Gainclone Help

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Well,
I received the chips from Peter today (thanks again!) and I finished one gainclone
i've decided i'll do one at a time .. get one working first, then the other

The power supply I've completely finished, and its putting the right voltage at the right output. So I'm sure of that at least!

The gainclone I've finished, but I'm afraid to power it up. I won't touch it until tomorrow at least. Get rest, then check everything :)

One thing I would like to know. Is there ANY measurements/tests I can do with a multimeter (that's all of my "testing" equipment I have) to check the gaiclone? The only thing I could think of is resistance, but not sure where to measure and what to expect?
Or is it mostly power up and duck? (I don't sadly have a variac or a variable power supply! one of these days i tell ya)

Thank You
 
oh yeah, and one thing i haven't paid mind to yet is heatsinking
my "heatsinks" are 2" wide, 2" long, 1" high .. will that be enough (1 of these per chip). Also, unfortonately its mounted upside down (i.e. the chip is facing up, fins facing down) and is enclosed in a box that's about 5.5"x3.5"x2" (and has holes on bottom).

Should this combo of a small heatsink and a small case cause a problem???
 
well i got enough guts to turn it on

no turn-on explosion - check
no overheating - check
dc offset - 28mV
rails - 33V

so far so good

put on a speaker - nothing, no turn on thump .. no sound
put another speaker - nothing, no turn on thump/no sound
a third speaker (that i KNOW works) - NOTHING!!!

so .. now i've a gainclone but no sound :(
 
also as far as i can tell, and i've checked it a billion times .. everything is wired correctly for the inverted:

pin 1 - +V
pin 3 - 220k resistor to pin 8, to one speaker out
pin 4 - -V
pin 7 - to star ground
pin 8 - 220k resistor to pin 3, 10k resistor to 4.7uF cap to input

the other speaker out comes from star ground

anything amiss in here?

edit: also there is no resistor/pot between input and ground (i.e. no connection between the 2)
 
thanks kev .. help always appreciated, but i work saturday/sunday :(
maybe if i get a day off and i don't get it workin i'll take you up on your offer :)

as an aside:
i know for sure that the 1000uF caps are working fine and both the resistors are working fine ..
peter sent me the lm3875's, so i'm pretty sure those are fine as well
the 4.7uF cap is MOST LIKELY fine .. don't know how it would have gotten damaged
orientation of the 2 polar caps looks fine to me
the one soldered to pin #1 is +, the - of that goes to star ground
the one soldered to pin #4 is -, the + goes to star ground as well

i've 6 things going to star ground
the ground from power supply (or 0 V), the negative speaker out, the input ground, pin #7, and the 2 caps (+ from one and - from the other)
 
*hangs head in shame*

ok .. i've been up since 6am this morning, so i have an excuse ... MAYBE!

the GC works PERFECT
the pre-amp works just as good

so .. what the problem was you ask?

the pre-amp had one cable hooked up to its outputs .. the gc had a different cable for inputs
for the life of me i couldn't figure it out .. until tried to switch cables and realized one end of the cable that goes out of pre-amp is unplugged, and one end of cable that goes into gc is unplugged ....
go figure .. heh ..

its true .. it IS all about the smallest things!!!
 
ok, and now i'm talkin to myself (for now), but that's ok :)

as james brown would say "I feel good"

i heard my speakers play music after almost a whole month (short of a week) of downtime .. that's LOTS of time!!!

first impression (this is just ONE speaker btw, one channel completed) is that its incredibly dynamic ..
the music just seems to jump at me :)

my speakers are not great, but they're moderately sensitive, 91dB
the amp is virtually hum-free .. i can turn the volume up 100%, and put my ear up to the speaker and i can BARELY hear anything .. just BARELY

at 75% volume and less there's nothing that i can hear when i put my ear right up to the speaker .. just when its super high volumes

the heatsink should hold up, also .. i've had it playing for about 15 minutes at slightly below what my listening level usually will be (low volumes, plus its 11pm and everyone is asleep), and the heatsink is just warm .. i'll estimate 30C at very most, room temp about 22C

overall .. an amazing feeling to finish like this

one more to go ;)

btw, thank you guys for making me stick ..
thank you peter for sending me free chips, i'm VERY grateful
and thank you all for great help

next up tomorrow - finish the second channel (SLOWLY!!!)

after that .. earn money .. and who knows, maybe an aleph 5 ;)
that's my next-on-the-list amp, although i'm not venturing into that one w/o saved up money, and LOTS of it ..
i could build an aleph 3 w/ the toroid/caps that i have .. or a P3A .. hmmmmmz ..
ok no ideas for me, and i'm goin to sleep now .. past 11 and gotta wake up at 6am!

(who can sleep with this much excitement!)
 
Hi!

elizard said:
*hangs head in shame*

so .. what the problem was you ask?

the pre-amp had one cable hooked up to its outputs .. the gc had a different cable for inputs
for the life of me i couldn't figure it out .. until tried to switch cables and realized one end of the cable that goes out of pre-amp is unplugged, and one end of cable that goes into gc is unplugged ....
go figure .. heh ..

its true .. it IS all about the smallest things!!!

Reminds me of myself trying to get a network of two computers working back about five years ago (and computers are what I do for a living...), the second computer belonging to a friend of mine, we had everything up and running, but no data could be send over the network. After checking and re-checking, we both installed the OS THREE TIMES from scratch, still no connection. :mad: :mad:

Then I realized that I hadn't plugged the network cable into the back of my computer... it was lying unused on the carpet... :rolleyes: :rolleyes:

My friend nearly killed me... :devily: :devily:

Bye,

Arndt
 
well boys and girls
i've just finished second channel of the gainclone, and voila .. it works!!! :)

hooked it up and all .. works ;)

then i cleaned up my room .. my parents were getting fed up with everything lying around, but meh :)

THANK you once again .. i'll make sure to stick around

oh yeah, and i can't wait till i start a new project, although my wallet seems to disagree VERY much so
 
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