unclej Posted December 11, 2004 Report Share Posted December 11, 2004 this is neither a question nor a social commentary but my personal opinion is that whoever decided that the schematic symbol for a rectangular component like, let's say an op amp, should be a triangle just for the sole purpose of confusing me should definitely be slapped...hard..maybe twice. Quote Link to comment Share on other sites More sharing options...
Kyle Cavanaugh Posted December 12, 2004 Report Share Posted December 12, 2004 OK, the flat side on the left is for the inverting(-) and non-inverting(+) inputs; + on top, - on bottom. The the pointy end to the right is the output. The line extending from the top is the positive DC voltage The line extending from the bottom is the negative DC voltage, a lot of the time this may just be common, but not always. To figure out what pins on the op-amp it's at you'll need to refer to some sort of datasheet, which can be found all over the net if you just type the name of it in a search engine. Some op-amps can be changed for others without problems which have slightly different specs to them. For example, a 4558 op-amp and a 741 op-amp are interchangable. Believe it or not guys, the 741 is superior according to the spec sheet! But what is truely desired by guitarists is the EQ curve of the clipping that the chip is responsible for (along with the diodes, of course). Basically, it will output mainly midrange and treble and cut off in a treble frequency. I sure hope I'm not flamed for saying what I just said. Right now, I'm trying to experiment right now with using an op-amp as a summing amplifier to allow having the sound of a series wired humbucker, while having less noise and more clarity. Quote Link to comment Share on other sites More sharing options...
JohnnyG Posted December 12, 2004 Report Share Posted December 12, 2004 kyle that all seems about right to me. i dunno about 741 actually being higher quality that the 4558 but since ive never actually bothered looking into any of the data sheets for noise specs etc i cant reallycomment lol Quote Link to comment Share on other sites More sharing options...
Paul Marossy Posted December 12, 2004 Report Share Posted December 12, 2004 (edited) The 741 is a general purpose single opamp and the 4558 is a general purpose dual opamp. The other thing about different types of opamps is that some of them are BJT, such as the 4558, and some are JFET, like the TL072. The Ibanez Tube Screamer (TS808 and TS-9) used the JRC4558D. A lot of the DIY circuits use a TL072. The TL072 has a nice breakup. In most circuits, I can't tell much of a difference between a BJT and JFET opamp. But there are some circuits where you can see a definite difference between the two types with a 'scope. Edited December 12, 2004 by Paul Marossy Quote Link to comment Share on other sites More sharing options...
Stalefish Posted December 14, 2004 Report Share Posted December 14, 2004 Try having to study the stupid things.. Quote Link to comment Share on other sites More sharing options...
unclej Posted December 14, 2004 Author Report Share Posted December 14, 2004 morning gentlemen..i actually found a diagram of all the pin numbers and what they were for quite easily...i was just making fun of the fact that a rectangular component should be symbolized by a triangle. there may be a logical reason for that but i'm guessing somebody just did as a joke. and kyle, thanks for going to the trouble of explaining. i appreciate it. Quote Link to comment Share on other sites More sharing options...
Paul Marossy Posted December 14, 2004 Report Share Posted December 14, 2004 Actually, that triangular symbol is a general block diagram symbol for an amplifier. It could be referring to a tube, transistor or an opamp in a block diagram. Somehow, it has become convention to use that to show an opamp in a schematic - I guess because there is no formal symbol for it like there is for a transistor, JFET, MOSFET, triode, diode, pentode, rectifier, etc. Quote Link to comment Share on other sites More sharing options...
unclej Posted December 14, 2004 Author Report Share Posted December 14, 2004 thanks paul..i knew there had to be a logical reason..well, i assumed there was anyway. Quote Link to comment Share on other sites More sharing options...
Kyle Cavanaugh Posted December 15, 2004 Report Share Posted December 15, 2004 Yeah, I studied more about op-amps. I was wrong, the 4558's are dual op-amps, duh! Hmm, it would be interesting to mod a tubescreamer to have 2 741's then... Quote Link to comment Share on other sites More sharing options...
Paul Marossy Posted December 15, 2004 Report Share Posted December 15, 2004 it would be interesting to mod a tubescreamer to have 2 741's then... Maybe. But, you might possibly end up with more noise, though. Quote Link to comment Share on other sites More sharing options...
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