Roland TB-303 Modification, what has been modified?

frankyl · 5th July 2011

Hi,
does someone have experience with tb303 modifications?
i do have a tb303 here at this moment and it has been modified but i don't know what exactly has been modified.
unfortunately there's no one else i could ask and i don't know the original owner.

i have uploaded some pictures. maybe someone can tell about what's modified by viewing the pictures.

i suppose it's a CV/Gate modification but i don't have a döpfer mcv oder similar midi-to-cv/gate converter here for a test.

the internal 303 sequencer still works but the headphone doesn't work. i suppose the headphone output does now have another function (for the CV/Gate converter) but i'm not sure.

hope someone can help.
thanks very much in advance.
cheers
frank

fudog · 5th July 2011

my guess,

CV/GATE input and filter input (as a cv control, not audio) on phone jack... at a guess, other things its likely to be is slide or accent.

buy yourself a cv/gate midi converter and test it. obvious answer I know, but really if youre gonna be playing with old gear you need one.

Kenton Pro 2000 is what I recommend

good luck

[edit]

for the phone jack it is actually most likely to be accent control, given the way the 303 circuits are designed. this is just a guess though.

Llitsor · 5th July 2011

If you get no joy here, ask on the Adafruit x0xb0x forums. There are definitely some knowledgeable 303 techs lurking there.

fudog · 5th July 2011

Quote:

Originally Posted by Llitsor

If you get no joy here, ask on the Adafruit x0xb0x forums. There are definitely some knowledgeable 303 techs lurking there.

Agreed!

bcaudio will prob know what the mod is, hes done extensive research on 303 mods - you'll find him over on the adafruit forums

NeilC · 5th July 2011

I have the Kenton socket kit in mine (CV/Gate/Filter/Accent/Slide in), and from memory, it's wired to pretty much the same points on the lower part of the board, right down the cut tracks. I'm not sure where the transistors come in, though; presumably it's to allow reuse of the existing jacks (otherwise you end up drilling holes between the pots).

5th July 2011	#1
frankyl Gear interested Joined: Jan 2010 Posts: 11 Thread Starter	Roland TB-303 Modification, what has been modified? Hi, does someone have experience with tb303 modifications? i do have a tb303 here at this moment and it has been modified but i don't know what exactly has been modified. unfortunately there's no one else i could ask and i don't know the original owner. i have uploaded some pictures. maybe someone can tell about what's modified by viewing the pictures. i suppose it's a CV/Gate modification but i don't have a döpfer mcv oder similar midi-to-cv/gate converter here for a test. the internal 303 sequencer still works but the headphone doesn't work. i suppose the headphone output does now have another function (for the CV/Gate converter) but i'm not sure. hope someone can help. thanks very much in advance. cheers frank

5th July 2011	#5
NeilC Gear interested Joined: May 2010 Posts: 11	CV/Gate inputs I have the Kenton socket kit in mine (CV/Gate/Filter/Accent/Slide in), and from memory, it's wired to pretty much the same points on the lower part of the board, right down the cut tracks. I'm not sure where the transistors come in, though; presumably it's to allow reuse of the existing jacks (otherwise you end up drilling holes between the pots).

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5th July 2011	#2
fudog Gear Head Joined: Jul 2010 Posts: 42	my guess, CV/GATE input and filter input (as a cv control, not audio) on phone jack... at a guess, other things its likely to be is slide or accent. buy yourself a cv/gate midi converter and test it. obvious answer I know, but really if youre gonna be playing with old gear you need one. Kenton Pro 2000 is what I recommend good luck [edit] for the phone jack it is actually most likely to be accent control, given the way the 303 circuits are designed. this is just a guess though.

5th July 2011	#3
Llitsor Lives for gear Joined: Aug 2009 Location: UK Posts: 1,569	If you get no joy here, ask on the Adafruit x0xb0x forums. There are definitely some knowledgeable 303 techs lurking there.