Thank you Genrlemen!
We should all move to our own country (maybe we could buy a small one somewhere). It would be nice to have you as neighbors. Although, when we got together for barbeques and events, the topics would always be the same... but the learning curve would be like a good stock investment. Up and to the right! (/)
I will do some ordering (eventually) and learning and report back. I am also reading some interesting stuff about different caps, Wima, Auricaps, Obbligato film/foil and PIO, Wima and PIO in parallel, Solen teflon, BG, etc., so I need to really understand the subtle differences (and sometimes not so subtle) before I order. It's amazing how the finish line keeps getting extended!
Every time you learn something, you realize there is another level that has even more details than the one you just completed! It's amazing DIYers have any time for their families! Eventually we will die out as a breed not finding the time to procreate.
Regards//Keith
We should all move to our own country (maybe we could buy a small one somewhere). It would be nice to have you as neighbors. Although, when we got together for barbeques and events, the topics would always be the same... but the learning curve would be like a good stock investment. Up and to the right! (/)
I will do some ordering (eventually) and learning and report back. I am also reading some interesting stuff about different caps, Wima, Auricaps, Obbligato film/foil and PIO, Wima and PIO in parallel, Solen teflon, BG, etc., so I need to really understand the subtle differences (and sometimes not so subtle) before I order. It's amazing how the finish line keeps getting extended!
Every time you learn something, you realize there is another level that has even more details than the one you just completed! It's amazing DIYers have any time for their families! Eventually we will die out as a breed not finding the time to procreate.
Regards//Keith
Hi Chris,
Don't worry I won't get stressed out, where did I put my coffee, Oh I finished it, let me get another one. OK where was I?
I am ordering four or maybe even eight Obbligato 4.7 uf 630 volt caps to try. Can't beat the value and the reviews. It's not 2.2 uf but a lot lower than 100 uf. I'll worry how to make them fit later but I am looking forward to the better overall sound most say you will get at $6.75 each USD. If they don't do anything for me, I'll find something else.
Did I finish my coffee already? This is stressing me out! Now I have to run to the bathroom too! see yaaaaaa...... Ahhhhhhhhh! That's better. Now I have room for more coffee!
Regards//Keith
Don't worry I won't get stressed out, where did I put my coffee, Oh I finished it, let me get another one. OK where was I?
I am ordering four or maybe even eight Obbligato 4.7 uf 630 volt caps to try. Can't beat the value and the reviews. It's not 2.2 uf but a lot lower than 100 uf. I'll worry how to make them fit later but I am looking forward to the better overall sound most say you will get at $6.75 each USD. If they don't do anything for me, I'll find something else.
Did I finish my coffee already? This is stressing me out! Now I have to run to the bathroom too! see yaaaaaa...... Ahhhhhhhhh! That's better. Now I have room for more coffee!
Regards//Keith
That spacing would be real convenient like the Wima caps. Think the difference can be heard between the Obbligatos and the Wimas and the Epcos?
Those Obbligatos are big 41 mm by 55 mm (around there).
This was an interesting article, not the end all, but informative and echoes what I read about the Obbligatos everywhere.
http://www.ecp.cc/cap-notes.html
Sound quality comes first, then money, then convenience (all within reason of course) in my mind anyway!
I am open to learn about the best way to handle the output caps and get the most value!
Regards//Keith
Those Obbligatos are big 41 mm by 55 mm (around there).
This was an interesting article, not the end all, but informative and echoes what I read about the Obbligatos everywhere.
http://www.ecp.cc/cap-notes.html
Sound quality comes first, then money, then convenience (all within reason of course) in my mind anyway!
I am open to learn about the best way to handle the output caps and get the most value!
Regards//Keith
I came upon this thread looking for more info about current regulating diodes. I'm thinking about using the CRD in my ezDAC output for biasing the op amps into Class A, just as was described above. To complicate matters, it seems these CRD's are becoming more and more hard to find (although they are definitely available right now). But maybe that's a side issue. The take home lesson for me from this thread is that the current sink/source amount should be greater than the op amp puts out, or else this is not worth the effort. The largest CRD's I found put out 4.7 mA, and even those are pretty expensive. I think the max op amp output on my DAC is in the range of 1-2 mA. Since the CRD can be added so easily to the design, and easily made optional, it may be worth it just to put the pads. Thanks, guys.
Hi EZ,
The one thing I learned from this exercize is to keep things flexible and try many combinations.
I was thinking about the best way to have the flexibility and sockets in the PCB are your starting point.
Then get a small proto board with one solder pad per hole that will accomodate a 10 or 12 pin dip socket. Install an 8 pin dip socket at one end with 3/8 inch solder tails (mill-max has them) so when you solder them into the board they stick through far enough to plug into the socket on the PCB. Then get two normal socket pins (pins only) with normal solder tails (.125 inch) and solder those to the other end of the proto board. Now connect wire from the two op amp pins sockets that you need to test (usually -Vs and output) to the two end pins (this maybe easier to do before soldering the sockets and pins ijnto the proto board). These end pins now have sockets to plug in different value resistors, CRDs and Cascodes. Plug in the op amp and then the assembly into the PCB socket and now populate the two empty socket pins with whatever you want and listen and then move to the next. This also alows using your DMM to test mA in a series so you know exactly what value works best or if you are where you want to be.
Don't discount the Cascode. It is supposed to be the best way to do this and has the least amount of negative side effects. As soon as I can find new OPA627APs and assemble these adapters, I will try the JFET Cascodes I made and test the actual mA and hope it is the best sounding. Then I will play with different resistors to see the impact on the sound. Hopefully the Cascodes will be the best if not, I will adapt the Cascode with a resistor to get the desired mA bias.
Then if it doesn't sound as good as a normal installation without this circuit, as some have said, I will lose them and just use the opA627APs in the socket on the PCB, and I will have learned a few things along the way (and it has been a long way).
Good luck!
Regards//Keith
PS anyone know where I can find small 10 or 12 hole proto boards, like what I am describing above? Thanks!
The one thing I learned from this exercize is to keep things flexible and try many combinations.
I was thinking about the best way to have the flexibility and sockets in the PCB are your starting point.
Then get a small proto board with one solder pad per hole that will accomodate a 10 or 12 pin dip socket. Install an 8 pin dip socket at one end with 3/8 inch solder tails (mill-max has them) so when you solder them into the board they stick through far enough to plug into the socket on the PCB. Then get two normal socket pins (pins only) with normal solder tails (.125 inch) and solder those to the other end of the proto board. Now connect wire from the two op amp pins sockets that you need to test (usually -Vs and output) to the two end pins (this maybe easier to do before soldering the sockets and pins ijnto the proto board). These end pins now have sockets to plug in different value resistors, CRDs and Cascodes. Plug in the op amp and then the assembly into the PCB socket and now populate the two empty socket pins with whatever you want and listen and then move to the next. This also alows using your DMM to test mA in a series so you know exactly what value works best or if you are where you want to be.
Don't discount the Cascode. It is supposed to be the best way to do this and has the least amount of negative side effects. As soon as I can find new OPA627APs and assemble these adapters, I will try the JFET Cascodes I made and test the actual mA and hope it is the best sounding. Then I will play with different resistors to see the impact on the sound. Hopefully the Cascodes will be the best if not, I will adapt the Cascode with a resistor to get the desired mA bias.
Then if it doesn't sound as good as a normal installation without this circuit, as some have said, I will lose them and just use the opA627APs in the socket on the PCB, and I will have learned a few things along the way (and it has been a long way).
Good luck!
Regards//Keith
PS anyone know where I can find small 10 or 12 hole proto boards, like what I am describing above? Thanks!
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