"Stacking" TDA1543

john65b · 5th October 2006, 03:53 AM

Hey all,

I have basic question...I have a single TDA1543/CS8414 setup and quite happy. I noticed a number of designs that have nore than one TDA1543 (up to eight) to improve sound quality and wonder if it would be worth it to literally Stack another one or two on top of the existing one I have...the same pins would be soldered t the same pins of the TDA1543 below it...these TDA1543 chips can be had quite cheap, but wonder if anyone done it, or worth it. One such design is attached from this site...

My power supply is 12V and 1.5A, so I think I have enough "juice" for another 5V TDA1543...

lucpes · 5th October 2006, 09:49 AM

Quote:

Originally posted by john65b
Hey all,

I have basic question...I have a single TDA1543/CS8414 setup and quite happy. I noticed a number of designs that have nore than one TDA1543 (up to eight) to improve sound quality and wonder if it would be worth it to literally Stack another one or two on top of the existing one I have...the same pins would be soldered t the same pins of the TDA1543 below it...these TDA1543 chips can be had quite cheap, but wonder if anyone done it, or worth it. One such design is attached from this site...

My power supply is 12V and 1.5A, so I think I have enough "juice" for another 5V TDA1543...

AFAIK they draw 60mA per chip, so you could get away with 4 or more pieces... watch out for cooling issues (maybe stick pieces of copper sheet between them). Additional cooling is mandatory with more than two stacked.

Should be ok, but you need to change Vref and the IV resistors as the Iout would add.

Here's a nice tool I discovered on another forum for calculating the resistors.

Spartacus · 5th October 2006, 10:41 AM

Go for it. I've got 16 in parallel.

Puffin · 5th October 2006, 11:30 AM

What difference do say 16 makes, say to one or eight ? I have a Dac with 8 in it. Is it worth adding 8 more i.e 2 lots of 8 to make 16 ?

Spartacus · 5th October 2006, 11:36 AM

16 is not a massive difference over 8. You can hear a little more.

Is it worth it? Yes, if you can deal with the practical problems.

john65b · 6th October 2006, 01:53 PM

Wow, that was a quick response...

I have ordered a few more TDA1543...and found a newer TDA1543 calc that corrects the Vout...Thanks lucpes...your ver was 24, newer ver is 28... I think...

Anyway, I have read that a few people run their TDA1543 at voltages above 5V (mine is 5V)...upwards of 8 - 9V with heatsink to increase the output to thier pre...I have a low gain tube amp and can use the input boost...

So I noticed my Vref and IV resistors are both 1K (single TDA1543) ....and according to the calc, if I stack one more TDA1543 and leave the 1K resistors as is, I have the same effect as running one TDA1543 at 8V (same increase in the output), and with two chips, it should sound "better"?

Is this correct and recommended?

To use a total of four stacked (I bought three more), I understand I would definitely need to modify the resistors, but I decided to try one first without changing any resistors...if recommended...

Here is a link to what I have...

http://us.hifidiy.net/Article.asp?ArticleId=152

Pretty simple, cheap, and basic, and I am liking it with my stepped attenuator on a few Gainclones, Tripaths and UCD180 amps...

Thanks all

lucpes · 6th October 2006, 02:23 PM

Quote:

Originally posted by john65b

I have ordered a few more TDA1543...and found a newer TDA1543 calc that corrects the Vout...Thanks lucpes...your ver was 24, newer ver is 28... I think...

Could you please attach is to this thread?

john65b · 6th October 2006, 02:35 PM

Here you go...

lucpes · 7th October 2006, 06:33 AM

Thanks.

hagtech · 7th October 2006, 06:47 AM

Uh, you can't just willy-nilly add stacked chips. You have a fanout issue here. First, you take care of the obvious power supply needs.

But then you have to drive the logic inputs. Will need some sort of heavy duty buffers to drive them properly without totally screwing up the rise/fall transitions. I'd suggest using a small series resistor for each receiver pin. Can be 100 ohms or so. Also helps separate the distributed capacitive load. Anyway, bottom line is you'll have to redesign the BCK, DIN, WCK drivers too. Proper fanout and clean terminations are in order.

Regardless, one problem you will have is different propogation delays. The output from each DAC will switch at a slightly different time. They're all close, but if in parallel, you will now add some jitter to the output currents. Or basically, not-so-clean edges. Filtering can help this problem.

Anyway, just paralleling devices can get you into a world of trouble. You have to appropriately design everything around the converter (on either side) to accommodate parallelism.

Of course, if all you are looking for is more volume, then go for it.

jh

7th October 2006, 06:33 AM	#9
lucpes diyAudio Member Join Date: Dec 2003 Location: Iasi	Thanks. __________________ Deep down inside.

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5th October 2006, 10:41 AM	#3
Spartacus diyAudio Member Join Date: Jan 2002 Location: Cheltenham	Go for it. I've got 16 in parallel.

5th October 2006, 11:30 AM	#4
Puffin diyAudio Member Join Date: Feb 2006 Location: U.K	What difference do say 16 makes, say to one or eight ? I have a Dac with 8 in it. Is it worth adding 8 more i.e 2 lots of 8 to make 16 ?

5th October 2006, 11:36 AM	#5
Spartacus diyAudio Member Join Date: Jan 2002 Location: Cheltenham	16 is not a massive difference over 8. You can hear a little more. Is it worth it? Yes, if you can deal with the practical problems.

6th October 2006, 01:53 PM	#6
john65b diyAudio Member Join Date: Jan 2005 Location: Chicago	Wow, that was a quick response... I have ordered a few more TDA1543...and found a newer TDA1543 calc that corrects the Vout...Thanks lucpes...your ver was 24, newer ver is 28... I think... Anyway, I have read that a few people run their TDA1543 at voltages above 5V (mine is 5V)...upwards of 8 - 9V with heatsink to increase the output to thier pre...I have a low gain tube amp and can use the input boost... So I noticed my Vref and IV resistors are both 1K (single TDA1543) ....and according to the calc, if I stack one more TDA1543 and leave the 1K resistors as is, I have the same effect as running one TDA1543 at 8V (same increase in the output), and with two chips, it should sound "better"? Is this correct and recommended? To use a total of four stacked (I bought three more), I understand I would definitely need to modify the resistors, but I decided to try one first without changing any resistors...if recommended... Here is a link to what I have... http://us.hifidiy.net/Article.asp?ArticleId=152 Pretty simple, cheap, and basic, and I am liking it with my stepped attenuator on a few Gainclones, Tripaths and UCD180 amps... Thanks all

7th October 2006, 06:47 AM	#10
hagtech diyAudio Member Join Date: Mar 2002 Location: Hawaii	Uh, you can't just willy-nilly add stacked chips. You have a fanout issue here. First, you take care of the obvious power supply needs. But then you have to drive the logic inputs. Will need some sort of heavy duty buffers to drive them properly without totally screwing up the rise/fall transitions. I'd suggest using a small series resistor for each receiver pin. Can be 100 ohms or so. Also helps separate the distributed capacitive load. Anyway, bottom line is you'll have to redesign the BCK, DIN, WCK drivers too. Proper fanout and clean terminations are in order. Regardless, one problem you will have is different propogation delays. The output from each DAC will switch at a slightly different time. They're all close, but if in parallel, you will now add some jitter to the output currents. Or basically, not-so-clean edges. Filtering can help this problem. Anyway, just paralleling devices can get you into a world of trouble. You have to appropriately design everything around the converter (on either side) to accommodate parallelism. Of course, if all you are looking for is more volume, then go for it. jh

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