Bellari RP503 opamp positions & mods
Posted: Thu Jun 06, 2013 9:09 pm
I'm having a heck of a time figuring out which opamp is for the compressor. Logically it would seem U2 would be the one as it corresponds with the front panel layout. However U5 appears to be connected to the compressors control if you follow circuit board traces.
I've read BOTH and have never found a schematic. Even Back Lion Audio doesn't have a clue as of today nor the group running this forum. I thank them both for really speedy replies.
This was originally a BLA mod but done by someone no longer associated with them. There are 5 opamps and U1 is the preamp, I found numerous replacement opamps but finally found one that really makes the most out of the unit. There's a toatal of 3 different opamps and one is for the preamp, one for the compressor and the others are either all for the eq section or dived between the eq and output.
I'm "thinking" that U2 is the compressor, U5 the output, U1 the preamp and U3&4 for the eq. However I have not found one sole on earth that can verify this. I'e aske guru Jim Williams and even he didn't know having not seen one of these little blue babies.
I can probably find a winning lottery ticket before I could find a schematic for this thing. It's really baffling me so I thought just maybe one of you folks have had 1st hand experience and give me the correct answer before I go completely bananas.
Anyone have any insight? All the links on the matter are dead so I'm going by info I found after a year of searching. There's also been several opamps used and I do know the final BLA one but just not sure the exact order of the chips.
I'll gladly share the opamps of choice if anyone can help me here. I don't have em in front of me or I'd post it now so I'll post later.
Thank you in advance for your help. A schematic would be a godsend if anyone is sitting on one.
Sincerely,
Richard T Puncsak
Risson Amplifiers R&D
PMR Speakers R&D
I've read BOTH and have never found a schematic. Even Back Lion Audio doesn't have a clue as of today nor the group running this forum. I thank them both for really speedy replies.
This was originally a BLA mod but done by someone no longer associated with them. There are 5 opamps and U1 is the preamp, I found numerous replacement opamps but finally found one that really makes the most out of the unit. There's a toatal of 3 different opamps and one is for the preamp, one for the compressor and the others are either all for the eq section or dived between the eq and output.
I'm "thinking" that U2 is the compressor, U5 the output, U1 the preamp and U3&4 for the eq. However I have not found one sole on earth that can verify this. I'e aske guru Jim Williams and even he didn't know having not seen one of these little blue babies.
I can probably find a winning lottery ticket before I could find a schematic for this thing. It's really baffling me so I thought just maybe one of you folks have had 1st hand experience and give me the correct answer before I go completely bananas.
Anyone have any insight? All the links on the matter are dead so I'm going by info I found after a year of searching. There's also been several opamps used and I do know the final BLA one but just not sure the exact order of the chips.
I'll gladly share the opamps of choice if anyone can help me here. I don't have em in front of me or I'd post it now so I'll post later.
Thank you in advance for your help. A schematic would be a godsend if anyone is sitting on one.
Sincerely,
Richard T Puncsak
Risson Amplifiers R&D
PMR Speakers R&D