SSL 4000G Why such Precision resistors?

[jwhmca]

See Schematic. R28,29 R30, 31, R32,33

The ** means .1% and the * means .5%

I think I can see why you would want a matched set going into IC5, but it seems you would "always want that" on any design... this is the first time I have seen that...

Is it just SSL trying to be HI-FI or what?

Any insight would be greatly appreciated... I'm a NOOB!

 

[ruckus328]

Not sure how old this schematic is - are they using smt resistors?  If so that would explain why, thin film will mostly only come in .1% & .5% tolerances.

 

[jwhmca]

This SSL is from the mid 80's... and they are through hole metal film "looking" 1/4 watt "looking"

 

[jwhmca]

I'm still trying to understand the function of IC6, IC14, IC7. Could you shed any light on what they do? I think I understand, but I would like another view point to see if I'm right.

 

[jwhmca]

Thanks! I was kinda right...

Why would you want IC6 to be the Polarity flip...? doesn't that happen at IC8? Maybe I'm missing what you are meaning with IC6

 

[jwhmca]

Ahhhh.... so the line gain control is using the opposite polarity to cancel out the signal?

Do you happen to know what type C15,16 are? they are strange metal boxes dipped with a blue coating just on the ends...

 

[jwhmca]

That seems awfully complicated for a gain control?