Anti-Resonant Treatment
As long as you have the PCB out of your mZ2, it would be a good time to do anti-resonant treatments.
As most mZ2 owners know, the mZ2 comes from the factory with basic rubber feet and a chassis that is protective, but not particularly heavy duty. That means there is room for improvement in the anti-resonant category. Anti-resonant treatments can be divided into three categories: chassis box, under chassis feet, and under PCB.
I'm sure you all have your personal favorites, and I've certainly not tried all of them, but the ones I'm about to describe are my personal favorites, and a bit on the extreme side (as if you couldn't have guessed). Please post your ideas and photos to give other H-F members a few options.
Now you may be asking yourself, "how much anti-resonant treatment do I need?"
Well that would depend on what you do with your mZ2, where you live, and what other anti-resonant products you use.
If you use your mZ2 as a preamp, play music at over 100db, and are a bit of a bass head, you could use all the help you could get.
If you only use your mZ2 with headphones, live out in the country, have a slab cement floor, and have expensive anti-resonant audio furniture, not so much.
If you live in an apartment in NYC that has squeaky wooden floors, and subways and trucks rattle your windows, even if you only use your mZ2 with headphones, some anti-resonant treatments would be noticeable.
I'm going to show you how to install these three products:
1. Anti-resonant adhesive sheeting.
2. Stillpoints PCB standoffs.
3. Stillpoints Ultra Mini feet.
There are several brands of anti-resonant sheeting. Most are like a thin layer of a gooey tar-like substance applied to a piece of heavy foil sheeting with a sticker backing material. One specification of concern with the mZ2 is thermal resistance (inside the mZ2 can get quite hot). For that reason I would recommend going to a local automotive sound install place and buying their best product. Likely they have packages with small quantities and the better automotive anti-res sheeting is engineered to withstand quite a bit of heat.
One small package that costs about $50 could do about five mZ2s, or you could do one mZ2 and a few other components you own. All the same principles apply.
Since we're doing these every week I made cardboard patterns, but if you're doing just one mZ2 you can simply follow the sizes outlined below and "draft" them onto the sheeting. Keep in mind that most of these products are rather gooey, so you may want to use a new razor knife just for this job, or use a pair of scissors that you don't particularly care about.
You'll need the following:
(1) 8.75" x 2.75" for the bottom
(2) 5.75" x 1.375" for the sides
(1) 6. 875 x 1.875" for the rear
(2) 8.75" x 1.375" for the front
The above measurements are maximum sizes. You're better cutting a bit smaller than a bit larger since this stuff is almost impossible to get off once applied. If you cover an edge, vent, or hole in the chassis you're going to have one heck of a time getting it off. And getting right up to the edges will not provide any higher-performance.
Below are my anti-res sheeting pieces cut.
Note there is one strip for above and one strip for below the switches, attenuator, and connector on the front panel.
Aside from cutting the pieces a bit smaller than a bit larger, be very careful when applying them. If you press them in wrong I have no idea how you're going to get them out
Below are photos of the anti-res sheeting applied. Note how all holes in the chassis are avoided.
Now you're ready for anti-res standoffs and feet. I chose the Stillpoints because I have them in stock for use with products we manufacture. There are some great values in anti-resonant feet and standoffs used in military and aerospace industries that can be purchased from industrial electronics and hardware vendors.
Just remember that both the standoff and the feet in the mZ2 chassis have a 6-32 thread and you should be OK no matter the brand.
Note the thin 1/8" thick 1/4" span wrench sitting next to the Stillpoints Ultra Minis. There is not enough space between the Stillpoints and the chassis to use a normal 1/4" open end wrench. You could grind a spare wrench thin as we originally did. You could find a wrench like the one in the photo that is commonly included with KD furniture. The only thing I wouldn't recommend is the official Stillpoints plastic wrench - they strip fairly easily if you put any amount of torque on them.
Keep in mind that both the Stillpoints Ultra Minis and standoffs should spin freely and have a bit of wiggle to them. That is all part of their secret technology. This also means they are a bit of a PIA to install if you're not used to them.
For the Standoffs I use model #10041, with a 6-32 male bottom and 6-32 female top. Since they spin, you need to attach them to the PCB first using the same 1/4" wrench to hold the hex in place while screwing in the stock mZ2 PCB mounting screws. Then you place the PCB into the chassis like a table, align with the threaded holes in the bottom, and tighten them in from the bottom using an Allen key. Start the threads on all four before attempting to tighten any of them.
Yea, Stillpoints may sound great, but they are a real PIA to install
The Ultra Minis are no easier to install. You need to carefully position the threaded shaft over the hole in the base of your chassis in perfect alignment. While holding the Ultra Mini in place with one hand you need to us the wrench to get a few threads caught using the wrench. In order to do this you need to hold the wrench up high aligned with the hex collar making sure to maintain proper alignment so as to not strip the threads. Once you have the threads started, it is fairly easy to keep the wrench positioned high and rotate until they are properly seated.
And you thought their standoffs were a PIA to install
Make sure to align the threads perfectly before tightening and don't over-tighten the Ultra Minis or standoffs or you'll strip something.
So now you've seen what I've done to my mZ2...show us all your favorite mZ2 anti-res treatments
