Home Theater Forum and Systems banner

1 - 20 of 26 Posts

·
Registered
Joined
·
80 Posts
Discussion Starter #1
Here's a cleaner, simpler mod to the Gizmo that eliminates the wire mess.

Front panel removed


Top slides off after the panel is removed


Front control panel connection removed from the board


Binding post connections removed from the board


Two screws at the rear removed


After unscrewing the 4 screws on the board, it comes completely free from the case.


Five electrolytic caps and 2 film caps (yellow caps) are removed from the amplifier portion on the top left. 4 orange electrolytic caps are removed from the input section on the bottom right.


Wire links are added in place of the output capacitors that were removed in the amp section. I cut off the very long legs of some new electrolytic caps for use as the wire links.


R2 and R4 smd resistors are removed. This isolates the RCA inputs from the input section.


10uf capacitors are added to where the + legs of the C19 and C53 capacitors used to be. In this case I used the Nichicon BP Muse capacitors.


The 10uf capacitors are then connected to the outputs of the volume control chip.


On the bottom of the board, I soldered in a pair of 2.2uf caps between the rca and the holes previously occupying the orange electrolytic caps.


3 470uf 35V electrolytic caps (Chemi-con KZE) are added to amp section. I used two 330nf capacitors (Wima MKP2) to replace each of the original 680nf yellow caps. The other pair of 330nf caps are on the bottom side of the board and are visible in later pictures.


Underside of the board showing the input caps and resistors.


The input caps and resistors are removed, and the copper traces are cut btween the caps and the resistors at the indicated line.


I soldered 4.7uf caps (Nichicon Muse) across the pads. You could get away with not cutting the traces in the previous picture if you use only the top and bottom pads, but the pads will be far more sensitive to tearing in that case.


A look at the bottom of the board.


Top of the modded board with one more step left.


Lastly, the red leads are cut and a 1000uf 35V electroytic cap is added to each. What isn't shown is a pair of bypass caps I used across these caps.


Connect all the parts back together, and you end up with a modded Gizmo with full range otuput and a variable subwoofer out. Parts selection is very subjective, and I used the best small parts that would fit in order to keep the signal path as short as I could. The previous Gizmo mod utilized larger componentts at the expensive of a wire mess.
 

·
Banned
Joined
·
127 Posts
Very nice! Now all we need is for you to demonstrate a crossover mod that fixes the input level issues and the blinking face when in standby fix. :D
After he figures that mod out, submit an address where everybody can send their Gizmos so he can mod them :sly:

(jk)
 

·
Registered
Joined
·
217 Posts
Dweekies versions of TCA products would cost a little more than Craigs price range.

That is OK, we have the TCA version at a reasonable cost, and for those that want to get more from it, there is room in the box to "tweak" it into something better.
 

·
Registered
Joined
·
40 Posts
Nice work, dweekie. Looks a lot cleaner than the first version, and the step-by-step instructions are very useful. Gotta get around to doing this at some point.

2 quick questions for you:
1. May be I missed it, but what are the 2 yellow caps that you added to the bottom of the board.
2. Where's the best place to get the Muse caps.

Thanks.
 

·
Registered
Joined
·
12 Posts
I jumped on one of the combo systems that AV123 has on sale. They are modding the amp so that the sub out tracks with the volume. Anyone know how they are doing this? MLS?

My ELTs will be here tomorrow but I bet it will be a few more weeks before the Gizmo shows up.

-Eli
 

·
Premium Member
Joined
·
629 Posts
Eli - I will see if we can get specifics about the Mod being done in Colorado.

This thread does have me doing a :scratchchin:

Dweekie .. there could be a cottage industry in your future, taking our basic products and doing some custom stuff for people.
 

·
Registered
Joined
·
286 Posts
Nice work, dweekie. Looks a lot cleaner than the first version, and the step-by-step instructions are very useful. Gotta get around to doing this at some point.

2 quick questions for you:
1. May be I missed it, but what are the 2 yellow caps that you added to the bottom of the board.
2. Where's the best place to get the Muse caps.

Thanks.
Ed,
Good to see you. :thumbsup:
Don
 

·
Registered
Joined
·
80 Posts
Discussion Starter #13
The yellow caps are 2.2uf Xicon MEA series polyester capacitors. They come in a flat shape, so they fit under the board. They are a little clearer and brighter than the MF / Radio Shack. There are 3 coupling caps to account for in the signal path, so the sound balances out across the caps.

I got the Muse caps from www.hndme.com, the other popular place to get them is www.minisemi.com. The parts are cheap, but, as usual, minimum shipping charges will get you.
 

·
Registered
Joined
·
14 Posts
dweekie,

Great mods and nice job with the write up. I really want the variable sub out, but not the full range out since I will always be using the sub. Is there anyway to easily describe which parts of the mod are for the variable sub out and which parts are the bypass?

Or better yet, how much would you charge to update a sub out :stirthepot:
 

·
Registered
Joined
·
12 Posts
dweekie,

Great mods and nice job with the write up. I really want the variable sub out, but not the full range out since I will always be using the sub. Is there anyway to easily describe which parts of the mod are for the variable sub out and which parts are the bypass?

Or better yet, how much would you charge to update a sub out :stirthepot:
MLS said that they are just cutting 2 wires and putting in 2 jumpers on the ones they are modding.

-Eli
 

·
Registered
Joined
·
15 Posts
With no future gizmo rev in the near future, I think I'm going to have to order up some capacitors and give this a try. Anyone else planning to do this? Is it possible to order in bulk and then have someone ship out kits? Never done any mods like this or ordered single parts since I was in college and had a large electronics parts lab in my building.
 

·
Registered
Joined
·
80 Posts
Discussion Starter #17
With no future gizmo rev in the near future, I think I'm going to have to order up some capacitors and give this a try. Anyone else planning to do this? Is it possible to order in bulk and then have someone ship out kits? Never done any mods like this or ordered single parts since I was in college and had a large electronics parts lab in my building.
That parts are easy to order.

From Mouser, go here (http://www.mouser.com/ezbuy/ezbuy.aspx) and fill in the "Mouser Part Number" and "Quantity"

Wima MKP2 0.33uf - Part number "505-MKP20.33/100/5" Quantity "4"
Xicon MEA 2.2uf - Part number "146-MEA2E225K" Quantity "2"
Chemi-con KZE 470uf 35V Part number "661-EKZE350ELL471MJ2" Quantity "3"

You may also want to get 2 of these (146-MEF2E105K) to use as bypasses for the Nichicon 1000uf capacitor listed below.

From Hndme, go here (http://www.hndme.com/productcart/pc/viewCategories.asp?idCategory=40) to order the Muse caps.

2 Nichicon ES 10uF/50vdc
2 Nichicon ES 4.7uF/50vdc
2 Nichicon ES 1000uF/25vdc

I think that's everything other than the miscellaneous wires and such you can get from Radio Shack. Somebody else will have to double check :crazy:
 

·
Registered
Joined
·
20 Posts
quick question, which part gives full range out and which part makes the sub out track with volume? I can't quite make out the pcb markings on your pictures.
 

·
Registered
Joined
·
80 Posts
Discussion Starter #19
The output caps determine part of the low frequency rolloff. The original 470uf caps right next to the binding post connectors are too small to maintain a decent range at the output. Those are the ones I removed and replaced with wire links. In its place, I put in the 1000uf caps. These will give -3db at 20hz for an 8ohm speaker load.

At the input, I bypassed the entire input section and sent the signal straight from the RCAs through the 2.2uf caps to the volume chip. There are 2 outputs on the volume chip. One set goes to the amplifier portion. The other was previously unused, but I used wires to tap this signal back to the original input section through the 10uf Nichicon Muse caps. In this way, the attenuated signal is sent through the crossover, allowing for the volume to track with the subwoofer. At the same time, I bypass the opamps for the main signal, which allows for an unaltered signal to pass through (this would avoid issues with distortion from high gain that some people were having).

Does that explain what I did a bit better?
 
1 - 20 of 26 Posts
Top