the AWG Aluminum chart.
24# is 20.1 mils diameter. 42.1 ohms/1000 feet and has a fusing of 21.6 amps. I'm guessing this is too large a wire. To get the panels about 4 ohm, DCR, you'd need about 100 feet.....Too much, I think.....
But that's the way I'd try to get an idea. Work backwards from the number of loops and length.
28 or 30 would be a reasonable place to start, as you suggest.....But than, people are always looking for 100 amp amps......I don't get it.
Too much is never enough
- RE: Can I suggest you try replacing the 6g Cu wire with 24g Cu wire ... - pictureguy 09:24:04 10/14/10
(0)
- RE: Maggie Wire Size... - thetintdoctor 16:48:03 10/14/10
(1)
- RE: Can I suggest you try replacing the 6g Cu wire with 24g Cu wire ... - pictureguy 23:35:25 10/13/10
(4)
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