Please help a newbie...

[snails07]

Hi all, i'm just looking into building my first chip amp and i have a couple of questions.
What do i need to do differently to build a stereo amp rather than a dual mono amp. I have a transformer that i would like to use (24v) but do i need another one.
Any help appreciated....

[wakibaki]

A stereo amp is just a dual mono amp, depending on definition, with a few less components.

Use a stereo chip or 2 mono chips and a single PSU.

You don't need more than 1 transformer.

w

[lineup]

Depends a bit on that transformer you have.

If it is a stronger/bigger transformer, it may give good enough power for both channels.

If it is not that heavy transformer ( say less than 1 kilo )
you may benefit from buying another one. And use one for each channel.

If you buy 1 big 24 VAC transformer, to supply both left+right,
you probably save some money.
Instead of buying 2 smaller trafos. One for each channel.

Both options are possible and will work as good.

[AndrewT]

A monoblock is a single amplifier with one ground connection to the source equipment and one Safety Earth connection to the mains.

A dual mono keeps both amps completely separate but in the same case and usually uses a common connection to the Safety Earth.
The audio grounds are separated.

A stereo amp has two separate amplifying channels but the audio ground and the Safety Earth are common to both channels.

The grounding of the stereo and the dual mono are far more complicated than the mono block.

A dual mono cannot operate off the common secondary windings.
A four secondary transformer can isolate the two channels. The common transformer core defeats the true dual mono definition, but does achieve most of the attributes of dual mono if the transformer rating is high enough to satisfy both channels with little regulation.

A stereo amplifier can have a single dual polarity PSU or could have two dual polarity PSUs. A twin PSU run from common secondaries forces one to adopt single rectifiers in each dual polarity PSU. This demands that the zero volts (centre tap) is shared between the audio grounds of both channels.
Whereas a four secondary transformer allows two sets of twin rectifiers to be run and thus allows the audio grounds and PSU zero volts to be kept separate.

Suggestion:-
build a small monoblock.
Now experiment to see if you can ever achieve the low hum/buzz performance of the monoblock in a dual mono or stereo amplifier.