how to Using single secondaries transformer for snubber psu

[triast]

Dear All,


Please someone explain how to do wiring If I use 2 single secondaries transformer ( 0v and 24v) on snubberized psu.
I am really confused ...

 

[AndrewT]

Hi,
is that two secondaries on one transformer?

or

two transformers each with a single secondary?

 

[AndrewT]

Hello,
have you gone to sleep or AWOL?

 

[triast]

two transformers with single secondaries,

 

[AndrewT]

Hi,
yes, you can use two separate tranformers each with a single secondary.
Just wire each secondary into the ~ of the bridge rectifier.
Then connect one + of a rectifier to one - of the other rectifier.
This common connection is then taken to your audio ground. The other + and - become your PSU supply points.

 

[triast]

thank you🙂

 

[triast]

Hi,
yes, you can use two separate tranformers each with a single secondary.
Just wire each secondary into the ~ of the bridge rectifier.
Then connect one + of a rectifier to one - of the other rectifier.
This common connection is then taken to your audio ground. The other + and - become your PSU supply points.

I still confuse, look at this diagram below, it's a sch of chipamp.com lm3886 psu:

An externally hosted image should be here but it was not working when we last tested it.

All output voltages (v+ and V-) are from "+" of the bridge. And the PG+ and PG- are from "-" of the bridge.
Is this correct?

It's different if compared to the original carlos snubberised psu, because the "v+ conected with "+" of the bridge, and the V- conected with "-" of the bridge. Also with the PG+ and PG- are connected as the same way. The diagram :

An externally hosted image should be here but it was not working when we last tested it.

Also can compared to Mick Feuerbacher (dogbreath.de) psu:

So somebody could explain this matter to me please?

 

[runebivrin]

I think it can safely be said that the schematic at chipamp.com suffers from an attack of the cut-and-paste disease.

Rune

 

[triast]

I also find this sch on his website:

An externally hosted image should be here but it was not working when we last tested it.

So which one is correct?

above sch or this one:

An externally hosted image should be here but it was not working when we last tested it.

 

[AndrewT]

Hi,
post 7
1st schematic.
Top half OK.
Bottom half bridge reversed.

2nd & 3rd schematics are OK.

Post9
1st schematic OK.
2nd top half OK.
Bottom half reversed bridge.

However ALL the diagrams need further work on the grounding.

They all show the power 0V feed from the end of a string of connections going to the amplifier. This is inviting trouble.

The transformer to rectifier loop should be short and compact.
The rectifier to smoothing cap loop should be short and compact.
The 0V common should be connectted to either the + & - of the rectifiers or to the + & - of the first smoothing caps. A link from this 0Vcommon line should then go to the audio ground.
The amplifier should get it's 0V power connection from the audio ground NOT from the string of connections remote from the 0V common point.

 

[kvholio]

However ALL the diagrams need further work on the grounding.

I agree. Strangely when you wire up the pcb's from chipamp.com the way you are "supposed to" you end up with a grounding-scheme exactly like in the posted schematics.

AndrewT is spot-on with his recommendations, i strongly suggest you follow them.

With kind regards,

Klaas

 

[AndrewT]

Hi Kv,
I have never built a chipamp or one of it's PCB mounted PSUs.
Have you tried to compare the hum/buzz performance of the chipamp PSU with a hardwired version matching the good audio grounding recommendations?

 

[planet10]

So which one is correct?

I drew the BrianGT's maps.... i've always had trouble with the orientation of diodes... the top one is correct (at least that is the one in my most current master file) -- the 2nd one should never have gotten on his website -- it was a beta that didn't pass QC.

dave

 

[planet10]

I agree. Strangely when you wire up the pcb's from chipamp.com the way you are "supposed to" you end up with a grounding-scheme exactly like in the posted schematics.

My BrianGT/Peter Daniel GC was dead quiet... grounds came together on the amp board and the filte caps are right next to the chip....

I don't know if he is the origin, but this was Thorsten's recommended scheme when he 1st introduced the start of the "official" GCs on the Full Range Forum.

dave

 

[kvholio]

Hi Andrew, i didn't try the psu-pcb's.The high-capacity gc's i built always had ps-ground simply between the two big c's.
Keeping the gnd's separate at the psu, and joining them at the amp's pcb didn't make any sense to me, so i didn't try it.
I never experienced any hum-problems with my gc's .
It might be fun to try though and compare performance.Need some new rectifiers to do this.(don't ask how i blew up the old ones- i'm a klutz).
I will do the experiment and report back on this

This picture shows clearly that ps-gnd is not at the psu-pcb from chipamp.com:
http://www.briangt.com/gallery/snubber/ps_020

planet10, were you using these psu-pcb's with your gc's ?

With kind regards,

Klaas
(waiting on my ati-case for the ksa-clone 😀 )

 

[planet10]

planet10, were you using these psu-pcb's with your gc's ?

Yes.

 

[kvholio]

Thanks for the info Planet10. btw, your hum-free result doesn't surprise me.
i just see no reason to keep those gnd's separate at the psu.
Guess i'll have to try and see how it works out.

With kind regards,

Klaas

 

[AndrewT]

Hi Kv,

always had ps-ground simply between the two big c's.

Can I assume the important word is HAD and that you now HAVE the audio ground elsewhere?

 

[kvholio]

Can I assume the important word is HAD and that you now HAVE the audio ground elsewhere?

nope.
I HAVE my ps-ground(should i say 0V common ?) between the big c's and i HAVE my audio-ground elsewhere.

With kind regards,

Klaas