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DIY Stompboxes => Building your own stompbox => Topic started by: Barcode80 on October 29, 2006, 01:37:15 AM

Title: IC problem
Post by: Barcode80 on October 29, 2006, 01:37:15 AM
okay, so i built the 741 booster according to dragonfly's vero layout. everything worked out of the box, then i put it in the housing and nothing. then i realize (due to the excessive and rapidly rising temperature of the battery) that there must be a solder bridge somewhere shorting the battery. sure enough, after remelting and making sure there are no shorts, she fired up. however, i think i must have blown the LED when i miswired. no problem, i have plenty, so i put another in. then i put it all back together, stick in the chip, and now i think the chip is dead. i only had that one 741, so would anyone know the effects of using, say, a 4558 in this thing?
Title: Re: IC problem
Post by: pyrop on October 29, 2006, 04:20:03 AM
It won't work..
The 741 is a single opamp where as the 4558 is a dual.
Check the datasheets.
There is a heap of compatible chips that are available.
e.g. TL071, LM308 etc

pyrop ;D
Title: Re: IC problem
Post by: Barcode80 on October 29, 2006, 12:14:58 PM
what about the LM386? is it dual or single?
Title: Re: IC problem
Post by: R.G. on October 29, 2006, 01:13:47 PM
The LM386 is a power amp chip, not an opamp. It may or may not work even if the pinout is correct. It's a single.
Title: Re: IC problem
Post by: Peter Snowberg on October 29, 2006, 02:03:34 PM
The LM386 is also different in how it biases the inputs and how the gain is set. Unlike an opamp, it contains internal resistors for both of these functions.
Title: Re: IC problem
Post by: Barcode80 on October 29, 2006, 07:00:44 PM
cool, i've got a mess of tl071's on the way, i'll just pop that in. thanks for all your help guys!
Title: Re: IC problem
Post by: navales314 on December 31, 2017, 10:16:58 PM
Quote from: R.G. on October 29, 2006, 01:13:47 PM
The LM386 is a power amp chip, not an opamp. It may or may not work even if the pinout is correct. It's a single.
What about cr18818 same pinout and same work?

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Title: Re: IC problem
Post by: PRR on December 31, 2017, 10:22:36 PM
Welcome.

The cr18818 is _not_ an audio amplifier. It is a PWM control chip for switch-mode supplies. Not even slightly similar.

LM386/NJM386 is widely available all over the world at low price.
Title: Re: IC problem
Post by: navales314 on December 31, 2017, 10:39:46 PM
Quote from: PRR on December 31, 2017, 10:22:36 PM
Welcome.

The cr18818 is _not_ an audio amplifier. It is a PWM control chip for switch-mode supplies. Not even slightly similar.

LM386/NJM386 is widely available all over the world at low price.
So what will i do its hard to find same pinout of this IC cr18818?

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