TDA1545 – possible to piggy back?

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Hi all,

I have built a TDA15454 DAC (NOS with passive I/V) with the battery PSU suggested by Kuei Yang Wang at post #21 in this thread:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=15551&highlight=

As for the TDA1545, just to put some cats among the pidgeons, I came across an interesting circuit from a French On-Line Mag, originated in the "dustcircle" of Pierre "Mr. MDI" Johannet for modding the Philips and Marantz Players using TDA1545 output Stages (Philips CD71X/72X and Marantz CD3X/4X) which I have attached.

You could use three "D-Cell" NIMH Batteries in this circuit, taking care to have a suitable "standby/float plus fast" charger which is simply disconnected when the Player is unmuted. Given the very low current Draw of this circuit you would likely get 2 - 3 Month battery life out of three non-rechargable high performance batteries, so completely omiting the charger and all may also be an option.

This would likely make for a VERY cost effective modification for the Philips and Marantz Players of this type, elimiating any active output Stage. Not shown in the Schematic are the Output Coupling Capacitors.

Oh, before I completely forgte, for adventerous souls, you could use a simple Silicon Diode (1N400X for example) string where each battery is replaced with three diodes as supply. Simply feed this diode string with a few 100mA current (from an LM317 connected as current source and a seperate mains supply) and things should work quite well to, you could even seek out adjustable references that can handle a few dozend mA and can supply 1.5 to 1.8V. In all cases I'd probably place one each BG NX-HiQ or Sanyo Os-Con on the Reference and Supply pin of the TDA1545 to ground.

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


My question is whether the TDA1545 can be operated in piggy back mode, and if so, what changes to the Iref & Vref (or anything else) would be needed. Also, how many 1545 chips can be piggybacked?

Cheers,

Joe
 
Hi Michael,

Thanks for reply. I have seen that thread and have built a 8 x tda1543 Dac (DDDac) (and an 8 x TDA1543A for EIAJ from a Sony CDROM)

The requirements for I/V conversion for TDA1543 are a bit different to TDA1545. I don't know enough to know whether TDA1545 can be used in parallel, or whether the particular I/V requirements for TDA1545 prevents parallel operation.

At present I am using a single TDA1545 with passive I/V and battery (for the moment).

I remember reading something on a DIY website not so long ago that was sceptical about TDA1545 in parallel, but I can't find the article now.

Cheers,

Joe.
 
Hi,

this is the output part of the 1545: what happens when you keep R 4 (for each dac a separate one) as is and adjust R3 for the same reference voltage as before? When you stack these devices you need more current for the additional dacs - the voltage drop at R3 will be higher. So lower the value...

michael
 

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Hi Mauricio,

I would say that the TDA1545 ( after just a few hours of operation) has a slightly more refined midrange than the TDA1543 and presents the female voice with a little more clarity.

I think the TDA1545 has a little more depth in the soundstage, although I don't think that this is major consideration.

My TDA1543 DAC uses Black Gate N output caps and Riken resistors while the 1545 uses Elna cerafines and Holco resistors. I don't know how these differences affect the relative sounds. My suspicion is, not much.

There are several other threads on this forum where people have expressed various opinions about the relative merits of TDA1543 vs TDA1545 (and TDA1541) posted by DIYers like jean-paul, Elso Kwak, Peter Daniels and Kuei Yang Wang (Thorsten Loesch) and others. They make interesting reading.

Personally, I could live quite happily with either 1545 or 1543, but prefer 8 x 1543 because of its higher output and more dynamic, if slightly less refined, sound.

Hope that helps.

By the way, I haven't yet got around to trying the suggestion of michael in post #4 above to see if I can piggy back the 1545. I hope to be able to try it this weekend, or next week.

Cheers,
 
Thanks Joe!
Maybe this guy Yeo at:
http://diyparadise.com/dackit/1545bdackit.html
will know if they can be biggy-backed. ;)
TDA1545 with a CDPRO transport. Maybe the ultimate project for me :D

>>>TDA1543 DAC uses Black Gate N output caps and Riken resistors <<<
I too like the Riken, to increase warmth and presence wich the DDDAC has already. Did you try increasing capacitance here?

>>>and Kuei Yang Wang (Thorsten Loesch)<<<
Do you mean they are the same person? I allways read his comments with fruition. This guy knows about what is he talking about :bigeyes:

Greetings
Mauricio
 
Hi Mauricio,

>>>TDA1543 DAC uses Black Gate N output caps and Riken resistors <<<
I too like the Riken, to increase warmth and presence which the DDDAC has already. Did you try increasing capacitance here?

The DAC with Black Gate N 4.7uF caps uses TDA1543A chips. 1543A accepts EIAJ or Sony format.

I have also built a DAC with 8 x TDA1543 with Crystal receiver 1543 accepts I2S from Crystal. This uses 220uF Elna Silmics bypassed by 2.2uF Axon polyprop and .022uF Wima polyprop and I/V with Vishay resistors. I like that combination but it seems to me that the 8 x TDA1543A with 4.7uF BG N, with no bypassing, has a slightly tighter and more articulate base.

This is not necessarily a straightforward comparison because the 1543 is fed with I2S from the crystal (Tent XO reclocking as per Doede DAC) and uses Rotel RCD965BX as transport, while the 1543A is fed EIAJ directly from the Sony chip with no reclocking. My preference is for the 1543A and Sony from NEC CDR.

I intend to reclock the NEC, one of these days.

By the way, I am currently using a single TDA1545 (with Elna Cerafine and Holco) in place of the 8 x 1543A DAC with the NEC CDR and there is not not so big a difference between the 1545 and 1543A as there is between the two versions of 1543. It could have something to do with the Sony chip in the NEC outputting EIAJ and no receiver between that and the DAC.

All of the above variations use passive I/V.

>>>and Kuei Yang Wang (Thorsten Loesch)<<<
Do you mean they are the same person? I allways read his comments with fruition. This guy knows about what is he talking about

Yes, they are one and the same. (Just as an aside, Kuei [Thorsten] is not wildly enthusiastic about passive I/V for TDA1545 and has offered a valve output which I might try, one of these days,)

Something else to think about. I have a CDP which uses a TDA7310 decoder with 12S output. I am building a new power supply and will use the same 8 x TDA1543A DAC board but replace the 1543A tower with 1543 chips, and then see how that combination compares with EIAJ direct. The Phillips transport can also be rechecked with a Tent XO, (11.2xxx).


Cheers,
 
Hi Mauricio,

QUOTE]TDA1545 with a CDPRO transport. Maybe the ultimate project for me
[/QUOTE]

I think the CDPRO outputs I2S while the TDA1545 (and TDA1453A) accepts only EIAJ. There have been some EIAJ to I2S conversion schemas offered on this forum, but you might be a better advised to use an I2S DAC such as TDA1543, TDA1541 or any of the other I2S DACs that have been posted on this forum.

You could do a search under CDPRO as starter. I know that Peter Daniels has initiated a thread on the making of a CDPRO and there are several others - but I can't direct you to the threads.

There will be at least one that suits your skill/budget/perseverance level.

I have chosen TDA1543/A and 1545 because of my low skill/budget but high perseverance level. Perth is also one of the most isolated capital cities in the world and getting parts here is a problem and postage is costly, so I tend to gravitate to the projects with a low parts count. :D

Cheers,

Joe:
 
Dear Joe:

Thanks for the answer. You go too fast for me :xeye:
I'll have to decode your thoughts...

>>>I think the CDPRO outputs I2S while the TDA1545 (and TDA1453A) accepts only EIAJ<<<

Sorry, I was thinking about TDA1541 perhaps. :eek:


>>>Perth is also one of the most isolated capital cities in the world<<<

I quite understand you! South Chile is not the center of the DIYer activity neither :mad:
Glad we have the Net to increase our ambition ;)

Good luck!
Mauricio
 
Bravo! Peter...

Your 16*1543 DAC is great!
Maybe I will try this next.
You had to halve R load, right?
VDC at pins 6/8 is the same 3.85V?
Have you mesured the max output from it? I have a nice TVC ;)

I liked your PS to Tent's clock. It doesn't seem so difficult.
I use a 36Ah battery :D

I suspect your long wires from tower to PCB. Have you tried vertical PCB + horizontal tower directly soldered? Maybe from the bottom... :angel:

Congratulations again...
When I grow up I want to be like Peter ...:D :D :D

Mauricio
 
Re: Bravo! Peter...

maxlorenz said:

You had to halve R load, right?
VDC at pins 6/8 is the same 3.85V?
Have you mesured the max output from it? I have a nice TVC ;)

I liked your PS to Tent's clock. It doesn't seem so difficult.
I use a 36Ah battery :D

I suspect your long wires from tower to PCB. Have you tried vertical PCB + horizontal tower directly soldered? Maybe from the bottom... :angel:

Congratulations again...
When I grow up I want to be like Peter ...:D :D :D

Mauricio


the formular for the resistors is on Doede's site - it's actually 137 ohms with 16 DACs. I first ran it with 270 and it sounded great until I hit a CD that was recorded at -0db - ouch!

The PS for the clock is Guido's spec with some changed resistors because his spec didn't work - search this forum for the thread. How the hell do you charge that monster battery? Even the 18ah lasts almost 20 hours with 16 chips :)

The wires moving the tower were a thing I was worried about but I cannot hear a difference between the tower on the PCB and moved 2" off to have better cooling. I tried all sorts of angle mounts and decided that a custom "dongle" with a 8-pin socket would be the best solution for cooling. The thing pulls a full amp - can't mess with the heat generated. I may wrap the wires for the next DAC I am building in ERS paper, but that's really not a concern compared to the heat generated in there. The case is only 40mm so vertical PCB is no go, unless I custom build one. Actually, given I moved most of the power supply parts off the board, that may be a solution in the future. Doede himself is working on an evolution of the DAC with mudular boards for folks wanting some features but not others. That may shrink the core board enough to fit it horizontally next to a large heat sink like the one I am using

The output is still set to 3.85v on pins 6/8 - sounds best with the 16 chips as well. No idea what the current is but it's substantial given you can easily drive Sennheiser 650s and get solid bass.

Peter
 
Hi Peter,

Your 16 X TDA1543 DAC is very impressive and I like the heat sinks for the DAC tower.

However I am interested in elminating the SPDIF interface alltogther and using either I2S or EIAJ from the transport to feed the DAC chips directly. The idea is to keep the DAC within the transport box and separate the power supply into another box.

At the moment I have chosen the 1453 for I2S and 1545 for EIAJ. I think they sound different enough, but equally enjoyable, to make this project interesting.

Cheers,
 
pburke said:
while you're getting ready to rebuild your DDDAC - here's a link to what I did over the last few months to "rebuild" mine. Maybe a little over the top given your comments about budget, but before you build a new DAC that sounds just like the old one, this link may give you some new ideas:

My new 16-chip DDDAC

Peter


Interesting project. Just wondering where do you get the aluminum heatsinks for the DAC tower?
 

Dino-Indo

Member
2007-01-19 6:18 am
Tried to Piggyback up to 3x TDA 1545A chip and confirmed:
1) dynamic improved a lot
2) clarity and wider soundstage also improved

1 suggestion only: please decouple the Vdd to GND as well as Vref to GND using polycaps (at least 22pF plus a ferrite bead)..

Enjoy!!:cool:
 
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