Hi,
First time poster so bear with me please.
Decided to purchase a random cheap power amp to play around with after purchasing a tube Buffer/Pre amp.
Didn't really know about the whole DIY thing till after the purchase, which lead me down this rabbit hole..
New Finished TDA7293 Stereo Amplifier 100W Class AB HIFI Big Power AMP|power amp|amplifier 100wstereo amplifier - AliExpress
That"s the amp i purchased. Hasn't arrived yet so kinda looking forward to it.
Wanting people's opinion on the layout and design/performance when compared to my current main amp- Yamaha AX490.
I've just sorta grasped what a bridge rectifier is and through my readings has lead me to believe the design isn't very well implemented?
I have no real electronics knowledge but have done some minor tinkering in that department. Really curious on the topic at the moment.
First time poster so bear with me please.
Decided to purchase a random cheap power amp to play around with after purchasing a tube Buffer/Pre amp.
Didn't really know about the whole DIY thing till after the purchase, which lead me down this rabbit hole..
New Finished TDA7293 Stereo Amplifier 100W Class AB HIFI Big Power AMP|power amp|amplifier 100wstereo amplifier - AliExpress
That"s the amp i purchased. Hasn't arrived yet so kinda looking forward to it.
Wanting people's opinion on the layout and design/performance when compared to my current main amp- Yamaha AX490.
I've just sorta grasped what a bridge rectifier is and through my readings has lead me to believe the design isn't very well implemented?
I have no real electronics knowledge but have done some minor tinkering in that department. Really curious on the topic at the moment.
Hi Billy,
I do not know the AX490. The amplifier looks fine.
The TDA7293 is a fine chip. I can see very little from the photo. The amount of decoupling of the power rails (2x3300uF/50V per rail) is not exaggerated. Space for more if you want to add.
Good luck with the amplifier.
I do not know the AX490. The amplifier looks fine.
The TDA7293 is a fine chip. I can see very little from the photo. The amount of decoupling of the power rails (2x3300uF/50V per rail) is not exaggerated. Space for more if you want to add.
Good luck with the amplifier.
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Hi French,
Would swapping the boards to this
TDA7293 Mono Amplifier Kit Plate Fever Stage 100W Oversized Power Ultra Wide Power Double 12 to 40V
be a worthy upgrade? or not worth the extra expense?
Pros and cons?
Is that something that can be answered without transformer specs?
Would swapping the boards to this
TDA7293 Mono Amplifier Kit Plate Fever Stage 100W Oversized Power Ultra Wide Power Double 12 to 40V
be a worthy upgrade? or not worth the extra expense?
Pros and cons?
Is that something that can be answered without transformer specs?
Hi Billy,
The other module you propose has exactly improved that situation by using four 3300uF on each board.
You have already bought the amplifier so the two first amplifier modules are “for free”.
You can then either:
1) replace the two initial amplifier modules with the better ones proposed in your second posting, or
2) add two 10000uF capacitors and a rectifier bridge in the space between the existing amplifier modules.
1) is probably most straight forward while 2) may save you a bit of money and you can have even better decoupling.
The other module you propose has exactly improved that situation by using four 3300uF on each board.
You have already bought the amplifier so the two first amplifier modules are “for free”.
You can then either:
1) replace the two initial amplifier modules with the better ones proposed in your second posting, or
2) add two 10000uF capacitors and a rectifier bridge in the space between the existing amplifier modules.
1) is probably most straight forward while 2) may save you a bit of money and you can have even better decoupling.
Place the R/C link between output and input on the back side of PCB so you get as short feedback loop as possible. I also put extra dec cap on the back side of the PCB from ground pin to +/- V pins.
Decouple the input cap with Wima PP.
I have also seen that the back side (cooling side) of the chip is not perfectly flat, take a 1200 grit paper and a glass plate and rub it flat.
I also have a metal rod with screw on both sides pressing the chip firmly to the cooling fin.
With a FLIR heat camera i monitored chip temp before and after those mods, and managed to reduce the chip amp surface temp from 62C to 55C...
I also had self oscillation that was eliminated with shorter loop.
Decouple the input cap with Wima PP.
I have also seen that the back side (cooling side) of the chip is not perfectly flat, take a 1200 grit paper and a glass plate and rub it flat.
I also have a metal rod with screw on both sides pressing the chip firmly to the cooling fin.
With a FLIR heat camera i monitored chip temp before and after those mods, and managed to reduce the chip amp surface temp from 62C to 55C...
I also had self oscillation that was eliminated with shorter loop.