[AGC]

Hi. I am in the process of making a mini3 amp right now.

I have a question. This is my first DIY amp so bear with me.

1. With my Glass Jar Audio Amb Mini3 kit, there came 15 parts that are a 2 1/2 inch thin wire with a small cylinder object in the middle. Im pretty darn sure these are resisters. ( You veterans must be laughing like crazy at me )

13 of these resisters are mostly a blue/purple with different color lines. I think some of the resisters have different color lines but im not entirely sure (colorblind + DIY amps is not the best combination). The other 2 are kind of light green with very light colored lines such as red, orange, yellow.

Can someone help me with these and give me the part number corresponding to the PCB board?

2. There are also 3 things that look like resisters but are twice as big and are all grey. I know one goes in the L16 slot. Where do the other 2 go?

3. The U1 slot has three holes in the shape of a triangle. The part that I got has 3 leads but all lined up in a straight line. How do i do this?

Here is the PCB board layout to make it easier for you guys to help me.

 

[amb]

1. Yes, those are resistors and correspond to the positions marked with a R-prefix (i.e., R1L, R6, etc.). If you can't read the color bands, use your DMM to measure each of them and correlate to the parts list at the official Mini³ website.

2. If you're referring to the ones with no markings, they are ferrite beads and go into positions L1L, L1R and L1G. There are also three 1N4001 diodes (D1, D2, D3) but they should be marked as such (use a magnifying glass if you can't read them). The D4 zener diode should be a smaller "clear glass" style device.

3. Bend the middle lead back just a tad and put it in as marked on the board silkscreen. Ditto with U3. The orientation is important.

By the way, judging from your questions you are definitely a newbie. Be sure to read the Mini³ website completely and make sure you understand everything before building it. It's not a difficult build but there are some common pitfalls which could cause damage. I suggest also that you practice soldering on something else before doing the Mini³.

 

[Uncle Erik]

I haven't built one of these, but can help out.

I never even considered that the color codes might not be for everyone. What a pain, and no, I don't think it's funny.

There are a couple of workarounds for you. One is to pick up a DMM and test the resistance of each part. A $10 DMM is fine for this. Then I'd sort the values into envelopes. The other way would be more helpful for your next project, but order the nice Vishay-Dale resistors. Those actually have the value printed on the side rather than the color code.

As for matching up the components with the PCB, look at the silkscreen mask on the board. You should see markings like R5 and C7 on there. The convention is to use R for resistor, C for capacitor, and so on. Look up R5, for example, on the build sheet and you'll see that it is a 10k ohm (by way of example) resistor. Take one of the 10k ohm resistors, put the leads through the holes, solder, and clip. You will get the hang of it and your next project will go twice as fast.

Don't let this get you down. You're learning and you can finish this. And I hope you get hooked, like the rest of us!

 

[MusicallySilent]

If you have a harbor freight near by this should work as a budget digital multimeter or you could order it but shipping is kind of expensive unless you order some more stuff, because it is based on price you can use this to test voltages, resistors etc.

Harbor Freight Tools - Quality Tools at the Lowest Prices

 

[AGC]

hey thanks uncle erik.

amb. I did the SMD soldering already. I haven't done a lot of this kind of stuff, but I catch on pretty quick.

On the resisters, I just used a DMM and i have the 6 330 resisters. I also have the 1 75 risister and 2 1.5k risisters. However, when i measure the 2 lighter color resisters with color bands, the DMM display stays at 1. The same happeneds with 4 other resisters.

1st unknown resister background babyblue:
brown black black red brown

2nd unknown resister background babyblue:
brown brown red blue green

3rd and 4th unknown resister background babyblue:
brown black black orange brown

5th and 6th unknown resister background peachy tan:
blue red gold gold

All these unknown show up as 1 on the DMM.. is that a bad thing? should i contact Jeff at Glass Jar Audio?

 

[AGC]

one more thing: Which parts should be elevated? if any?

 

[Uncle Erik]

You probably need to change the range on the DMM. Look at the build list and see what values are missing. My guess is they're above or below the range on your DMM. The DMM should have a selector switch for ranges - if you put it on the right setting you'll get the correct reading for those resistors.

 

[AGC]

bingo uncle erik. bingo. thanks a lot

 

[amb]

Quote:

Originally Posted by AGC /img/forum/go_quote.gif one more thing: Which parts should be elevated? if any?

It's all in the "Instructions" section of the Mini³ website... Please read and re-read it again. There are also pics of the assembled board that you could see as reference.

 

[qspeedss]

answered

 

[AGC]

answered what?

anyways, amb. What does the rail-splitter do? I looked at the site and there was no description. How should the amp work without the rail-splitter? Jeff at Glass Jar Audio sent me the wrong part for the rail-splitter and will be sending me it soon. I just need to troubleshoot my amp without it.

 

[Colonel Panic]

Quote:

Originally Posted by AGC /img/forum/go_quote.gif answered what? anyways, amb. What does the rail-splitter do? I looked at the site and there was no description. How should the amp work without the rail-splitter? Jeff at Glass Jar Audio sent me the wrong part for the rail-splitter and will be sending me it soon. I just need to troubleshoot my amp without it.

Same thing happened to me recently. my replacement should be in the mail along with my AlienDAC kit.

I'm just going to wait until the replacement comes before I start troubleshooting the amp.

 

[AGC]

hey colonel panic. How is your amp working without the rail-splitter? does it turn on at all with the battery in?

 

[dgbiker1]

Quote:

Originally Posted by AGC /img/forum/go_quote.gif answered what? anyways, amb. What does the rail-splitter do? I looked at the site and there was no description. How should the amp work without the rail-splitter? Jeff at Glass Jar Audio sent me the wrong part for the rail-splitter and will be sending me it soon. I just need to troubleshoot my amp without it.

Since you're using a battery you don't really have a "ground", so a rail splitter takes the battery voltage and splits it in two and puts a ground in the middle. For example a 12V battery would have +6V, -6V, and ground (minus some losses). The nice thing is that the + and - stay evenly split as the battery wears down.

AMB can probably give more insight into this, but I don't think you can really troubleshoot the amp until you get the rail splitter, other than checking for continuity and solder bridges with a DMM. You need the rail splitter to provide power to the amp, and most of the checks on the amb.org site have to do with checking quiescent current draw, DC offsets and the such which can't really be done without power.

 

[amb]

Yes, wait until you get the correct part from Jeff and install it before turning it on for the first time. The amp won't work properly with the wrong part in there.

The purpose of the rail splitter chip is to derive a virtual ground centered between V+ and V-. There has been lots of discussions about rail splitters, in particular the TLE2426 is very commonly used in several popular amp designs. Search the forums here and at headwize.com (where the official Mini³ builders' support thread is).