freestompboxes.org

Only gutshots I've encountered on the internet

http://yustech.blogspot.nl/2012/03/ibanez-bb9.html

enjoy!

Green dots = GND

Schem:
Ibanez BB9 Bottom Booster schematic

Is this pedal a clone of something? Is it a reissue?

The gain control introduces splattery overdrive. Is there a way to mod it for a more useable overdrive or eliminate the fizz?

Is there a way to introduced compression and make the gain knob control the comp?

I just got one of these. Thx to Dirk for the schem! I'm not sure on the circuit but the charge pump makes me think of a Klon, although the rest of the circuit doesn't exactly. It seems Ibanez is using 1n4002 diodes as clippers on the gain control, I'm not sure this is the best choice of diodes. In fact, I'm not sure that just about anything might not be better, say 1n914's or 2 transistors wired to use the internal diodes. Note that this unit is: made in China, allegedly true bypass, and has board mounted pots and jacks.

Guiltyspark

guiltyspark wrote: I'm not sure on the circuit but the charge pump makes me think of a Klon,

This a similar remark als "The Klon buffer" for a standard non-inverting opamp buffer. Using an LT1044 (or similar) DCDC converter chip this way is a standard application for the 1044 and no more "Klon" than the Boeing 737 cockpit clock I had on my desk a week ago (which utilizes the same circuit).

guiltyspark wrote:
It seems Ibanez is using 1n4002 diodes as clippers on the gain control, I'm not sure this is the best choice of diodes.

Thousands went before this utilizing these as clippers

guiltyspark wrote: or 2 transistors wired to use the internal diodes.

Correction: 2 diodes wired as diodes. Transistors do not have internal diodes. That's a FET thing having reverse protection diodes.

guiltyspark wrote: Note that this unit is: made in China, allegedly true bypass, and has board mounted pots and jacks.

Well, it is True Bypass. And, and I am repeating myself here again, the thought that board mounted jacks and pots is bad is incorrect. As long as the board mounted components have a mechanical strain relief that ensures possible force on the component does not load the solder joints there is nothing wrong. Many don't seem to understand that simple concept.

Well, to my ear the 1n4002 do not sound especially good in this circuit. As someone said above, it's somewhat "splattery" sounding and that's who I was addressing with that comment. Note that I didn't say board mounted jacks/pots were bad - I simply pointed out that Ibanez has changed their construction methods from the common 9 series pedals. However, the board mounted pots/lacks are not a great help to most of the members of this forum. They just make repairs and mods more difficult. Maybe you can understand this simple concept.

If the sound is splattery that speaks to me of the gain stage being at fault, not the clipping diode. Clipping diodes are more commonly at fault when something is too squished, or too harsh.

I can see how the drive control could aide in adding some filth to a dirty amp but I run my amps clean. Any suggestions on where to start modding for a more pleasant drive sound?