[cire]

despite contrary belief, Daniel is an ugly chick with ginormous breasts

 

[Filburt]

That is just such a strange looking picture. It looks like a photochop or something, but knowing the mighty internet it's probably real in some way.

 

[tangent]

Quote:

Originally Posted by DieInAFire what's the difference in the boards?

It can only be manufacturing variation...there has only been one board run.

Quote:

A pad came off on my old one though :|

Sorry to hear that, but that can happen with any board with enough abuse. Repeated soldering and resoldering, putting strain on the joint while it's being heated, using too hot an iron, etc. Technique and using the right tools can prevent some of these problems.

What were you doing when it happened?

 

[Heady]

Quote:

Originally Posted by tangent Sorry to hear that, but that can happen with any board with enough abuse. Repeated soldering and resoldering, putting strain on the joint while it's being heated, using too hot an iron, etc. Technique and using the right tools can prevent some of these problems. What were you doing when it happened?

Well, I now know one thing I must never do when trying to desolder parts - stick the iron tip down the hole of the PCB, nothing's worse for lifting the traces off!

 

[FallenAngel]

This is such a great thread, I decided to post my Mini3fied PINT difficulties here. I am building 2 PINTs, one of them I woun't even mention until later cause I think the Ground OpAmp is fried, so here is the second that's still kicking.

First off, these are my modifications to the config:

R3: 1.5k
R4: 3.0k
C7: 25V 1.5uF 10% "B" Tantalum Cap (Mouser URL)
C6: Not used

I made the pin 6 lead to the Ground OpAmp and soldered Pins 6 & 7 together. As far as I know, all instructions were followed to the dot, but of course as with most DIY, there are funky problems. I have also went over every single solder joint and reflowed them so they're nice and shiny.

The Ground OpAmp gets pretty hot, not like burning hot right away, but I woun't want to keep my finger on it for more than 5-10 seconds.
I also get a very precise and constand 4.0V of DC offset on both channels. The really weird part was, I measured and got this DC offset, put the amp to rest, next day I tried it and DC offset was 2mV! Of course I was like WOW! it fixed itself and cased it up. Then I tried playing something and it sounded like crap, tons of distortion, I measured DC offset again, still very low, but like 5 minutes later, it jumped up to 4.0V again. That's when I got totally confused.

I also noticed one very strange thing, I get 7.0VDC between OG and IG, which I've read means my ground channel is broken, but I have no idea what that means so I'm not sure how to fix that. Can somebody help?

I will post pics tonight when I get back from work.

Thanks guys!

 

[Filburt]

Did you make sure that, after cutting the one trace, that continuity was actually broken?

 

[FallenAngel]

Yes, used DMM to check discontinuity between Pin 6 and OG. It was cut ok.

 

[Filburt]

Quote:

Originally Posted by FallenAngel Yes, used DMM to check discontinuity between Pin 6 and OG. It was cut ok.

Alright. It sounds like your ground chip is blown.

 

[FallenAngel]

I'm curious as to why/how? I mean the PINT did play, just really badly.

 

[Filburt]

Quote:

Originally Posted by FallenAngel I'm curious as to why/how? I mean the PINT did play, just really badly.

There are many things that could have happened. Oscillation could have fried it. Too much heat might have been able to. Momentary reverse supply could have as well. AD8397s fry really easily.

 

[FallenAngel]

Damn, that sucks! Just to confirm though... would the amp really still play music with a fried ground chip and would it really have such precise DC offsets on both channels?

 

[The Monkey]

Hi gang,

I'm measuring between 29-30 mA current draw with my Pint (stock, from Tangent's parts list (AD8397)) with 1 9V battery. Does that sound right?

 

[cire]

Quote:

Originally Posted by The Monkey Hi gang, I'm measuring between 29-30 mA current draw with my Pint (stock, from Tangent's parts list (AD8397)) with 1 9V battery. Does that sound right?

its slightly on the low side i believe, but should be ok.

 

[Heady]

I have finished my second built of the PINT and have done so very carefully. And I still have the same problem of oscillations and thus high current draw of about 170mA.

Tangent has suggested replacing the L1 inductors with low values resistors. My questions are:
1. What values are suitable?
2. Do I replace the L1 only for the ground or all 3 L1s.

The built uses the mini3 configuration suggested by amb.

Thanks.

 

[tangent]

Quote:

Originally Posted by Heady What values are suitable?

As it says in the documentation, 10 to 100 ohms.

Quote:

Do I replace the L1 only for the ground or all 3 L1s.

Since the resistors are outside the feedback loop now, you can only do it with the left and right channel resistors. With the resistors inside the loop, I believe you could have done it with the ground channel resistor as well.