Hi --
I am working on building some of the Thomas Henry drum machine modules. I have some simple questions:
1) A drum pad controller sends a +5V positive square wave out through "a jack." Should the jack be a 1/4" input? Or what about other types of connectors, like banana plugs/jacks? What is the difference between a banana jack and a 1/4" jack?
2) I am having trouble with some 741 ICs not functioning properly. They are new ICs and should be functioning properly. They are being used in the circuit as comparators. Does each 741 need a + and - power source? It looks from the schematics that some only have + or -. Maybe the problem with one of the 741s is that it is not receiving voltage in its V+ or V-?
I know this is hard to explain without the schematics. But any constructive feedback would be appreciated. Thanks!
I am working on building some of the Thomas Henry drum machine modules. I have some simple questions:
1) A drum pad controller sends a +5V positive square wave out through "a jack." Should the jack be a 1/4" input? Or what about other types of connectors, like banana plugs/jacks? What is the difference between a banana jack and a 1/4" jack?
2) I am having trouble with some 741 ICs not functioning properly. They are new ICs and should be functioning properly. They are being used in the circuit as comparators. Does each 741 need a + and - power source? It looks from the schematics that some only have + or -. Maybe the problem with one of the 741s is that it is not receiving voltage in its V+ or V-?
I know this is hard to explain without the schematics. But any constructive feedback would be appreciated. Thanks!
A jack is a jack. In the USA that means a female connector. What makes it an input or output is its use. A 1/4" jack can be either. SO you might not want to refer to a "1/4" input" if you are referring to the OUTPUT of the drum trigger.
The connector you chose is up to you. It is there so you can disconnect one part from another instead of permanently wiring them together. 1/4" connectors are common in the music industry. They are also called phone connectors. (NOT phono connectors. Phono connectors is another name for RCA connectors) If you intend this to work with other commercial gear, you would want to use the same connectors as the rest of the industry. But if you are making this for yourself and it is complete without other gear, then use whatever connectors you have.
For a 5v pulse, I don't see how the type of connector matters a lot. I wouldn't use bananas myself though. If you mean what is the physical difference between the types, look them up in a catalog, that will be better than any description I could make.
Yes every op amp needs power supplies connected to it. If the IC is a single op amp, then it will need supplies. SOme ICs are dual or quad op amps, meaning ther are two or four op amp circuits in one IC. Those ICs have one common set of power pins, and all the op amps inside share it. On schematics, they often draw the power pins on one of the internal sections, so the remaining section will appear not to have power connections, but they are understood to be there from the other side.
The connector you chose is up to you. It is there so you can disconnect one part from another instead of permanently wiring them together. 1/4" connectors are common in the music industry. They are also called phone connectors. (NOT phono connectors. Phono connectors is another name for RCA connectors) If you intend this to work with other commercial gear, you would want to use the same connectors as the rest of the industry. But if you are making this for yourself and it is complete without other gear, then use whatever connectors you have.
For a 5v pulse, I don't see how the type of connector matters a lot. I wouldn't use bananas myself though. If you mean what is the physical difference between the types, look them up in a catalog, that will be better than any description I could make.
Yes every op amp needs power supplies connected to it. If the IC is a single op amp, then it will need supplies. SOme ICs are dual or quad op amps, meaning ther are two or four op amp circuits in one IC. Those ICs have one common set of power pins, and all the op amps inside share it. On schematics, they often draw the power pins on one of the internal sections, so the remaining section will appear not to have power connections, but they are understood to be there from the other side.
Thanks so much for this informative answer.
1) One circuit module accepts an "input" jack and the circuit's job is to create a stable +12V pulse to send to other module units. This circuit uses a 741 op amp (I don't have the schematic in front of me), but it doesn't have the power pins on the schematic marked as hooked up. There is a chain of voltage that goes to the inverted and noninverted inputs on the opamp, but I guess what you're saying is that it should be "understood" that I hook the +V and -V to the respective voltages.
2) The second module I'm working with also has a 741, and again there are connections in the schematic to its +V or -V. This module is for a transducer drum pad that takes a transduced signal, sends it to the 741, and then sends a +5 V square wave pulse to circuit #1 above. This circuit is able to light an LED saying that it receives the hit from the drum pad, but I've tested pin #6 (the output) and there should be current coming out of it, but there is not. Maybe this is because the V+ and V- to the IC are not connected.
I'm going to keep working on this. Thank you.
1) One circuit module accepts an "input" jack and the circuit's job is to create a stable +12V pulse to send to other module units. This circuit uses a 741 op amp (I don't have the schematic in front of me), but it doesn't have the power pins on the schematic marked as hooked up. There is a chain of voltage that goes to the inverted and noninverted inputs on the opamp, but I guess what you're saying is that it should be "understood" that I hook the +V and -V to the respective voltages.
2) The second module I'm working with also has a 741, and again there are connections in the schematic to its +V or -V. This module is for a transducer drum pad that takes a transduced signal, sends it to the 741, and then sends a +5 V square wave pulse to circuit #1 above. This circuit is able to light an LED saying that it receives the hit from the drum pad, but I've tested pin #6 (the output) and there should be current coming out of it, but there is not. Maybe this is because the V+ and V- to the IC are not connected.
I'm going to keep working on this. Thank you.
A 741 wont function very well as a comparator because its not a comparator and has limitations about the levels into the + and - inputs.
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