Ibanez - No.88 Distortion Booster (1972-1985) by Maxon
- modman
- a d m i n
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https://www.tonehome.de/ibanez/first-se ... t-booster/
Basic Vox Distortion Booster circuit with hard clipping diodes...
I have no information on the transistors.... I suppose any usual suspect could work here...
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Is there a schematic available for this? I tried to figure it out from the pcb tracks but couldn't get the top section. Any hope for that? Thanks.
- george giblet
- Resistor Ronker
The Distortion Booster schematic is essentially this with no supply cap,
Electro Harmonix - Two transistor Muff Fuzz:
I'm not sure about the pot value, 47k linear is very likely (as used on other models).
Transistors in that series of pedals were 2SC828. Most pedals used 2SC828Q but in the back of my mind
one of those pedals had 2SC828R or 2SC828Y and it might have been that one.
Maxon and Ibanez had the same series of "pedals":
Maxon MB10 Ibanez No.85 Distortion Booster
Maxon MB20 Ibanez No.86 Power Booster
Maxon MB30 Ibanez No.87 Treble Booster
Maxon MB40 Ibanez No.88 Bass Booster
The Treble Booster and Bass Booster were just a single NPN transistor stage:
470k + 47k base resisistors, 10k collector resistor 390R emitter resistor.
They varied in that the Treble Booster had small coupling caps and Bass Booster had large coupling
caps and some extra low-pass caps on the input and output.
I can't remember the Power booster.
The pedal loads the pickup in bypass and the power is cut off which means you get a large "bang" when you change modes.
The pedals were very similar to the Electro Harmonix Screaming Tree/Screaming Bird/Hog's Foot (Mole) era of pedals.
I'm just quoting from memory here. I have better notes in my archives.
Electro Harmonix - Two transistor Muff Fuzz:
I'm not sure about the pot value, 47k linear is very likely (as used on other models).
Transistors in that series of pedals were 2SC828. Most pedals used 2SC828Q but in the back of my mind
one of those pedals had 2SC828R or 2SC828Y and it might have been that one.
Maxon and Ibanez had the same series of "pedals":
Maxon MB10 Ibanez No.85 Distortion Booster
Maxon MB20 Ibanez No.86 Power Booster
Maxon MB30 Ibanez No.87 Treble Booster
Maxon MB40 Ibanez No.88 Bass Booster
The Treble Booster and Bass Booster were just a single NPN transistor stage:
470k + 47k base resisistors, 10k collector resistor 390R emitter resistor.
They varied in that the Treble Booster had small coupling caps and Bass Booster had large coupling
caps and some extra low-pass caps on the input and output.
I can't remember the Power booster.
The pedal loads the pickup in bypass and the power is cut off which means you get a large "bang" when you change modes.
The pedals were very similar to the Electro Harmonix Screaming Tree/Screaming Bird/Hog's Foot (Mole) era of pedals.
I'm just quoting from memory here. I have better notes in my archives.
Last edited by george giblet on 08 Mar 2023, 22:33, edited 1 time in total.
- george giblet
- Resistor Ronker
Here's the Power Booster.
Transistor 2SC828Q.
Looks similar to the Treble Booster and Bass Booster but with moderate caps.
Forgot to mention (IIRC) :
- Treble Booster has the level control on the output side.
- Bass Booster has the level control on the input side.
Transistor 2SC828Q.
Looks similar to the Treble Booster and Bass Booster but with moderate caps.
Forgot to mention (IIRC) :
- Treble Booster has the level control on the output side.
- Bass Booster has the level control on the input side.
- george giblet
- Resistor Ronker
I forgot to mention, like the EHX products Maxon sold "For Amp" and "For Guitar" versions.
On the "For Guitar" versions the 6.5mm jack plugs into the guitar.
On the "For Amp" versions the 6.5mm jack plugs into the amp.
ie. the Jack and Socket are wired differently.
I'm quite sure that the "For Amp" version exists for all four models/pedals.
I don't know how the part numbers were handled.
I'm not sure if Ibanez sold the "For Amp" versions.
On the "For Guitar" versions the 6.5mm jack plugs into the guitar.
On the "For Amp" versions the 6.5mm jack plugs into the amp.
ie. the Jack and Socket are wired differently.
I'm quite sure that the "For Amp" version exists for all four models/pedals.
I don't know how the part numbers were handled.
I'm not sure if Ibanez sold the "For Amp" versions.
- BMS1971
- Solder Soldier
So yes 1k is actually 10K, Orange line is different color than the red ones on the 2.7K resistorgeorge giblet wrote: ↑08 Mar 2023, 22:15 The Distortion Booster schematic is essentially this with no supply cap,
Electro Harmonix - Two transistor Muff Fuzz:
I'm not sure about the pot value, 47k linear is very likely (as used on other models).
Ben
Last edited by BMS1971 on 03 Apr 2023, 15:20, edited 2 times in total.
- BMS1971
- Solder Soldier
The 1K is actually a 10K I think, hard to tell if it's orange or red line but 1K makes no sens...modman wrote: ↑06 Jun 2020, 11:11 1972 Ibanez catalog.pngibanez distortion booster 01.jpegIbanez Distortion Booster 02.jpegibanez distortion booster 03.jpegIbanez Distortion Booster 04.jpegIbanez Distortion Booster 05.jpeg
I don't know what it is with booster plugs lately... this one wasn't documented yet. Great pictures on this website
https://www.tonehome.de/ibanez/first-se ... t-booster/
maxon_distortionbooster.jpg
Screen Shot 2020-06-06 at 13.03.35.png
Basic Vox Distortion Booster circuit with hard clipping diodes...
I have no information on the transistors.... I suppose any usual suspect could work here...
Ben
- george giblet
- Resistor Ronker
- modman
- a d m i n
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- Joined: 19 Jun 2007, 16:57
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Thanks guys, I updated the image
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