Studiomaster 16-4-8

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Studiomaster 16-4-8

Postby paulrichards7 » Sun Feb 15, 2009 10:08 pm

So, I have noise on multiple channnels of my Studiomaster
Ive checked them individually connected to power supply, there are 2 that are fine which means that this is not a power supply problem
It seems to me to be white noise/static with some intermittent spikes
I have been using a crystal earpiece and checking from the tape/line input, which on my mixer is the unbalanced tape input marked on schematic(see pic) and the noise seems to be starting at the collector of the 1st transistor(see pic)
I have been advised to check caps, IC and diodes
All of these have been checked and/or replaced(see pic and yellow circles for those)
Unfortunately the noise still seems to be present
As I am kind of new to electronics I am relying on your guys experience
I know, I know, take a class. Well if there was one around my area I would. Unfortunately there isn't
Could you please help
Also, even though the schematic I have is for my mixer, things dont seem to be exactly correct leading up to 1st IC!
See pics for evidence
The middle pic of the multi 3 way view has been flipped to help me in locating components on the trace side
Thanks for your help
Paul

http://i390.photobucket.com/albums/oo34 ... 3-way2.jpg
http://i390.photobucket.com/albums/oo34 ... nnel-2.jpg
http://i390.photobucket.com/albums/oo34 ... tshere.jpg
http://i390.photobucket.com/albums/oo34 ... placed.jpg
http://i390.photobucket.com/albums/oo34 ... lschem.jpg




Whilst comparing the 2 different channels, Ive realised that there are different resistors elswhere
These are the ones in the pics with red rings around them
http://i390.photobucket.com/albums/oo34 ... -green.jpg
http://i390.photobucket.com/albums/oo34 ... -schem.jpg
They seem a lot smaller than ordinary resistors
They are off of the auxes and the L/R and buss switches
I was wondering why these are different and if it had to do with noise issues?
Also seen in the pic with green rings around them are jumper wires.
However these are 0 ohm metal film resistors compared to the other channels which are just strips of wire
Would these pick up noise?
Thanks
Paul
http://freedom7project.wordpress.com/

myspace.com/paulrichards7
paulrichards7
Analog Enthusiast
 
Posts: 8
Joined: Thu Feb 05, 2009 11:20 pm
Location: Bath, England

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