solderdude
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Post by solderdude on Jan 5, 2017 7:18:52 GMT
I suspect the distotion you hear is because of lack of headroom (the amp works on 12V) or incorrect biassing (which cannot be set on that amp)
G1217 amps will not have those problems because they have way more headroom.
The tinging you get is because of high leakage currents, most likely from an SMPS power supply.
Grounding the amp to safety ground will most likely cure that problem
a ground loop isolator won't work here because the leakage comes probably from the amps power supply and will thus still be there, possibly even be worse.
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Post by darkarn on Jan 5, 2017 11:52:16 GMT
Thanks, sounds like I really need a new amp; it was what I thought of for a long while but just needed the correct info to confirm it
The tube amp is now using a SMPS; will changing it to another SMPS help? Also I am not sure how to ground the amp to safety ground...
As for G1217 amps, I am quite close to deciding what I want soon, but just not sure of the following:
1. Is the power supply still an SMPS? If yes, will the same issue occur or not? (i.e. is the issue caused by all SMPS or just "bad" SMPS?)
2. How long will the kit or the completed amp take to ship once ordered?
3. Will the line-out ports of Sunrise/Horizon/Ember be affected by the output impedance? (I am asking as I am starting to like to use the attenuator even for the speakers lol, but then again I think this is due to other reasons)
4. Line-out bypass: Will audio play again from the line-out once I remove the headphones from the headphones plug or do I need to restart the amp?
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solderdude
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Post by solderdude on Jan 5, 2017 12:56:46 GMT
It could be the SMPS of the amp BUT could also be coming from the DAC/PC it is connected to...
When the amp is not connected to anything else but its own power supply (no RCA connected) do you still get the same 'tingling'?
When no amp is connected and you touch the sheeth of the RCA that normally would connect to the amp do you still get the tinging ?
Changing the PSU to a linear (MUST be regulated) power supply COULD help when only the amplifier power supply is the culprit.
grounding means connecting a piece of electrical wiring from the sheeth of the input RCA to either the safety ground prong of a mains outlet or (bare metal) part of copper waterpiping or bare metal part of central heating (when it has metal piping).
1: Yes
2: I have no idea, you have to ask Jeremy.
3: No
4: there is no line-out bypass. The line out signal is volume controled and passes through the entire amp. Once the headphones are plugged in line-out is disconnected. Once the headphone plug is pulled out the line-out is present.
However, you can ask Jeremy to make it so the line-out is always present, regardless of a headphone being plugged in or not. In the latter case the output R setting may be of influence depending on the used headphone and setting (M or H output R)
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Post by darkarn on Jan 5, 2017 13:52:09 GMT
It could be the SMPS of the amp BUT could also be coming from the DAC/PC it is connected to... When the amp is not connected to anything else but its own power supply (no RCA connected) do you still get the same 'tingling'? When no amp is connected and you touch the sheeth of the RCA that normally would connect to the amp do you still get the tinging ? Changing the PSU to a linear (MUST be regulated) power supply COULD help when only the amplifier power supply is the culprit. grounding means connecting a piece of electrical wiring from the sheeth of the input RCA to either the safety ground prong of a mains outlet or (bare metal) part of copper waterpiping or bare metal part of central heating (when it has metal piping). 1: Yes 2: I have no idea, you have to ask Jeremy. 3: No 4: there is no line-out bypass. The line out signal is volume controled and passes through the entire amp. Once the headphones are plugged in line-out is disconnected. Once the headphone plug is pulled out the line-out is present. However, you can ask Jeremy to make it so the line-out is always present, regardless of a headphone being plugged in or not. In the latter case the output R setting may be of influence depending on the used headphone and setting (M or H output R) Apparently the amp I am using now is using 3.5mm jacks and not RCA jacks; not sure if this will affect anything. Also my DAC is a Fiio Taishan; its RCA sheaths have no such tingling and the 3.5mm socket is recessed such that I cannot touch it (planning to get a Modi Multibit) When the amp is not connected to anything but its own power supply: No tingling (cos I not sure what to touch other than the metallic parts of the 3.5mm sockets) When the amp is not connected to anything but its own power supply and has a 3.5mm cable dangling (not connected to DAC or headphones) from line out port of amp: No tingling When the amp is not connected to anything but its own power supply and has a 3.5mm cable dangling (not connected to DAC or headphones) from line in port of amp: Have tingling
When no amp is connected and you touch the sheeth of the RCA: No tingling As for grounding, I don't think I can do that unfortunately; I may have to be just more careful in using the amp until I get a new one. I just hope that the new G1217 amp will indeed help with all these problems... |
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Post by darkarn on Jan 12, 2017 12:02:35 GMT
Alright, I did some more tests and found the following: 1. The attenuator is indeed beneficial for sound for all headphones and even powered speakers. Less hiss => Can focus on the music better => More details. Lower noise floor => More highs, tighter bass. This is however quite nuanced though (i.e. no "night and day" difference) 2. EMI/RF noise almost gone for headphones. They are audible only when at near 100% volume, which by then, would have causing audio distortion and deafness  3. EMI/RF noise for powered speakers are more audible when used with the attenuator. 4. EMI/RF noise for powered speakers can also be heard when not connected to anything. Not surprising seeing how the noise could have travelled through the power supply of the powered speakers. Thanks for getting me to build the attenuator! It helps to reduce the EMI/RFI noises by making them less audible. It also helps in exposing the weak parts of my audio chain (e.g. lack of headroom of the tube amp, powered speakers being more susceptible to EMI/RFI noises meaning that I should look into getting non-powered speakers in the near future). More importantly, I feel more confident in my skills and tools; I feel more ready to take on a bigger project now! Now let's see what happens when my Schiit Modi Multibit and new Garage1217 amp comes... |
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Post by darkarn on Jan 24, 2017 19:21:59 GMT
My very good friend loaned me a Denon DA-10 after he heard about this problem that I am having. Let me see how it can further diagnose the issue.
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Post by darkarn on Jan 31, 2017 8:13:21 GMT
I have done more checks, apparently both the powered speakers and the tube amp are vulnerable to the noises. I suspect their power supplies are too sensitive to such noises. The Modi Multibit is not affected by this due to its linear power supply; no such noises are heard when using this with the Denon DA-10 on battery mode. And of course, the Denon DA-10 too is not affected due to it being a portable amp (I have not tested when using it with USB power though)
Also, I can confirm that the attenuator will increase such noise if used with the powered speakers but not the headphones. Nonetheless, other benefits (e.g. lower noise floor, more volpot travel) still apply to all.
For now, I have removed the homeplugs and now testing if I need them in the first place. Things seem promising seeing that I can get 2 bars of signal but if on 2.4GHz. I am also awaiting my Project Ember to arrive to further test before concluding.
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Post by darkarn on Feb 19, 2017 16:36:26 GMT
I have tried using a Belkin SurgeMaster MasterCube with a Belkin Home Theater surge protector that also has RFI/EMI protection and can confirm that these effects do stack to keep such noises lower than compared to using a Weiduka with the MasterCube. However, the sound quality feels off. Using only the Belkin Home Theater surge protector will help keep RFI/EMI lower but not as low as using both surge protectors while not affecting sound quality badly.
Either way, it is best to just avoid homeplugs altogether, especially with the advent of "mesh" WiFi products that can spread Internet connectivity around the house more effectively while not creating such RFI/EMI noise. Of course, having the house rewired such that every room has Ethernet and new electrical wiring will be best of both worlds, but very exorbitant. Meanwhile, I am using a Netgear Orbi to resolve WiFi issues, which is promising so far, but I withhold judgement until more testing.
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Post by darkarn on Mar 6, 2017 19:27:52 GMT
Alright, finally!
I have tested the Project Ember against this issue and I can safely say that it is not as sensitive to this problem as compared to my previous tube amp; even at full volume for both the speakers and amp, the noise is barely audible unlike when on my previous tube amp. This confirms that somehow the Project Ember can hold up against these noises better. I think the combination of using higher voltage at 48V, more complex design of the Ember and the usage of a good Meanwell SMPS instead of some random SMPS helped achieve this. The caveat is that I am using a 100K attenuation module kindly provided by Jeremy as I am using sensitive headphones.
Once the linear power supply of the Project Ember comes out, I *may* want to get it and see if it helps kill off the problem entirely.
As for the Orbi, it is awesome too; we are talking about full Wifi coverage even in previous deadspots and almost seamless changing between the router and satellite. Netgear just needs to make its Guest Mode properly! But either way, it looks like I won't be needing HomePlugs anyway for now...
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