Great.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.
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?
That must be the first time I've seen +/- misused like that, well done! 😉🙂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?
Yes
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.
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.
It would be wrong to write - or + for an AC supply, although sometimes people use this to indicate opposite phase AC.spaceman5 said:On the left connector, they write on 2 different contacts "AC 9-12v",
but they don't write that 1 is - and 1 is +,
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.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?
- Status
- Not open for further replies.
- Home
- Amplifiers
- Chip Amps
- Why Some Amplifier Chips Require only Vcc,Gnd, While Others Require V+,Gnd,V-?