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Schiit Saga Grounding and Hum Issues?

amirm

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#1
Readers of the forum probably remember a discovery I made regarding lack of proper grounding for safety and guarding against hum in Schiit Jotunheim. It seems that we may have a repeat of that same case with another Schiit product, the Saga preamplifier.

A forum member reached out to me regarding hum in his Saga preamplifier. He is in Europe and I don't have access to his unit so he sent me pictures of what is inside. Here is the overall shot of the inside of the unit:

Schiit Saga Hum Chassis Not Grounded.jpg

Looking at the chassis, the paint and protective coating remains which means that the top of the unit is likely not making a good connection to the rest of the chassis. As such, hum from the transformer can couple to the volume control just as it did with the Schiit Jotunheim.

Focusing on safety issues, just as well we see an IEC mains connector that does not have its earth/safety ground connected to the chassis:
Schiit Saga Hum IEC Mains Not Grounded.jpg


As I showed in the case of Jotunheim, there needs to be a proper green earthing lug to the chassis such as this example:



This is a tube amplifier with potentially high voltages running around in the PCB in addition to the power supply input. So this is more of a serious safety issue than what occured in Jotunheim.

My response to the owner after receiving the pictures was to reach out to Schiit and ask them if this is proper or not. He lives in Europe and sadly Schiit just told him to ship his unit at his expense to the European distributor. With round trip shipping expense becoming a substantial cost percentage of the cost of the unit, that is an improper burden on him. He is hearing hum in his unit and likes a resolution.

So I told him that I would post the data here in the hopes that Schiit sees it and does the right thing by reaching out to owners with such issues and performs remedies free of charge to them. These are both safety and performance issues in my opinion that must not be there. It is only right that the company goes out of its way to troubleshoot them lest they want to be known as a company that doesn't care about safety of its customers or audio performance of their products.

At the same time, if Schiit believes these products are to spec and compliant with safety marks on the unit, it would be good to read that affirmatively.
 

garbulky

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#3
Schiit's procedure to ground the chassis is not with a wire. You don't have any evidence that the thing is not grounded. All you got is somebody reporting a hum. You also don't know what's causing the hum. Wouldn't you want to get a reading first to confirm lack of grounding before putting alarmist headlines? I think that's being a little unfair to the manufacturer.

Edit: Later in the thread I found out from Amir;s post that a multimeter was used to test grounding and it showed that it wasn't. Also that a picture of the multimeter test was sent to Schiit. I haven't seen a picture, but I withdraw my objections and agree that the case is not grounded.
 
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March Audio

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#4
Apart of course from the fact that nothing is connected to the earth terminal on the IEC connector. Plainly clear in the picture.

What other earthing "procedure" are you referring to? If not with a wire then how? Psychic link?
 

amirm

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#5
Schiit's procedure to ground the chassis is not with a wire.
How are you aware of their procedure?

You don't have any evidence that the thing is not grounded.
I have pretty good evidence given the lack of grounding lug altogether to the mains terminal.

As to electrical grounding, I have experience with Jotunheim where that paint insulates the lid and does not allow proper grounding. This was confirmed by Schiit as a problem. Exact same thing is visible here with the top part of the bottom case fully painted, not allowing electrical contact.

What I explained and other engineers in the forum attest to, is standard practice that is missing in Schiit. here is the top enclosure of Benchmark DAC3. Notice how they properly masked the area around the screws to avoid have it be coated with the finish:

Benchmark DAC3 Case Grounding.jpg


Honestly, we are talking about seeing a new car without seat belts. These are common measures and need to be followed for best performance and safest product design.

Again, Schiit has accepted and clearly indicated in the case of Jotunheim that their manufacturing process called for such removal of finish from the case and we don't see it here. So please don't run interference unless you have a proper technical explanation. This is my field of knowledge and if there is a dispute there better be an engineer with clear qualifications and references to state it.
 

March Audio

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#6
@garbulky the other option if the case is not properly connected to the earth terminal is that it conforms to class ii double insulated regulations. This can be typically be achieved with an additional layer of insulation between the live parts or at least a 6 mm Air gap. The objective is that no single failure can cause the chassis to become live.

If compliant it should have the 2 squares symbol on the case.
 

Blumlein 88

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#7
Saw an approach Schiit could use. This in a new super cheap electronic meter. A grounded corner of the circuit board had a chromed spring which stuck up an inch past the lid. When you put the lid down it contacted a square patch of tinned copper on the lid so it grounded the lid. Now this seems mickey mouse to me though it actually works at least for some period of time. Being mickey mouse it seems perfect for Schiit.

They could use this.
https://www.amazon.com/Shielding-Re...coding=UTF8&psc=1&refRID=DH2ADQB34XMMYAV4NGMK

Folded over the lip of the lower case and used as a gasket between it and the upper lid. Then clearing away some of the inside surface of the lid for contact. Would provide a little mechanical damping to the case as well.
 
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March Audio

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#8
Question. I presume that's a voltage selection switch next to the IEC socket. Would that be considered a point of potential failure without chassis earthing? I have certainly had similar toggle switches fall apart before.
 

amirm

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#9
That switch (SW1) is a power switch.

What I worry about is high voltage feed to the tube right in the middle. Shorts there could easily travel to the outside shield of RCA cable and energize one's entire audio system with potentially lethal voltages.
 

garbulky

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#10
How are you aware of their procedure?
I was under the impression it's using that chassis contact you are talking about. I recall Jason talking about it on headfi . I'm just saying, you don't have the unit. You don't know that it's ungrounded. You don't even know if it's causing a hum.
Now if this guy is so concerned, he shouldto stick a cheap multimeter on there to show that it's ungrounded, sure I would say there's less assumptions then. But you want to trust some guy from europe and some pics he sent, that's your call! I suggest more evidence.

In related news the Emotiva DC-1 also doesn't have a ground lug
https://audiosciencereview.com/forum/index.php?attachments/emotiva-dc-1-missing-ground-lug-20180202_132521-jpg.10318/
 
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March Audio

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#11
Wrong. We can plainly see it is not connected to mains earth. There is no connection to the IEC socket earth terminal. If you understood the subject you wouldn't be questioning this.

Can you Please quit the Schiit apologist routine you keep indulging in.

The only question in my mind is if there is an insulation sheet under the circuit board in which case it might, and stress might, have a chance of being considered class ii.

Emotiva, haven't seen pictures. If it has no ground lug I would suspect it has been correctly designed to class ii standards.

Edit just looked at the pictures here
https://audiosciencereview.com/forum/index.php?threads/teardown-of-the-emotiva-dc-1-dac.2310/

IME it does indeed have 6mm air gap around the live components and would be considered class ii compliant so no need for an earth connection.
 
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amirm

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#12
But you want to trust some guy from europe and some pics he sent, that's your call!
The evidence as I explained is clear from the picture:

1. The grounding lug from the IEC mains is NOT connected to anything.

2. The top of the case still has full paint/coating which insulates the top from being grounded. And per Schiit, is required to be brushed off to conform with their manufacturing spec.

And again, both of these are highly consistent with the issues of Jotunheim. Schiit confirmed my findings.
 

garbulky

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#13
The evidence as I explained is clear from the picture:

1. The grounding lug from the IEC mains is NOT connected to anything.

2. The top of the case still has full paint/coating which insulates the top from being grounded. And per Schiit, is required to be brushed off to conform with their manufacturing spec.

And again, both of these are highly consistent with the issues of Jotunheim. Schiit confirmed my findings.
Sounds like you've got it figured out then! No need for any testing.
 

amirm

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#14
Sounds like you've got it figured out then! No need for any testing.
What you need to do is ask Schiit if they think these pictures represent proper manufacturing of their product or not. You are active in a forum where they participate and would read your posts. Are you willing to do so?

If Schiit wants to test the product then that is great and is what I wished they would have done when the owner asked. They need to fetch his machine free of charge and get it for testing in California and not some distributor in Europe.

We are dealing with serious safety and performance issues here. This is no place for debating tactics such as you practicing on me.
 

restorer-john

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#16
The double insulation standard seems to have watered down either by manufacturers or due to the lack of continuing oversight. It used to be simple- two distinct layers of insulation between any live (mains) or potentially live parts and anything that could be touched by a user.

Now we have 6mm air gaps. Air gaps are useless, especially with perforated tops for ventilation and small children 'posting' objects. More and more people using this small form factor chit on desktops where items such as staples and paper clips are likely to be found...

I wouldn't bring to market any product that wasn't correctly earthed and the only reason they do, is because a massive amount of modern HiFi simply cannot be trusted to not hum and buzz like a bag full of wasps due to poor design.

We just had a chitfight on AK about proper earthing (Australian regulations used to be excellent in that regard) and poor earthing practices in the past, and, it seems now. A 3 pin IEC chassis male should have all three pins connected. The proliferation of two pin IEC chassis males on 'double insulated' gear is widespread in audio/video gear. I don't like it.

The chit stuff doesn't even secure their power transformer except by the solder lugs. There is no insulation over the mains (metal unearthed toggle) switch, the IEC socket or the line fuse. God knows what is underneath the PCB- I don't want to know, but unless its a thick layer or two of elephanthide, it's a death trap down the track when it gets dropped, stood-on or dented in transit.

I've said it before and I'll say it again- the standard of construction in modern affordable 'hifi' is crap.
 
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#17
I would be more worried about the PCB designer who flooded a top side plane without observing the 3mm insulation distance (if a class I device) to mains power....

And although the used power connector seems to have its ground pin going down to the PCB, that's not enough according to EU rules for class I devices, which apply as the unit is sold in EU.... And it can't be a class II device as it's missing the required markings, according to the pictures on Schiits website....

Seems like the designer is not up to date on both US and EU electrical safety rules, I wouldn't want to plug that device into live mains power anywhere in the world....
 

Blumlein 88

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#18
You can do a quick search and find a good many posts on forums about hum on the Saga or noise when you touch the top of the case. I would guess it is the same issue as the Jotunheim.
 

amirm

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#19
You can do a quick search and find a good many posts on forums about hum on the Saga or noise when you touch the top of the case. I would guess it is the same issue as the Jotunheim.
Oh, that then confirms the issue and calls into doubt Schiit's prior statement that the broken Jotunheimen were a fluke.
 

restorer-john

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#20
My question is, how many regulators are asleep at the wheel?

All this direct selling straight from websites, all over the world, is resulting in stuff like this and some of awfully bad Chinese stuff we are seeing.

It was only a few weeks ago we saw some Chinese JLH design that looked positively dangerous just based on the few internal shots with potentially live chassis situations from predictable insulation compression under a toroid can.

We know what's it's going to take- a bunch of electrocutions before 'regulators' wake up, but it's a pity that is what is needed.
 

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