Curcio TDA 1541 dac modification

Discussion in 'DIY Discussion' started by Eduard, Jun 28, 2015.

  1. Eduard


    Jun 28, 2015
    Likes Received:
    I am a new mermber from the Netherlands and i did end up here using google in search for modification of my Curcio TDA 1541 dac.
    It is a dac with a tube output stage and the topology is a bit similar to the Daniel preamp that was designed by Curcio as well.
    What i did do so far was replacing some 3 watt metal oxide resistors that are dissipating some power by mills wirewound resistors.
    Did replace 10mF caps that did serve as decoupling caps in the high voltage supply. One of them did kind of bulge because of being to close to one of the 3 watt resistors so i did move the new wirewound a bit further away from the cap.
    Later some of the new 10mF were replaced by B Gate which i still had in stock.
    Did replace the high voltage transformer, put a tube rectifier ( 6x4), a choke input with a common mode connected Lundahl choke, another Black Gate, then another Lundahl and finally another Black Gate.
    So to say a BIG transformation.
    I did order the parts for changing the low voltage power supplies into choke input too.
    Also did get 3 os con 470mF 20 volt to be mounted near the dac chip.
    The 14 caps around the TDA are all 100 nF 160volt wima mkp. I have some surplus candidates lying around but most of them are just to big.
    In some other forum i did read about people having good result for digital circuit using so called PPS caps made by Kemet, Rifa/Evox because they can be had in lower voltages you can have a higher value like 1000nF 100 volts. They are not cheap and they are a bit '' fat '' so will have to mount half of them on the soldering side but that is easy because they have longer leads than usual.
    Of course can also change some resistors in the circuit that dont get warm but coulkd do with better quality.
    Cannot publish the circuit because it is still being sold.
    I will try to attach some pics.
    Greetings, Eduard 20150626_204039.jpg 20150621_165341.jpg
    Eduard, Jun 28, 2015
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