Hoffman Amplifiers Tube Amplifier Forum

Other Stuff => Solid State => Topic started by: firemedic on February 05, 2011, 12:39:51 am

Title: Where's the notch?
Post by: firemedic on February 05, 2011, 12:39:51 am

I'm trying to build a tremolo pedal based on a NTE 858M opamp. I have to confess I have lousy luck building SS things, but it would help if the one I bought had a notch on it so I could orient it right. Anyone use these before?

Title: Re: Where's the notch?
Post by: sluckey on February 05, 2011, 11:07:13 am

Maybe you have one with that stupid beveled edge rather than a dot or notch? Like this...

Oops. Sorry. I just realized the beveled edge applies to the surface mount version.

http://www.nteinc.com/specs/800to899/pdf/nte858m.pdf

Title: Re: Where's the notch?
Post by: firemedic on February 05, 2011, 07:30:31 pm

It does have the little dot, thanks for that sluckey. I tried plugging it in both ways & the pedal doesn't work, see DIY tremolo.

Title: Re: Where's the notch?
Post by: 38Super on February 05, 2011, 09:43:33 pm

For a dip pkg, the dot is pin 1.  Typically, when you are looking at the dip pkg so that you can read the label normally, the lower leftmost pin is pin 1 and the pin opposite is pin 8.

cheers,

rob

Title: Re: Where's the notch?
Post by: firemedic on February 06, 2011, 08:34:43 am

Thanks gentlemen. Could I have fried it if I had in in backwards for a while?

Title: Re: Where's the notch?
Post by: sluckey on February 06, 2011, 09:04:29 am

Very likely. The power supply pins would have been reversed and the inputs/outputs would have been jumbled.

Title: Re: Where's the notch?
Post by: 38Super on February 07, 2011, 11:38:03 am

Quote

Thanks gentlemen. Could I have fried it if I had in in backwards for a while?

For future reference:

This probably doesn't help your current problem, but IMO, it is advisable to order several extra pieces when you buy opamps, transistors, diodes, etc.  It's like getting extra fittings when you start a plumbing job.  You'll have extra parts for replacement and might find you have parts for the next project.  I learned this the hard way and a few extra $$ is worth it IMHO.

cheers,

rob

Title: Re: Where's the notch?
Post by: firemedic on February 07, 2011, 11:42:39 am

Right you are. I did get an extra one & lo & behold the circuit works. Thanx guys!