Not sure which forum to put this is, but this seems as good as any.
Would there be any advantage to using an output transformer instead of an output cap for a NOS DAC? As I understand it, both block DC and allow AC through, but a transformer with a 1:1 winding should be able to do this while avoiding phase problems and a frequency rolloff. So, what is it I don't understand that would suggest that a cap is a better choice?
-d
Would there be any advantage to using an output transformer instead of an output cap for a NOS DAC? As I understand it, both block DC and allow AC through, but a transformer with a 1:1 winding should be able to do this while avoiding phase problems and a frequency rolloff. So, what is it I don't understand that would suggest that a cap is a better choice?
-d
Use a transformer, it can provide isolation for ground loops. You should however not allow dc to flow in the primary, so depending on the spdif driver topology you may need a cap. If you are using a reclocked FF to drive it I don't think the cap is necessary.
Kevin
edit typo
Kevin
edit typo
Depending on your analog stage there may be no need for coupling capacitor before primary windings. However, if there's more than 10mV DC offset (with a temerature drift), it could affect high frequency transfer to secondary - so you'll have to use the capacitor. If you have to use capacitor, there's no point in using transformer. Very good, for the money, is Black Gate type C 4.7uF / 50V.
Regards,
Extreme_Boky
Regards,
Extreme_Boky
Hi Boky,
He was talking about spdif output, not analog output, and here I think the transformer is superior in terms of providing isolation between the transport/player electronics and the outside world - ground loops, etc.
Kevin
He was talking about spdif output, not analog output, and here I think the transformer is superior in terms of providing isolation between the transport/player electronics and the outside world - ground loops, etc.
Kevin
Extreme_Boky said:
It currently has BG type N 4.7uf/50V caps and I am trying to find soemthing to replace them. It is essentially between oil caps, Auricaps or RelCaps.
kevinkr said:
I meant on the analog end, sorry I wasn't clearer.
-d
ideally, a transformer should work great.
Practically, you're dealing with leakage inductance (hello, phase!), saturation at low frequency, core loss at high frequency, etc... And if you're driving the transformer with a voltage source (eg, an op-amp), you'll want to put a series C in there anyway.
Practically, you're dealing with leakage inductance (hello, phase!), saturation at low frequency, core loss at high frequency, etc... And if you're driving the transformer with a voltage source (eg, an op-amp), you'll want to put a series C in there anyway.
Sorry, I misinterpreted your question, seemed natural to me that this would relate to the spdif end and not the analog output end. Transformers are occasionally used and can sound very good, however a good one is going to cost more than a very good capacitor, a bad one may be worse than any capacitor you could find.. LOL
IMHO they make a lot of sense in I/V applications, but not much sense in a voltage source driven application unless you need galvanic isolation (LOL), need impedance transformation and/or want to drive a balanced line without any additional active circuitry. BTW the BG N type capacitor is pretty good, I would be surprised if the was a lot to be gained by replacing it with another type - I could be wrong.
Kevin
IMHO they make a lot of sense in I/V applications, but not much sense in a voltage source driven application unless you need galvanic isolation (LOL), need impedance transformation and/or want to drive a balanced line without any additional active circuitry. BTW the BG N type capacitor is pretty good, I would be surprised if the was a lot to be gained by replacing it with another type - I could be wrong.
Kevin
I have tried N type and wasn't impressed. Give C type a try... It is very close to 4.7uF / 200V AURICap I use in certain applications. I personally prefer Black Gate 4.7uF / 50 V C Type.
Regarding SPDIF output, I agree that using transformers for isolation and impedance matching is the best way to go. SCHOTT's are good and I tried couple - the lower leakage inductance - the better!
Regards,
Extreme_Boky
Extreme_Boky said:
Where does one get "C Type"? I have looked at http://www.kyoto-electro.com/ and Percy and neither list these?
http://www.partsconnexion.com/catalog/CapacitorsElectrolytic.html
8th from the top.
Regards,
Extreme_Boky
8th from the top.
Regards,
Extreme_Boky
Hi Jocko,
I intended to show my everlasting gratitude to you regarding the advise on pulse transformers in a separate thread discussing DAC's and its sections. They do make huge difference! SPDIF and receivers section would be dedicated to you and only you!
Thank you,
Extreme_Boky
I intended to show my everlasting gratitude to you regarding the advise on pulse transformers in a separate thread discussing DAC's and its sections. They do make huge difference! SPDIF and receivers section would be dedicated to you and only you!
Thank you,
Extreme_Boky
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