Hello Friends and abrax, Just finished testing my Miro ad1862 in these days... One question, has this stage output opamps or what? Will I be able tu use my tube output stage? Or I can apply that magic smoothing in some other way with this board(s)?
Thanks
Thanks
Hi @Michelag - the 'Dark LED' I/V doesn't have any opamps in it anywhere. It uses discrete transistors (bipolar and MOSFET) and does I/V passively. If you want to bypass the on-board output buffer after the I/V resistor, I think you could modify the board to do that then you'd be well placed to employ a tube buffer instead. You'd need a coupling cap between the I/V resistor and the tube.
Another one of Miro's PCM63 DACs getting the Dark treatment. This is very very good. This thing is so simple and effective it feels like cheating. At least the output caps can be played with 😉
Good work Richard.
Good work Richard.
I agree!! For the past two weeks or so I have been listening to Miro's AD1862 with the Dark IV and am quite pleased with the sound.
@kirks and @passive420: What did you use prior to the DARK IV? What types of power supplies are you using with the different stages of the Miro DAC and the DARK IV?
If the AD1862 is better than the PCM63 then you have one of the best NOS DACs and discrete stage on the forum. The PCM are very nice indeed.
What input do you have? The Amanero on it's own is very good with Richards recommended isolator. I may possibly explore Ian's PCM drive at some point.
@Sorenm Just before the Dark I had the CEN folded cascode I/V from EUVL. They are certainly excellent, I can't tell if they are better than the Dark iv, there is not much in it, but the Dark seems more focused, brought forward maybe. Both are superb but the CEN boards need skill and patience to build. And ultimately cost a bit more than the Dark iv, which is built, tested and sounds great straight away.
I will swap back and forth a few times, the CENs run at 15V and the Dark iv likes at least 17V so I will put sockets to quickly change a couple setting resistors.
Miro DAC is run by DEXA discrete regs, Dark iv is run from Gilmore Golden reference PSU which is total overkill but was handy and built.
Thanks for sharing the details of your setup! I have the boards for the CEN I/V and have been thinking about getting those finished, but your notes on the Dark I/V caught my attention.
The input is a JLSounds powered separately. The 18V for the IV and the 12V for the DAC are powered by MJ's VRDNs. The 5V for the DACis a repurposed TP Placid. Like you said the Dark IV is easy, just plug and play.
Managed to really get to grips with both I/V kits today, switching between the CEN and Dark IVs has been very enjoyable. Even got some sun, fixed a chair. All good.
So, both the CEN and Dark solutions are excellent, I enjoy both very much. I will try and be as objective as possible in my subjective review.
There is a difference, quite subtle but it's there. If I had to describe, then the CENs give a raw unfiltered presentation, you hear the DAC chip. There is more of everything in terms of the fullness of sound you hear. Lots of bass, surprising how much in fact, the music is very clear and enjoyable. It's hard to turn them off.
The Dark IV is somewhat more refined, I want to say the soundstage is brought forward and in front of you. Decay of notes is very nice, definitely coherent during complicated stuff. Plenty of bass and range. We are certainly hearing the filter here, it seems to shape the music slightly, but in a good way.
The CEN I feel ironically, is darker, the Dark IV has a tighter, more focussed sound. The CENs are naked, the Dark IV keeps it's knickers on... you feel me.
I have no idea what I'm talking about. But it should be noted that the CEN circuit is essentially just an op-amp, I believe, the AD844 with some serious improvements. The Dark IV is much more than that - this is Area 51 stuff people. Richards Dark IV is a bespoke solution ( the journey of which can be found here as Richard posted his research ) which is engineered from the ground up to work with NOS DACs. It is very effective.
Both are really impressive, still need to try this kit with the AD1862 soon.
Previously I had 15V rails and I can tell you running the Dark at 18V is definitely recommended. Always listen to Richard there is a reason for everything. In his explanation to me regarding having 18V rails, he said:
Also put a pair of 4u7 MKP caps on the output, why not eh? All very nice indeed, I think better than the FCs but not night and day.
So, both the CEN and Dark solutions are excellent, I enjoy both very much. I will try and be as objective as possible in my subjective review.
There is a difference, quite subtle but it's there. If I had to describe, then the CENs give a raw unfiltered presentation, you hear the DAC chip. There is more of everything in terms of the fullness of sound you hear. Lots of bass, surprising how much in fact, the music is very clear and enjoyable. It's hard to turn them off.
The Dark IV is somewhat more refined, I want to say the soundstage is brought forward and in front of you. Decay of notes is very nice, definitely coherent during complicated stuff. Plenty of bass and range. We are certainly hearing the filter here, it seems to shape the music slightly, but in a good way.
The CEN I feel ironically, is darker, the Dark IV has a tighter, more focussed sound. The CENs are naked, the Dark IV keeps it's knickers on... you feel me.
I have no idea what I'm talking about. But it should be noted that the CEN circuit is essentially just an op-amp, I believe, the AD844 with some serious improvements. The Dark IV is much more than that - this is Area 51 stuff people. Richards Dark IV is a bespoke solution ( the journey of which can be found here as Richard posted his research ) which is engineered from the ground up to work with NOS DACs. It is very effective.
Both are really impressive, still need to try this kit with the AD1862 soon.
Previously I had 15V rails and I can tell you running the Dark at 18V is definitely recommended. Always listen to Richard there is a reason for everything. In his explanation to me regarding having 18V rails, he said:
Also put a pair of 4u7 MKP caps on the output, why not eh? All very nice indeed, I think better than the FCs but not night and day.
Remove C31,R8 and OP1. That's all the parts which connect to the DAC Iout.
Do you actually have to remove C31 and R8 when using the output from the Dark LED IV? C31 and R8 are connected to leg 2 of OP1 but would be floating on the other end.
Yes their other ends are floating. I'd remove them to minimize parasitic capacitances on the Iout node but I like to err on the side of safety.
Hi Richard,
Finally got around to adding the dark IV to my copy of Miro's AD1862 dac. I've had been listening to it with no filters and a discrete opamp as the IV, and JLsounds isolated USB input for about four months now. Over that time I've upgraded the build to include five separate psus. The dark brings a nice noticeable improvement all around. Much better, more solid and focused.
Finally got around to adding the dark IV to my copy of Miro's AD1862 dac. I've had been listening to it with no filters and a discrete opamp as the IV, and JLsounds isolated USB input for about four months now. Over that time I've upgraded the build to include five separate psus. The dark brings a nice noticeable improvement all around. Much better, more solid and focused.