TDA7293 pcb from eBay

Stunt · 17th December 2011, 09:43 AM

Hi! I want to buy this PCB from eBay:
eBay - New & used electronics, cars, apparel, collectibles, sporting goods & more at low prices
So here is the problem. There is no schematic, or component list. I don't want to buy the KIT because I already have 2 TDA7293. Does anybody have schematic, component list of this specific board? If anyboy bought whole KIT he must got installation instructions, so if there is anyone have this please fell free to scan or picture it and upload here. Thanks

AndrewT · 17th December 2011, 10:20 AM

You either pay for customer service or you choose not to.

If not then you have to invest your time in determining what you want from your project.

Stunt · 17th December 2011, 02:14 PM

I asked him but he doesn't give the instructions without buying the whole KIT.

! · 08:57 PM

It shouldn't be too hard to wing it, to build without a schematic specific to that PCB.

Look at the TDA7293 datasheet, it has a schematic and suggested parts values. Compare to same place in the circuit on the PCB, but note the PCB component lead spacing, capacitor diameters, etc so the parts you order fit in the space available and the silkscreen outlines.

The PCB alone is $6 while the whole kit is only $26. By the time you add the cost to buy one or a few pieces each of the components needed, I doubt you save much money by already having the two amp chips, it's not much of a price difference relative to the time and cost to add the rest of the parts for a complete amp. You could resell the spare chips on ebay or in an audio For Sale forum.

On the other hand, instead of paying the shipping charge it seems like as good a value to get the entire kit with the power supply board and components too for only $9 more. This takes away a lot of the DIY, but so does being limited to someone else's PCB design.
http://www.ebay.com/itm/New-TDA7293-...item3362d8855e

harryz33 · 17th December 2011, 09:55 PM

I found this chip in a 100W subwoofer amplifier for a philips home cinema, 'tis alright, distorts quite a bit, you will need a large heatsink as well.

Minion · 19th December 2011, 08:46 PM

I have bought that PCB before and the Schematic that came with it was different than the Layout , which is very common on boards bought on e-bay , at least in my experience ......

Grega · 21st December 2011, 07:50 AM

Hi
Unfortunately they don't appear to have a schematic
I can tell you that the polar capacitors are all 22uf
the small non polar caps on either end are 0.1uf
the two non polar caps in the middle are 1uf
the rest of the resistors are exactly as per the tda7293 datasheet believe it or not - 680ohm, 22k and 10k - the number of what you install / don't install depends on the config you are using (ie: BTL / OCL)
i've bought stuff from hi-fi spot - (6n3 valve preamp, tda7293 boards and pots before) and no issues whatsoever - the quality of the boards is quite good
as AndrewT suggested, for $5USD for a board you're getting what you pay for -
i hope this helps you.

! · 21st December 2011, 10:46 PM

Quote:

Originally Posted by harryz33

I found this chip in a 100W subwoofer amplifier for a philips home cinema, 'tis alright, distorts quite a bit, you will need a large heatsink as well.

I'd imagine the majority of the distortion is just wrong gain setting vs (budgetized) power supply they used... or eventual capacitor degradation from longer term heat exposure which is arguably same thing, a budget based design decision.

harryz33 · 22nd December 2011, 09:47 AM

Thats true, nearly everything on the board get toasty, resistors, capacitors, the transformer, the chips. And I did buy it second hand, so it probably sounded quite good at the start; now I just use for testing subs to see if they work.

17th December 2011, 09:43 AM	#1
Stunt diyAudio Member Join Date: Aug 2011	TDA7293 pcb from eBay Hi! I want to buy this PCB from eBay: eBay - New & used electronics, cars, apparel, collectibles, sporting goods & more at low prices So here is the problem. There is no schematic, or component list. I don't want to buy the KIT because I already have 2 TDA7293. Does anybody have schematic, component list of this specific board? If anyboy bought whole KIT he must got installation instructions, so if there is anyone have this please fell free to scan or picture it and upload here. Thanks

17th December 2011, 08:47 PM	#4
! diyAudio Member Join Date: Jun 2005 Location: Midwest	It shouldn't be too hard to wing it, to build without a schematic specific to that PCB. Look at the TDA7293 datasheet, it has a schematic and suggested parts values. Compare to same place in the circuit on the PCB, but note the PCB component lead spacing, capacitor diameters, etc so the parts you order fit in the space available and the silkscreen outlines. The PCB alone is $6 while the whole kit is only $26. By the time you add the cost to buy one or a few pieces each of the components needed, I doubt you save much money by already having the two amp chips, it's not much of a price difference relative to the time and cost to add the rest of the parts for a complete amp. You could resell the spare chips on ebay or in an audio For Sale forum. On the other hand, instead of paying the shipping charge it seems like as good a value to get the entire kit with the power supply board and components too for only $9 more. This takes away a lot of the DIY, but so does being limited to someone else's PCB design. http://www.ebay.com/itm/New-TDA7293-...item3362d8855e Last edited by !; 17th December 2011 at 08:57 PM.

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17th December 2011, 10:20 AM	#2
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	You either pay for customer service or you choose not to. If not then you have to invest your time in determining what you want from your project.

17th December 2011, 02:14 PM	#3
Stunt diyAudio Member Join Date: Aug 2011	I asked him but he doesn't give the instructions without buying the whole KIT.

17th December 2011, 09:55 PM	#5
harryz33 diyAudio Member Join Date: Nov 2011	I found this chip in a 100W subwoofer amplifier for a philips home cinema, 'tis alright, distorts quite a bit, you will need a large heatsink as well.

19th December 2011, 08:46 PM	#6
Minion diyAudio Member Join Date: May 2006	I have bought that PCB before and the Schematic that came with it was different than the Layout , which is very common on boards bought on e-bay , at least in my experience ......

21st December 2011, 07:50 AM	#7
Grega diyAudio Member Join Date: Sep 2011 Location: Hoppers Crossing VIC	Hi Unfortunately they don't appear to have a schematic I can tell you that the polar capacitors are all 22uf the small non polar caps on either end are 0.1uf the two non polar caps in the middle are 1uf the rest of the resistors are exactly as per the tda7293 datasheet believe it or not - 680ohm, 22k and 10k - the number of what you install / don't install depends on the config you are using (ie: BTL / OCL) i've bought stuff from hi-fi spot - (6n3 valve preamp, tda7293 boards and pots before) and no issues whatsoever - the quality of the boards is quite good as AndrewT suggested, for $5USD for a board you're getting what you pay for - i hope this helps you.

22nd December 2011, 09:47 AM	#9
harryz33 diyAudio Member Join Date: Nov 2011	Thats true, nearly everything on the board get toasty, resistors, capacitors, the transformer, the chips. And I did buy it second hand, so it probably sounded quite good at the start; now I just use for testing subs to see if they work.