UCD 180 input buffer

[RX5]

so i guess I JUST LEAVE the NE5532 in...

 

[beppe61]

I swear. This is the my last one post on the topic (more or less).
I got this final answer from Hypex to my questions.

Hi Giuseppe,
>> Can the UcD module actually work without the input dual op-amp ?
That is possible.
>> It has a voltage gain of 6 times and it can drive comfortably
>> impedances as low as 5kohm without particular problems.
The input impedance of the UcD modulator goes down to about 1k8.
>> Is a balanced input driver stage mandatory ?
UcD modules are balanced from input to output.
A non balanced input would not be beneficial for the total.


This mirrors completely the kind and extremely valuable advices I got in this 3D from friends.
Have a nice day !

beppe

 

[rotation]

Bruno said "his" discrete front ends sound better. What's most foolproof is leaving the stock op amp in, unless maybe you think you can outdo the performance of an AD8620 ...

Personally I would not be too quick to think I can simply download whatever schematic from the web and slap it in there, and honestly expect some improvement. No way. It'd have to be taken a little more seriously.

Hmmm, i think i metioned somewhere that 990 discrete op amp (from kit) sounds MUCH better if done with kit. I tried doing it on a veroboard and result was much worse than anything i heard before
So if you are not really experienced don't even think of outperforming TL, AD, NE with your design.
I never heard ucd from Hypex, but i think reason for mods is curiosity, not bad design by Hypex. So don't worry too much about mods. I think it's not so easy to outperform Hypex's design..But it's worth trying it, that's DIY, isn't it?

About 990 op amp: This design is proven by many recording studios around the world. Its the hearth of some most famous designs. It sounds excellent as it is, and outperforms commercial AD like op amps. I don't say AD and other op amps used mostly by audiophiles are not good, but by my experiences professional stuff is always much better. It's always possible to add nice tube preamp or even input transformer if some color is needed.

Regards from Miha

 

[gl]

Hi Daveis,

In your case the DAC1 should be able to drive the UCD modulator directly. It I were in your place I would try it. Let us know how it turns out.

Graeme