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heady

Building the PINT

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heady

 

one minor difference between our builds is that I use different inductor

urs is a 60Z impedance, whereas mine is 30z

urs: http://sg.farnell.com/jsp/endecaSearch/par...jsp?SKU=3237965

mine: http://sg.farnell.com/jsp/endecaSearch/par...jsp?SKU=3056582

 

I personally wouldnt know if this can cause trouble

my suggestion is, just try to rebuild first

and see wat happens

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those ferrites are rated at 100mHz

 

so a very quick calc would yield that ur ferrites have 95nH inductance

while mine have half of that

 

still I dun see why this shd cause problems

but I put it up for u to note smile.gif

 

 

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Ok, thanks, squalle.Don't really understand the details but will try with my ferrites and then if not working, will get those you used. Hope things will be ok second time around or I will be out of $$$ sad1.gif and very frust... wallbash.gif

Edited by heady

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errm heady

 

I forget to ask till now

 

when u measure 100+mA draw, did you have ur input plugged in? with anything will do

sometimes, 0 input will cause the amp to oscillate.

that happens to other amps too

 

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Squalle, I measured it without anything plugged in, measured it with just the cable plugged in and then with the input cable actually connected to a MP3 player and with earphones (cheapie) plugged in. All has the same high current draw.

 

I have a plug which I used for testing DC offset on my Pimeta which has all 3 sections shorted together. But I did not use it to test for DC offset in the PINT as Tangent did not mention it. Anyway, I had no DC offset at all.

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I blame the flux but actually I have no idea what lah. Maybe I got some of the parts wrong, like the ferrites?

 

The good news is that I managed to re-use the board and soldered in all the parts although I have no time to check if it is working. This time, I checked with DMM all the connections are good.

 

I bought only 2 boards, so if this board really cannot work, I will use exactly same parts you used for yours. I will ask you for your list of parts you got from Farnell.

 

Thanks.

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squalle - just completed the second round of soldering the components on the PCB. Exactly the same results. I think I must have ordered some capacitors or the ferrite wrong. Can you please send me the list of capacitors and ferrite Farnell order codes you used, so I can compare. I know the ferrites are different already.

 

Thanks

 

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Aiyah, office hours only can post lah. Did the building last night, late.... last night. wacko.gif

Thanks.

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so heady,

have u got some new parts? done with the assembly? I hope nothing wrong this time

Haven't started on the second PCB yet. Re-did the first one after salvaging some traces. Got exactly the same high current draw of 170mA.

 

Looked thru your list of parts and found my 0.1uF and 10pF caps and the inductor are different from those you used. So, I will order those you used from Farnell and try them on my bad PINT first and see if any improvement.

 

 

BTW - 2 more questions:

1. You found a casing?

2. Are you charging the 3 AAs in the casing?

 

Thanks, you have been a great help.

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how different are they?

 

if only due to different manufacturer, well, I dont think that's a big deal

 

but inductor is different basically, 30Z and 60Z.

 

let's see how things turn out after you try

 

totally no casing yet tongue.gif

so yea, no charging or watever

hahaha

havent even started real use of it yet

 

still using the cmoy2 amp on the go and in office

at home, I'm on SOHA, powered by class A mosfet stage, either to DT880 or my bookshelves

 

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I think the capacitors dielectric characteristics are different. Anyway, small amount to pay to try out. So no big deal.

 

Wow, the SOHA can drive speakers? Am getting the board from digi01, hope can tap on your experience.

 

I have the CMOY2 too but I hate the 9V battery as the rechargeable as so small in capacity while the alkalines are so ex... I was hoping the PINT will run well and can find a casing for 3xAA batteries plus the PCB and I am set.

 

Thanks

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hmmm

 

my CMOY2 runs on 3 AAAs laugh.gif

it all depends on the chip

I actually had put it up long time ago abt this laugh.gif

I'm using maxim chips in there

so it can run on low voltage

 

SOHA on its own cant drive bookshelves LOL

the power stage, as I've put it, is done using mosfets. combo with LM317's working as CCS

power supply gotta be large. and yea, I bought wrong size of heatsinks, so gotta use fans to cool it down LOL

 

sure, as you've started on SOHA, if there's any prob can just ask me

smile.gif

I've brought the PINT to work btw

uncased tho'

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