question about boss hm-2

[kristoipher612]

h'llo everyone.  i have aquestion about the boss hm-2.  im having trouble finding the opamps used in it, and was wondering what i could use as a sub, or is there somewhere i can get those at. im pretty sure i got the schematic from aron's schematic page.  any info would be great.
thanks
kris

[Peter Snowberg]

Those are pretty standard dual opamps in SIP packaging.

Mouser has a couple of substitution possibilities for you....

NE5532: http://www.mouser.com/index.cfm?handler=displayproduct&lstdispproductid=482316&e_categoryid=268&e_pcodeid=5130
TL072: http://www.mouser.com/index.cfm?handler=displayproduct&lstdispproductid=483375&e_categoryid=268&e_pcodeid=51301
4558: http://www.mouser.com/index.cfm?handler=displayproduct&lstdispproductid=525646&e_categoryid=268&e_pcodeid=51303
4556: http://www.mouser.com/index.cfm?handler=displayproduct&lstdispproductid=526374&e_categoryid=268&e_pcodeid=51309
2114: http://www.mouser.com/index.cfm?handler=displayproduct&lstdispproductid=482553&e_categoryid=268&e_pcodeid=51309

I've never looked at the last two before so I'm assuming ther're standard units. See the data sheets for all units. The 5532 will probably be the overall best performer with the lowest noise, but it will suck more current than a TL072. Mix and match maybe?  The stock chips are a 4558 equiv.

One mod to try on yours which is easily reversable and requires no parts.... just jumper across the pair of Ge diodes and one of the 10K resistors that are attached to either end of the diodes.

I have mine on the bench right now.

[kristoipher612]

thanks a lot!  i was at work around 630 this morning and thought to myself "you know i really should have done a datasheet search before i posted that".  so i made myself feel a little slow on the pickup, especially when i was walking home and thought that it would be funny if they're just standard dual op amps.  and lo n behold...but really thanks again.  you guys on the board have been very helpful when i have a question.  maybe one day i'll be able to answer some of them too.  
kris