Schiit Saga Grounding and Hum Issues?

[amirm]

A short self-tapping screw is another option to get a secure chassis electrical connection without sanding/grinding the paint off.

The problem is that the chamfer from the top of the lid is coated. So one way or the other, you still have to sand off something to make a connection from top to bottom.

 

[DonH56]

They make special screws that are both self-tapping and have sharp little "ridges" on the bottom side of the head for exactly this application. They will scrape off the paint to make good electrical contact as you tighten them down. I do not know where to get them but have seen them often around work (I think we use them on some of our products -- procurement is outside my area).

 

[amirm]

Ah, it would be good to have those. Would make the work easier.

 

[Blumlein 88]

They make special screws that are both self-tapping and have sharp little "ridges" on the bottom side of the head for exactly this application. They will scrape off the paint to make good electrical contact as you tighten them down. I do not know where to get them but have seen them often around work (I think we use them on some of our products -- procurement is outside my area).

If you are talking about the type with a head like above those are meant to act like a lock washer without the washer. But they do also dig into painted metal and make good contact. They are called a serrated head if you are looking to find some. Sometimes they also have serrated nuts to go with them. The serrated bottoms on both sides of metal lock down firmly and do provide contact thru paint more reliably than other types.

Any good fastener place or hardware store should have some. You also can order them on Amazon.

 

[Blumlein 88]

https://en.wikipedia.org/wiki/Serrated_face_nut

 

[amirm]

I don't think any of those will work since the top lid has a chamfer where the screw goes into. And it is part of the aesthetics of the device.

 

[Blumlein 88]

You can get countersunk serrated head fasteners.
https://www.tfgusa.com/products/cold-heading/counter-sunk-head-serrated-screws/

But I've not seen any that are also self tapping. Perhaps someone makes them.

 

[DonH56]

View attachment 16587
If you are talking about the type with a head like above those are meant to act like a lock washer without the washer. But they do also dig into painted metal and make good contact. They are called a serrated head if you are looking to find some. Sometimes they also have serrated nuts to go with them. The serrated bottoms on both sides of metal lock down firmly and do provide contact thru paint more reliably than other types.

Any good fastener place or hardware store should have some. You also can order them on Amazon.

Those are very close except the ones we have have about a half-dozen sharp ridges that stick up a little higher (maybe, don't have one with me, should try to grab one and take a picture). The PO says they are "grounding screws" specially made for electronic boxes but they are probably the same as, or a variant of, what you are showing. I'll have to see if I can find one tomorrow; my memory may be off and they are the same thing. I remember them having sharper ridges, however.

 

[amirm]

The ridges need to be awfully sharp to cut through the armor in the case. The little ridges won't do anything.

 

[DonH56]

They are designed to cut through paint of the epoxy (baked-on) variety. The ridges are fairly thick at the base then end in a knife edge (they will cut). Think of a knife-edge ridge on a mountain, or a triangular knife with a thick back tapered to a sharp edge. They look much taller than what @Blumlein 88's pix show. e usd to have a stock of them but I've not seen them for a while -- we laid off most of our tech staff a few years ago and a lot of our local parts stock was tossed with all assembly moved to other sites (or contracted out). Then of course management figured out engineers doing product design and test do actually need to build things once in a while...

 

[Blumlein 88]

They are designed to cut through paint of the epoxy (baked-on) variety. The ridges are fairly thick at the base then end in a knife edge (they will cut). Think of a knife-edge ridge on a mountain, or a triangular knife with a thick back tapered to a sharp edge. They look much taller than what @Blumlein 88's pix show. e usd to have a stock of them but I've not seen them for a while -- we laid off most of our tech staff a few years ago and a lot of our local parts stock was tossed with all assembly moved to other sites (or contracted out). Then of course management figured out engineers doing product design and test do actually need to build things once in a while...

My friend who is an ME was let go because his "superiors" decided engineering was a commodity. And having on staff engineers was a waste of money. Especially those who wanted to build prototypes and work thru getting an efficient production ready design. So gone they were, and engineering handled remotely with designs going straight into production. 5 years later that company is kaput. I suppose production companies are a commodity too now!

 

[restorer-john]

Many Japanese (JIS) pan head exterior casework screws (both machine thread and self-tap) on CE gear, have small triple protrusion points under the rim designed to score paint/coatings and electrically couple exterior panels to the chassis. The beauty of these is they create a circular contact 'track' within and concealed under the the skirt of the head. They don't just tear off surface indiscriminately. Here's a few pics I just took.

The classic 'star-washer' with its evil teeth are also very effective when under compression too.

These offset spline type machine screws are a combination of shakeproof and surface destroying- a good option for decent electrical panel contact too.

 

[JJB70]

Earthing/grounding is as simple as it gets and there are any number of cheap and simple methods available, I still think it is a rather damning reflection of Schiit that they haven't managed to properly earth their products. Maybe I'm suffering from PTSD, apparently that's their latest excuse to dismiss anybody pointing out the emperors clothes.

 

[restorer-john]

I still think it is a rather damning reflection of Schiit that they haven't managed to properly earth their products.

It's not just Schiit. They are really no better or worse than others, especially many Chinese products. Safety on mains powered gear is number one. Metal casework and inadequate earthing of same is inexcusable.

When we are chasing noise levels and hum/noise down to >-110dB, earthing/grounding practices become (black) art and years of experience. DonH would have much knowledge in this area, shielding and chasing down extraneous and spurious noise. I pretty much only deal with low frequency mains related stuff in audio (apart from our friends, the SMPS supplies...)

Would I buy Schiit product? No, but I think they are a young company, capitalizing on a clever name, premise, and perceived industry irreverence. I sincerely hope they lift their collective game and become a US company people are proud to own and engineers/technicians/designers grudgingly give them credit for bringing to market products they didn't have the guts to do themselves.

 

[shutterspeed1000]

I wanted to check my Saga preamp and found it seems to be grounded to the 3rd prong on the power input. I did not open it, but I did check from the earth connection on the power input to each RCA and each of the screws in the lid. I had a good connection from each. I also get continuity when touching the edges of the drilled vent holes in the sides and top cover. I did not get continuity on the painted sections, including the lid, but I expected that. Maybe they drill the holes after it is painted? The one spot I could not get any reading on was the power switch.

Is there something else I should check to see if my unit could have a ground issue? Any other tests anyone would like me to try, without opening the unit.

 

[amirm]

No, yours is fine then. I have one in for review which I will check....

 

[shutterspeed1000]

Thanks, I am looking forward to seeing how the unit performs with your audio tests. So far, I have enjoyed the sound it produces compared to my old preamp. I did find replacing the factory tube with a Tung-Sol improved the sound a lot.

 

[PoLoMoTo]

Dunno if this is a necro post but as a Saga owner that was too lazy to check if the case was grounded but wanted to know for other reasons, I googled and found myself here thus feel it would be important to add.

First I'd like to point out in the picture in the OP you can clearly see that the IEC socket pictured is a PCB thru hole mount version and you can clearly see the pin going down from the unused lug down to the PCB, the PCB is then clearly mounted to the case in multiple places with metal stand offs as well as the volume potentiometer not using an insulted shaft or insulating washers, these would all obviously be grounded point of the circuit and I see no reason to blindly assume otherwise. You can also clearly see the IEC socket shown in the Jotunheim is not a thru hole PCB mount version thus the need for a live, neutral, and earth wire. I think all of this known it should definitely be assumed that if no one is going to take the time to actually check that the chassis is grounded.

I checked my unit with a multimeter chassis to earth is a dead short.

Now I was at one point a Schiit hater but being a hater is never helpful, as has been shown, again, clearly in this thread. Everyone seemed to jump on the no grounding band wagon immediately with the only logic being that it wasn't grounded in the same way as the Jotunheim, completely blinding themselves to all of the overwhelming evidence to the contrary. Someone should've actually checked before this thread got so toxic.

 

[amirm]

First I'd like to point out in the picture in the OP you can clearly see that the IEC socket pictured is a PCB thru hole mount version and you can clearly see the pin going down from the unused lug down to the PCB, the PCB is then clearly mounted to the case in multiple places with metal stand offs as well as the volume potentiometer not using an insulted shaft or insulating washers, these would all obviously be grounded point of the circuit and I see no reason to blindly assume otherwise.

That is insufficient. Those PCB traces can burn out in the case of a short well before the breaker pops in your panel. As I showed in the original post, the accepted practice is with a green wire lug firmly tightened to the chassis. And those screws you are counting on, many of them are isolated from the chassis due to the finish. This is why I had to scratch off the chamfer on those in addition to the top.

Regardless, the issue here is that the top of the unit is not grounded in many of these products resulting in transmission of hum to the audio circuits. I and others have fixed this by making sure the top connects to the bottom. And same has been confirmed by Schiit as being their manufacturing process (which obviously has failed).

Now I was at one point a Schiit hater but being a hater is never helpful, as has been shown, again, clearly in this thread.

When it comes to safety of products, my standards are very high. We are talking about someone getting hurt or worse, killed. Industry standards have been developed and there is no reason whatsoever to deviate from them. There is nothing here about loving or hating Schiit. If a product is mis-manufactured as these clearly are, we need to call them on it.

I have praised Schiit products that are engineered well, and point out where they fail. This is a failure. Privately I have had to help others resolve this exact problem. So please don't imply some bias in our intentions. There is none although members clearly get annoyed with the response we get from Schiit (instead of acknowledging clear issue here, they blame it in manufacturing process not being followed).

 

[Wombat]

I read it on the internet or came to a definite opinion based on little depth of knowledge:

Danger Alert