Allo DigiOne board

(johan ) #216

You use directly the RCA and BNC cables connecting to RCA/BNC inputs on oscilloscope ?

(Jeffrey Dam) #217

My first sound impressions with the Digione compared to the USBRIDGE:

My setup is:
Digione and USBRIDGE to the Gracedesign M920 DAC directly running a Hypex nCore amp and two Hypex UcD D4.0 sub-amps. Speakers I build myself too consisting of tweeter ScanSpeak Berylium, Mark Audio Alpair 10.3 mid bass and Dayton HF 265 subs with passive slave units. Subs are corrected by a miniDSP with Dirac live and fine tuned with REW. Silver speaker and interlink cabling is also build by myself. Digione’ coax is a KHARMA Supreme cable
Digione is connected to a raspberry with Allo switch mode power supply.
USBRIDGE is connected to Sparky with double linear power supplies.
Both boards run dietpi and Roonendpoint’s RAAT protocol.
If you want to further extend the SQ you should try a very decent Ethernet cable. I use the Audioquest Vodka. I also use a galvanic isolator between the cable and the Sparky made by Pink Faun. Switch between computer and Sparky is a TPlink 108 managed hub fed by an iFi switch mode power. This makes the sound fare more realistic.

I think the usbridge on the Gracedesign is a better combo then the spdif. Mainly due to the better power supply’s I suppose. the digione is a little more rough. S sounds are more pronounced. Stereo image is less wide and deep and more diffuse with the Digione. In coming weeks I will build a linear ps for the Digione and see if they match more closely together.
The USBRIDGE also sounds a little bit better with an Audioquest Jitterbug. Just slightly better air around instruments and voices. A little cleaner.
The USBRIDGE is far better then my old Cubietruck combo. Giving the little step with the jitterbug. The Cubietruck really needed the jitterbug to sound good. This is a big step forward. Timing, image whith and depth, details, black background etc. etc. is much better. I didn’t expect that. A raspberry sounds even worse then the Cubietruck so I didn’t compare it to the USBRIDGE.
One thing I like very much on the Digione combo is the natural warmth this setup displays. I heard this more with spdif sources but not as natural as with the Digione. The USBRIDGE sounds a little less involved, more analytical.
I hope the lps will clean up the other elements mentioned previously. I also hope the future Digione 2.0 will have a separate power input so I can feed sbc and hat separately.
The USBRIDGE eventually will find its place at my friends house together with a Devialet Pro 250 and KHARMA Elegance db9s speakers. I build it for him together with a very nice cabinet custom made by HIFI2000 in Italy.

I also want to mention the beyond great customer support from Allo. They put hard work in there products and Allo community. It seems they are working 24/7 on mail, fora etc. I can’t imagine this being healthy for the staff, but as a customer a really enjoy there responsiveness with technical support.
Shipping is quick and packaging sufficient.
Keep up the good work @ALLO_audio_boards!

(James Lee) #218

I connected the DigiOne directly to the oscilloscope with a coaxial cable. I did not use any adapters.
I used two types of coaxial cables. (RCA to BNC cable and BNC to BNC cable.)
I used an RCA to BNC cable to connect to DigiOne’s RCA and a BNC to BNC cable to connect to DigiOne’s BNC.

(johan ) #219

Hi James

we will post shortly the cables output readings.
In any case , we already established that your unit has a problem (and I think replacement is on the way).

(James Lee) #221

Hi Johan,

I received the tracking number by e-mail and confirmed that it was already shipped.
Thank you for your prompt and friendly service.
I experienced Allo’s impressive customer service.
Great service!

Thank you very much.

(johan ) #223

Please find attached the readings at the cables output (RCA cable 50Ohm connected to RCA of Digione) and BNC cable 75Ohm connected to BNC of DigiOne.

Also note that by standard of BNC and RCA , there has to be a termination (50Ohm R in case of RCA and 75Ohm in case of BNC) . Measuring without termination resistor will show distorted signals .(ringing )

(Elvin Chan) #224

It seems that nobody mentioned i2s output, could I get out of the DigiOne?

(johan ) #225

Nope you cannot. Please use Kali for that.

(Elvin Chan) #226

Hi Johan, I could not find a detailed specifications and support documents for the DigiOne. For example, is it 192/24 max? Please let me know where to find it if I overlooked, Thx.

(johan ) #227

I will check the manual, but yes 24/192Khz tested.

(James Lee) #228

I forgot to connect the terminating resistor.

(johan ) #229

No issues James. Lets see what the new (tested) Digione does to your system

(Elvin Chan) #230

My DAC supports both i2s and BNC input, do you think I should use Kali or DigiOne to get the best sound quality?

(Sean) #231

Hi Johan

We briefly discussed over PM but I was just wondering why a 50-ohm RCA connector was used and not the SPDIF 75-ohm standard for RCA?

Whether we can find true 75-ohm RCA connectors on 75-ohm cable is one thing but I would have thought to find the 75-ohm standard here to reduce impedance mismatches from the SPDIF standard.

I would expect most people to be using 75-ohm cable (the most common), but I could be wrong.

I would also expect most DACs to follow the SPDIF standard of 75-ohm RCA connectors.

(Elvin Chan) #232

Yes, I also know that it should be 75 ohm. According to this site, it is 75 ohm but hard to find one.

(Sean) #233

I did mention above that cables with 75 ohm connectors can be hard to find because I know about that BJC site.

But as I mentioned I would have thought you’d try to reduce the number of impedance mismatches.

But is the board connector (not cable connector) really hard to find at 75 ohm?

(Sean) #234

And it appears the HiFiBerry Digi cards conform to SPDIF 75 ohm standard but I’ll get confirmation:

While I don’t think it will make an audible difference I wanted to know why the decision to select 50 ohm

(Sean) #235

And according to BJC:

the Canare RCA plug maintains the coaxial geometry through its entire length, and maintains a 75 ohm impedance as far as possible into the plug. While it’s inaccurate to call this a “true 75 ohm” RCA plug, it’s accurate to say that no other plug on the market does such a good job of minimizing the effects of the impedance mismatch caused by the RCA plug’s unfortunate dimensions. The RCAP’s reliability, durability, high pull strength, and excellent spring-grip outer contact complete the package, making it, in our opinion, far and away the best RCA plug available

(Wayne Waananen) #236

No RCA connector can be 75 ohm. Impedance is a part of cable geometry. The diameter of the center conductor and the distance to the outer shield will determine the impedance. The RCA connector has too wide a center conductor for the distance to the outer shield to come close to 75 ohm.

The “F” type connector and some BNC connectors can be made in 75 ohm. They use very thin center conductors, compared to RCA.

The closest you can get is the design by WBT NextGen where the outer ring is not fully connected. That will then let the cable used determine the impedance. The WBT NextGen male connectors and the Eichman Bullet connectors are designed similarly.

Bottom line, if you want true 75 ohm impedance for digital, you would have to use BNC connectors on both ends of a 75 ohm cable.

(Sean) #237

Yes that’s the same as Blue Jeans Cable say above.