Maybe give a try to the OPA1611 first, as I'm so very happy with it. I just don't like to talk by superlatives. 😛 It even costs nothing when you order it as a free sample 🙂
Then and only then you can have reason to be masochist enough to desire buying output transformers...😛
Then and only then you can have reason to be masochist enough to desire buying output transformers...😛
No, and I don't want to. I like active output stages, be them discrete or integrated. I don't want in the signal path a transformer that I can avoid.
That said, I say WOW too, bacause you have no idea of how good the OPA1611 is. 🙂
Also I don't want to have no clue if my DAC is outputting dangerous high frequency energy from the D/A conversion, unfilterered or not filtered enough by that transformer. 😉
Opamps filter a lot less than transformers ..... unless you add capacitors into the circuit of course. But wait! You can add caps around a transformer too!
I was talking of an existing DAC circuit, and whether it is wiser to tweak it by means of better opamps (so much better, in a few cases), or by removing the filter stage completely and using a transformer carelessly.. 🙂
It's simple to add a cap or two to a transformer if someone wants more filtering than the transformer already provides. Also, any active filter circuit is dependant on feedback, so as open loop gain runs out at high frequencies, so does the filtering ....
A quick update on the power supply thing.
I tried many different configurations the last days, but now I made my decision. This version sounds by far best to power my Super Pro 707.
It sounds better than all the other ones I tried, including various switch mode supplies, larger capacitors etc.
The sound is open, 3-dimensional, spacious, liquid, groovy, detailed, non-fatiguing, in two words: just great!
A few notes, if you want to give it a try:
- Use only high quality toroid transformers with AT LEAST 30VA rating. It really makes a difference! In fact, I think the transformer is the most important part here.
- The caps can of course be of lower voltage rating. Everything from 25V up is ok.
- Discrete Shottky's are a must!
- The small Wima foils can be of a value up to 1,0uF, if space is no problem.
- The large caps (220uF and 1000uF) should be low ESR types of a decent brand (e.g. BC Components or similar). Be careful when unsing Panasonic FC's! I found them to have a different sound which I didn't like that much (a bit more "holographic", but not as fluid and full-bodied than the BC's).
P.S.: Andrea, don't worry! Of course I will try different opamps first ;-)
The thing with the transformers is that this would be a quite expensive solution :-(
Martin
I tried many different configurations the last days, but now I made my decision. This version sounds by far best to power my Super Pro 707.
It sounds better than all the other ones I tried, including various switch mode supplies, larger capacitors etc.
The sound is open, 3-dimensional, spacious, liquid, groovy, detailed, non-fatiguing, in two words: just great!
A few notes, if you want to give it a try:
- Use only high quality toroid transformers with AT LEAST 30VA rating. It really makes a difference! In fact, I think the transformer is the most important part here.
- The caps can of course be of lower voltage rating. Everything from 25V up is ok.
- Discrete Shottky's are a must!
- The small Wima foils can be of a value up to 1,0uF, if space is no problem.
- The large caps (220uF and 1000uF) should be low ESR types of a decent brand (e.g. BC Components or similar). Be careful when unsing Panasonic FC's! I found them to have a different sound which I didn't like that much (a bit more "holographic", but not as fluid and full-bodied than the BC's).
P.S.: Andrea, don't worry! Of course I will try different opamps first ;-)
The thing with the transformers is that this would be a quite expensive solution :-(
Martin
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Not to change the subject, but does anyone have any opinions/experience with any of the following?
RAKK DAC K & K Audio - Lundahl Transformers, audio DIY kits and more
HagDAC Hagerman Technology LLC: HagDac PCM1704K Audio Digital-to-Analog Converter with Low Jitter Reclocking
Guido Tent's DAC Welcome to the Audio DAC page
I have been trying to find recent information comparing these three. Any help would be appreciated!
RAKK DAC K & K Audio - Lundahl Transformers, audio DIY kits and more
HagDAC Hagerman Technology LLC: HagDac PCM1704K Audio Digital-to-Analog Converter with Low Jitter Reclocking
Guido Tent's DAC Welcome to the Audio DAC page
I have been trying to find recent information comparing these three. Any help would be appreciated!
Thanks for the update, Martin! Glad to hear you have something you like. (The Panasonic FM have somewhat better specs than the FC and IIRC cost no more than they do, btw. Not that these BCs are a bank-breaker. --Which series BC did you use?)
My Super Pro, here, unmodded, with merely a ferrite piece snapped over the AC cord just before the transformer -- to good effect -- is sounding *really* good. I've read a lot about this 1364 op-amp now, which I didn't know at all before. People mostly love it. Also, it is not all that cheap for an op-amp, and this is a very low-cost DAC -- so the PopPulse/Wai Wai Valve people must have thought it was a great fit.
At this point mine really does not sound overly bright as was said here -- and this is through pretty unforgiving speakers. (To the point where I often have a piece of toilet tissue over the tweeter.)
Most definitely they must...
Only the OPA1611 (or OPA1612) has made me forget about it... while the expensive LT1028 improved on it in most ways, but there was still something unique to the LT1364 mid-treble (a kind of "luminous" quality & sonic color) that was partly lost.
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The AD8599 is another one that's promising... Pacific Valve chose it to modify the Musiland MD10 (which uses the CS4398 too, and comes with the OP275). Not as promising as an OPA1612 though.
Hi Ecaroh!
I use BC capacitors of serie 136. I would not at all say that the sound is "overly" bright. I just find it to be a bit more on the bright side than on the dark side of neutral. The overall sound is indeed very good, and in the end it's a matter of personal taste. But to me, I would love it if the sound becomes a tad more dark and weighty. Than I would be totally satisfied, I guess!
I use BC capacitors of serie 136. I would not at all say that the sound is "overly" bright. I just find it to be a bit more on the bright side than on the dark side of neutral. The overall sound is indeed very good, and in the end it's a matter of personal taste. But to me, I would love it if the sound becomes a tad more dark and weighty. Than I would be totally satisfied, I guess!
I adore the sound the DAC produces combined with the Blacksheep Mars interconnect, playing Giant Sand - Selections ca. 1990-2000. Wonderful, perfect.
Not that the King Cobra gave worse results...but this really feels good. I'd say it's more important to spend money on the digital and analog interconnects.. 🙂 (I personally chose the Supra TRICO-RCA for the digital side)
Not that the King Cobra gave worse results...but this really feels good. I'd say it's more important to spend money on the digital and analog interconnects.. 🙂 (I personally chose the Supra TRICO-RCA for the digital side)
Then I would really try the OP275 op-amp, which sounds exactly like that -- along with the others. You can pick it up very cheaply, or get samples from AD.
An OPA2604, the classic, is definitely worth a try too -- sometimes called "tube-like."
Both give you a clean sound with plenty of detail, and a good bit of punch, too.
I have them both in multiple pieces of gear and they continue to please me more than newer chips, in those applications.
Thanks for the BC info!
Well, that's perfect: I allready ordered OP275, OPA2604, OPA2134 and a LME49720NA.
Last night I opened the super pro and desoldered the 1364, the power supply cap (in my case it was a 470uF/25V), and the output coupling caps. I soldered in a DIP-socket, a BC 136 220uF/35V cap and a matched pair of Black Gate N 4,7uF/50V as coupling caps. Right now I'm letting the whole stuff burn in (with the 49720 in the socket). I will give all the opamps a proper burn in before serious listening.
I will post a few pictures later.
Last night I opened the super pro and desoldered the 1364, the power supply cap (in my case it was a 470uF/25V), and the output coupling caps. I soldered in a DIP-socket, a BC 136 220uF/35V cap and a matched pair of Black Gate N 4,7uF/50V as coupling caps. Right now I'm letting the whole stuff burn in (with the 49720 in the socket). I will give all the opamps a proper burn in before serious listening.
I will post a few pictures later.
Important update!
IMPORTANT UPDATE!
I don't know if anybody of you wants to try the kind of unregulated power supply I suggested, but IF so, please:
Use a 3W/15Ohm resistor in place of R1, not 1W!
The 1W resistor runs pretty hot after a few hours. So use at least 3W here, like I did in the first place!
Thanks!
IMPORTANT UPDATE!
I don't know if anybody of you wants to try the kind of unregulated power supply I suggested, but IF so, please:
Use a 3W/15Ohm resistor in place of R1, not 1W!
The 1W resistor runs pretty hot after a few hours. So use at least 3W here, like I did in the first place!
Thanks!
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