[Boldakov]

Hibiki SDS

Good DAC, I was using it for some time with CFA-3
Upgraded it to Aqua Formula xHD rev.2
Still good memories about Hibiki SDS

 

[rsbrsvp]

I have the signature version of the Hibiki SDS, and I replaced the standard fuse with a SR Master. To say there was a substantial improvement would be an understatement. IMHO- it is twice as good. Like a brand new piece of equipment. Double the speed, authority, detail, punch, soundstage, while maintaining the DSD tonal richness and smoothness which is irresistable. I got the Hibiki External OXCO clock as well. That was worth maybe another 10%, not more..

Aqua DAC sounds fantastic. I just need $18,000.

 

[rsbrsvp]

another odd one - another chinese "prodigy designer"...

Correct. Not looking to same the same chips, same usb inputs, same basic designs in a different chassis like 95% of everything out there. I like innovation.

 

[rsbrsvp]

By the way, IMHO not all of what is going on with tube premps mellowing the sound is from the tubes. I mentioned erlier that I find SS preamps also mellow the sound of my headphone amplifiers (with much less distortion) and IMHO this change is pleasant.

I believe based on my experimentation (and complete lack of technical knowledge) that when controlling the volume from further back in the electronics chain- there is a more mellow result; it feels like one is furthur back in the audience and the sound is rounder and less harsh. Controlling the volume from the last point closest to the headphones results in a more upfront in the face, ultra hard hitting result.

This has nothing to do with volume gain as I can get to blistering volumes using either my preamps or headphone amps. volume control. For the most powerful, in the face, hardest slam, front row seat- I use the headphone amplfiers volume control. For a softer approach- further back in the audience with a larger soundstage, I lower the gain on the headphone amplifier to the minimum possible and use the preamp to get the gain I need to drive the headphones. It is also nice to combine the two for a middle ground.

SO- IMHO, preamps have a lot of value in effecting the sound and are very valuable to providing flexibility in controlling the type of sound one wants.

So I think a part of the reason so many like a tube preamp when using the CFA3 is for that more mellow, less harsh result- which I believe is partly comming from the tubes and partly from the fact that any preamp due to being further back in the chain will contribute to this result.

 

[MN8372]

By the way, IMHO not all of what is going on with tube premps mellowing the sound is from the tubes. I mentioned erlier that I find SS preamps also mellow the sound of my headphone amplifiers (with much less distortion) and IMHO this change is pleasant.

I believe based on my experimentation (and complete lack of technical knowledge) that when controlling the volume from further back in the electronics chain- there is a more mellow result; it feels like one is furthur back in the audience and the sound is rounder and less harsh. Controlling the volume from the last point closest to the headphones results in a more upfront in the face, ultra hard hitting result.

This has nothing to do with volume gain as I can get to blistering volumes using either my preamps or headphone amps. volume control. For the most powerful, in the face, hardest slam, front row seat- I use the headphone amplfiers volume control. For a softer approach- further back in the audience with a larger soundstage, I lower the gain on the headphone amplifier to the minimum possible and use the preamp to get the gain I need to drive the headphones. It is also nice to combine the two for a middle ground.

SO- IMHO, preamps have a lot of value in effecting the sound and are very valuable to providing flexibility in controlling the type of sound one wants.

So I think a part of the reason so many like a tube preamp when using the CFA3 is for that more mellow, less harsh result- which I believe is partly comming from the tubes and partly from the fact that any preamp due to being further back in the chain will contribute to this result.

Not sure I entirely agree with the more mellow description. My system with a tube pre is not more mellow/recessed to my ears. It’s more holographic but the mid-range is not recessed and the mid-bass is actually elevated. It’s not a more “relaxed” listen. Although this may be tube dependent/vary from pre-amp to pre-amp.

But I do agree with a lot of what you say. There has to be a reason why 2 channel systems have been using pre-amps (both solid state and tube) for decades. It also seems that the CFA3 appreciates more voltage/gain which a pre-amp can provide. The cool thing about the Supratek pre is the variable gain control so you can dial this in to taste. Like you I also run my headphone amp in low gain which I think sounds best. Although turning the gain up on the tube pre made a much bigger difference In my opinion. It had a huge impact. So yes I agree that not everything is due to the sound of the tubes. That’s just part of the picture. But I do think the tubes bring their own special flavour - not necessarily a more mellow sound (although with certain tubes I’m sure that’s an option). For me DHT tubes bring a more holographic/tactile soundstage with wonderful spatial clues. That to me is just plain ”better” sound (as opposed to a more mellow vs more aggressive sound which is more a matter of taste).

Would be great to see more pre/power amp options in the headphone space. Would the CFA3 sound even better without a volume control (i.e. a pure power amp)?

 

[audioguru1]

Not sure I entirely agree with the more mellow description. My system with a tube pre is not more mellow/recessed to my ears. It’s more holographic but the mid-range is not recessed and the mid-bass is actually elevated. It’s not a more “relaxed” listen. Although this may be tube dependent/vary from pre-amp to pre-amp.

But I do agree with a lot of what you say. There has to be a reason why 2 channel systems have been using pre-amps (both solid state and tube) for decades. It also seems that the CFA3 appreciates more voltage/gain which a pre-amp can provide. The cool thing about the Supratek pre is the variable gain control so you can dial this in to taste. Like you I also run my headphone amp in low gain which I think sounds best. Although turning the gain up on the tube pre made a much bigger difference In my opinion. It had a huge impact. So yes I agree that not everything is due to the sound of the tubes. That’s just part of the picture. But I do think the tubes bring their own special flavour - not necessarily a more mellow sound (although with certain tubes I’m sure that’s an option). For me DHT tubes bring a more holographic/tactile soundstage with wonderful spatial clues. That to me is just plain ”better” sound (as opposed to a more mellow vs more aggressive sound which is more a matter of taste).

Would be great to see more pre/power amp options in the headphone space. Would the CFA3 sound even better without a volume control (i.e. a pure power amp)?

It really depends. I have a pro audio DAC (Mytek Brooklyn dac+) that outputs 9+ volts. Pre-amp territory. I don't hear a huge difference between that and Dac's with more modest ~3v output (Gustard, which I prefer). I put a Bryston BP25 in front of the CFA 3 (its a VERY transparent well designed pre-amp) and heard no improvement. It all depends on your source though, I can see a dac that only outputs 2v (standard spec for consumer) maybe benefiting from a boost.

re "power amp mode" the CFA3 has additional stages before the output transistors, so its a little different than a speaker power amp. If you have a split board setup, there are gerbers for tube input stages. I digress. Bypassing a low quality volume may provide value, though if you are using quality units there is not much to gain. I have been using Khozmo discrete ladder units which use high quality resistors as opposed to carbon plastic film. Granted the parts alone exceed $500, so there is that. Given the quality, I actually think they are an incredible value. I've also had relatively noticeable gains by using quality connectors with copper base material. Parts quality does matter, just have to avoid the snake oil stuff (there is unfortunately a TON of it in our hobby). Case in point, AECO sells pure copper base (plated with gold or silver)4 pin and 3.5mm jacks for $30-40. I've seen botique brands (not naming names here) sell brass or mixed materials for far more money. Why do I say all this - if you are chasing sound quality before trying preamps, i'd see about actual parts improvements that can be made. We are DIYers after all.

In terms of improvements i've been playing with power supplies and feeding the protector board from yet a 3rd power supply and am hearing big gains in sound. At present I have dual discrete 250VA supplies for each channel, a 5v supply for the Khozmo, and a supply for the protector board. My theory is that since the protector board runs at 12v the regulators dropping 15 or so volts off the grlv to get to 12v is at the very minimum inefficent, and probably degrades things to an extent when its shared with the audio amp section. Theres a few posts over on head case about folks getting noise from excessive voltage dropping from the protector board regulators. Is this excessive, probably. It sure sounds good though.

Back to saving up money and parts for the CFA3large/P.

 

[Satyrnine]

In terms of improvements i've been playing with power supplies and feeding the protector board from yet a 3rd power supply and am hearing big gains in sound. At present I have dual discrete 250VA supplies for each channel, a 5v supply for the Khozmo, and a supply for the protector board. My theory is that since the protector board runs at 12v the regulators dropping 15 or so volts off the grlv to get to 12v is at the very minimum inefficent, and probably degrades things to an extent when its shared with the audio amp section. Theres a few posts over on head case about folks getting noise from excessive voltage dropping from the protector board regulators. Is this excessive, probably. It sure sounds good though.

I’m running 30v rails, and had noise from protector board regs as well. Solved it with 1k resistors between the 30v rails and the protector board. And run its ground to star ground if possible. No noise even with high sensitivity cans now.

Note cable management in psu case is not complete, and speaker terminals not yet wired. Running Siemens E288CC tubes too, 1/2” taller “uber” 6922 with slightly higher plate and heater current.

 

[audioguru1]

I’m running 30v rails, and had noise from protector board regs as well. Solved it with 1k resistors between the 30v rails and the protector board. And run its ground to star ground if possible. No noise even with high sensitivity cans now.

Note cable management in psu case is not complete, and speaker terminals not yet wired. Running Siemens E288CC tubes too, 1/2” taller “uber” 6922 with slightly higher plate and heater current.

Very cool. I really admire your build. The tube front end is cool, as is the engraving (laser?)

Thankfully mine is totally silent even with IEMs (which is kinda stupid to try but good to test for noise floor).

 

[SolidSlug]

I have large CFA3 boards v1.20. Does anyone have Mouser projects for those?