1641 or opa627 : Is it possible to have a good diy layout without drawing a pcb for avoiding distorsion (need a very good care about decoupling and powersupply, no ?
Maybe BUF03 is more proof to such problems...)
For the discussion, I assume we talk eachtime of unitygain for all the design when it comes to benchmark them ? I read sometimes some may use x2 with the 627, although it is stable (with good layout) in unity gain operation ! 627 should be near the Buf03 in timber : BB sound ?!
Maybe BUF03 is more proof to such problems...)
For the discussion, I assume we talk eachtime of unitygain for all the design when it comes to benchmark them ? I read sometimes some may use x2 with the 627, although it is stable (with good layout) in unity gain operation ! 627 should be near the Buf03 in timber : BB sound ?!
Oh, scary! An IC that is cannibalistic?
I used to have some, it must have been 20 years ago, somehow I must have missed their magic? I know I can buy 10 AD844 for the price of a single 627. Makes me wonder, would a single 627 be as good as 10 stacked AD844?
I don't know if I am being serious? Or may it it's just that it sounds amusing to me? Or maybe it would actually work?
Mouser sells 627, so fairly sure they will not be fake, $36 AUD.
.
I've listen to 3 stack AD844 output buffers, BUF03 was better in the bass but not in the mids and highs, and both don't come close to a single "real" OPA627. Except the bass of the BUF03, it's just a tad better than the OPA627, but the mids and highs are dirty and not transparent in comparison, I think it could have something to do with the distortion differences. The OPA627 having 0.00003% the BUF03 I think is no where near that.
Cheers George
Cheers George
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Can I ask why you choose this IC for regulation? What is the good thing about it beside the high power capability? AFAIK, it's noise spec is quite poor even compared to 78XX series.
In my experience, this i/v stage and buffer perform much better with some proper discrete regulators. I tried to used LM317 and Lm337 once and the sound immediately became muddy compared to the Kubota regulator based on LM329 and MOSFET power transistors. I use this regulator for the receiver chip and DAC chip too with very good result.
I had a 9V power supply for another DAC based on LT1085. When I replace the LT1085 in this one with LT3080 I found big improvement in clarity.
Yeah .... me too as I described in this post of this thread I used a power supply with the LT3080 regulator to serve the IV converter. I found myself very well. Quiet and clean.
Now I want to test the shunt power supply with TL431 and two BD140 of Rogic in his Aya DAC. Who will be the best?
I adopted the TL431 also to power the PCM1704 .... very satisfied.
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Yep, I'm asking what could be a better buffer than the inverted opa861 in the AYA II DAC ! ... with 5V PS shared with the front OPA861 I/V stage !
I find the opa 861 inverted quite neutral (on my 47 k input preamp) but not the ideal conf for this chip ! Though works exceptionnaly well : there is any close decoupling cap and with the buf or without (I mean just the first opa861 as I/V with the TDA1541A S1) I can not hear a difference !!!!!
hey the 627 is as expensive as a greek Muse !
If you want the best performance, try Salas shunt regulator that is very popular on this forum.
If you want something simpler please try the attached deaign. PCB can be obtained from ebay. LM329 is much better than TL431 if you use as voltage reference.
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Here you are https://www.ebay.com/itm/291686204228
Beware of the fake version which does not use LM329 and constant current diodes.
Make sure you can find the constant current diodes before ordering the PCB. They can be purchased from farnell or digikey, I think.
The Lm329 substitute the two zener diodes in the schematic. They are Z1 and Z2 on the PCB. You can use normal zener diodes but Lm329 is best.
LT1083
In my experience the LT1083 out performs 78 and 79 series regulators. I have had no noise issues with them. In some builds I use LM317 and LM337's as final regulators. Now this is with line level DAC projects. In a preamp, a critical application. I choose to use Jung/Didden Super regulators with good results. I have been using Jim's audio LT1083 board from Ebay. Makes for a nice power supply + regulator combination. In future projects I plan to try the Salas and Kubota regulators. My PCM1704 dac beat a Mytek that cost $2000 USD. Muddy sound? This I suspect is a layout or ground loop issue. I can't see how a regulator "that works properly" could impose that sound on your circuit. I do composite noise testing on all my builds. I am limited in equipment however I do have a solution. The noise in the 1704 dac is just about the same as the Pass BA-3 at maximum output. Below the the LSB (least significant bit) in a 24 bit DAC. Nice thing is I can still retrofit better regulators in the future and I likely will.
In my experience the LT1083 out performs 78 and 79 series regulators. I have had no noise issues with them. In some builds I use LM317 and LM337's as final regulators. Now this is with line level DAC projects. In a preamp, a critical application. I choose to use Jung/Didden Super regulators with good results. I have been using Jim's audio LT1083 board from Ebay. Makes for a nice power supply + regulator combination. In future projects I plan to try the Salas and Kubota regulators. My PCM1704 dac beat a Mytek that cost $2000 USD. Muddy sound? This I suspect is a layout or ground loop issue. I can't see how a regulator "that works properly" could impose that sound on your circuit. I do composite noise testing on all my builds. I am limited in equipment however I do have a solution. The noise in the 1704 dac is just about the same as the Pass BA-3 at maximum output. Below the the LSB (least significant bit) in a 24 bit DAC. Nice thing is I can still retrofit better regulators in the future and I likely will.
Torchwood
Nice to here your experience. FYI, JIM's audio does sell the Kubota regulator that I mentioned in kit form ;-)
At first I bought the kit from him and was very impressed when I used it for the DAC board and receiver. Later I only bought the PCB and purchased parts from other sources to assemble the regulator.
Nice to here your experience. FYI, JIM's audio does sell the Kubota regulator that I mentioned in kit form ;-)
At first I bought the kit from him and was very impressed when I used it for the DAC board and receiver. Later I only bought the PCB and purchased parts from other sources to assemble the regulator.
Kubota Regulator's
Hi quantran, Yes, he does have the Kubota. I should order up some boards. I am sadly looking at another knee replacement and a medical leave. I will probably order boards and in 3 months I should be up to working on them. Wish I could skip all that pain and suffering. Good news is that should be it. Becoming a Cyborg is no fun. 
Hi quantran, Yes, he does have the Kubota. I should order up some boards.
I am sadly looking at another knee replacement and a medical leave. I will probably order boards and in 3 months I should be up to working on them. Wish I could skip all that pain and suffering. Good news is that should be it. Becoming a Cyborg is no fun.