Studiomaster 8 into 4 refresh
 

hi everyone, i'm new here and i can see a lot of good informations!.
maybe some of you could help me doing something.

here's the deal :
i recently bought an old studiomaster 8 into 4 that i would like to "refresh" a bit..
my knownledge in electronics is actually poor but growing everyday ;)
i don't have the schematics for this console and i can not actually find it, so let's start "a blind".

what i d'like to do is to make the sound more "transparent" or clear (for the summing part). so by looking around, i can read that changing the opamps could be a start.
it's equiped with tl072 originaly, and i would like to give it a try with 5532's or 2134..
what do you think about it?
would i expect real improvement from this?
i also have in mind to follow with changing coupling caps and some resistors that need to (because they went over heated)..

does this step make any sense for someone, or am i trying to play mad scientist?

btw, this board was built in 1981, and as you can see, caps already been changed since (not my job).
here are some pictures:
the whole master section
http://adnk.free.fr/depot_ftp/photos...r/P1020450.JPG
the master bus summing part zoomed
http://adnk.free.fr/depot_ftp/photos...r/P1020449.JPG

well, thanks by advance for any return !

mathieu

Studiomaster 8 into 4 refresh
 

mat_432 wrote:
hi everyone, i'm new here and i can see a lot of good informations!.
maybe some of you could help me doing something.

here's the deal :
i recently bought an old studiomaster 8 into 4 that i would like to
"refresh" a bit..
my knownledge in electronics is actually poor but growing everyday ;)
i don't have the schematics for this console and i can not actually find
it, so let's start "a blind".

what i d'like to do is to make the sound more "transparent" or clear
(for the summing part). so by looking around, i can read that changing
the opamps could be a start.
it's equiped with tl072 originaly, and i would like to give it a try
with 5532's or 2134..
what do you think about it?
would i expect real improvement from this?
i also have in mind to follow with changing coupling caps and some
resistors that need to (because they went over heated)..

does this step make any sense for someone, or am i trying to play mad
scientist?

btw, this board was built in 1981, and as you can see, caps already been
changed since (not my job).
here are some pictures:
the whole master section
http://adnk.free.fr/depot_ftp/photos...r/P1020450.JPG
the master bus summing part zoomed
http://adnk.free.fr/depot_ftp/photos...r/P1020449.JPG

well, thanks by advance for any return !

mathieu

I would stick with fet input amps. Sometimes more bypassing is required
with higher frequency amps, else instability. 2134 should have less noise.

Greg

Studiomaster 8 into 4 refresh
 

"mat_432"


what i d'like to do is to make the sound more "transparent" or clear
(for the summing part). so by looking around, i can read that changing
the opamps could be a start.
it's equiped with tl072 originaly, and i would like to give it a try
with 5532's or 2134..
what do you think about it?

** Nuts.

would i expect real improvement from this?

** Nope.

The summing stages involve transistors at the inputs to the TL072s - so are
very quiet.

The op-amps you mention take much higher DC supply current so would
overload the PSU if you changed them all.

Their higher bandwidths could easily lead to HF oscillation problems to.

The scorched resistors seem to be in the headphone amplifier ( cos some dope
used a mono plug) and simply need replacing.


..... Phil

Ok, thanks for replys,

so i maybe won't touch te opamp,
at least instabillity or oscillation are last thing expected!

this boards has its sound like it is, well
but it's still bit noisy,
what if i would replace capacitors or transistors with high quality ones?

Studiomaster 8 into 4 refresh
 

"mat_432"

what i d'like to do is to make the sound more "transparent" or clear
(for the summing part). so by looking around, i can read that changing
the opamps could be a start.
it's equiped with tl072 originaly, and i would like to give it a try
with 5532's or 2134..
what do you think about it?-

** Nuts.
-
would i expect real improvement from this?-

** Nope.

The summing stages involve transistors at the inputs to the TL072s - so
are
very quiet.

The op-amps you mention take much higher DC supply current so would
overload the PSU if you changed them all.

Their higher bandwidths could easily lead to HF oscillation problems
to.

The scorched resistors seem to be in the headphone amplifier ( cos some
dope
used a mono plug) and simply need replacing.


so i maybe won't touch te opamp,
at least instabillity or oscillation are last thing expected!

this boards has its sound like it is, well
but it's still bit noisy,


** Studiomaster desks were known to be very quiet.

Very few people have the gear or know how to test a desk for background
noise levels.

Turning up all the knobs and listening is the fool's way.


what if i would replace capacitors or transistors with high quality
ones?


** Waste of time and money.


.... Phil

Studiomaster 8 into 4 refresh
 

mat_432 wrote in message
...

hi everyone, i'm new here and i can see a lot of good informations!.
maybe some of you could help me doing something.

here's the deal :
i recently bought an old studiomaster 8 into 4 that i would like to
"refresh" a bit..
my knownledge in electronics is actually poor but growing everyday ;)
i don't have the schematics for this console and i can not actually find
it, so let's start "a blind".

what i d'like to do is to make the sound more "transparent" or clear
(for the summing part). so by looking around, i can read that changing
the opamps could be a start.
it's equiped with tl072 originaly, and i would like to give it a try
with 5532's or 2134..
what do you think about it?
would i expect real improvement from this?
i also have in mind to follow with changing coupling caps and some
resistors that need to (because they went over heated)..

does this step make any sense for someone, or am i trying to play mad
scientist?

btw, this board was built in 1981, and as you can see, caps already been
changed since (not my job).
here are some pictures:
the whole master section
http://adnk.free.fr/depot_ftp/photos...r/P1020450.JPG
the master bus summing part zoomed
http://adnk.free.fr/depot_ftp/photos...r/P1020449.JPG

well, thanks by advance for any return !

mathieu




--
mat_432


So what happens to the noise, assuming you can meter it somehow, if you
either locally squirt freezer spray or warm with hot air, individual op-amps
?

--
mat_432[/i][/color]


So what happens to the noise, assuming you can meter it somehow, if you
either locally squirt freezer spray or warm with hot air, individual op-amps
?[/quote]

i'm in the cleaning process, so, as each module is separated, i have mounted 2 channels, 2 buses an the master fader (cleaned).

For now, what i can hear is some "white" noise without any gain or fader level, juste the mixer powered on.

by selecting mic source and pushing master fader, i'm getting some hum with nothing plugged in.

my headphone left channel is completly distorded, and changing the scorched resistor had effect..

well, i'm a bit dispponted just now, but i will clean the rest of the channels and give it some more try. just don't know what to do to "fix" things so i'll go step by step... (oh baby)

i'm in the cleaning process, so, as each module is separated, i have mounted 2 channels, 2 buses an the master fader (cleaned).

For now, what i can hear is some "white" noise without any gain or fader level, juste the mixer powered on.

by selecting mic source and pushing master fader, i'm getting some hum with nothing plugged in.

my headphone left channel is completly distorded, and changing the scorched resistor had any effect..

well, i'm a bit dispponted just now, but i will clean the rest of the channels and give it some more try. just don't know what to do to "fix" things so i'll go step by step... (oh baby)