BA2 OEP/99v Newbie- 47uF Cap Query
Posted: Sat Jul 03, 2010 10:24 am
Hi All,
I have been trying to find some info on this to no avail- here or @ Prodigy Pro- so forgive me if this has been covered:
There are two 47uF caps which end up underneath the 99V opamp. Their pads are extremely close to those of several resistors (a 10k and a 51R each). I have soldered these in and there look to be shorts between the outside legs of each 47uF, and the nearest 10k to each, and the leg of each 51R closest to the IC socket (which has the jumper from 4 to 7). Sort of like 2 small triangles.... Forgive my electronics ignorance, but having checked the schematic- which is for the 99v/JLM14 config - I can't say for sure if this is safe. See this screen grab.
To me it looks ok. Having said that, I seem to recall reading that the second of the two 47uF caps is not required for the 99v/JLM14 config, and can't see it on the schematic, so I really don't know if either are going to be ok or safe. The pads themselves, even without solder, seem to be close enough to short anyway so maybe there is no cause at all for concern?
One further question: as the BA2 has variable impedance, what are the Rload/RZobel resistor values I need? I have failed to uncover this info in my hours of web trawling.
Any help will go a long way! Thanks in advance.
As an aside, my experience with DIY'ing is very limited. I have built a couple of stomp boxes and a small Tube amp designed by Bruce McBean. I really want to learn a lot from doing this project, but I also am under pressure to get this thing built as I need to use it on upcoming sessions, so a few short-cuts and prevention from frying an opamp or a resistor or three are going to be a vast help. (I'm still awaiting delivery of an Electronics textbook to help some more!)
Cheers,
Luke
I have been trying to find some info on this to no avail- here or @ Prodigy Pro- so forgive me if this has been covered:
There are two 47uF caps which end up underneath the 99V opamp. Their pads are extremely close to those of several resistors (a 10k and a 51R each). I have soldered these in and there look to be shorts between the outside legs of each 47uF, and the nearest 10k to each, and the leg of each 51R closest to the IC socket (which has the jumper from 4 to 7). Sort of like 2 small triangles.... Forgive my electronics ignorance, but having checked the schematic- which is for the 99v/JLM14 config - I can't say for sure if this is safe. See this screen grab.
To me it looks ok. Having said that, I seem to recall reading that the second of the two 47uF caps is not required for the 99v/JLM14 config, and can't see it on the schematic, so I really don't know if either are going to be ok or safe. The pads themselves, even without solder, seem to be close enough to short anyway so maybe there is no cause at all for concern?
One further question: as the BA2 has variable impedance, what are the Rload/RZobel resistor values I need? I have failed to uncover this info in my hours of web trawling.
Any help will go a long way! Thanks in advance.
As an aside, my experience with DIY'ing is very limited. I have built a couple of stomp boxes and a small Tube amp designed by Bruce McBean. I really want to learn a lot from doing this project, but I also am under pressure to get this thing built as I need to use it on upcoming sessions, so a few short-cuts and prevention from frying an opamp or a resistor or three are going to be a vast help. (I'm still awaiting delivery of an Electronics textbook to help some more!)
Cheers,
Luke