I do believe that is it. I kept thinking it was buried within some other thread for various projects I've built here. guess it was its own thread. I think it was the Iron Pre thread over on the Pass forum. That board has some "quasimodo" part locations.
Thanks for locating, seems I remember more than one project was covered that interested me.
Russellc
I find the 650 kind easy listening, bit rounded on purpose. I prefer the 660S for its extra focus and transparency without escaping the 6xx family resemblance sound still.
I've seen that thread, but it doesnt cover the antek model here. Perhaps it was the Iron Pre thread, I think it used the same transformer, i'll rescan it.
I guess I need to just build one, that would do it!
Russellc
The construction lasts forever in 6xx headphones, special plastics, light and sturdy but elastic enough. After a week they loosen up and the initial head clamp feeling goes away. I have HD600 among others and that explains why I don't prefer the HD650. You have to go Focal Clear territory to get something overall better than the HD660S IMHO.
That's the one salas pointed out in #3181 above, I guess it was in one of my preamp builds. I think they All have that Antek! About half way through scanning the BA 2018 thread, then to Iron Pre. Has to be one of those. May be quicker to build Quasi device. Think I will read there! Thanks all,
Oh....and I re book marked those pages.
Russellc
Oh....and I re book marked those pages.
Russellc
Did you look up this thread? https://www.diyaudio.com/community/threads/quasimodo-results-only.313202/
Some of the results only mention the antek‘s type, but not their values, so I couldn’t look it up thoroughly…
Edit: diamonddust was probably more thorough than me
Reading the notes for R9, I may have made a mistake using 470R. Re reading, I see it says for 300mA to 600mA use 1K ohm. I misread and thought that was associated 750R. Will 750R be problematic requiring me to switch to the 1K resistor? Not sure where I picked this up, I was thinking I have read in the DCG3 thread it needs 300mA? Hoping not!
Russellc
Russellc
Says spare current, not current limiter setting. Those are two different things. Spare is your setting minus the load draw. Spare is constantly burned in the M2 output shunt Mosfet to ground.
For your now 3.3R or 3R R1 in Ubib vs DCG3 output stage bias choice, combining 470R R9 offers good enough M2 gate damping and its the recommended value. 750R R9 would not unsettle something at this level of spare current. But increasing R9 is for providing better stability when the M2 runs high spare current so its transconductance goes up. Bit lower hf shunt reg feedback is the result if R9 gets increased when the spare current is not also increased.
Nonetheless some early adopters preferred the higher damping in general. I personally settled for different damping vs different spare current levels. About 100mA spare per channel is produced with your R1 value & DCG3 bias situation. In any case you avoid much heat on your shunt regs sinks while your now spare mA allows enough output current ceiling for DCG3 line level use or for connecting it with medium to higher Ohms headphones.
For your now 3.3R or 3R R1 in Ubib vs DCG3 output stage bias choice, combining 470R R9 offers good enough M2 gate damping and its the recommended value. 750R R9 would not unsettle something at this level of spare current. But increasing R9 is for providing better stability when the M2 runs high spare current so its transconductance goes up. Bit lower hf shunt reg feedback is the result if R9 gets increased when the spare current is not also increased.
Nonetheless some early adopters preferred the higher damping in general. I personally settled for different damping vs different spare current levels. About 100mA spare per channel is produced with your R1 value & DCG3 bias situation. In any case you avoid much heat on your shunt regs sinks while your now spare mA allows enough output current ceiling for DCG3 line level use or for connecting it with medium to higher Ohms headphones.
The Massdrop 6XX is by far the better value proposition. Analogous to the 650 but at $240.
I had not began the "unsoldering" procedure, I kept rereading, thanks for the clarity. Transformers should be here for new DCG3 today.
Russellc
Another paranoid question....my kit has those nice green muse caps, marked "BP" and no negative stripe down side so assume they are bipolar.
BUT, I also notice they have one leg shorter that the other. Is there a preferred orientation of short leg, + or - hole on board? If so, I assume orientation
is opposite comparing positive to negative boards?
Russellc
BUT, I also notice they have one leg shorter that the other. Is there a preferred orientation of short leg, + or - hole on board? If so, I assume orientation
is opposite comparing positive to negative boards?
Russellc
I want to design my own pcb.
If we introduce a CRC before the CCS could we get better results?
I had thought 10,000+10,000uF and 4.7 ohm 5w (for a max consumption of 200mA in total and 150mA the final consumer) do you think it's too much? worth?
I have enough nichicon VR 10,000uF/35v capacitors in the drawer to use...
Is a single 10,000uF KZ capacitor better than the previous crc I say?
If we introduce a CRC before the CCS could we get better results?
I had thought 10,000+10,000uF and 4.7 ohm 5w (for a max consumption of 200mA in total and 150mA the final consumer) do you think it's too much? worth?
I have enough nichicon VR 10,000uF/35v capacitors in the drawer to use...
Is a single 10,000uF KZ capacitor better than the previous crc I say?
There's lttle RC already (Rf+C1) in the official board to mitigate EMI. For how many uF as a minimum reservoir vs load current there is a formula or PSU simulator software to calculate ripple magnitude against input voltage headroom. Excessive uF isn't usually an error except anti-economical and CRC isn't a negative either. Single 10mF I have seen used before in this but not CRC. Can't tell if there's some benefit.
Inrush current and charge pulses grow bigger with more uF in more capacitors though and can strain fuse, transformer, bridge diodes, inline resistor, create more peaking.
Inrush current and charge pulses grow bigger with more uF in more capacitors though and can strain fuse, transformer, bridge diodes, inline resistor, create more peaking.