Why Some Amplifier Chips Require only Vcc,Gnd, While Others Require V+,Gnd,V-?

[KatieandDad]

When you see a circuit that is referring to +/- AC it is usually referring to a Centre Tapped Transformer - or a Twin Secondary Transformer wired as a CT.

 

[spaceman5]

When you see a circuit that is referring to +/- AC it is usually referring to a Centre Tapped Transformer - or a Twin Secondary Transformer wired as a CT.

Great.
Thank you very much.


In this drawing:

On the left connector, they write on 2 different contacts "AC 9-12v",
but they don't write that 1 is - and 1 is +,
so we should still assume that those are 2 different ends of the transformer,
and not the same wire being split to these 2 contacts, right?

 

[scottjoplin]

When you see a circuit that is referring to +/- AC it is usually referring to a Centre Tapped Transformer - or a Twin Secondary Transformer wired as a CT.

That must be the first time I've seen +/- misused like that, well done!

 

[scottjoplin]

Great.
Thank you very much.


In this drawing:

On the left connector, they write on 2 different contacts "AC 9-12v",
but they don't write that 1 is - and 1 is +,
so we should still assume that those are 2 different ends of the transformer,
and not the same wire being split to these 2 contacts, right?

Yes

 

[KatieandDad]

9-12V simply means that this circuit is pretty tolerant of voltage.

In general you will get better performance towards the upper limit in as far as the voltage swing will be greater before distortion creeps in.


It is VERY VERY unusual for an amplifier to have unbalanced supplies.


A dual secondary or CT transformer with secondaries between 9 and 12V will be fine. Personally I would go for 12-0-12V.

 

[spaceman5]

Thank you..

 

[DF96]

On the left connector, they write on 2 different contacts "AC 9-12v",
but they don't write that 1 is - and 1 is +,

It would be wrong to write - or + for an AC supply, although sometimes people use this to indicate opposite phase AC.

so we should still assume that those are 2 different ends of the transformer,
and not the same wire being split to these 2 contacts, right?

Yes, this is a centre-tapped secondary. They assume that people will know this when there are three AC contacts with the centre marked as 0 or Common.