marshall 5010 different version schematic attached

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i was chillin' on the ssguitar forum recently, hoping to find a schematic for the 30 watt "redbox" combo... i'd picked up a "scrap" board on ebay, and rebuilt it to get it running.
my friend tassieviking took the info i supplied him and drew up an actual schematic for the jm pcb-78 5010 variant, which marshall doesn't have and has never been on the net.
so here's the schematic for this odd rare beast.... this is for the one with hi and lo ins, and the line out/headphone jack on the front panel with presence control which is literally a simple treble booster between the output of the treble control and the input of the master volume. i guess they call 'em redbox's cuzza all the little red mylar box caps used for blocking/coupling.
these are great amps! i really diggit.

5010 early version BOM
board jm78-2

vr1 gain b22k
vr2 volume al00k
vr3 treble b220k
vr4 mids b22k
vr5 bass a1m
vr6 pres b22k

ic 1 mc1458e

q1 bc184
q2 bc182
q3 bc182
q4 bc212
q5 bc184

q6 mj3001 darlington
q7 mj2501 darlington

zd1 9.1v <4739>
u
db1 br62

r= red box cap
t= tantalum
e= electro
c= ceramic

c1 [email protected] r
c2 [email protected] t
c3 [email protected] t
c4 2.2n c
c5 100n c
c6 [email protected] t
c7 2.2n c
c8 [email protected] r
c9 4.7n c
c10 220p c
c11 [email protected] r
c12 [email protected] r
c13 [email protected] r
c14 [email protected] t
c15 [email protected] e
c16 [email protected] e
c17 [email protected] r
c18 [email protected] e, axial
c19 2.2n c
c20 220p c
c21 [email protected] e, axial
c22 non existant
c23 [email protected] e, radial
c24 [email protected] e, radial

all resistors 5% cc 1/4 watt unless specified

r1 1m
r2 68k
r3 68k
r4 10k
r5 100r
r6 22k
r7 10k
r8 470r
r9 non existant
r10 22k
r11 68k
r12 10k
r13 33k
r14 4.7k
r15 2.7k
r16 2.7k
r17 10r
r18 6r 1 watt
r19 270r 3 watt
r20 470r
r21 10k
r22 3.9k
r23 4.7k
r24 680r
r25 10r
r26 2.2k
r27 1.5k
r28 1.5k
r29 1.5k
r30 10r
r31 39r


Hammond Power Transformers 166J28 28vac center tapped (14-0-14)

Marshall 5010 PCB 78-2 Schematic.jpg


gerber files available by request if needed by anyone.

hope this helps someone out... big props to tassieviking for the drafting and files to recreate this beast!

a couple mods i found that seem to help are

make all preamp resistors 1% metal film resistors
make the big power supply filter caps bigger... 2200 is ok, but a lot of ripple when the amp is pegged. 4400uf, 6800uf are good, i have 10,000uf in the last one i did.
make the two filter caps for the preamp 220uf or 470uf instead of 100. that makes it "sag" a bit less, and gives slightly better bass response, or seem like it.
my bro mark says standard marshall values in the tone stack are an improvement, but i haven't tried doing that yet.

you can hack an fx loop in between the output of the master volume and the input to the driver. i've been experimenting, but nothing i'm truly happy with yet. even a passive one works fairly well, but i like the amp to be dead quiet when pegged, and the fx loop seemed to add noise a bit so i removed it.

anyways... onwards n upwards... and happy 420, if so inclined.
peace
PjP
 
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I know, a bit of a dead thread...
Thanks for posting this. I just picked up a 5010 a few weeks ago. This info helped quite a bit. Although mine is an '82, with High and Low inputs and no headphone/line out jacks. Also has the red frame McKenzie speaker, which surprisingly, sounds pretty decent.

If I could, I'd like to ask two questions:

1) Running any distortion/OD in front of this tends to lose bass and push the mids up. Aside from running an EQ pedal after the OD/Distortion, any suggestions?

2) Mine has a "knee" in the gain. The amp slowly gets a little more hair on it until you get to ~9 and then *WHAM* all the distortion you want. Is there a way to smooth out this transition or do you think this is a function of the circuit as designed?


Thanks again for the time and help.
 
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hey bro
i generally don't use any pedals myself, i just crank it. but from your description, it sounds like you're adding enough distortion on top of it where its compressing the hell out of the signal;
a symptom would be, like, no matter how high you boost the volume on the dirt box, it doesn't really get louder. this happens when you've crushed the wave into a square wave pretty much. distortion is caused by clipping, and clipping compresses the sound wave a lot. once it hits a buzzy square wave, it can't really get more distorted, but it CAN get more squished. i've seen a lot of guys have this problem over the years.
there's a few solutions... first, use less gain on the amp. crank the master up full or almost full, bring the gain up to taste, and use only stompboxes for your distortion tone. that will give you the headroom back, and may alleviate the problem.
but it depends on the style of music, and the volume actually played at. i love these little suckers pretty much dimed, and turn my guitar up and down. for me, they're perfect, and i ditched an 80 lb pedalboard.
an eq after the dirt box may work, but i'd assume its gonna just cause more signal compression, and tho you'll have a bit more freedom to sculpt your tone, the enemy here is volume/gain. the more signal you put in, the more compression you get, and the more dynamics you lose.
you could be having issues with phasing if losing bass, too. its possible the dirt box is inverting the phase. each gain stage of the device will often invert the phase, which can lead to in particular bass frequency loss.
but in this case, i don't think thats it. most high gain circuits attenuate bass because bass frequencies have a tendency to be unstable and "motorboat"... low frequency oscillations that sound like a motorboat running kinda. so the designers usually use smaller value caps, which tend to lower bass knock and boost mids and hi's.
these amps already put out about as much bass as possible from this kind of circuit. you can add larger coupling caps, but they make you lose volume and distortion and tend to make the tone much harsher as the subharmonic content gets amplified more, and the whole amp gets mushy and unstable.
most of us guitar players tend to want more bass, but a lot of times its a fudge. we're looking for frequencies existing below the guitar's actual frequency range, so ya feel that knock in your chest.
it ain't gonna happen with this amp, unfortunately.
if you need to boost the bass into the amp, you can try an eq, but as the amp is designed, its still gonna limit low end going into the circuit.
i think Tassieviking can confirm, making the caps bigger in the amp can shoot you in the foot.

now... as for the gain.... it works the way it does by design pretty much. that last twist of the knob is what takes it from cleanish to filth. all of them do this in this series.
its already an audio taper pot if memory serves. trying to find a reverse audio as i'd seen suggested made that sweep even worse.
the only way around it would be to lift one side of the pot <center/wiper is grounded in this case if memory serves> and add a secondary smaller pot as a vernier to give more fine control, but it's probably not worth it.

it is what it is. there ARE mods that can be done, but i don't think any of them other than beefier power supply caps really has proven useful.

i DO work on these if it needs help, and am willing to modify the circuit too, but the returns are frankly kinda meagre.

hope this helps your understanding of this amp a little bit.

peace
retrofitting with much larger filter caps will give it less ripple to the power supply, which can make it seem like it has more bottom by clarifying the signal and making it more robust, but too much robs the amp of personality and dirt.
these weren't really designed for pedals, they were designed to plug straight in and control them with the guitar.
doing that, they're brilliant, but with pedals, imho, not so much.
 
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Tatzmann

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What i liked about the 2199 and the 5010
Model was the low noise, atleast if one doesnt
dime the preamp gain. This and that they cleaned up exceptionally well with the guitarpot,
atleast if one doesnt dime the preamp gain.

What i didnt liked about them was the speakers.
The G12L30 speakers in the 2199 were kind of
dead sounding and the G12M-70 in the 5010
were sterile city.

But fun amps to toy around with nonetheless.
:yesway:
 
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best way to bring these to life imho is start with the tone stack on 6, crank the gain full, the master at least half way <better, full> hit an open a power chord and sweep the tmb til it roars, then turn the guitar up and down. been doing this for years, i abandoned my pedalboard.
i DO agree on the speakers. these amps plain sound better into a tighter speaker. my personal favs are 12" peavey scorpion. they put out an octave or so more high end, so ya get more "glass", and they clean up much better, and can generally hold up to anything ya throw at them. makes it a bit louder than stock, too.
 
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hey bro
i generally don't use any pedals myself, i just crank it. but from your description, it sounds like you're adding enough distortion on top of it where its compressing the hell out of the signal;
....

peace
retrofitting with much larger filter caps will give it less ripple to the power supply, which can make it seem like it has more bottom by clarifying the signal and making it more robust, but too much robs the amp of personality and dirt.
these weren't really designed for pedals, they were designed to plug straight in and control them with the guitar.
doing that, they're brilliant, but with pedals, imho, not so much.
Ah, I see I wasn't entirely clear in my description of the issue I had encountered, leading you to a very verbose answer. However, you did answer my questions.
I was trying to dial in a bit of hair on the amp (preamp at 7-8), then back of guitar volume to totally clean it up where needed, and adding a bit of stomp box gain for full on (similiar to the preamp volume cranked) grind.

Alas, this amp won't do as I had hoped. No worries. I can certainly deal with full twist on the preamp gain and back down guitar volume for mild grit. By itself, the amp produces plenty of low end (much more would get lost in the band mix anyway).

Your explanation makes total sense. Thank you for the time and help.
 
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no prob, glad it worked for you. have you ever tried a fuzzface with this circuit? it may do what you want a LITTLE better. maybe. should help it clean up better when rolled back.
 
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pinkjimiphoton, wanted to thank you for your post at the start of the thread. I read that through several times before starting work on the 5010 I just acquired. It needed new pots (Presence had the shaft knocked out of it), input jacks were... jacked by a previous hack job... and I wanted to replace the electrolytics while I was in there. I did bump the filter caps to 4700 uf per your recommendations.​

The beast lives now and sounds better than most of my amps. My once-beloved Legend Rock n Roll 50 is being put out to pasture. Thanks again.​

 
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the big diff is more high end harmonix, and better clean up when ya got the amp pegged and your guitar way down.
for me, they just work better than the stock speakers did.
 

AlvisX

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What i liked about the 2199 and the 5010
Model was the low noise, atleast if one doesnt
dime the preamp gain. This and that they cleaned up exceptionally well with the guitarpot,
atleast if one doesnt dime the preamp gain.

What i didnt liked about them was the speakers.
The G12L30 speakers in the 2199 were kind of
dead sounding and the G12M-70 in the 5010
were sterile city.

But fun amps to toy around with nonetheless.
:yesway:

I love both these amps ,and use them for work more and more frequently , leaving the good sh*t at home
Weber makes a 4 ohm G 12 65 copy , which sounds GREAT in the 5010
I have stuck WGS Green Berets in the 2199
IMO, the 2199 mushes up, in that undesirable solid state way when you overdrive it on it's own . I cannot hear that as much with the band as I hear it just playin at the house . BUT the 2199 ,backed off to just before breakup ,WITH an old DOD 250 in front is an absolute perfect Marshall .............AND they look cool too
My wish is that they would do a 2199 with 5010 guts !!
 


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