Author Topic: IC interchangeability idea!  (Read 8880 times)

lerxst88

IC interchangeability idea!
« on: March 30, 2009, 09:52:16 AM »
an III as it were....

Anyway if you soldered pins 8 and 7 together and 1 and 6 together couldnt you switch between a 741 and a 4558? (provided youre using a socket)

blackcorvo

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Re: IC interchangeability idea!
« Reply #1 on: July 13, 2009, 02:43:47 PM »
no, because you have a control that is made in some circuits with the 741 that puts a potentiometer between the 5 and 1, if I'm not wrong. these pins are marked in 741's datasheet as "offset null". pin 8 has no connections to the internal circuitry of the 741.

also, 6 is the inverting input of one of the 4558 op-amps (because 4558 is a dual op-amp) and 7 is the output for this same op-amp so if you connect it to the v+ you could easily make your 4558 burn...

blackcorvo

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Re: IC interchangeability idea!
« Reply #2 on: October 23, 2009, 11:55:06 PM »
...unless you added a switch to change the conections to these pins, like a little DPDT switchso you could change the IC safetly. yeah, that could work.

jacobyjd

Re: IC interchangeability idea!
« Reply #3 on: October 26, 2009, 09:11:00 AM »
an III as it were....

Anyway if you soldered pins 8 and 7 together and 1 and 6 together couldnt you switch between a 741 and a 4558? (provided youre using a socket)

........why?
Warsaw, Indiana's poetic love rock band: http://www.bellwethermusic.net

blackcorvo

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Re: IC interchangeability idea!
« Reply #4 on: October 26, 2009, 04:30:51 PM »
usually thigs like that are made for changing the characteristic of the sound.

Just try building a Rat with a LM741 then try using the original LM308... you'll notice a HUGE diferrence in the sound.

its the same thing with the idea of using the 4558, famous because of the Tube Screamer, in place of a 741. but the pinout is totally different since the 4558 is a dual op-amp and the 741 is a single op-amp.

jacobyjd

Re: IC interchangeability idea!
« Reply #5 on: October 27, 2009, 02:02:43 PM »
You shouldn't really see any difference in changing opamps. Nothing more significant than swapping out certain caps, diodes, or resistors. All the opamp really does is serve to boost the signal so it can be clipped harder by the diodes. Going out of the way to change opamps might be a cool exercise, but it's marginally useless when compared to the changes other mods to the circuit could accomplish.
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blackcorvo

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Re: IC interchangeability idea!
« Reply #6 on: October 27, 2009, 05:20:22 PM »
just try changing the op-amp in a RAT and you'll see what i was talking about  :icon_wink:

jacobyjd

Re: IC interchangeability idea!
« Reply #7 on: October 27, 2009, 08:32:57 PM »
The IC in a Rat is different than a basic switch between a 741 and a 4558 or TL072--in this case, you'd be switching from a single opamp to a dual opamp, of which you would use one. Aside from noise levels, it's essentially the same animal.
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