IC8 cmos vs ttl

[Kevin Heieis]

Hi, I wish to improve my HH rev c in future by swapping IC8 (TLO72) with a cmos opamp (such as a TLC272) as the HH document says would be best. Although, after explaining this to my dad, he profoundly argued (and researched) how a cmos will not be compatible with the inputs and outputs of a ttl (as shown in this document: http://www.allaboutcircuits.com/textbook/digital/chpt-3/logic-signal-voltage-levels/ [9th paragraph]), though it can use the same power supply. As the HH document says a cmos would work best in replacement of IC8, I would assume that there will be no problem, but I would like to hear from anybody with knowledge or experience of this.

Thanks,

-Kevin

[Davor]

TLO72 and TLC272 are operational amplifiers, that means analogue devices through and through, and not logical gates, so there are no compatibility issues.

[Qiaozhi]

Davor is correct. There are no TTL components in the HH design.
Your Dad's probably getting confused because he saw the +5V supply and make an incorrect assumption.

[kt315]

Kevin, I want to open you a true. any swapping of IC's in HH does not given nothing of to improve.
you can set better opamps, in your opinion, but all that is only futile attempts.
better read how a man set in Eric's Foster's housing a shield foil.
try something another way and do not waste time on a swapping.
http://www.findmall.com/read.php?34,...21#msg-2242321