Project M2 DIY Thread

[4313B]

Does anyone how close this network is to being a drop in to the M2? I know both use the same D2 and the 2216nd's are somewhat similar, but I don't want to assume it would be a lock because of the differences in 2216's and the waveguide. I went back to read the post Mr Timbers gave on the 4367 and originally missed this statement about passive systems and I got to thinking about building a pair.

The quick "fix" is to:
1. Change R9 from 3.6 ohms to something like 10 ohms. This props up the response in the 1k to 2k region.
2. Add a 30 ohm rheostat ala 4430 right before C7 and set it to something around 20 ohms and viola! flat as a frozen pond. We can call it R10 This affects the response on the top end, otherwise it would be too hot.
Basically you would play around with these two values along with the two switches to get it how you want it (I set the switches to C8 and R6 for example and that looked flat).

Once I get better response data there is a good chance that I will look at this again. If you really want to try it though just build a cheapie non-cc version and try it out (only if you have money to blow, you know, for the sake of science).

[srm51555]

The quick "fix" is to:
1. Change R9 from 3.6 ohms to something like 10 ohms. This props up the response in the 1k to 2k region.
2. Add a 30 ohm rheostat ala 4430 right before C7 and set it to something around 20 ohms and viola! flat as a frozen pond. We can call it R10 This affects the response on the top end, otherwise it would be too hot.
Basically you would play around with these two values along with the two switches to get it how you want it (I set the switches to C8 and R6 for example and that looked flat).

Once I get better response data there is a good chance that I will look at this again. If you really want to try it though just build a cheapie non-cc version and try it out (only if you have money to blow, you know, for the sake of science).

Thanks for posting this, I have a couple of other things I need to shore up but would like try this.

[srm51555]

Since I started this project I wanted to try one of the large format drivers on my DIY M2. This requires a modification to the mounting plate so it would accept countersunk screws. I'm not a machinist but I wanted to document what I used just in the event someone else wants to do the same.

I started off by using a 90 degree, 1/2" counter sink bit attached to a cordless drill (In my case the drill was attached to a Flex Arm, but a standard drill will work). Use of aluminum cutting fluid is needed. I started off by adding couple of drops and adding more when necessary. When cutting the countersink the bit should moving slow and putting downward force on drill to put pressure on the bit is necessary. The plate was held down by a drill press vise.

I had a machinist buddy guide me with the above process. He also told me the drill press wasn't the best choice here because if you are not centered your countersink would be less than perfect.

I was able to pick up 2450SL's so the driver mounting holes didn't need attention. Bolts used were M6x1.0 35mm from Fastenal

Hope this helps,
Scott

[grumpy]

Helpful info indeed, esp. the hardware info.

My own choice (given what I have) would be to use the drill press,
accurately index/center the workpiece with a matched drill, then clamp,
swap bits, and have at it...perhaps more work than with a flex arm
(nice to have that available!), but a nice round/centered countersink
is more likely vs handheld.

Happy to hear it worked out.

[srm51555]

I was looking over the low pass side of the 4376 network didn't see any nodes on the capacitor side after D1 so does that indicate C1-C4 all have the some connection point to D1 or is this a mistake? Thanks, Scott

[grumpy]

All connected. Could have done it with two caps, but perhaps the design wasn't a standard value or the cap physical size was an issue.

[4313B]

GT used electrolytics for the larger values and put them in parallel with smaller Solen caps to achieve the correct total capacitance. It is a way to cut down on cost and size.