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ALLO BOSS DAC 1.2 Performance
ALLO BOSS DAC 1.2 Performance
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Old 9th February 2018, 11:39 AM   #41
SanjeevM is offline SanjeevM
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Quote:
Originally Posted by cdsgames View Post
Already included.
Ah! Good. My v1.2 is on its way.
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Old 14th February 2018, 04:31 AM   #42
SanjeevM is offline SanjeevM
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Quote:
Originally Posted by cdsgames View Post
Already included.
Cdsgames,

the older boss dac also has a supercap. Is the ver 1.2's supercap different?
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Old 14th February 2018, 10:40 AM   #43
CallMeMike is offline CallMeMike  United Kingdom
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Quote:
Originally Posted by SanjeevM View Post
Cdsgames,

the older boss dac also has a supercap. Is the ver 1.2's supercap different?
A picture (a quick look on the manufacturer's board) tells a thousand of stories... 404 Not Found
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Old 14th February 2018, 01:51 PM   #44
CallMeMike is offline CallMeMike  United Kingdom
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Quote:
Originally Posted by CallMeMike View Post
A picture (a quick look on the manufacturer's board) tells a thousand of stories... 404 Not Found
Quite bizarre, the link in the previous post does not work... let's try again:
BOSS I2S DAC v 1.2
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Old 7th January 2019, 12:32 PM   #45
smallangryboy is offline smallangryboy  United Kingdom
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Question Allo Isolator or Ian Isolator Pi

Quote:
Originally Posted by Greg Stewart View Post
The BOSS is sitting on an Ian Isolator-Pi
Greg did you ever do an A/B with and without the isolator? I wonder if there is an advantage of going with a same brand (Allo Isolator) with the BOSS 1.2 or using Ians?

I'm getting good results with a naked Boss 1.2 and a cheap Linear supply powering both the Pi and DAC. I hope to use two supplies one for each in the future but my next step is the Isolator, I'm just wondering if it's worth it.

I've heard a lot of opinions about investing in a good linear supply is more worthwhile, making noticeable and positive changes in comparison to the Isolator and some saying the Isolator introduces jitter? Not sure about that though...

Last edited by smallangryboy; 7th January 2019 at 12:34 PM.
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Old 7th January 2019, 10:37 PM   #46
Greg Stewart is offline Greg Stewart  United States
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Location: Columbus, Mississippi
ALLO BOSS DAC 1.2 Performance
@smallangryboy,

I honestly don't remember if I tried it without an Isolator. By the time the Boss 1.2 came out, I had tried every other RPi DAC I had with either Ian's or Allo's isolator and preferred all with them in place. I did also slightly prefer Allo's over Ian's... I assume it has to do with theoretically better regulators on Allo's.

I do have a friend who prefers the Boss 1.2 without an isolator. I can see if I can get more details from him. BUT he's also recently done a bunch of listening to various combinations of power supplies and a few configurations of the Katana AND prefers it with the Isolator 1.2. Go figure!

On an isolator board and jitter, no question that the devices used to produce the isolation add jitter to the I2S signals. That will vary depending on the specific isolator chip used... some are bad, some are ok, I've heard that some are very good. BUT the questions are:

1. How immune the target DAC chip and it's configuration are to the added jitter?

2. Is the negative impact of the added jitter larger than the positive impact of having separate grounds between the I2S source and the DAC board?

3. Can you use reclocking to reduce or elminate the jitter hit?

4. How good (low-jitter and low-noise) is the I2S source?

The RPi is a moderately to pretty noisy source (IMHO, based on the the power supply used) and unless it is being used in master mode (like with either of the Boss DACs, the Katana, and the HiFiBerry DAC+Pro series) is pretty jittery. In situations other than master mode DACs, an Allo Kali does a good job of cleaning up the inherent RPi jitter, especially when paired with an isolator to limit the effect of RPi processing noise on causing more jitter.

Using a quieter power supply with a low output impedance over a very broad frequency range (like a Salas shunt regulator) on the RPi does reduce the noise from its processing. So using a supply like that should lower the relative benefit of an isolator. AND to be honest, I haven't done ANY comparisons with supplies such as this.

Finally, some DAC chips running in master mode AND configured well, is generally more immune to incoming I2S jitter. That configured well is important, it is not inherent with master mode.

I found I preferred the Boss 1.2 without a Kali... some of the magic that had me admire and enjoy the Boss 1.2 without a Kali is lost after adding a Kali, even though in some ways it sounds better.

BUT I can't answer your question of isolator or note... partly because I didn't do it, and partly because it will depend on your specific setup.

SORRY!

Greg in Mississippi
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Old 8th January 2019, 09:25 AM   #47
smallangryboy is offline smallangryboy  United Kingdom
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Thanks Greg for the in depth reply, it was helpful.

It is very small margins I guess at this point. Interestingly I had to use a linear supply with the Boss 1.2 to beat a naked ChromeCast Audio - well to my ears anyway. I figure unless you have two identical setups a comparison would be awkward and I'm never going to have dual linear supplies to do any worthwhile A/B testing with and without the Isolator.

My hunch is to go with the Allo Isolator and then remove it if I think it's masking anything.
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