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I think when you use the dac as voltage output the regulation for parts of the dac has even greater influence on the sound .
Is the 470uf kz cap before or after the regulator ? if its before the regulator on the raw DC it maybe worth making it a little bigger, if its after the regulator it should be fine.
Hi Leo,
I think it proves once again that PH regs are just that much better than 3-pin regulators ;)
The 470uf KZ is before the regulator. Would a 2200uf cap be excessive (the current draw is about 530ma)?
Thanks,
By increasing the capacitance on the DC rail prior to the regulator you'll reduce the ripple voltage that the regulator has to deal with. Reduced ripple on the input will result in a reduced ripple on the output (even though it might be vanishingly small anyway).
With just over a half Amp of current draw i'd definately be tempted to increase the storage capacitance. 2200uf would result in less than a quarter of the ripple voltage on the DC rail, sounds good to me if you have a similar specification capacitor :)
Hi Alex,
2200uf should be fine used on the RAW DC if its nice and stiff, The shunts take more current anyway so the transformer is obviously meaty enough so not to sag too much on the output
If its ok now though with the 470uf you may want to leave it as is ;)
Hi Mark,
In fact I do have a 2200uf/35v Black Gate FK lying around somewhere. I'm not sure about the specifications, but from past experience BG FKs rarely disappoint. Now I just have to find it...
Regards,
Hi Leo,
The transformer is 72VA rated, but I'm only using "18V/1A" of it right now.
The sound is really good, but it could be a little bit more bassy and less straightforward. Hmm, I think I'll invite Miss Golden Ears over tomorrow and see what she thinks.
Regards,
Alex
Edit: Leo, can you please elaborate? I only got the part that "using a 470uf as main filter cap is okay", but not sure what you meant by "the shunts take more current anyway so the transformer is obviously meaty enough so not to sag too much on the output". Are the two sentences related, or am I just being a confused newbie?
Just a thought... since I'm using a LM317 reg module as a pre-reg to the Paul Hynes shunt, the ripple at the shunt's input should be quite low anyway (compared to "normal" rectified DC), right? If so, then perhaps I can get away with using a small filter cap on the 317 module. :confused:
Hi Alex,
I just mean't a shunt reg consumes more current than say a LM317, your linear psu is running it fine so upping the capacitance of the filter cap won't be a problem. Sometimes using high value capacitance with a weedy transformer can give poor results, yours is fine so 2200uf may even give you a bit more bass.
BG FK's are supposed to make great filter caps, It maybe worth giving it a go anyway if you can find it.
The only real way to know is try it, your now getting to the icing on the cake stage :)
Hi Leo,
I just found a 1000uf BG NX! Too bad that it's rated at 25v.
I'll keep looking for that 2200uf/35v FK. This is one of the rare occasions where I wish I was more organized... :doh:
Oh, and I disagree. I won't even have my new cake until September! ;)
Cheers,
Just wired up quick for testing out
Sweet :eek: Eager to hear your thoughts on the BufII/IVYIII!
Edit: Do you still plan on trying out Nick's tube output stage?