Fixing Hum/Buzz issues with Schiit Jotunheim Headphone Amplifier

[amirm]

Seems like it. Will try the fix later this week when I get the time. Just to be clear, I should also sand the chamfers for the bottom screws?

You do. Without it doing the keyhole won't do any good since the bottom is not grounded.

At this rate though looks like Schiit knows the problem and will fix the issue. So unless they stick you with shipping costs back and forth, or you can't wait, I suggest having them fix it.

 

[IdiotCustomer]

You do. Without it doing the keyhole won't do any good since the bottom is not grounded.

At this rate though looks like Schiit knows the problem and will fix the issue. So unless they stick you with shipping costs back and forth, or you can't wait, I suggest having them fix it.

Hmm well I guess the best thing would be to contact them and ask what the shipping cost and time would be. From experience though I'm afraid it's going to be rather expensive and time consuming. Not really their fault though but our high taxes here and all the bureaucracy nonsense. Well I've learned my lesson, never buy anything abroad again when living in the socialist republic of Sweden

 

[amirm]

Given the safety risk, I expect them to step up and pay for your shipping both ways. Otherwise they could risk you complaining to EU branch for CE certification. Pretty sure they wouldn't want to see you do that.

 

[jsm59]

It only impacts units with internal power supplies. The only such unit I have right now is the loaned Yggdrasil and while I can't power it down to really check, it seems fine. It has a bunch of screws holding the lid down which give nice electrical connection. It is the friction fit with the Jotunheim that is the problem.

Thanks. I guess I misspoke questioning if MANI could be effected then.

 

[IdiotCustomer]

Given the safety risk, I expect them to step up and pay for your shipping both ways. Otherwise they could risk you complaining to EU branch for CE certification. Pretty sure they wouldn't want to see you do that.

I sent a new request so I'll see how they respond. Not holding my breath to get an answer except for "start a ticket and we'll send you information on how to start the procedure"

 

[Jimster480]

It only impacts units with internal power supplies. The only such unit I have right now is the loaned Yggdrasil and while I can't power it down to really check, it seems fine. It has a bunch of screws holding the lid down which give nice electrical connection. It is the friction fit with the Jotunheim that is the problem.

Cant you check it with your multimeter while it is plugged in?

 

[Jimster480]

Just another piece of Schiit Headphone Amp/DAC to avoid. This Forum is great !! ....View attachment 13932 going to order the Topping D30 on Amazon for 95.00

D30 is a great product, but its not the same type of product like a jot, you will also need an amp as the Jot is primarily an amp that has Dac options.

 

[IdiotCustomer]

D30 is a great product, but its not the same type of product like a jot, you will also need an amp as the Jot is primarily an amp that has Dac options.

What separate dac+amp would you recommend with xlr inputs and outputs similar to jot? So source>dac usb in>dac xlr out>amp xlr in> amp xlr headphone out>sennheiser hd650. Budget $500-$700 for separate dac and amp with the main focus on the amp

 

[amirm]

Cant you check it with your multimeter while it is plugged in?

I did. Problem is that if there are mains currents running through it, it screws up the delicate measurements of ohms in the meter.

 

[garbulky]

@amirm
I was looking at your grounding instructions. So if I'm correct in interpreting, the case is not grounded. And it's supposed to be right? And the way you found this out is that if it is not grounded then the impedance should be HIGHER than 1 ohm? And if it is successfully grounded it has to be less than 1 ohm? What value did you get when you concluded that it was not grounded?

 

[Blumlein 88]

It occurs to me you could also scrape away a small area underneath the washer where the volume control screws down to the front panel for another point of ground. This also would not show.

Then if you get the pins clean of paint to connect side/bottom to the lid it would all be grounded.

 

[Blumlein 88]

@amirm
I was looking at your grounding instructions. So if I'm correct in interpreting, the case is not grounded. And it's supposed to be right? And the way you found this out is that if it is not grounded then the impedance should be HIGHER than 1 ohm? And if it is successfully grounded it has to be less than 1 ohm? What value did you get when you concluded that it was not grounded?

He got an open circuit. See the photo upthread. When his multimeter was reading OL. That is what you get if you hold the probes in the air apart from each other as there is no conductive path. It is what you get when two parts are insulated electrically from each other.

 

[amirm]

@amirm
I was looking at your grounding instructions. So if I'm correct in interpreting, the case is not grounded. And it's supposed to be right? And the way you found this out is that if it is not grounded then the impedance should be HIGHER than 1 ohm? And if it is successfully grounded it has to be less than 1 ohm? What value did you get when you concluded that it was not grounded?

I got complete open connection when I measured it originally (meter says "OL" for open load). In other words no electrical connection at all. The "1 ohm" value is a nominal one as how good the probe is and the meter impacts the exact measurement. If done correctly and precisely, it should be essentially zero.

 

[amirm]

It occurs to me you could also scrape away a small area underneath the washer where the volume control screws down to the front panel for another point of ground. This also would not show.

I thought of that but the shaft of the volume control is not grounded so getting the two to mate makes no difference. And at any rate a path through the volume control shaft would not be advisable for the type of currents this needs to handle (hundreds of amps for milliseconds until breaker trips).

I think you are assuming the threads are connected to the chassis but they are not.

 

[garbulky]

I got complete open connection when I measured it originally (meter says "OL" for open load). In other words no electrical connection at all. The "1 ohm" value is a nominal one as how good the probe is and the meter impacts the exact measurement. If done correctly and precisely, it should be essentially zero.

So by correctly you mean if the case is grounded it should be less than 1 ohm or close to zero? Like that's what you would want ideally?

 

[Blumlein 88]

I thought of that but the shaft of the volume control is not grounded so getting the two to mate makes no difference. And at any rate a path through the volume control shaft would not be advisable for the type of currents this needs to handle (hundreds of amps for milliseconds until breaker trips).

I think you are assuming the threads are connected to the chassis but they are not.

Yes I was assuming the threads were connected to the chassis ground.

Well, just a thought. I won't have any Schiit here so no worries to me.

 

[amirm]

So by correctly you mean if the case is grounded it should be less than 1 ohm or close to zero? Like that's what you would want ideally?

Correct. That is why the best way to achieve that is with a screw with locking washer into the chassis like this: (green wire)

That upper part of the IEC connector on the Schiit Jotunheim is unused:

The friction fit that we have here is insufficient in my opinion from safety point of view (but good to get rid of buzz/hum). And its path through the PC Board will have insufficient current carrying capability.

To expand, we want the 14 or 20 amp home circuit breaker to pop. These being mechanical devices, in the short term they allow 100 or more amps before they blow. We need the chassis connection to be able to handle such massive amount of current and energy. This is why you want as close of an impedance at zero as you can get. 100 amps at 1 ohm is still 100 volts!!! (Volt = Resistance * Current). We want that let through voltage to be as close to zero as to avoid an electric shock.

I have generated such shorts and it is incredible the amount of power there is. I once cut through a live "Romex" wire that was live. Before the breaker popped, there was an amazing spark and it completely vaporized the cutting portions of the plier! And this is with our weak 120 volt system in US. Make that 240 volts and power delivery doubles yet again.

 

[restorer-john]

In my opinion, there should be a earth wire from the IEC socket straight to chassis ground screw/PCB earth and then another earth jumper to a ring under the hex nut of the volume control. The area immediately around the volume control pot nut on the upper chassis cover would be masked during painting and left exposed to make good contact with the nut, the ring and the upper chassis. The knob, if metal, is then also at chassis earth.

Using the keyhole pins is inadequate and may result in eddy currents in any case.

I cannot see how the device in its current (no pun intended) state would pass safety standards in any country.

 

[Blumlein 88]

snip.....

I have generated such shorts and it is incredible the amount of power there is. I once cut through a live "Romex" wire that was live. Before the breaker popped, there was an amazing spark and it completely vaporized the cutting portions of the plier! And this is with our weak 120 volt system in US. Make that 240 volts and power delivery doubles yet again.

Actually, power delivery quadruples. Current doubles.

 

[Alcophone]

Excellent. The only surprise is that he is showing a keyhole that he says has good connection but all I see is paint. That was the same as my unit until I sanded it off.

He said this:

The masking is only on the edges of the slot, not on top, but they are showing bare metal as intended.

And his picture is too blurry to see how much paint is in there, unfortunately. I ordered a multimeter and will check mine, too, once I get it.