I am impressed by all the modifications you introduced and how quickly you finished the build since receiving the boards. Great work. Congratulations!
Dear Grimberg, thanks for the M2 boards. Without which I could never had started. Some challenges during the build. Like most have encountered, getting the Edcor to ship overseas was rather expensive. This was built with a couple of Chinese made transformers. Did a check on the frequency response and they were good to go. Except the core saturates with even a small DC at the input. Did not have matched genuine J74/K170. Had to settle with J103/K246. Took quite a while to get these matched but eventually did with good results.
Only drawback as I mentioned earlier is the Long start up of the output current due to the large value of C3, 3,300uF which took a Long time to charge up.
After learning from previous builder regarding him pickup by the input transformer, I chose to place the main transformer as gas as possible and it did the trick without the need for any shielding of the input transformer.
Only drawback as I mentioned earlier is the Long start up of the output current due to the large value of C3, 3,300uF which took a Long time to charge up.
After learning from previous builder regarding him pickup by the input transformer, I chose to place the main transformer as gas as possible and it did the trick without the need for any shielding of the input transformer.
When I finished building my first channel and connected it to the PSU, the long charge time of the capacitor made me think it was not working. As I reached for the portable multi-meter to start diagnosing it, I heard music playing. Nelson has commented on it earlier in this thread, that is the expected behavior.
http://www.diyaudio.com/forums/pass-labs/281520-official-m2-schematic-6.html#post4499438
http://www.diyaudio.com/forums/pass-labs/281520-official-m2-schematic-6.html#post4499438
it would be easier and neater , with probably same sonic result , "just" cascoding buffer JFets
Will cascoding give the same 'ripple rejection' effect as a well designed regulator, or even a regular-regulator?
in vicinity of,practically
count on fact that practical execution of circuit is of same importance as schematic itself ;
good regulator is one with well engineered schematic and equally well engineered pcb (energy routes and sense routes well separate) , situated close to stage it feeds
can't see that in KweSong Lim's pictures , and thinking that cascoding could be easily made local to JFets , thus resulting in better performance
considering minuscule consumption of JFets and their work in A class , also complementary (think of rail consumption balance) nature of stage , this contemplation about difference is probably academic , but nonetheless valid
and remember that I'm World's biggest Shunt Reg advocate ........ sole thing I'm routinely sparing of pressing in OPLDF are shunt regs from PL and FW gadgets
count on fact that practical execution of circuit is of same importance as schematic itself ;
good regulator is one with well engineered schematic and equally well engineered pcb (energy routes and sense routes well separate) , situated close to stage it feeds
can't see that in KweSong Lim's pictures , and thinking that cascoding could be easily made local to JFets , thus resulting in better performance
considering minuscule consumption of JFets and their work in A class , also complementary (think of rail consumption balance) nature of stage , this contemplation about difference is probably academic , but nonetheless valid
and remember that I'm World's biggest Shunt Reg advocate ........ sole thing I'm routinely sparing of pressing in OPLDF are shunt regs from PL and FW gadgets
There is no doubt that you are a fan and practitioner of fancy pants regulators, so I respect your opinion here. Just here
I have to get off my buttt and make one of these things, or wait for the one NP promised to send me a page back 😉 I'll design cascodes into mine, if only if to bring the voltage up if I want.
I am suffering from serious J-fet angst just like so many others. I have some left but it's hard not to hoard; although it makes more sense to take them out of the drawer. For the cost of a set, I could buy nearly 10 pages of a textbook for one of the kids starting college next year 😱
I have to get off my buttt and make one of these things, or wait for the one NP promised to send me a page back 😉 I'll design cascodes into mine, if only if to bring the voltage up if I want.
I am suffering from serious J-fet angst just like so many others. I have some left but it's hard not to hoard; although it makes more sense to take them out of the drawer. For the cost of a set, I could buy nearly 10 pages of a textbook for one of the kids starting college next year 😱
Yo , man , just chill ;
increase it to 6800uF , at least
Dear ZenMod, thanks I will just chill, have a coffee as the amp warms up.
I think that's another of ZM's Babelfish projects, probably Babelfish M2. The buffer is made of what appears to be dual N-channel JFETs, cascoded so the delicate critters don't get hurt. Gain, bias and back-end look the same for the most part. I think he is really teasing us with those black boxes.
🙁
🙁
hopefully , it'll be Babelfish M25
also coming SEF/Babelfish M2 (two amps , same pcb) , and LuDEF amp
all with same buffer , autoformer by choice Edcor or Jensen (so 5V/V or 4V/V gain) while OS differentiating those 4 amps
I just wish I have more time , to speed up things a little
also coming SEF/Babelfish M2 (two amps , same pcb) , and LuDEF amp
all with same buffer , autoformer by choice Edcor or Jensen (so 5V/V or 4V/V gain) while OS differentiating those 4 amps
I just wish I have more time , to speed up things a little