MXR - Custom Audio Electronics - Boost/Overdrive MC-402 [schematic]
- okgb
- Diode Debunker
I thought this one sounded decent for a chip
i opened the boost / dist combo box but the smt parts
are impossible for me to see and it was a little harder to
tell where each was [ horrible sounding dist. imho ]
i need glasses but i keep spending money on gear, ha !
I thought the sinle boost pedal sounded better than the combo version
but that may be my imagination as i didn't listen to them at the same time
I can post pix of the combo , or send it
whatdya say ?
i opened the boost / dist combo box but the smt parts
are impossible for me to see and it was a little harder to
tell where each was [ horrible sounding dist. imho ]
i need glasses but i keep spending money on gear, ha !
I thought the sinle boost pedal sounded better than the combo version
but that may be my imagination as i didn't listen to them at the same time
I can post pix of the combo , or send it
whatdya say ?
Last edited by lolbou on 21 Jul 2010, 15:24, edited 2 times in total.
Reason: Topic renamed to match the unit shown and moved to "Modern..."
Reason: Topic renamed to match the unit shown and moved to "Modern..."
- okgb
- Diode Debunker
even with macro camera doesn't seem to focus well
[ i do need glasses ] but here's a couple for interest
curoius the better OP 275 i.c. is closer to the overdrive section ??
I'd be happy to sent this to any established member , I just can't see that well
photobucket's being a dink today as well , can't see all the pix
image code isn't showing up here ??
[ i do need glasses ] but here's a couple for interest
curoius the better OP 275 i.c. is closer to the overdrive section ??
I'd be happy to sent this to any established member , I just can't see that well
photobucket's being a dink today as well , can't see all the pix
image code isn't showing up here ??
- lolbou
- Old Solderhand
I've read in a french guitar magazine (an article by "Dr Boost" - which I hate) that these MXR/CAE were having a steel case instead of aluminium, and the author claims that it brings a better shielding (and also more weight).
Can you confirm this?
Can you confirm this?
- Are you a mod or a rocker?
- Uh, no, I'm a mocker.
- Uh, no, I'm a mocker.
- Steven_M
- Resistor Ronker
Upload the images as attachments on the forum, that way we can see them in full res, and also, if your account becomes inactive, the pictures dont disappear for all of eternity.okgb wrote:even with macro camera doesn't seem to focus well
[ i do need glasses ] but here's a couple for interest
curoius the better OP 275 i.c. is closer to the overdrive section ??
I'd be happy to sent this to any established member , I just can't see that well
photobucket's being a dink today as well , can't see all the pix
image code isn't showing up here ??
Any chance of getting pictures of the bottom side of the board too? Perhaps if you have a scanner, you could use that.
Any idea what the markings are on the transistors?
hi,
more picture (bottom side) please so i can try tracing it
more picture (bottom side) please so i can try tracing it
- okgb
- Diode Debunker
transisters as seen from top of , the formatting doesn't stay
to physically represent their location once i save this but
if you think of it as 3 rows then this is the order
-----2n5088 ---------------- 5087 ---- j177
------------- 5087
5087 ------------5087 ---------- j177--- 5087 -------j177
hope that makes sense , I'll take a bottom pic tomorrow
to physically represent their location once i save this but
if you think of it as 3 rows then this is the order
-----2n5088 ---------------- 5087 ---- j177
------------- 5087
5087 ------------5087 ---------- j177--- 5087 -------j177
hope that makes sense , I'll take a bottom pic tomorrow
- Jarno
- Resistor Ronker
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These enclosures are nearly always metal die-cast products, and you can't die-cast steel. There are a number of other options ranging from zinc to aluminium and brass as well. There are weight differences in that range. With regard to shielding, I would expect better shielding with brass or copper, but I don't think that's necessary/ noticeable, and it's WAAYYYY more expensive.lolbou wrote:I've read in a french guitar magazine (an article by "Dr Boost" - which I hate) that these MXR/CAE were having a steel case instead of aluminium, and the author claims that it brings a better shielding (and also more weight).
Can you confirm this?
From the picture, looks like your average zinc die-cast.
"It crackles....., but that's ok"
- Dirk_Hendrik
- Old Solderhand
Information
Whatever the discussion, the MC402's cases are definitely not made of aluminum.
Now I was going to wonder why anyone would want to trace this one. Until I figuired that's the only option to invent modifications to make the distortion side sound better. Those are easy mods though since it cannot get any worse.
Now I was going to wonder why anyone would want to trace this one. Until I figuired that's the only option to invent modifications to make the distortion side sound better. Those are easy mods though since it cannot get any worse.
- Nikifena
- Solder Soldier
- okgb
- Diode Debunker
It's the boost which i liked and wanted to know what
made it so [ just happened to get this combo ]
Totally agree with you about the overdrive , don't know how it
made it to market or why CAE put their name on it
[ just a not very interesting buzzsaw sound , is it just
a Dist+ or variation ]
I'm assuming a couple of mosfets in place of the clipping
diodes may help ala ocd , anyone know who was the first to use mosfets this way ?
made it so [ just happened to get this combo ]
Totally agree with you about the overdrive , don't know how it
made it to market or why CAE put their name on it
[ just a not very interesting buzzsaw sound , is it just
a Dist+ or variation ]
I'm assuming a couple of mosfets in place of the clipping
diodes may help ala ocd , anyone know who was the first to use mosfets this way ?
- okgb
- Diode Debunker
Hey thanks for posting the circuit , I'm still fine to send the pedal out
if someone wants to delve further , As Dirk mentions , I would'nt
use the Dist. side but wonder if it can be made usable enough ?
Anything that gives the boost a slight hf lift ?
and is that 220 uf on the input ?
if someone wants to delve further , As Dirk mentions , I would'nt
use the Dist. side but wonder if it can be made usable enough ?
Anything that gives the boost a slight hf lift ?
and is that 220 uf on the input ?
- Nikifena
- Solder Soldier
okgb, the input cap is 220nF. the bias resistors 2x100k are connected to +V and GND. This resistors give 1/2V to the 1meg resistor.
Sorry I'm left handed bass player and I write very ugly with hand
EDIT: about modification, first you need to know how and where in the schem this pedal make distortion effect. Then use your favorite clipping method for modification. If you like to modify the tone ( AFC - amplitude frequency characteristic), than you need to get all the schematics with all component values.
As I remember this pedal use a lot of FET's for switching the signal path. All they are at the bottom of the pcb near the switches.
Sorry I'm left handed bass player and I write very ugly with hand
EDIT: about modification, first you need to know how and where in the schem this pedal make distortion effect. Then use your favorite clipping method for modification. If you like to modify the tone ( AFC - amplitude frequency characteristic), than you need to get all the schematics with all component values.
As I remember this pedal use a lot of FET's for switching the signal path. All they are at the bottom of the pcb near the switches.
- Dirk_Hendrik
- Old Solderhand
Information
The first start is having a schematic so we can wonder why the thing has such a crappy drive section.okgb wrote:Since the boost schemo got posted [ thanks ]
maybe i'll look at " fixing " the dist side, but
any suggestions [ Dirk ? ] where to start ?
typical Dist+ mods ?
- Gila_Crisis
- Resistor Ronker
Information
this is another schem of the boost section, it comes from an italian forum.
the guy who traced it, reverse-engineered it from the MC401 Boost-Linedriver and it's verified!
oh well forget the flip-flop bypass section an build it with a normal true-bypass
the boost pot is a 100k lin, and R12 100k
the guy who traced it, reverse-engineered it from the MC401 Boost-Linedriver and it's verified!
oh well forget the flip-flop bypass section an build it with a normal true-bypass
the boost pot is a 100k lin, and R12 100k
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Zwischen Ordnung und Chaos fangt die Musik an
- okgb
- Diode Debunker
Thanks for posting that
it looked like the list said 1k for r 12
but 100k makes sense with the other schematic showing 47k
for the gain pot , dispointing that they went with the fet switching
That's bradshaw selling out ? must be by the sound of the dist+ side
Anyone seen the circuit for the Dist ? see if it's fixable
Any comments on the i.c. used for boost ? why they choose it ?
was it used out of cheapness or sound , why not paralell the halves if you're
going to use a dual ?
can anyone deny / verify my opinions earlier that the stand alone one seem to sound better
[ or that it seemed to have a slight hf lift ] of course maybe there was some bad loading
going on with my pedal chain or i had too much coffee that day
it looked like the list said 1k for r 12
but 100k makes sense with the other schematic showing 47k
for the gain pot , dispointing that they went with the fet switching
That's bradshaw selling out ? must be by the sound of the dist+ side
Anyone seen the circuit for the Dist ? see if it's fixable
Any comments on the i.c. used for boost ? why they choose it ?
was it used out of cheapness or sound , why not paralell the halves if you're
going to use a dual ?
can anyone deny / verify my opinions earlier that the stand alone one seem to sound better
[ or that it seemed to have a slight hf lift ] of course maybe there was some bad loading
going on with my pedal chain or i had too much coffee that day