Schiit Skoll Balanced Phono Stage Review

[dzerig]

Ended up purchasing some 5-pin DIN to balanced XLR for my TT (Technics SL-1210 Mk2 with Jelco SA-250 + Hana ML). Yes, they were expensive but wanted to go full XLR for my phono chain.

BJC states: "For the less usual situation where you're running out of a turntable DIN into XLR inputs, our recommendation is Canare MS203-2BS, a two-pair cable with shielding both on the two pairs and on the whole bundle; we telescope the overall shield, tying it only to the DIN end, and ground the pair shields to the same pin at the DIN end as well as to pin 1 of the XLR output. You shouldn't ordinarily need an additional grounding wire with this configuration, so we've left it off."

I plugged them in and noticed a very slight hum at 40dB gain. At 50dB+ gain, it's a massive ground hum. Are these wired to assume there's another ground inside the tonearm to the TT chassis or something? I noticed there are other (and absurdly expensive) 5-pin DIN to XLR that DO have a ground wire, so wasn't sure what the deal is with the BJC cables.

This ground hum was not there with my old RCA din cable (BJC MSA-1) with ground wire, so I reverted back to that and it sounds fine, so I'll just keep using that. Just curious if anyone has any insight to the ground issue using a 5-pin DIN with those BJC XLR cables.

With my Denon 103 (MC) and Schiit SOL, using rca cables to SKOL I do not use a grounding wire. No hum or anything.

 

[dzerig]

The low note on an 88 key piano is at 27 Hz, if I am correct. I think that it would be worth it to have an FR that extends at least to there.

It does just leave out the high pass filter and you are flat to below 20 hz. If you have low frequency noise it is unlikely you'd hear any musical information anyway.

 

[EJ3]

It does just leave out the high pass filter and you are flat to below 20 hz. If you have low frequency noise it is unlikely you'd hear any musical information anyway.

Frequency Response, Normal (left) and 15 Hz filter (right), Apt Holman Preamplifier.

The 15 Hz filter is selected with a rear-panel switch.

It's -1/2 dB at 20 Hz, -1 dB at 17.5 Hz, -2 dB at 15 Hz, -3 dB at 14 Hz, - 5 dB at 12 Hz and -10 dB at 10 Hz.

That does the trick & allows you to have the whole 20 Hz-20KHz (unless you are looking for the low note on some organs, you are good with this setup).

 

[mike70]

Somebody knows some news / Schiit feedback about the left channel noise in Skol?

It seems something more general than one unit problem.

 

[Toroid]

Somebody knows some news / Schiit feedback about the left channel noise in Skol?

It seems something more general than one unit problem.

So far, Schiit has not acknowledged this as a problem. It's just a byproduct of their new discreet topology. I think if you were to get a response from Jason, the president of Schiit, he would say that the issue is minor enough were the people that are complaining about it are suffering from "audio nervousa". In my eyes the folks he's targeting with this new better, more expensive product care about these "minor" issues, so they should look into a different board layout. I doubt we will ever hear anything from Schiit on the topic, however. Most likely they would sneak a fix into Skoll v2 whenever that comes out.

 

[GPJ]

Somebody knows some news / Schiit feedback about the left channel noise in Skol?

It seems something more general than one unit problem.

Agree. And ...... there should be no reports ....... like other phono pre's in the price range.

 

[scottdavis0801]

Sounding very fluid to me. Lots of slam and warmth. You can hear the flavors of the instruments, with lots of detail. I'm impressed. And that's not easy to do!!

 

[mike70]

Sounding very fluid to me. Lots of slam and warmth. You can hear the flavors of the instruments, with lots of detail. I'm impressed. And that's not easy to do!!

Only tell me the brand of what you consume ... I want it too

 

[Sophoheilip]

I am wondering if the left channel (internally) is closer to the AC input rectified to DC section on the circuit board. If so, there may not be much you can do about it. One thing to try - add a grounded metal shield between power supply and input relays. That could possibly reduce coupling.

View attachment 325833

This is what can be found in a Reddit thread about exactly this issue.

Link to Reddit

User jaxtherogue wrote:

I reached out to Schiit support and after going through some troubleshooting steps I ended up with this response from them:

>This isn't an issue, this is physics. The hum in the left channel is a few db higher because of its location on the board. The left channel is further away from the input, which allows it to pick up more interference. The best way to mitigate this problem is to have short, well-shielded cables. Some hum, in this case, is inevitable.

The buzz I am hearing is only at quite loud volumes which I don't normally listen to and, even in quiet passages it does not seem to be occuring during playback ?! So for me, this is not a huge deal- but if you are getting the buzz at even low volumes I would follow up with them.

They also shared this troubleshooting guide: https://www.schiit.com/guides/phono-problems

Also for the record, I have pretty good well shielded cables (Blue Jeans LC1 and Blue Jeans 1800F Balanced).

I will do some basic measurements with the Skoll today. Maybe, if I'd like a void warranty, I try a shielding cage over the PS or left channel in the future.

 

[Sophoheilip]

I did a basic measurement of my Skoll and it looks not optimal, to say the least. Fully Balanced in and output should make this look much better (I did use the XLR output of my RME ADI DAC, but I had to use a RCA adaptor for a cheap Behringer Interface.)
So also take Distortion with a big grain of salt, because 200 Ohms output of the RME...
I should also mention, that with keeping the interconnects as far away as possible from the PS cable, I did gain like 4 db less hum.

Subjectively I do like the Skoll very much. Using headphones, the hum is barely audible between tracks or in quiet passages.

500 µV input from REW Generator and 50 db Gain:

 

[Digital1955]

I did a basic measurement of my Skoll and it looks not optimal, to say the least. Fully Balanced in and output should make this look much better (I did use the XLR output of my RME ADI DAC, but I had to use a RCA adaptor for a cheap Behringer Interface.)
So also take Distortion with a big grain of salt, because 200 Ohms output of the RME...
I should also mention, that with keeping the interconnects as far away as possible from the PS cable, I did gain like 4 db less hum.

Subjectively I do like the Skoll very much. Using headphones, the hum is barely audible between tracks or in quiet passages.

500 µV input from REW Generator and 50 db Gain:

I don't know if you were simulating your normal setup i.e. a 0.5 mV MC cartridge, and 50dB of gain, but sheesh in this scenario, that 100 Hz harmonic looks like its only 16 dB down from the 1Khz tone. This thing would be humming your face off listening through headphones.

 

[Sophoheilip]

I don't know if you were simulating your normal setup i.e. a 0.5 mV MC cartridge, and 50dB of gain, but sheesh in this scenario, that 100 Hz harmonic looks like its only 16 dB down from the 1Khz tone. This thing would be humming your face off listening through headphones.

Yeah, that could not have been, It was a grounding issue caused by the XLR adaptors (Pin 1, 3 and shield connected). Rushed it and didn't gave it another thought. Here is a far better one, where the 60Hz noise is even on both channels. So it really depends much upon placement and cable length, etc.

Why the distortion is quite high, I don't really know. I think still, because of mismatched impedance, Using 47k input will not make it better though. Maybe some more experienced home-brew measurements user may have an answer.

 

[Daviede]

I am not very clear about this, can any kind-hearted person tell me:I don't quite understand this picture, doesn't it mean high distortion? Can it be accepted at -20DB?

 

[Digital1955]

I am not very clear about this, can any kind-hearted person tell me:I don't quite understand this picture, doesn't it mean high distortion? Can it be accepted at -20DB?

This simulation demonstrates a record defect characterized by pops and clicks. Typically, the highest normal playback levels are 20 mV and below. However, a pop can significantly increase these levels, resembling a pulse that spans a wide range of frequencies. Although normal playback does not occur at these elevated levels, the test evaluates how the preamp manages overload in relation to frequency, albeit momentarily as the defect is played.

I personally prefer to see the THD+N (Total Harmonic Distortion + Noise) continue to decrease all the way through at least the 50mV level. It indicates that the click and pop won't cause noticeable distortion as they occur. In this regard, the Schiit Mani 2 performs better. However when the Mani 2 hits it's limit around 65 mV, you see distortion rises quickly, whereas it doesn't on the Skoll.

 

[Digital1955]

Why the distortion is quite high, I don't really know. I think still, because of mismatched impedance, Using 47k input will not make it better though. Maybe some more experienced home-brew measurements user may have an answer.

Start by bench marking your test setup without the phono amp by going straight from the DAC (signal generator) to the ADC input.

 

[Daviede]

hello
I would like to ask about the parameter diagram of this phono preamplifier. Does his headroom not have a higher clipping point as the rated voltage of the product design increases? For example, the Clipping point for 24V power supply is generally higher than that for 12V power supply, right?

 

[Daviede]

Or 5V and 14V
Pyxi Phono Stage by SOTA：https://www.audiosciencereview.com/forum/index.php?threads/sota-pyxi-phono-stage-review.45076/
ifi Zen Phono pre-amp：https://www.audiosciencereview.com/forum/index.php?threads/ifi-zen-phono-review-phono-stage.35240/

 

[Skeeter]

If you want those notes, as the linked article says, then just switch the HPF T/O frequency from 45 Hz to 20 Hz. I listen to a lot of classical music, and unless it's organ music or something esoteric, I don't miss much below 40 Hz.

Separately, there's also this to consider when thinking about stuff below 40 Hz (via Quora)

 

[Sophoheilip]

Start by bench marking your test setup without the phono amp by going straight from the DAC (signal generator) to the ADC input.

I did that like 2 years ago and had no distortion and around -100 dB noise floor with dithering. BUT I got a new PC since and it seems to originate (the high distortion) from my new hardware. I guess a better interface like a Focusrite would be in order, and/or play with grounding options.