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USSA-5 PCB GB

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#565
Transformer question

About the transformer. I have this heatsink for each channel. Dimension 20X21.5X11.5 cm and weighs 6,3 kgr. (6.300gr). Safe choice is 2X18V, but can i choose something bigger ?


Thank you
 

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#569
Oracle1 said:
About the transformer. I have this heatsink for each channel. Dimension 20X21.5X11.5 cm and weighs 6,3 kgr. (6.300gr). Safe choice is 2X18V, but can i choose something bigger ?


Thank you
Click to expand...

Hi Oracle1
I will suggest you stick with 2x18vac or use 2x 20vac max with your actual heatsinks if you want class A at 25Wrms into 8 ohms. Otherwise you will have turn down the bias current thus will reduce class A power. However you would have higher power in class AB mode. If you have 4 ohms speakers, to optimize class A you need more bias current so a reduced PSU voltage for same heatsink size.

Fab
 
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#571
Hello Oracle1

Good choice for the 5.1 version with no obsolete parts.

If you use the SLB please take into consideration that you will have probably 3vdc or so of voltage drop to the amp. if so you need about 2vac more (ex: 18 to 20) for the same desired voltage at the amp.
Unfortunately I was not able to ship your USSA5 pcb last week because of postal office reduced hours during confinement along with extended amount of work.... I have the envelope ready to ship since one week, so I am sorry. I will ensure to find a small window of time this week.

Same thing for the USSA5 pcbs of Nfsgame.

Fab
 
#572
Hello Oracle1
I forgot to consider that the SLB may have an ideal rectifier bridge. In this case you will get about 2vdc more. Thus I am not sure of the end voltage after voltage drop in transistors...you ate better asking peoples who have used the SLB because I have not.
Fab
 
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