Euro Sequencer - TL074CDR selection

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eljay
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Euro Sequencer - TL074CDR selection

Post by eljay » Mon Feb 10, 2020 5:47 am

Just building the Euro Sequencer and I have a query about the TL074CDR that is required. I assume either a TL074CDR or TL074CDRG4 is ok to use? They have different supply voltage ranges, the TL074CDR is 7V to 36V, I'm assuming that is a 'total voltage range' i.e could be using +/- 12V giving 24V, or the G4 variant uses either +/-5V to +/-15V. I noticed in the schematic the supply rails are +/-15V throughout, should this be +/-12V given it is a Eurorack module?

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Synthbuilder
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Re: Euro Sequencer - TL074CDR selection

Post by Synthbuilder » Mon Feb 10, 2020 7:11 am

eljay wrote:
Mon Feb 10, 2020 5:47 am
I assume either a TL074CDR or TL074CDRG4 is ok to use?
I think they're the same part. It's probably just the packaging that they come in is different. It may also be due to differences between National Semiconductor and Texas Instruments parts. They're now the same company, TI, but some legacy naming conventions remain in place.
They have different supply voltage ranges, the TL074CDR is 7V to 36V, I'm assuming that is a 'total voltage range'...
Yes, that's right. Op-amps actually don't actually know what voltage is on their pins with respect to 0V. All they 'see' is the difference in voltage between the +ve and the -ve pins. Going above their rated voltage makes them overheat and/or die. Generally 36V is their maximum voltage and some pro audio gear will use +/-18V to get the biggest swing from the op-amp outputs. The datasheet for the TL074 doesn't actually state any difference between the G4 and non G4 part in the full specifications sections as far as I can see.
I noticed in the schematic the supply rails are +/-15V throughout, should this be +/-12V given it is a Eurorack module?
Yes. Mea culpa. My schematic application has a limited number of default power supply symbols and I hadn't got around to manually making new ones for this module. Everything schematic that came after uses a new set of +12V and -12V symbols. I could change them but I didn't think it would matter too much so have left them as they are. I will do so for any new revision of the boards.

Tony

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