HOLO Audio - Official Thread

What about the Red? :slight_smile:

I won’t have a video on the RED. I don’t usually do videos on DDCs cause there’s not really much to talk about. I’ll have a measurements post though

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Hi @GoldenSound Saw your measurements and look forward to your review! Do you think Hugo 2 would work well with RCA line out to Bliss? Would love your input, and if you can try it even better. Thank you!!

and a Holo Bliss competitor emerges… The Silver and Black Foxes built to push the Sus to the limit.




Per Slim’s post:

9i-906 “Silver Fox” Headphone Amplifier​

The nickname of 9i-906 headphone amplifier is “silver fox”. Purpose is to drive “monster” headphones. Its circuit architecture originates from a large power amplifier. When many redesigns for electrical characteristics and adjustments of sound style were completed, “silver fox” became a wonderful headphone Amp. High analytical, high density and neutral without tendency, especially power driving force, make it leader in similar products. Whether high sensitivity or low, high resistance or low, dynamic earphone or flat panel headset, “silver fox” can adapts to them by it’s super driving ability and quality. It can show the characteristics of headphone more than normal headphone amp.

1. Introduction:​

9i-906 “silver fox” is a headphone power amplifier with high performance, strong power supply and high current output. It’s circuit design is complex and perfect, 4 pairs of high-power British FET are used in output part, the output power is 30Ω/20W. Ultra low sensitivity headphones can also be driven with excellent audio performance.

It has four output modes: Normal, Balanced(BTL), Virtual Ground(Active G) and Parallel, as well as three low resistance modes and one high resistance mode. A variety of headphones can be matched.

It has two balanced and two unbalanced inputs. Even if you input an unbalanced signal, the internal circuit will convert it into balanced signal. Therefore, even if you input an unbalanced signal you will also get the maximum output power.

“Silver fox” has four output interfaces: 4 pin XLR balanced, 6.35 single, 4.4 balanced as well as double 3 pin XLR balanced.

2. Operating Instructions:​

“Silver fox” is a pure headphone Amp and the operation is very simple. There are only several function keys: power switch, input selection, output mode selection, high/low resistance selection.

Long press the out key to switch between high and low resistance modes. There are four kinds of headphone impedance options for choice: high resistance, low resistance 1, 2, 3. You can selected any mode according to whether you hear noise. High resistance mode is recommended in most cases.

3. Performance Parameters:​

  • Power: 20W (30 Ω BTL, distortion 0.02%)
  • Frequency response: 20-20KHz (0.2db)
  • Net Weight: 12kg
  • Gross Weight: 13.7kg
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Will be interesting to see how this does.

A fair bit more expensive though and significantly higher distortion so I don’t think it’s going for a similar approach. 6Moons says the Enleum AMP-23R is leaner than this so it’s probably going to be more for those wanting a much warmer sound.

They’re not likely to be at canjam are they?

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A post was merged into an existing topic: Bakoon AMP-13R / Enleum AMP-23R Discussion

High praises

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It is generally understood that resistor ladder DACs work best when the resistors are kept warm at a constant temperature. Does “standby” mode on the May keep enough electricity flowing through the unit to keep the resistors warm or is it recommended to leave the May powered on 24/7? I’ve kept Bifrost powered on 24/7 for years (as is recommended by most users AND the manufacturer), though I’m not sure I’m quite as confident leaving May powered on for years on end given its price tag? Is there any common agreement on this?

I leave my Wavedream on 24/7 and would do the same if I owned a May

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The conventional wisdom and my experience is that many on/off cycles stress electronics, are worse than a steady-state (either on or off), and may cause solder cracking. Capacitors tend to degrade when driven past their limits or over a few decades too, and I don’t think cap aging can be prevented.

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We’re talking 30+ years in most cases though (often a lot more than that) have amps built in the 90’s that I wouldn’t recap yet. But yes eventually they need to be replaced.
The bigger replacement issue in vintage electronics though is if the layers of the transformer core start to separate, that can often be not worthwhile even for expensive pieces.

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I leave my May and Spring 2 on all the time, behind ZeroSurge surge protectors.

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Same here…I leave the May on. I do turn off the display so it’s not lit 24/7.

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I left my Wavedream Signature on since I got it 2 years ago. Only turned off when I’m out of town. I think you’ll be fine.

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Thanks all, I appreciate the input. :slight_smile:

On at all time is the rec from Kitsune, I asked. Takes about 24-48 hours to thermally stabilize from my experience when starting from cold. It does put out a fair bit of heat.

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I’m waiting in the queue for a Holo Spring 3 KTE and Bliss KTE. I’ve been peripherally aware of i^s but never had a kit with that capability. What are the typical use cases for using i^s hdmi with Holo Audio Spring 3 DAC? My current chain uses a JCAT USB XE card (LPS powered) output to a Chord DAVE DAC that I sold to fund the Spring. I’ve never detected any shortcomings with my chain that I couldn’t address but I’m mildly curious to learn if there are sonic benefits for using i^s for my 2 channel audio. My library consists of PGGB 24-bit 706.6/768 kHz music files so I’m not sure whether this tech handles PCM of this sample rate better than USB. This is an opportunity for me to learn something new! After all I’m desperate to pass time until my Bliss KTE and Spring 3 arrive next month!

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First, welcome to the forum!

I’m not an expert, but my understanding is that I2S splits the signal so that the time domain information is NOT transmitted, thus allowing the Spring 3 to control the time domain information with its higher end clock. So, you would feed a streamer or CD transport I2S out to Spring 3’s I2S in and theoretically achieve a more coherent analog result. In essence, it lets you leverage your high end dac to do more of the work to achieve the best possible result.

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I2S like SPDIF/AES carries the clock, but unlike SPDIF and AES, the device doesn’t have to recover the clock from the logic signal because it’s sent independently.
So all 3 are usually dependent of the quality of the clock in the source.
There is nothing to stop a device “cleaning” up that clock using a PLL or similar.

USB on the other hand the DAC is entirely responsible for generating the clock, in fact there are many DAC’s that will internally generate an SPDIF or I2S signal from USB sources.

Theoretically the separate clock could make I2S better from a jitter standpoint but there is a lot more than just the connection involved in that.

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You’ll need a DDC like the Holo Red to convert from USB to I2S.

According to Goldensound’s review, the Red I2S output supports up to 768khz PCM and DSD512.

Depending on how noisy your PC is, you may find that a DDC will clean up your signal to the DAC even more. I also own a JCAT USB XE (LPS powered) and noticed that the sound quality got subjectively better (i.e. changed in a way that I liked :grinning:) when I put a Mutec DDC in my chain, to convert the signal from USB to SPDIF.

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