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non-profit ver.3 TDA1541a DAC for limited budget diyers

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#1,244
hi korben69,

let me one by one post this new one.

I made four to five sample for test which one was lower noise, easy to upgrade.

finally I build this one.

This final version was same as your home computor. U can one by one upgrade. Not need to waste any PCB & chips.

photos show was cheapest SE version. totally contain 4 PCBs.

Power supply was was good, low noise & poweful, low ripple. but quite heavy. it cost total 36 pcs of 470uf BC caps parallel for the main supply.

there will had two IV & LPF PCB follow with the kit.
since one was active & another one was passive.

U can see there will had one PCB which was use two op-amp( everyone in one channel) pre fit into the 1541a PCB, another one was funish & test, But U need to buy two more single op-amp.

this is digital receiver PCB, use nickel base Nano amorphous core.
pls compare size of the EL34. U will know this kit was quite large in size & heavy too.

It will be same running in three mode.

1. NOS
2. NOS + re-clck
3. NOS + re-clock + DF SAA7220P/B

Digital receiver chip was CS8412-IS ( Industrial standard ) more stable!



thx

thomas
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#1,249
hi Tachyon,

this protype finally i hadn't production because I thought it can perform better!

I test this protype insingle chip, parallel two chips.

although I very close to match coupling caps. change resistors value ( because of parallel two chips). I still not satify!3

Take a look for parallel two chips.

thx

thomas
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#1,252
hi nordic,

I always did unexpensive or said cheap items.

don't worry for this!


THis protype had little bit area not good was IV,LPF was too close to 1541a. probably some people said or thought close more distance signal purity will be better. but... on the other hand for diyers will not flexible choose active or passive IV + LPF.
Another reason was tested lower noise in seperate IV+ LPF with 1541a PCB. Probably noise was from the ground area, some hum or interference was cause to catch noise. But after seperate the IV+ LPF with 1541a PCB. noise lower much more!


thx


thomas
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#1,254
tube output stage too easy to funish.
only a few parts.
so I hope diyers can diy by themselves.

Use diode rectifing & use one 5687 ( double triode ) one triode for one channel but 5687 running in HV & H(current) CF( athode follower condition. output impendance will very low.

I will supply full list of dale resistors for them.


thx


thomas
 
#1,259
hi all,

since nowadays 1541a( real one) & saa7220P/b all not easy to get.

I produce 20sets of this 1541a already.

for cheap single end funish kit.

Will USD 165 per set. include postage post to U.

If U like to get AD797 or OP42
USD 20 per pair.

for one cheap single end kit.

include.


check photo for the kit pls.


thx

thomas

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