did you mannage to get rid of the noice? / Mikael

http://members.chello.nl/~m.heijlige...decoupling.pdf here is a direct link to the document i was refering to, it is good read / Mikael

Hello, I meant a Capacitor between the PS pins on the IC you use to drive the transformer, The Ic handles pretty high frequencies these will modulate the Current drawn from the chip if you dont decouple them (make a short circuit for high frequencies) you will have a very large loop...

you should decouple the ic /mikael

When can one expect these board to be ready for the public? /micke

Exactly I did not mean for the pot to be facing backwards but ofcourse the useage of a shaft / micke

more a question then a suggestion, why is the pot not in the back of the board?... it should free upp some space and shorten the signalpaths / micke

I belive the Torx input needs +5V and decoupling..buts that just about the only hazzle I have never used such a device so i dont know about the waweform quality jitter and such....and btw you could always use a transformer for just as good galvanic shielding.. Anyway I have made my Psu board...

Here is the layout of the psu board...still no eagle so its a converted bmp and no scheme.. Also it is made for a Talema encapsulated toroid so it needs a slight redraw to accomodate the Xformer I will be using for the NEC. Descripton: Discrete rectifier => elyt/bypas => CMC =>...

Okie, but still it hurs my soul not to overdimension the PSU ,) but the psu mounted Xformer do makes for a realy nice board, i also find a 55VA (30VA 12V 25VA 5V) witch just might fit, What are your Psu plans?...btw have you been under the "hood" of the NEC? /micke

Damn thats not good, not good at all I had my heart set on a nice PCB mounted toroid with 4x6v 30VA ....but that will not cut it... Well good thing I asked thoug I was going to buy the Xformer later today...guess I´ll have to change that now / micke

btw ..could you specify the current rating on the 12V /5V lines i need to buy a usable transformer for this drive and i dont have it nearby to check my self. thanks / micke

http://members.chello.nl/~m.heijlige...tml/dactop.htm I dont know how far you have come with that dac but i think you shoud check this one out 4layer boards are availble (!!) / micke

hello, how many RA1 thread do we need?...anyway the circuit used in the RA1 is very basic and they would have a hard time getting a patent ont that ... http://www.geocities.com/dip16amp/ I think that would be your best bet.. /micke

they are avilble at some specialised "video repair" shops, no problem there... I think the prices where set when the dollar was at its highest a year ago or so..now when it has plumeted, the distributor keeps the prices high since they have a monopoly on grado here and thus no reason to lower...

In sweden the RA-1 Costs about 700usd....(!!) / micke

4,7uF is about 6% of from the 5.0uF and i believe the tolerances on the original is 5% so the engineer in me also think it will be quite allright i think i even draw a copy of their board, anybody know who makes the decoupling caps?...(even if thats a stretch.. The bi*ch will be to make...

also, anybody know where i can get the proper measurments on the original mahogny box? /micke

so....then the only thing i cant get seem to be the 5.0uF caps (4.7uF solen is the closest i can get) ill have a SDSlabs and a pimeta to compare it with at about xmas time /micke

...So the resitors should be BC components? / micke

but the 4,7 to 5uf cap? thats about 5% off...thats about the tolerance of the caps?.. /micke

I think it is a much better idea to reclock in the dac instead of in the source since the spdif encode/decode will add much jitter /micke

sorry...ofcorse its easy when your in the know anyway i try to explane it in words (with my poor enlgish i might add) anyway the regulator is a TL431 shunt regulator this sets the reference for the pass transistor giving a cleen and stable 5V there is also a lc filter att the input giving...

okey....the 4,7uF is availble in sweden..and that should be close enough i believe... anyhow its harder to source the pot owerhere...everything else i can find... madisound dont accept paypal and so small orders ?.. /micke

i got it in eagle but it is brooken down for the moment, ill post it as soon as i fix it though but the circuit is pretty simple /micke