many regulators compared to your shunt regs sound crippled, so not a very good comparison 
The sigma22 with bjt cap multiplier replaced with crc filter or lm337/317 makes its signature sounds more towards your shunt reg, according to my ears.
i'm personnally and generally not fond of cap multipliers supplies, but that is me and very subjective.
The sigma22 with bjt cap multiplier replaced with crc filter or lm337/317 makes its signature sounds more towards your shunt reg, according to my ears.
i'm personnally and generally not fond of cap multipliers supplies, but that is me and very subjective.
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If you will try a matrix board AC coupled test build watch the layout to be tight and the ground paths clean. Make two completely separate channels even if on same board to be sure. High rails will make the output MOSFETS more linear, THD noticeably drops at the high swings you need to drive the F4. I have tested that during the original development. Had used up to +/-25V and the dissipation starts to get serious but the bias holds well steady if the sinking is adequate.
Salas DCG3 and OBL15 speakers
Just want to let you all know how great this preamp sounds with my newly completed OBL-15 speakers. This with the Diotec 327-40 mirror mods detailed in post #2870.
OBL-15_Nash
Greg, don't skimp on the attenuator. Quality makes the difference here between good and great sound. I am using a custom Shinkoh/ Takman.
Nash
Just want to let you all know how great this preamp sounds with my newly completed OBL-15 speakers. This with the Diotec 327-40 mirror mods detailed in post #2870.
OBL-15_Nash
Greg, don't skimp on the attenuator. Quality makes the difference here between good and great sound. I am using a custom Shinkoh/ Takman.
Nash
thanks salas, i'm not sure 100% i will build it yet but will keep you guys informed if i can get to listen to it and if it sounds good...but my inner voice as well as outer voices i ear all around tells me it should sounds at least OK
PS: as i only have irf610 as medium power mosfet, i would build a reversed polarity version with j74, first
PS: as i only have irf610 as medium power mosfet, i would build a reversed polarity version with j74, first
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The NEC input monolithic is a high breakdown voltage JFET pair stated with VGDO >50V
The BF256B is a 30V device so that's the practical limit. But the PASS F4 is a +/- 23V rails power amp and +/-25V should be a good rails choice for the preamp.
I wouldn't go into a redesign process with BJTs because that will bring radical changes to input impedance and open loop gain that will take proof testing plus it will not be a DCG3 sound anymore.
The BF256B is a 30V device so that's the practical limit. But the PASS F4 is a +/- 23V rails power amp and +/-25V should be a good rails choice for the preamp.
I wouldn't go into a redesign process with BJTs because that will bring radical changes to input impedance and open loop gain that will take proof testing plus it will not be a DCG3 sound anymore.
Nice DIY speakers and a great finish. Congrats
I agree that in revealing builds the pot quality counts. Those "DACT type" cheap ones are great for the price but they have a little sibilant sting in the highs compared to Goldpoint and the like in my experience. In moving coil headphones and speakers it may pass as a second layer nuisance but in planar and electrostatic it sticks out more. Especially when there is more gain and dynamics added in the chain. The servo chips can differentiate or complement a bit there also. Like OPA vs AD etc. we discussed here before. Greg has hi-res electrostatic hybrid speakers and a detailed amp so he is to scrutinize bit more but he will find his most adequate parts and values combo sooner or later. More hours of play will give him more clues anyway. Some carbon track pots can be very nice for tone and smooth attenuation feeling but they will give up a bit of focus vs switcers. Resistance tracks can't be perfectly L-R matched. But a horizontally curved Martin Logan diaphragm is for sweet spot widening thus not a focus champion so it may not betray that trait too much. There isn't much sense of focus in auditoriums though. But in studio work sometimes there is.
Nash,
25 years ago I used to build my own attenuators using Shallco decks and through-hole resistors. So, I agree-you don't want to skimp here. I listen for transparency, linearity, smoothness, among a few.
I test attenuators and pots with my system using a rig a built to swap them out: even running without any device to see what I'm hearing. So, I do understand how important this one part of the whole is.
Having said that, the Dact ones I'm using are Vishay smds and allow me to dial in the sound I want with the right value. I spent a god-awful amount of money on my hot-rod DCB1 (naked foil Rs) and used it for about 8 years with one of these. Very, very neutral sounding attenuator.
When it comes to source material I run Roon on top of Tidal or Hirez downloads only. The system is fed with a fanless server with nothing running in the background. In short, how things contribute or not to my system is very important to me.
If you haven't heard Tidal through Roon via Win10 you are missing out. Check out the free Roon trial.
At some point I would like to try a Kosmo, and I probably will when I get this issue resolved. Fortunately, it's pretty minor, I will figure it out.
The brilliant thing about the DCG3 is that sonically, it's like the DCB1 with gain and dynamics: recordings come to life in the room. Where a recording was flat, it now comes to life. With ~500 sq. in. of radiating area, my loudspeaker doesn't radiate the recording into the room, it recreates the actual experience with the DCG3. Huge, voluminous space between instruments and the venue around them. Violin plucks with all of the overtones emanate into the space and decay in poly-radial fashion. Female voices propagate and fall with true dimension and tone.
Cheers,
Greg
i have no trouble believing people praising this pre/headamp.
With all the characteritics an amplifier must achieve with imperfect parts, it is easy to make something sound good in some particular areas, which will be surprisingly pleasing at firt listen. However i think the main challenge to make a amplifier non fatiguing and performing, is to make an amp that doesn't sound bad in any aspect, while not being the best at anything, and i believe this amp could be just that.
not too simple, not too complicated with 2 stages,not too much open loop gain, not too much noise, not too wimpy at driving low impedance, not too much heat, just enough bandwidth, a touch of cascode,etc....really just a good middle point
plus single-end toplogy has not the punch of complementary, but it sounds more like the real thing,widens the soundstage even if it distorts the signal more overall.
i don't know why but i like this amp more as my next build after writing this
With all the characteritics an amplifier must achieve with imperfect parts, it is easy to make something sound good in some particular areas, which will be surprisingly pleasing at firt listen. However i think the main challenge to make a amplifier non fatiguing and performing, is to make an amp that doesn't sound bad in any aspect, while not being the best at anything, and i believe this amp could be just that.
not too simple, not too complicated with 2 stages,not too much open loop gain, not too much noise, not too wimpy at driving low impedance, not too much heat, just enough bandwidth, a touch of cascode,etc....really just a good middle point
plus single-end toplogy has not the punch of complementary, but it sounds more like the real thing,widens the soundstage even if it distorts the signal more overall.
i don't know why but i like this amp more as my next build after writing this
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@Greg
With such good initial DCG3 results in your system, beyond the worthy effort of dialing the tonal details with pot trials, you should also consider extending your UltraBiB PSU to dual mono at a point. To possibly squeeze out even more dynamic and spatial performance. Maybe de-ring the transformer(s) with Quasimodo as well. Whatever you may do in the future for best performance possible, just do one thing at a time, to can control and even reverse each step's influence on the total audio system's synergy.
With such good initial DCG3 results in your system, beyond the worthy effort of dialing the tonal details with pot trials, you should also consider extending your UltraBiB PSU to dual mono at a point. To possibly squeeze out even more dynamic and spatial performance. Maybe de-ring the transformer(s) with Quasimodo as well. Whatever you may do in the future for best performance possible, just do one thing at a time, to can control and even reverse each step's influence on the total audio system's synergy.
Salas,
Yes, that is the plan. Maybe I will quazi first. What I need to do is let the DCG3 see different input impedance via R1 and find what works. I need to run R1 up and down and find the right input impedance for my system. I just got home last night and had a very enjoyable session....amazing detail. Just paint peeling on female vocals. That's the test for system brightness: female soprano.
The first thing I did when I had a chance was to go completely through my hook-up wiring and ground. Everything looks good. Again, I hear nothing out of the loudspeaker but very faint white noise. At this point, I really just have to look at the pot choice.
With the DCB1 and a 20k my system was very neutral. Maybe a tiny bit bright at times, but very close to perfect.
With my BA-3, the system was way bright with the same 20k, and just perfect with 10k, no brightness at all. As you said, this is a ridiculous load for my 22k output dac. And there-in lies the problem. It's an incredibly wimpy output, but I love the way it sounds. Again, my system was perfect with the DCB1, so, there's got to be a solution here.
I will probably play with R1 to see what works.
Cheers,
Greg
I may try that, but I don't think it will be necessary. I think I need to sit on my hands and wait (like we are supposed to do a work) and think and let it break-in first. I'm running all these scenarios, but I just need to let it play for awhile.
I can tell that you spent a lot of time optimizing from a part standpoint before publishing the project. It really is like the DCB1 with gain and dynamics.
At 22k on the tube output I am across the universe from every other source component out there, and certainly what you designed this thing to see.
Cheers,
Greg
I'm using C0G as came with the BOM kit. So, that shouldn't be the problem...