CHIPS

[ldavid at lae.lad.gmeds.com]

> 
> >> 
> >>     Ok I have an Oberheim OB-Xa and I want to change the 741 & 1458 
op amps
> >>  I need to know if  LF-351 & LF-353 (I think) are direct replacements 
for the
> >>  741 & 1458. If they are replacements and I change the ones on the 
voice
> >> Boards what will it do.  I know the slew rates for the 741 & 1458 
sux.
> >
> >Hi again.  I should have put this in my last message...  I'm planning 
to do
> the 
> >same thing in general, i.e. replace the old opamps with better ones.  
I'll 
> >probably just go around the boards swapping them one at a time and see 
if/how 
> >the sound changes.  I can't answer your question, but I'll have to 
figure
> it out 
> >eventually.  If/when I do I'll let you know.  In general I'm expecting 
the 
> >bandwidth to improve and the distortion to go down.  Whether that
> "improves" the 
> >sound remains to be seen.
> >
> >ld
> >--
> >----------------------------------~~~~~~~*--------------~~~~~~~*    
> >Larry David                    "I no longer live, 
> >ldavid at lae.lad.gmeds.com        but Christ lives in me." 
> >
> 
> 
>     Thanks for the repley so , I guess the 741 = LF 351 and the 1458 = 
LF 353
> right?
> thanks again

The LF351 is definitely the single and the LF353 is definitely the double, 
but I don't know if the pinouts match the 741 and 1458 resp.  Here's the 
pinout of each according to Jung:

LF351:
1- offset adjust; connect to pin 5 via 10k pot w/wiper to V-
2- - input
3- + input
4- V-
5- offset adjust
6- output
7- V+
8- apparently not connected

LF353:
1- A output
2- A - input
3- A + input
4- V-
5- B + input
6- B - input
7- B output
8- V+

I'm sure someone on synth-diy can say whether these are the same pinouts 
as the 741 and 1458... (hint, hint :)

ld
--
----------------------------------~~~~~~~*--------------~~~~~~~*    
Larry David                    "I no longer live, 
ldavid at lae.lad.gmeds.com        but Christ lives in me."