Sansui 9090db Filter Caps installed in Series Why?

[Vinnie Stu]

Filter Caps installed in Series Why?

 

[Scott Muni]

Never noticed that.
.

 

[petehall347]

plus and minus power supply . centre tap is ground .

 

[Scott Muni]

plus and minus power supply . centre tap is ground .

I see said the blind man...

 

[Hipocrates]

Filter Caps installed in Series Why?

http://buildaudioamps.com/power-supplies/

 

[dr*audio]

Schematic error. Should have a ground symbol where the 2 caps are connected together.

 

[Vinnie Stu]

No Error mine are wired in series from the factory. never seen this before. I installed new filter caps in parallel and it lit up the DBT like the Sun. Rewired in Series working Fine. just looking for a detailed explanation. thamks

 

[Hipocrates]

ok let's try

Error mine are wired in series from the factory. never seen this before.

Is one of the most common and simple unregulated power supply, did you read the link that I posted?

 

[Hyperion]

They're not wired in series, it just looks that way. You have a positive supply and a negative supply referenced to ground, (sometimes called a 'split rail' supply), the capacitors are positioned to smooth the +ve rail and the -ve rail. Obviously the -ve rail capacitor is wired with its positive to ground because ground is considered more positive than any negative voltage.

Very common n00b mistake to think they should be in parallel, even when it is clear the unit has been working wired as it is for decades.

 

[GrisPato]

They're not wired in series, it just looks that way. You have a positive supply and a negative supply referenced to ground, (sometimes called a 'split rail' supply), the capacitors are positioned to smooth the +ve rail and the -ve rail. Obviously the -ve rail capacitor is wired with its positive to ground because ground is considered more positive than any negative voltage.

Very common n00b mistake to think they should be in parallel, even when it is clear the unit has been working wired as it is for decades.

Yes, I do remember trying to understand that a few years ago. Luckily I never tried wiring them in parallel, at least not on purpose. I did wire one wrong polarity ( which did put them in parallel in a way ).
That's why it's important to read up a little on electronics while searching for the replacement parts .
On this topic. In the patent of Sansui for the X-balanced circuit design the engineers say that this wiring is like series for the load and for that with the X-balanced design they can half the capacitance. My understanding of electronics is not good enough to know if this is a correct claim but they did put a lott less capacitance in there X-balanced/ alpha amplifiers.

 

[Scott Muni]

While on topic of center tap transformers, why does the 9090db use four rectifiers. The 555a uses 2 and is a center tap.
What are the advantages/disadvantages of center tap versus non?

 

[Hyperion]

View attachment 2724000


While on topic of center tap transformers, why does the 9090db use four rectifiers. The 555a uses 2 and is a center tap.
What are the advantages/disadvantages of center tap versus non?

Some light reading on the subject.
https://www.allaboutcircuits.com/textbook/semiconductors/chpt-3/rectifier-circuits/

 

[llwhtt]

The 9090db uses a bridge rectifier, four diodes, to develop both + and - DC voltages. The 555a uses a full wave rectifier setup, two diodes, to develop only + DC voltage. The 555A is probably Capacitor Coupled on the output, I didn't look.

Craig

 

[Scott Muni]

The 9090db uses a bridge rectifier, four diodes, to develop both + and - DC voltages. The 555a uses a full wave rectifier setup, two diodes, to develop only + DC voltage. The 555A is probably Capacitor Coupled on the output, I didn't look.

Craig

Yes, cap coupled. Thanks.

 

[Vinnie Stu]

Thank You everyone