Ibanez - SM-9 / Maxon SM-01 Super Metal  [schematic]

All about modern commercial stompbox circuits from Electro Harmonix over MXR, Boss and Ibanez into the nineties.
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nitraus
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Post by nitraus »

It seems I have another issue with the switch: when I turn it on, the sound comes in really slowly, it takes like 5-10 seconds.
Some months ago, when I got the stompbox I first noticed it and fixed it just cleaning the switch, but now the problem came out again.
What should I check?
Thanks in advance.

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Dirk_Hendrik
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Post by Dirk_Hendrik »

nitraus wrote:It seems I have another issue with the switch: when I turn it on, the sound comes in really slowly, it takes like 5-10 seconds.
Some months ago, when I got the stompbox I first noticed it and fixed it just cleaning the switch, but now the problem came out again.
What should I check?
Thanks in advance.
1) Verify the 47uF/6/3 volts capacitor that filters the vbias supply isn't leaking. This means you have to desolder it. If there's whitish residue on it's bottom end and the PCB is turning black it was leaking.
2) Replace the switching FET's and the diodes going to the gates.
Sorry. Plain out of planes.

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TWSpedals
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Post by TWSpedals »

Recently traced my Ibanez Super Metal SML, from the master series. The PCB number is MP-SM2001. Matches up very well if the schematics online already. There is a few differences mind: TR1 is a 2SK118 FET not a BJT. There is no LEDs used as clipping diodes. All the clipping diodes are silicon diodes. Both schematics I've seen online show at least 1 clipping LED and that doesn't match up with my unit, nor anyone elses I've cross refrenced with. Below is a link to my schematic: https://drive.google.com/drive/folders/ ... sp=sharing

If you don't want to change the clipping diodes there is a few things you can do to make the pedal louder:
Jumper R56
Make R22 100K instead of the stock 4.7K
Make R15 1K instead of the stock 10K
These changes will make unity volume below 12 noon on the Level control.

If you don't mind changing the clipping diodes then removing D5 & D6 or make them LEDs, that will raise the volume significantly . If that's still not enough then changing D1-4 LEDs will make it louder still.

I have to say that this is one of the most overlooked and underrated gain pedals I know of. It does a little bit of everything. If the stock unit was louder I reckon it'd be hailed as the best high gain pedal for metal.
Attachments
Ibanez SML Super Metal MP-SM2001 Schematic.pdf
(629.51 KiB) Downloaded 344 times
Have a nice day!

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Bernardduur
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Post by Bernardduur »

Today I modded my MS10 for some better tones.

I also, as did the former poster, didn't notice any LED's in this pedal. So I connected it with the casing removed and started to play

And behold: D1 and D3, which looks like normal Si diodes, light up!!
D1 and D3 ARE LED's that really look like a diode!

Awesome!!
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Post by aion »

Bernardduur wrote: 05 Sep 2021, 18:39 And behold: D1 and D3, which looks like normal Si diodes, light up!!
D1 and D3 ARE LED's that really look like a diode!
That definitely clears up the discrepancies! Can you post a picture of the diodes? Curious what they look like - I've seen SMD diodes that were in a resistor form factor but never through-hole.

(Extra credit would be measuring the forward voltage of one of them :thumbsup )

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Post by Bernardduur »

Hi!

In this picture you can easily spot the LED: the normal diode has a blue band, the LED has a black band.
MS10.jpg
Also, on my instagram post there is a video of me playing the (stock) pedal on which you see the LED's light up
(

The forward voltage is 1.8V btw
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Post by aion »

Fascinating! Never seen anything like that before. It seems like it's intentionally manufactured for the voltage drop characteristic. I've seen axial LEDs before, but never one that wasn't intended to be seen in some way. Thanks for sharing!

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