Ibanez - SD9M Sonic Distortion mods [schematic]
This is also something that I am interested in. I was getting ready to order parts to use the SD9 PCB that I have had laying around for yrs and ran across the new version on the web. From the videos it appears the high gain setting is the normal SD9 setting, but to my ear the normal old school SD9 is more inbetween the settings on the mid switch.
Anyone got ideas on these Mods?
Anyone got ideas on these Mods?
- aion
- Solder Soldier
Information
I noticed there weren't any schematics available for the Ibanez SD9M (2012 reissue) or any documentation on how it differed from the regular SD9. I particularly just wanted to find out what the switches do.
Well, when I opened it up, I found good news and bad news. The bad news is that there are two 4558 op amps and only 3 transistors, which means the differences are a bit more than just a couple of toggle switches on the front to switch out a component or two, so it will probably need a full trace - or at least a very thorough checking with Dirk's schematic of the original SD-9. The good news is that Ibanez is using Molex-style connectors for everything, so it was really easy to pull the board out without having to desolder anything at all.
So: I have great photos and a full visual trace of the circuit. I haven't had time to work up a schematic yet, so I thought I would post my progress here in case anyone wanted to take a shot at it.
Here's the PSD: https://www.sendspace.com/file/r5oque
Everything is done with layers - the front, the back (mirrored), each individual net, and the labels - so you can turn them on and off as needed.
Here's the component side of the board:
https://i1249.photobucket.com/albums/hh ... ligned.jpg
Here's the trace side of the board, mirrored to match the component side:
https://i1249.photobucket.com/albums/hh ... ligned.jpg
And here's a flat trace of the component side of the board, if you don't have Photoshop to look at the better one above:
https://i1249.photobucket.com/albums/hh ... -trace.jpg
In addition to the photos, here are the offboard components.
Input jack board: jack input -> 47n capacitor -> 47k resistor (Yellow, Violet, Orange) -> PCB "In" connection
There's also a ceramic capacitor marked "47" (47pF) after the resistor, going to ground.
Pot board: The 6-pin connector in the bottom-left corner of the board has the following connections. (numbered so the bottom pin to ground is "1")
1 Ground (green dot)
2 Vol 2 (blue dot)
3 Tone 1 (white dot)
4 Tone 3 (orange dot)
5 Dist 2/3 (brown dot)
6 Dist 1 (gold dot)
On the pot board itself:
Vol 1 -> 1k resistor -> ground
Tone 2 -> Vol 3
Output jack board: 330pf capacitor (code 331) to ground immediately before the output jack
The one thing I still need to do is to pull out C5, the teal bipolar capacitor, and measure it. The sleeve on the capacitor was cut just perfectly before the "uF" marking so it's impossible to read. If someone had another SD9M I'm sure the cap would be readable - just unlucky on my part!
Well, when I opened it up, I found good news and bad news. The bad news is that there are two 4558 op amps and only 3 transistors, which means the differences are a bit more than just a couple of toggle switches on the front to switch out a component or two, so it will probably need a full trace - or at least a very thorough checking with Dirk's schematic of the original SD-9. The good news is that Ibanez is using Molex-style connectors for everything, so it was really easy to pull the board out without having to desolder anything at all.
So: I have great photos and a full visual trace of the circuit. I haven't had time to work up a schematic yet, so I thought I would post my progress here in case anyone wanted to take a shot at it.
Here's the PSD: https://www.sendspace.com/file/r5oque
Everything is done with layers - the front, the back (mirrored), each individual net, and the labels - so you can turn them on and off as needed.
Here's the component side of the board:
https://i1249.photobucket.com/albums/hh ... ligned.jpg
Here's the trace side of the board, mirrored to match the component side:
https://i1249.photobucket.com/albums/hh ... ligned.jpg
And here's a flat trace of the component side of the board, if you don't have Photoshop to look at the better one above:
https://i1249.photobucket.com/albums/hh ... -trace.jpg
In addition to the photos, here are the offboard components.
Input jack board: jack input -> 47n capacitor -> 47k resistor (Yellow, Violet, Orange) -> PCB "In" connection
There's also a ceramic capacitor marked "47" (47pF) after the resistor, going to ground.
Pot board: The 6-pin connector in the bottom-left corner of the board has the following connections. (numbered so the bottom pin to ground is "1")
1 Ground (green dot)
2 Vol 2 (blue dot)
3 Tone 1 (white dot)
4 Tone 3 (orange dot)
5 Dist 2/3 (brown dot)
6 Dist 1 (gold dot)
On the pot board itself:
Vol 1 -> 1k resistor -> ground
Tone 2 -> Vol 3
Output jack board: 330pf capacitor (code 331) to ground immediately before the output jack
The one thing I still need to do is to pull out C5, the teal bipolar capacitor, and measure it. The sleeve on the capacitor was cut just perfectly before the "uF" marking so it's impossible to read. If someone had another SD9M I'm sure the cap would be readable - just unlucky on my part!
- aion
- Solder Soldier
Information
C5 is a 1uF bipolar capacitor. First draft schematic coming soon.
- aion
- Solder Soldier
Information
Here's the schematic. I left off the power section and FET switching, but from initial glance the power section is pretty well the same as the SD9 and the FET switching should be the same as well (but isn't needed for true bypass). I didn't double-check anything, so this should be considered entirely unverified, but it should be pretty easy to cross-check it with the trace I posted earlier.
The major change is the addition of the op amp gain stage between IC1A and the clipping diodes. I haven't played an original SD9 but I imagine this would change the sound a fair amount - hardly just a "modded" version. The gain switch is pretty intense, actually. I'm not too crazy about it. A little too much metal, even for an already high-gain pedal. I thought the Mids switch was pretty useful and made it a bit more Tube Screamery. A lot of people think the Mids switch is too drastic, so it'd be pretty easy to play around with the values of C10 and C11 to get a better balance - maybe two 47n's would be better.
The second half of IC2 is used to buffer the dry signal for switching, as in the original, so for a true-bypass version you might want to use it to buffer Vref per Dirk's suggestion.
The major change is the addition of the op amp gain stage between IC1A and the clipping diodes. I haven't played an original SD9 but I imagine this would change the sound a fair amount - hardly just a "modded" version. The gain switch is pretty intense, actually. I'm not too crazy about it. A little too much metal, even for an already high-gain pedal. I thought the Mids switch was pretty useful and made it a bit more Tube Screamery. A lot of people think the Mids switch is too drastic, so it'd be pretty easy to play around with the values of C10 and C11 to get a better balance - maybe two 47n's would be better.
The second half of IC2 is used to buffer the dry signal for switching, as in the original, so for a true-bypass version you might want to use it to buffer Vref per Dirk's suggestion.
- aion
- Solder Soldier
Information
Yep, you're right. Good catch. It's been updated:
http://aionelectronics.com/wp-content/u ... ematic.png
And sorry the first one was so small! I thought it would show the full size version if you saved it or viewed it by itself but it did not. The one above is a bit more legible :)
http://aionelectronics.com/wp-content/u ... ematic.png
And sorry the first one was so small! I thought it would show the full size version if you saved it or viewed it by itself but it did not. The one above is a bit more legible :)
- Dirk_Hendrik
- Old Solderhand
Information
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- aion
- Solder Soldier
Information
Unbelievable - the second one was just as small as the first one. It's supposed to be around 2200px wide. Try the above link one more time - it should actually be readable now. Sorry for making all of you get out your glasses!
- mirosol
- Resistor Ronker
Thought i'd draw a layout for the circuit, so here you go. As suggested, i used the remaining half of an opamp as a buffer for vref. One could take a third switch for clipping diodes pretty easy.
Unverified for now.
Unverified for now.
http://tagboardeffects.blogspot.com/
http://mirosol.kapsi.fi/
"No such thing as innocence" -Iron Chic
http://mirosol.kapsi.fi/
"No such thing as innocence" -Iron Chic
- Dirk_Hendrik
- Old Solderhand
Information
With some 2nd thoughts while spending some time..
- The input buffer suddenly changed transistor P/N?
- The photo's show a FET, the schem doesn't?
- The photo's show a 4v7 Zenet, the schem doesn't.
How accurate is the schem really?
- The input buffer suddenly changed transistor P/N?
- The photo's show a FET, the schem doesn't?
- The photo's show a 4v7 Zenet, the schem doesn't.
How accurate is the schem really?
- Dirk_Hendrik
- Old Solderhand
Information
Ah I see. Not at all:
so this should be considered entirely unverified,
so this should be considered entirely unverified,
- alexradium
- Resistor Ronker
the 2 fets are switching the outputs,classic Ibanez.Dirk_Hendrik wrote:With some 2nd thoughts while spending some time..
- The input buffer suddenly changed transistor P/N?
- The photo's show a FET, the schem doesn't?
- The photo's show a 4v7 Zenet, the schem doesn't.
How accurate is the schem really?
Zener is part of the led supply.
It was stated by original poster he left off switching and power circuit.
- Dirk_Hendrik
- Old Solderhand
Information
As I answered myself already.
Have a full version in the make. I don't like ommissions. Ommissions take time in repairs.
For now my main frown remains:
When looking at the schematic I do not see an input capacitor. Since this box is mecahnically switched but not true bypass this does not result in a Pop. nevertheless, non-popping of a full setup has come to rely on the DC decoupling of the other devices in the FX chain since the input gives a 4.5 volts loading in the device that preceeds this pedal in the signal chain. I do consider this a defect in the design.
Have a full version in the make. I don't like ommissions. Ommissions take time in repairs.
For now my main frown remains:
When looking at the schematic I do not see an input capacitor. Since this box is mecahnically switched but not true bypass this does not result in a Pop. nevertheless, non-popping of a full setup has come to rely on the DC decoupling of the other devices in the FX chain since the input gives a 4.5 volts loading in the device that preceeds this pedal in the signal chain. I do consider this a defect in the design.
- tube-exorcist
- Resistor Ronker
How true.Dirk_Hendrik wrote:..... Have a full version in the make. I don't like ommissions. Ommissions take time in repairs.
.......
I think you missed this in the first post:Dirk_Hendrik wrote: For now my main frown remains:
When looking at the schematic I do not see an input capacitor. .......
aionios wrote: ......
In addition to the photos, here are the offboard components.
Input jack board: jack input -> 47n capacitor -> 47k resistor (Yellow, Violet, Orange) -> PCB "In" connection
There's also a ceramic capacitor marked "47" (47pF) after the resistor, going to ground.
......
"I've noticed there's an inverse relationship between cost of gear and talent. If you need the most expensive gear to get decent tones, then you suck as a player."
- aion
- Solder Soldier
Information
The input capacitor (47n in the schematic) is actually located on the input jack PCB, along with the 47k resistor. So the wire going to the board is actually the R2/Q1 junction, and those first two parts can't be seen in the photos.
Also, the input buffer transistor is actually a 2SC3198 rather than a 2N5088. Shouldn't matter since it's just a buffer, but wanted to mention it!
Also, the input buffer transistor is actually a 2SC3198 rather than a 2N5088. Shouldn't matter since it's just a buffer, but wanted to mention it!
- Dirk_Hendrik
- Old Solderhand
Information
I couldn't care less for the transistor type for an emitter follower. Unfortunately there's some willing to discuss the sonic differences for days. Just as well there's some who are in the opinion that when one traces a circuit the trace shouls be as correct as possible. Changin transistor type in such a situation already suggests pure laziness. "It doesn't matter electronically so why bother". I tend to be of the 2nd camp. When you do something push yourself to do it accurate. Leave your own engineering opinions for a later stage.
Which leaves 2 capacitors which are unidentified on the board photo's and have a value in the schem. Since the schem is unverified and does contain errors...
here's my go based on the info provided so far...
Which leaves 2 capacitors which are unidentified on the board photo's and have a value in the schem. Since the schem is unverified and does contain errors...
here's my go based on the info provided so far...
- tube-exorcist
- Resistor Ronker
Thanks for you effort. Output pulldown resistor is a 100k (instead of 1M).Dirk_Hendrik wrote: .....
Which leaves 2 capacitors which are unidentified on the board photo's and have a value in the schem. Since the schem is unverified and does contain errors...
Cap values:
and from the draft schematic the other cap is a 10n . This matches with the SD9.aionios wrote: C5 is a 1uF bipolar capacitor.
"I've noticed there's an inverse relationship between cost of gear and talent. If you need the most expensive gear to get decent tones, then you suck as a player."
- Dirk_Hendrik
- Old Solderhand
Information
Thanks. Though i already corrected that 1Meg. Seemingly not.
As that 10n. That's what I suspected but I did not really trust that draft.
As that 10n. That's what I suspected but I did not really trust that draft.