Eskamo is just a Holo hater that’s all. No hot takes here.
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I did not mean to come across as anxious - It’s just that I feel as if I’m at the outer edges of a whirlpool and its getting harder to resist the current pulling towards the center…
Silly thing is I think it’s as much FOMO as curiosity.
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Just join the HM1 whirlpool and forget the Bliss one exists 
but on our side it’s just a deep canyon you jump deep in hoping you survive the fall!
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Just watched the review through. Honestly, its a lot more even and well metered than his chat opinions have been. I honestly would like to get one in to properly demo if you want to move it on (or even just stash it somewhere for a few weeks to see if you miss it) @Rhodey
Canjam impressions are what they are obviously, but I still leaning ferrum having heard may + bliss. Maybe the technicalities are way higher than I give it credit for due to the floor noise, but even adding a tier to the technicalities cause of that would just kind put it as a different flavor of oor tier.
pretty much. They tend to trade off texture for other traits and lacking texture is basicaly my buggest pet peve in audio. Will be perfect for lots of people and prices of stuff like the spring 3 are super compelling, but not realy for me from what ive heard so far.
I wouldnt bother sweating bliss in the vaugest. HM1 and wa23 are both massive steps up IMO. Ignore bliss, aquire all gold dac to match your amp 
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I appreciate your candor and ‘hot takes’.
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I guess I’ve never read the full holo may product page before, but there is some realy cool info from Jeff Zhu (the creator of holo) on it. Honestly, like his products or not, I absalutely love when companies are willing to talk about their tech like this (rob watts is also awesome for this even if his ideas on r2r are a decade+ behind the times)
Many have asked about how does a discrete resistor network accurately reproduce sound. This email is a good read for those who want a technical explanation on how Jeff was capable of achieving flawless linearity and ultra good specs on THD. This was a reply to a customer who had a technical question about resistors and their limitations.
“About the resistor tolerance, his word is partly right, but not accurate. The MSB of 16bits value only represent 32768, not 65536, all 16bits is 65535, but the MSB is only 32768. There are techniques to reduce this requirement. For example, segment+R2R, using segment into the first few bits, then r2r for the rest of them. Rockna is segment+R2R, TotalDAC is all R2R. And you can see, Rockna’s THD spec. is much better than Total. Total uses foil resistor, but they used the simplest architecture. That results an unsatisfied test performance. To my opinion, it’s some kind of wasting foil resistors. Soekris also uses segment+R2R. MSB’s old model is all R2R, but I don’t know about their new models.
Anyway, There are ways to improve the performance, the segment+R2R is one way. Trimming is another way. There is an additional R2R ladder in Spring, it compensate the main R2R ladder. It works like trimming, but trimming is to change the resistor value. This additional R2R ladder are digital controlled and is to compensate the resistor tolerance. For example, the MSB of 16 bits should have the value of 32768, but due to tolerance, it represent 32700 in real world. Then that additional R2R ladder will compensate 68 into it. Then it became 32700+68=32768.
Actually there are other ways to improve performance, I just told you two stories. There are more stories behind the design. It is really hard. I must count every via holes in layout, every PCB wire has it’s impedance and must put attention on it. A via hole can be 50 m Ohm, it is 1/20000 of 1 kilo-ohm, and you see, it covers 32768 which is the MSB of 16bits. Also the switches has self-impedance which is about several ohms to 30 ohms. If you find this issue. Maybe you will go crazy, it seems to be an impossible mission. But a good designer will overcome all these problems. It’s our value at HOLO Audio.
All the resistor tolerance, switch impedance, line impedance, via hole impedance, finally reflect as linearity. There is a chart that shows Spring’s linearity, it’s excellent. But I suggest you to look at THD performance. Bad linearity must result a bad THD performance. But good linearity doesn’t mean there will be good THD performance. THD is dynamic performance, more critical than linearity which is a static performance.
If you look at the THD performance, you will find Spring to maybe the best among those competitors. I’m applying a patent which contribute a lot of that performance. But I can’t tell you how. It’s confidential now.
Best Regards
Jeff Zhu”
And another note on Linear Compensation. As Some have asked what happens when the Resistors values change over time? Jeff responds:
No matter it is a digital switch or analog switch, they are built by transistors, can be either bjt, mosfet or jfet. They have self-impedance call Ron(impedance when at on state). If we expect a lower Ron, the a bigger transistor is needed. But bigger transistor has bigger self-capacitance that will cause switching speed to be lower. So there is no perfect components in the real world.
About long term drift, the modern resistor technology has made it much better than older process. But the most important thing is, we don’t care absolute drift, we only care relative drift. That means, if all resistors are drifted in the same direction and same speed. Then it will be no impact for this application. So, we make sure to use the same batch of components in a single board. That will minimize the problem causing by long term drift.
As I mentioned in the earlier email. Spring is not using trimming, but using compensation. Not matter it is trimming or compensation, their goal is same, to make the resistance much more accurate so the linearity and distortion can be improved a lot.
Best Regards
Jeff Zhu
Also, another customer asking about the oversampling, Jeff replied and has some good information to those who are curious.
The oversampling is done by AK4137, ‘OS PCM’ converts the input stream to PCM no matter it is PCM or DSD, then send to DAC. ‘OS DSD’ converts the input stream to DSD no matter is is PCM or DSD, then send to DAC. ‘OS’ over-samples the input stream. If it is DSD input, it over-sample to DSD256. If it is PCM input, it over-samples to PCM384K or 352.8K ‘NOS’ does no oversampling. send the input stream directly to DAC module. About DSD ‘native’, it is the way the USB transfer the stream. You know DOP, which is DSD Over PCM. DOP put the DSD into a PCM stream. At the receiver end, it just unpack the PCM stream and get the DSD back. DOP does NOT change any bit of DSD stream, just sending it with the package. So it waste some data rate. At the same data rate, DOP is 1/2 of DSD native, the other 1/2 is the package. So DOP and DSD native are all bit perfect. The DSD stream sending to DAC is all the same. So, now you should know, DSD native is just about the way it transfers the stream. Not describing the way it does digital to analog conversion. At the DAC stage, the DSD stream can convert to PCM then do the final digital to analog conversion. Actually, most DAC chips do this inside the chip. One point needs to be remembered, DSD streams can’t do volume attenuation. If this chip can do digital volume control under DSD mode, then is must converted to PCM already. Let’s go back to Spring. If Spring works in ‘NOS’ mode. There is no oversampling, no conversion, just the original data doing the final digital to analog conversion. I will not explain how it does PCM conversion, you should already know quite well about it. There is a lot of resistor ladder DAC, they are born to do this. I just explain how Spring can do ‘discrete DSD conversion’. Actually it is like DCS and CHORD. If you looking to DCS and CHORD’s PCB, you will find ‘discrete DSD conversion’ is also using switches and precision resistors, like resistor ladder DACs. So, no matter it is ‘discrete DSD conversion’ or ‘discrete PCM conversion’, they all use the same discrete devices. Just work in different architecture. That makes possible to combine these two modes in one device.
Best Regards
Jeff Zhu
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Hell in a box arrived - Holo Red. No idea what all the possible setup configs are, or what ports are ins or outs. Garbage manual. I thought this was a DAC or DDC, but apparently it’s only a DDC with digital outs… 
The only software I’ve gotten it to work with so far, as a streamer, is Media Monkey. It works fine via USB/Eth In, then coax out, but I can’t get USB Out to do anything but silence or static with BP DAC.
PC → USB/Eth → Red → Coax → SMSL DAC = works (Redirector off) (Holo USB Output)
PC → USB/Eth → Red → USB → BP DAC = silence (Redirector off) (Holo USB Output)
PC → Eth → Red → USB → SMSL DAC = silence (Redirector off) (Holo USB Output)
- DAC display = “d-8” (DSD, apparently)
PC → Eth → Red → USB → SMSL DAC = works (Redirector off) (SMSL USB Output)
- Was able to see/select SMSL as output device in Holo web page config. Is this DSD mode, or just regular USB whatever? DAC display now says “44”, not “d-8”.
PC → Eth → Red → USB → BP DAC = 95% static, 5% music (Redirector off) (USB2.0 High-Speed Output)
PC → Eth → Red → USB → BP DAC = silence (Redirector off) (Holo Audio UAC2.0 Output)
PC → Eth → Red → USB → BP DAC = silence (Redirector: C-MEDIA) (Holo Audio UAC2.0 Output)
PC → Eth → Red → USB → BP DAC = 95% static, 5% music (Redirector: Holo UAC2) (USB2.0 High-Speed Output)
Is this BP DAC just incompatible, because it doesn’t have plug & play USB?
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I have no idea what “BP dac” is referring to, but USB out I’m fairly sure only works with ethernet in. AFAIK, you need to select the USB redirector for the output to work, but it can’t stream so I can’t confirm on mine. As for native dsd VS dop, that depends on the dac you are going into, not the streamer.
As for software to see it as a streamer, you need to select what protocol you want it to use in the configuration and then set your software to the same thing
Also, you may want to test using cheap cables for now. If your USB doesn’t have 5v that can throw things off some times
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Border Patrol. Only has USB input, sadly.
I will see if my USB dongle is recognized and works from Red’s USB Out tonight. I suspect the issue is just BP’s USB being so dated, that it isn’t recognized.
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I would say, for sure, my sound from speakers is now obviously more natural/non-digital, smooth and liquid-like, with more resolution, than without the Red. Gets an A+ from me, sound-wise! Right out of the PC with USB.
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Hahaha. Well I’m glad it sounds good at least. Hopefully you get it fully working on all outputs eventually
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It needs to send signal at 44.1 or 96khz only and below. Whatever setting you have somewhere along the line is well pst that and the BP DAC doesn’t play output beyond the 96 khz. I had messed up a setting in my computer audio output one time and the same thing happened to me. Or at least i think i’m prettyclose to your issue based on my own experiences snd minimal technical knowledge 
I’m sorry I wish i was more technically capable to ne able to help.
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Haha, no worries. Pretty sure the BP just doesn’t have the plug & play brains to work in a setup like this. Pretty sure I had to download special drivers just to get it working with direct USB by itself. Oh well, no biggie. 
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Edited the title to add the Red and added ddc+streamer tags.
Also, a few weeks ago I was curious about reinstalling Red OS onto my Red since I switched to Ropieee and didn’t think to use a separate SD card to keep the stock OS. Then I discovered that there aren’t any easily accessible/“official” links to download Red OS. The only link I could easily find was the Red’s user manual on KitsuneHiFi. So at that point I gave up and resigned myself to only using 3rd party OS images for the Red… Until Today!
I tried my search once more and noticed that when I typed “holo red os download” into the Google that Kitsune Hifi had a very interesting link description…
There it is! “HoloAudio Red OS IMG file 12/28/2022- Download Here.”
But when you go onto the page that download is nowhere to be found. So I decided to go the inspect element route, searched the elements of the page and viola! The link which was in a DIV with “display: none; visibility: hidden;” CSS style tags. This DIV also was hiding an additional link to the user manual for some reason. I have no clue why both of those links were hidden but still baked into the page itself. I’m just happy I was able to find it so I can reinstall the stock OS.
Anyways, here’s the link if anyone else finds themselves in a similar predicament with their Red.
Hope y’all are having a great week, happy listening!
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Any first hand feedback on the Azure HP amp from the membership?
I’ve read the typical reviews and it sounds like it’s an amp that would pair well with the BF2.
I’m curious about it simply for the great desktop form factor. Comparisons to a similar used price range amp like the Bryston BHA1?
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I`m primarily looking for DDC around 1k, to do PC->USB ->Chord Hugo TT2->headpones/stereo setup. Streamer looks like an option.
Has anyone compared Red to other price-relevant DDCs, Singxer SU6? Any feedbacks?
Read the fine print on the Red.
It can be a DDC or it can be a streamer, it won’t do both. There are plenty of good mid tier components out there and they’ll all sound head and shoulders better than what you’re getting now feeding your DAC from the PC.
Buy something used, try it out and see. You often find used Kitsumi Editions or other great reclockers for $400 to $500 used. Although they will show some different sonic characteristics, it’s not enough to be too concerned about and yo can always tweak them with cables. What you’re primarily looking for in a DDC is the output capabilities (one or multiple outputs at once) and the connectivity options. AES, BNC, Word Clock etc.
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