Ibanez Super Metal SM-9

[Zerro]

First stage is J-FET buffer, preparing stronger, lower impedantion signal to second stage - preamp with max. gain cca 5. This first ATTACK opamp "heats" and equalizing (slight high pass) signal for overdrive stages with clipping diodes in feedback. There are LED and normal Si diode paralelly, which will give unsymetrical clipping, closing sound to valve clipping. After those clipping stages is distortion segment - two diodes and capacitor to ground. Again, clipping signal, giving to it more even harmonics, typical for valve distortion. Then are correctors opamps. First PUNCH is typical Baxandall corrector, which you can find in common audio amplifiers as TONE knobs. Here is used for freqs around LOW-MID, giving "body" to signal. Another stage is EDGE EQ. Typical EQ circuit with two freqs, enhanced or muted with pot. Gyrators and their functions are fairly described here:

http://www.muzique.com/lab/gyrator.htm

At the end is output buffer giving strong power output, to kick up your power amp. Volume pot and serial resistor 10k is described upper by Space Monkey.

[aion]

The SML , SM9 is not the same as a Metal Charger it has a transistor output buffer. It is the same as a SM7 and there's a schematic http://www.freeinfosociety.com/media.php?id=4071  I know it's an old topic but some people do search like me.

Btw, this is super-duper not true. The SM7 has nothing to do with the earlier Super Metal pedals. The SM-9, SML, MS-10 are all the same circuit, although IC3 and IC4 are sometimes different (either 4558 or 1458 depending on the model). The MS-10 may use a BJT instead of JFET for the input buffer, but this could be a tracing error. Otherwise—notwithstanding that some of the traces have obvious errors that are easily corrected when comparing other schematics—the three pedals are identical inside, even the part values.

The Maxon SM-01 appears to be the same as well, same PCB layout as the Ibanez SM-9. I can't confirm the values but there's no reason to think it's any different.

The Maxon SM-9 reissue from a few years ago is different, however. It only has 4 knobs, replacing "Attack" and "Punch" with one called "Scoop", and it has an optional 18V charge pump. I haven't seen a trace of this one, but just from appearance we can tell it's not an accurate reissue.

[Aentons]

There is an etchable layout and build doc here if anyone is interested. It's the only project for the SM that I have been able to find. It is very likey following the schematics above. Alas, I am not an etcher.

http://www.zeta-sound.se/clipping/

http://zeta-sound.se/wp-content/uploads/zeta-sound/distortion/Ibanez_SM-9/Ibanez_SM-9.pdf

[Aentons]

First stage is J-FET buffer, preparing stronger, lower impedantion signal to second stage - preamp with max. gain cca 5. This first ATTACK opamp "heats" and equalizing (slight high pass) signal for overdrive stages with clipping diodes in feedback. There are LED and normal Si diode paralelly, which will give unsymetrical clipping, closing sound to valve clipping. After those clipping stages is distortion segment - two diodes and capacitor to ground. Again, clipping signal, giving to it more even harmonics, typical for valve distortion. Then are correctors opamps. First PUNCH is typical Baxandall corrector, which you can find in common audio amplifiers as TONE knobs. Here is used for freqs around MID, giving "body" to signal. Another stage is EDGE EQ. Typical EQ circuit with two freqs, enhanced or muted with pot. Gyrators and their functions are fairly described here:

http://www.muzique.com/lab/gyrator.htm

At the end is output buffer giving strong power output, to kick up your power amp. Volume pot and serial resistor 10k is described upper by Space Monkey.

Thanks for the description and analysis.
My low-tech interpretation the schematics is that the SM seems to be as if you squezzed two asymmetrical tubscreamers and an SD9 together, moved the regular tone control (attack) to the front and replaced it with a couple of graphic eq active tone controls for bass and high-mid (punch and edge)

[Aentons]

First stage is J-FET buffer, preparing stronger, lower impedantion signal to second stage - preamp with max. gain cca 5. This first ATTACK opamp "heats" and equalizing (slight high pass) signal for overdrive stages with clipping diodes in feedback. There are LED and normal Si diode paralelly, which will give unsymetrical clipping, closing sound to valve clipping. After those clipping stages is distortion segment - two diodes and capacitor to ground. Again, clipping signal, giving to it more even harmonics, typical for valve distortion. Then are correctors opamps. First PUNCH is typical Baxandall corrector, which you can find in common audio amplifiers as TONE knobs. Here is used for freqs around MID, giving "body" to signal. Another stage is EDGE EQ. Typical EQ circuit with two freqs, enhanced or muted with pot. Gyrators and their functions are fairly described here:

http://www.muzique.com/lab/gyrator.htm

At the end is output buffer giving strong power output, to kick up your power amp. Volume pot and serial resistor 10k is described upper by Space Monkey.

Thanks for the description and analysis.
My low-tech interpretation the schematics is that the SM seems to be as if you squezzed two asymmetrical tubscteamers and an SD9 together, moved the regular tone control (attack) to the front and replaced it with a couple of graphic eq active tone controls for bass and high-mid (punch and edge)

There is also a nice write-up of the functions by 11gauge here.

From:
https://www.tdpri.com/threads/ibanez-mt10-awesome.260198/

"
- The Attack control is basically a "pre gain" variation of the tone control in a TS.

- The first gain stage is sort of like a TS (soft clipping), and this is where the Distortion control is.

- The second gain stage is also TS-like, but uses a LED with a traditional TS diode, and it isn't adjustable.

- You then get the hard clipping diodes to ground just like a DS-1/Rat/D+, but the extra gain is going to make this thing more on par with the DOD and Boss pedals of the time (HM-2, American Metal, etc.).

- Next is the Punch circuitry - it's an active EQ that adjusts bass.

- Next is the Edge circuitry, which is an active EQ "blender," with a "band" for treble and a "band" for midrange.

...Compared to it's contemporaries, it's a smarter design, IMO. The HM-2 "hardwired" the mid and treble "EQ bands," making them non-adjustable. The DOD copies of the HM-2 were even worse - they blended the bass EQ boost with the fixed mid/treble EQ boost!

And - the pre-gain tone control predates the Boss MT-2. The MT-2 is also not adjustable and is responsible for that big honking upper mid boost that you can't dial out at any setting.

Ibanez was WAY ahead of the curve with this one, too. I can see a lot of elements that other companies "borrowed" and implemented in their "metal pedals."

Luckily for those who like them, the MS10 is much cheaper!
"

[Aentons]

https://www.freestompboxes.org/viewtopic.php?f=1&t=9005&start=20

Interesting, from the pics above it looks like the SM9 has the disguised black band LEDs for D1 and D3 as well. I'll have to see if they light up.

Yep, they light up. I made a quick video that shows it.

https://youtube.com/shorts/kDq5eK8v_qw?


Edit: I measured d1 and d3 at 1.4v forward voltage and just out of curiousity the others measure at 0.6v

[Aentons]

While I had the SM9 open I decided to document the pot values and tapers.

Level = 10kA
Drive = 100kB
Attack = 20kG
Edge = 20kG
Punch = 100kB

[Aentons]

For those who search or who may have missed it. aion has a board for the Super Metal now.

https://aionfx.com/project/sentinel-metal-distortion/

Thank you, thank you, thank you, aion

[WonkoTheSane]

I'd change the 10k output pot to 50k or 100k for gobs more output myself.

[Aentons]

I'd change the 10k output pot to 50k or 100k for gobs more output myself.

There is a different fix in the build notes of the aion project. It also adds a charge pump for an 18v switch

"Increased volume

The stock SM-9 is known for having low volume. There are two confusing and easily-remedied design
decisions causing this.
• R19, the 4.7k bias resistor for IC3A, cuts the signal in half when combined with R18.
• R27, the 10k resistor in series with the volume control, halves the maximum volume again.
We have corrected both of these in the default parts list for this project, raising R19 to 100k and
recommending to jumper R27. With these two changes, the maximum volume is comparable to other
distortion effects."

[WonkoTheSane]

Hrm I dunno if any of the schematics are accurate, I'll trace mine.

[Aentons]

Hrm I dunno if any of the schematics are accurate, I'll trace mine.

That would be awesome of you!