I dissected my MiDock portfolio

nadams

So, I decided to see what was inside the MiDock portfolio, as I was quite underwhelmed by the quality of sound. It's better than my laptop speakers, for sure, but I didn't feel it was up to my expectations of a product with the Polk Audio name on it. I understand that the larger docks sound much better.

Anyway, to start with, I opened up the main amplifier casing. Two screws in the battery compartment, and 4 under the feet. What I found was... well... not much at all. Some caps, a few ICs, and that's about it.I wasn't expecting much, but boy it's sparse in there.

I then started poking around trying to see how to get the speakers apart. Finally got aggrivated and ripped off the speaker grill, exposing 4 screws at the bottom of each side, and three across the top. Took the speakers apart, removed the control board so it wouldn't get damaged, and proceeded to untether the speaker wires via a pair of cutters.

My next plan was to see if I could pop the amp. I wanted to see just what that little board could do. So, I hooked it up to my pair of EPI M50's. http://humanspeakers.com/e/epi50.htm

Obviously, this amp was not designed for such a load. The EPIs are 8 ohm nominal. But, what the hell, right? So I hooked er up, and was actually very surprised at the volume this little amp was able to produce. I was surprised that the bass was not distorted. However, I was running at 100% all the way across the board, hooked directly to my PC. One thing I did notice was that even at very low volumes, the high frequencies were very muddled. This is not an audiophile grade amp, then . Also, after about 10 minutes of messing around with different music, I shut it all down, unplugged, and touched every component on the board... not a single one was even warm. There's a possibility that I may have been reaching the power adaptor's current limit to the board, thereby robbing extra power that could've been created. I'm going to dig around and find a higher amperage adaptor to see if I get better results.

Now, I decided to torture-test the speakers. They were reassembled, and wired into my Marantz 2220b receiver. http://www.classic-audio.com/marantz/2220b.html One thing I overlooked here is what resistance is presented to the receiver by these little speakers. I'm guessing that, like headphones, it's well beyond the range that the receiver would prefer to drive. As such, I had to turn the volume way over half to get a good amount of noise. Typically, driving the M50's, I only have to turn it halfway if I feel like blowing myself away from the desk. Anyway, hooked up to the receiver, the speakers tried really, really hard. They really did.... they move an impressive amount of air out of the top-mounted ports, but couple the plastic casing with bass-heavy music and two full-range drivers per channel... well... ****.

So I've narrowed my disappointment down to the speakers themselves. Not that there's any real big surprise there.

However, I was happy with the amp. If it weren't for the muddled highs, you might be able to fashion one into an interesting headphone amp. Sadly, the overall frequency response isn't there, I don't think.

I can post pictures of the destruction and mayhem if anyone's interested.

dorokusai

I can't read English so pics would be best.

nadams

I can't type english, either, so you're safe. I'll get pics when I get home from work.

disneyjoe7

I did the same thing except the speaker end of it, I found the MY8008E chip which I believe is the digital amp which drives the speakers. I also was quite impressed with it and needed to see just what makes that thing tick.

And Doro sorry back together no pics.

strider

I, too, felt it was lacking. After I disassembled mine I upgraded caps to Auricaps and replaced the resistors with Mills. The case is getting lined with Dynamat Extreme and the dock and inputs are being cryo treated as we speak. Boulder Mods is doing a new power supply for me, and I've been trading e-mails with Nelson Pass to try and figure out how to integrate a tube stage into the signal path. I'm hoping to gain some liquidity in the midrange, which I feel the MiDock lacks severely.

Face

strider wrote: »

I, too, felt it was lacking. After I disassembled mine I upgraded caps to Auricaps and replaced the resistors with Mills. The case is getting lined with Dynamat Extreme and the dock and inputs are being cryo treated as we speak. Boulder Mods is doing a new power supply for me, and I've been trading e-mails with Nelson Pass to try and figure out how to integrate a tube stage into the signal path. I'm hoping to gain some liquidity in the midrange, which I feel the MiDock lacks severely.

I hope at least a few of you read that.

nadams

The first sentence had me along for the ride I got to cryo treated and lost it

nadams

Okay, here's some pics.

First shot:


This is what you have to do to the grill to get it off. It's glued fast to the front of the unit.


This is what you see. Lots of screws, and we've revealed the two ports at the top of the enclosure. The ports are specific to their sides, so each side is sealed from the other.


Polk added some polyfill to help the poor things out.


Polyfill removed, we see the mounting mechanism. Each driver is held to the front of the enclosure by retaining clips and some foam rubber.


Each driver is rated for 8 ohms, 3.5 watts. They're presenting a 16 ohm load to the amplifier.


Here we have the control board for the unit. Speaker leads and battery compartment leads have been clipped, but the dock interface and volume/power board are still attached.


Different angle. The tiny chip you see at the top center of the board appears to be the main amp chip. I'm guessing the larger has to do with the volume controls and interface for the iPod


The bottom of the board. Not much to see here.

So, that's it. I didn't take any pics of the actual torture, but nothing interesting happened anyway.

nadams

I'm guessing that these are not polk-designed drivers. I say that because they front place has 4 screw holes in it, but they're held down by a different method. Plus, I can't see Polk spending the time and money to develop drivers for this little thing when they could just buy some cheap chinese jobbys for pennies. For the larger miDocks, sure.

disneyjoe7

Nice but you KILLED IT :eek:

nadams

It's the only way to get it apart. I tried unplugging the speakers from the board, but they're soldered fast. Luckily, the control board was able to be unplugged so I could remove it from the case and free the control board without having to resolder wires.

McLoki

He is having a new case custom made out of titanium to better withstand the cryogenic processes. We can make it better than it was before....

nadams

And, it's not dead... just... DISASSEMBLED!!!! (Short Circuit anyone?)

dkg999

Mines happily running on my desk at work. I thought it sounded pretty good. I'm sure the cleaning crew at night is rocking out to some Mexican polka music through it.

I guess I'm just not curious enough to tear apart the toys Polk Audio so graciously provided!

disneyjoe7

Well I tore it apart but have it back together so I can enjoy it.

croutons

nadams wrote: »

and, it's not dead... Just... Disassembled!!!! (short circuit anyone?)

number 5 alive!!!