Ferrum OOR - headphone amplifier with a soul ?
Sep 2, 2023 at 2:02 PM Post #3,661 of 3,858
Do you also hear some faint humming from hypsos when powered on like i do, when standing around 0,5-1 meters from it. Or is yours completely quiet?
I've reached out to Ferrum already but ask anyone using a Hypos the following:

I'm sitting in a quiet room and after turning on the Hypos the device is kinda "loud", a distinct buzz, humming is noticable from even one meter away. When I "listen for it" I can notice it from even 2m away...

That doesn't seem right, right?
Thanks
I've raised that question before, email to Ferrum and on here. You might want to go back to the original post above and read on for a bit.

Responses have been too superficial for my liking and I was kind of disappointed.

However after changing the fuse to a HiFi Tuning Supreme lll the noise came down sub- and objectively.
 
Sep 2, 2023 at 2:41 PM Post #3,662 of 3,858
I've raised that question before, email to Ferrum and on here. You might want to go back to the original post above and read on for a bit.

Responses have been too superficial for my liking and I was kind of disappointed.

However after changing the fuse to a HiFi Tuning Supreme lll the noise came down sub- and objectively.

I haven't experienced this humming issue, but I'm not stoked to hear about the customer service shortcomings. For the cash people are shelling out for the Oor/Hypsos, CS should be top shelf. Period.
 
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Sep 2, 2023 at 3:19 PM Post #3,664 of 3,858
I haven't experienced this humming issue, but I'm not stoked to hear about the customer service shortcomings. For the cash people are shelling out for the Door/Hypsos, CS should be top shelf. Period.
I've also sent it in to the dealer. Both Ferrum and dealer couldn't h e a r anything suspicious.
But my complaint is that nobody (Head-Fiers as well) was capable to carry out one simple measurement which I did meaning putting a DB meter on the Hypsos and measure the difference between it turned off then on.

Maybe I'm uber sensitive...
 
Sep 2, 2023 at 4:27 PM Post #3,665 of 3,858
I've also sent it in to the dealer. Both Ferrum and dealer couldn't h e a r anything suspicious.
But my complaint is that nobody (Head-Fiers as well) was capable to carry out one simple measurement which I did meaning putting a DB meter on the Hypsos and measure the difference between it turned off then on.

Maybe I'm uber sensitive...
With my cheap DB meter my hypos measured no difference.

I put my ear next to the hyspos in my very quiet room and could not hear any noise.

If the dealer could not hear the hum it could be your power source.

I had the same problem with my Yggy and got a couple of replies. Mine turned out to be the the transformer.

1st reply - DC offset on AC power makes some transformers hum. The solution is to use a DC offset blocker. My choice is the Emotiva CMX-2.

2nd reply - From GoldenOne
Worth noting that transformer hum can be caused not only by DC offset but also high levels of harmonic distortion on the mains. In which case a DC blocker will not be effective (neither will a power conditioner, they can't fix mains THD only higher frequency noise). Many people buy a DC blocker hoping to fix this issue but then it does not get resolved. In some cases then assuming the device itself must be at fault when actually it isn't.

Not uncommon for some areas to have mains THD of over 1%. IEEE recommends a maximum limit of 5% but some areas may have as high as 10%.

It can also vary over time, in my old place mains THD was low most of the time, then at just after 8AM like clockwork it'd go up and transformers would start humming. Then calm down around 11AM. You may also hear things hum more when reactive loads like a fridge compressor or washing machine are on.

The hum won't actually cause an issue though. It just means the transformers will not be operating as efficiently as possible but most devices have comfortably overspecced transformers anyway. It won't cause any damage, it's just a bit annoying.
 
Sep 2, 2023 at 6:20 PM Post #3,666 of 3,858
If the dealer could not hear the hum it could be your power source.
That makes sense
Worth noting that transformer hum can be caused not only by DC offset but also high levels of harmonic distortion on the mains. In which case a DC blocker will not be effective
Interesting. I use a ifi DC Blocker but not directly on the Hypsos device (i must try that soon) but on my powerconditioner. This explains alot though if a DC Blocker wont help. At the moment the ifi Dc blocker is on the other niagara 1000 powerconditioner where hypsos is not connected. But i have bought a second Dc blocker to try where hypsos is at and direct on Hypsos.
The hum won't actually cause an issue though. It just means the transformers will not be operating as efficiently as possible but most devices have comfortably overspecced transformers anyway. It won't cause any damage, it's just a bit annoying.
It might effect sound quality subtly?

Also it was buzzing very loud when i reversed the power cable on my wall outlet at one time. L and N turned around.
 

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Sep 2, 2023 at 11:56 PM Post #3,667 of 3,858
So, I just received an Oor and there seems to be an issue with the TRS output. There is only volume below the noise floor. To be specific, there is no sound throu the -db and 0db gain settings. Switching to high gain and volume at 80% finally introduces the faintest of signals.

This issue holds for anything connected through the RCA jack. Any thoughts/advice, am I missing something obvious, or is my unit DOA?

Thanks for any assistance. Balanced/XLR works beautifully, btw.
 
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Sep 8, 2023 at 7:00 PM Post #3,668 of 3,858
I have a oor/hypsos, and the oor isn't putting out any sound. I noticed that the output power and output current on the hypsos show 0 for each. I have restarted both units multiple times. The light on the front of the oor is working fine, so it is getting power. Anyone have any ideas of what might be happening?
 
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Sep 8, 2023 at 7:27 PM Post #3,669 of 3,858
I have a oor/hypsos, and the oor isn't putting out any sound. I noticed that the output power and output current on the hypsos show 0 for each. I have restarted both units multiple times. The light on the front of the oor is working fine, so it is getting power. Anyone have any ideas of what might be happening?
Have you checked if Oor is selected as target device in the Hypsos settings menue?
You can also do a quick functionality check by connecting Oor without Hypsos directly to AC power and see if Oor is defective without digging into Hypsos..
 
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Sep 8, 2023 at 7:55 PM Post #3,670 of 3,858
Yes. I have been using it for months with no issue. I just plugged it into the wall directly and nothing. When you have it turned on and plugged in, is the hypsos output power and output current 0 or is it some number?
 
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Sep 8, 2023 at 8:02 PM Post #3,671 of 3,858
Yes. I have been using it for months with no issue. I just plugged it into the wall directly and nothing. When you have it turned on and plugged in, is the hypsos output power and output current 0 or is it some number?
It's showing a voltage number that you can pre-configure within the allowed range of the target device.
If Oor isn't working without Hypsos too you clearly have at least a defective Oor
 
Sep 10, 2023 at 9:14 AM Post #3,672 of 3,858
With my cheap DB meter my hypos measured no difference.

I put my ear next to the hyspos in my very quiet room and could not hear any noise.

If the dealer could not hear the hum it could be your power source.

I had the same problem with my Yggy and got a couple of replies. Mine turned out to be the the transformer.

1st reply - DC offset on AC power makes some transformers hum. The solution is to use a DC offset blocker. My choice is the Emotiva CMX-2.

2nd reply - From GoldenOne
Worth noting that transformer hum can be caused not only by DC offset but also high levels of harmonic distortion on the mains. In which case a DC blocker will not be effective (neither will a power conditioner, they can't fix mains THD only higher frequency noise). Many people buy a DC blocker hoping to fix this issue but then it does not get resolved. In some cases then assuming the device itself must be at fault when actually it isn't.

Not uncommon for some areas to have mains THD of over 1%. IEEE recommends a maximum limit of 5% but some areas may have as high as 10%.

It can also vary over time, in my old place mains THD was low most of the time, then at just after 8AM like clockwork it'd go up and transformers would start humming. Then calm down around 11AM. You may also hear things hum more when reactive loads like a fridge compressor or washing machine are on.

The hum won't actually cause an issue though. It just means the transformers will not be operating as efficiently as possible but most devices have comfortably overspecced transformers anyway. It won't cause any damage, it's just a bit annoying.
Thank you for the tipps. Coming back to the idea of radically approaching this with an audiophile circuit breaker + dedicated line (decent quality cable) first... then measure what comes out of the "audio" wall socket... to find out if I still "need" to take care of DC offset or add another box for filtering whatever else may be noisey.
I mean I sometimes switch off the fridge because it's coming through, although living room and kitchen circuits are separated of course.
Not onley does Hypsos' but also the DAC's transformer hum slightley...

Again, maybe I'm uber sensitive...
 
Sep 18, 2023 at 2:17 PM Post #3,675 of 3,858
A couple weeks ago I was using my Oor/Hypsos. I was plugging in my Beyerdynamic DT 880 600 Ohm headphones into the jack while the music was on. Since the 880s require a lot of power, the volume knob was most of the way up, and the gain was on high. As I was inserting the plug into the 1/4" jack, the music stopped. Since it is still under warranty, I contacted Ferrum and the store I bought it from (Upscale Audio) and they had me send it to the importer and distributor of Ferrum products in the United States, a company called Vana LTD. I just found out it has been fixed and is being sent back to me. Turns out the entire motherboard was fried. It is known that 1/4" jacks can cause shorts, since it is possible for the hot and cold connectors to touch, which would then route all that power that should go out to the headphone back into the amp, frying the motherboard. I saw Golden Sound's review of the Holo Bliss mention this as the reason the Bliss has relatively high output impedance on its 1/4" and 4.4mm jacks, since that greatly reduces the amount of power that would come back into the system if there is a short. From the specs, it looks like the Oor, like most amps, has a very low output impedance on its 1/4" jack, probably since IEMs sound better when plugged into a jack with low output impedance. I saw the guy from ConvinceMeAudio also review the Holo Bliss, and he made the same comment about the high impedance on the Bliss' jacks. He said that if the jack had low output impedance, a short would cause 200 watts to turn back in on the amp, which would fry it.

Ferrum's distributor/warranty administrator, Vana LTD, replaced my Oor's motherboard with a brand new motherboard straight from Ferrum. Apparently when they do that, the only thing that isn't replaced is the sheet metal and the knobs. This motherboard is "of the latest specification" which might suggest there are small "silent" updates to the Oor's motherboard over time. This has been a learning experience. It sounds like this can happen to any amp, and so it is best not to have music playing when you insert or remove a plug from a 1/4" or 4.4mm jack. Apparently this can't happen to a 4 pin XLR jack since the hot and cold connectors can never touch.
 
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