Nobels ODR-S

[zeta55]

Hi there.
I'm planning to build myself a Nobels ODR-S.
The schematic calls for two 4558S opamps. Looking at the schematic they seem to have an unusual pinout. I've looked at some datasheets of 4558S and none seem to have that pinout.
Could i change em with TL072:s?

Schematic here: http://www.schematicheaven.com/effects/nobels_odrs_overdrivespecial.pdf

/Krister

[new]

4558s is 9-SIP package.pls look at

http://www.fairchildsemi.com/ds/KA/KA4558.pdf

you can use dual opamp 8-DIP Package but you have to design pcb for them.

[Mark Hammer]

Or http://keccorp.ru/data/cat_products/M_kia4558s.pdf

The 9-pin SIP equivalent of 8-pin DIP chips often has two, count 'em, TWO V+ pins.  Why, I do not know.  But it affords some flexibility in layout since they are parallel (i.e., you don't have to use both of them).

Were you to perf or vero a clone of this, using regular DIP chips, just substitute the functionally equivalent DIP pins for those on the SIP version.  So, 2 , 3, and 4 on the schematic become 1, 2, and 3 in "real life", and 8, 7, and 6 become 7, 6, and 5.

[zeta55]

Thanks for the replies, guess I'm a lousy googler

/Krister

[Mark Hammer]

Nah.  It wouldn't have been the first time that an "official" factory schematic contained erroneous information.  It was only reasonable to be puzzled.

[zeta55]

Here's a draft for the schematic.
Any thoughts about the omitted bypass switching, other obvious errors?



/Krister

[Mark Hammer]

Is the bias resistor on the + input to IC1A supposed to be 10k?   I know that's what it shows on the Nobels schematic, but that seems awfully low.  IN tandem with the 2k7 resistor, that would attenuate the signal.  So why attenuate immediately before a high gain stage intended to clip?

[Johan]

Is the bias resistor on the + input to IC1A supposed to be 10k?   I know that's what it shows on the Nobels schematic, but that seems awfully low.  IN tandem with the 2k7 resistor, that would attenuate the signal.  So why attenuate immediately before a high gain stage intended to clip?

..it could be for changing the slope in the filtering R6/C4?...

...and regarding 9pin SIL...they are oftern used in tight spaces, like inside mixers, between filter/EQ pots..I don't know if that is the reason, but I know from experience it makes them a lot easier to replace when doing repairs..symetrical and mirrored....if you get it in, it works..... no need to keep trak of orientation....
j

[slideman82]

Also, there are some 8IL 4558... try the 4558L or the one that come with Metalzones... M5218L, I think, it's the same.

[zeta55]

Thanks for the input everyone.
I'm gonna give it a go with the usual DIL8 package for the IC:s, and component values from the schematic.

/Krister

[zeta55]

Well, I finally completed my build. I removed the old schematic as I found some errors in it.
I've uploaded layouts and build instructions on my homepage for anyone who wants to give it a try.
Visit http://www.zeta-sound.se/




/Krister