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ghettocomp2apcb.jpg



finished and built this pcb layout , the only problem is that

i have had to replace

r34(10k2w) to a 68k 2w
r35(220k) to a 1meg

the 6aq5a kept showing voltages of above 200v

( i reviewed the layout a million times , but in my connect the dots

puzzle , everything looks correct.)


r33(220k) to a 180k

then, all the voltages fell into place(or at least near or inbetween

the reissue voltages , and the dave " error filled book" jhansen

chart.

sounds great (or nice and juicy if you prefer)

/ as good as my UA reissue and the pile of other la-2a

p2p Clones that ive built,

but i am worried that the voltages being so high after r34/r35

that i have done something wrong.

much apreciated if anyone had any tips , suggestions or ideas

on improving .

or obviouse fatal errors .

im just trying to turn this from the "burn the house down"-2a

to the la2a pcb .

aka. the ghetto compressor or the g-unit 2a, :) heh :grin:



oh and ill apologize for the image size now / me and photoshop
are having relationship problems.

thanks in advance/

driller45
 
Nice work, thought there would have been a bit more interest in this. It would make an La2a an easy build, you could even make a stompbox version almost. :grin:
Vikki(uk)
 
Hi Gregory

Your LA2A PCB and your web page look very nice. :thumb:
What software you used to make the PCB and the circuit.
Maybe if you can upload the schem in file format, we can open it and verify it easyer.
Just a sugestion.

chrissugar
 
At first look it seems good. I examined the high voltage from the two 1N4007 diodes to each tube and I think it is OK.
I have just one problem with the fact that C7B is too far away from C7A and the connection between them and the transformer should be the point for star grounding. There are a lot of small curent elements conected to this ground between the two capacitors and also the ground for the 12BH7 is at the other end. This means that there is some high curent that circulate between these points and it can affect the way some elements will behave.

chrissugar
 
thanks so much for the input ,
once the circuit board was made, it took very little time to assemble it
and connect it to the off board stuff .
i did not not make a components silk screen , cause i felt i would probably
make some revisions , (goold old sharpie marker)

////////////////////////////////

im using altium dxp (protel)
but im actually only using the pcb designing section of it .
it exports in 11 file formats .

i placed an EMF image here ,

http://driprecords.com/pcb/index.php

and the file name is "pcb_emf_image"
im not sure if it is only for windows, but it seems to blow up into infinity
(a vector image?)
im hoping to gather enough info
and suggestions to do a version 4 with molex connectors and other
things to make it clean etc.
ive also been trying to run some frequency sweeps between my UA
reissue
and the proto type pcb that is assembled , but the nice audio tester
keeps crashing my computer.
thanks :grin:
 
Geat driller45! For guys who cant open EMF files i converted and optimized file into small PDF.
Here's the link :green:
http://www.imagerely.com/imagehost/uimages/8172la2-pcb.pdf
 
Someone was searching for this, so thought i would bring it to the top.
Vikki :grin:
 
ah that board was 8x10 inches , the newest board is 4"x8.5"

the power supply/metering/audio in and out are on small boards

so they can be crammed into a custom box.

at that time i was having voltage problems because of the way

the ground vs the two electolytic caps that where too far away from

the main ground.
,

so that design worked , but a few resistors had to be changed from

from the original specs, to bring the voltages down ,

thats been solved , the other post in the lab , has the new revised version. (pic)

this new version works , with all the voltages in rage of the reissue/

and other schematics.

:thumb: thanks
 
Excellent work. I didn't see your other post...thanks for the redirection to it.

Are you going to post your revision PCB? I'd like to try this layout myself!

Thanks.

TW :thumb: :thumb: :thumb:
 
cleaning up the layout and silk screen and some other small kinks.

then up she goes.

also running the newest revision prototype through the paces.

leaving it on for a week , (the metal table test)

a stack of sweeps/test tones/ and freq. analysis.

my newest test song of choice is

Destinys Child ft Lil Wayne and TI - Soldier

because the thump and bass is dope , after it passes that its all good. :thumb:
 
Hey the old Bloo will be a collectors item when the new PCB version comes available! :grin:
Vikki(uk)
 
Hi
I made this PCB drawing based on original "turret" layout. Also, I add place for 4 elco caps and two 4,7uF poly caps instead one C5 - 10uF and possibility to add two diodes in series in full wave rectifier.
I put this on all my amps. You will get drop voltage in one diode but it would be safely.
PCB_LA-2A.gif

Dimension is 50mmx160mm. One Eurocard is enought for this. Here is a small pcb for 4 resistors.
I made this because is difficult here to find original turret board.
You have a pdf too.
http://www.dukasound.cg.yu/Data/PCB_LA-2A_layout.pdf
Cheers
Duka
 
ah very cool , good job !! :thumb: heres the power section

ill post the rest tonight


juicemaster2000.jpg


the etching files in pdf
 

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