I can tell its definitely a 60hz hum, actually not that dissimilar from a street lamp but ive heard this type of hum from other tube amps.
Im not sure what to tell “Mike” from quicksilver but I think what I put on the previous post may be a good start.
Remember that the right preamp tube socket has some sort of false? When the tube is at a certain position it will flash its light as if trying to turn on but fail and stay off.
Does it make more sense now that theres some wiring damage related to that? I do suspect RF based on the hum; wheter related to the “damaged socket?” Or not.
Also I purchased some tubes with as little microphonics as possible, for phono that I could test with. Theyll take a while to arrive tho.
This is distinct from Microphonics, every piece of wire in a device is an aerial, transmitting and receiving, that includes the filaments in the tubes, if something happens to be just the right length, it’ll pick up noise, everything from AM radio to mains hum.
Assuming you’ve tested without a source connected, this is critical, you can’t rule out a ground loop if you have a source connected at all.
It could be damage to the socket or the wiring to it, but without knowing what normal is for the amp, it’s hard to say if quicksilver would even consider it a problem, which is why I suggested contacting them before sending it back for repairs.
I went through this with A&S, talked to Justin sent the amp back for testing and all they did was test it, say it was normal and send it back with the same hum. ZMF and A&S payed for the round trip but it was still annoying.
Is there a distinct sound to a ground noise to that of RF?
This noise ive heard before when my yamamoto ha02 was broken, that one had a broken metal rod that connected the pot to the handle
The BHC also hummed as the screws on the transformer got loose by the vibrations.
I call all these 3 transformer hum but they had a distinct sound, the yamamoto I would describe as “feedbacky” like in noise music it was manipulated by even getting the hand close to the amp
The one on the BHC would stay the same no matter what changed (source, tubes, etc) much like the one im having on the Quicksilver, until I tighten the screws.
Thanks for the suggestion. Ill see what mike suggests and only send him if he requests, I would think he would want to fix the malfunction on the socket, although that could be an easy fix he should have the first say on that. Also I dont think its meant for users to open as you point out its danger is overstated.
Thats quite annoying. I hope you could fix it or find a good use for it.
No it’s mostly just a mains hum.
A ground loop is caused when there are multiple paths to ground, we’re taught to think of ground as an absolute 0V potential, but that’s not how it works, in fact every ground in a device will be at a slightly different potential, and as a result current will c\flow between them.
If at any point one of those currents flows through signal ground you hear it.
There are at least 2 grounds in pretty much every device in an audio chain with a 3 pin plug, depending on how the device is grounded. Signal ground may or may not be connected to power ground and if it is, it could be ac or dc coupled.
Your Amp has grounds at the Inputs and the power connector which is why you need to disconnect one of those to test and you can’t test it without power, There can be ground loops inside a device but those are the designers problem.
If it is a ground loop there are solutions, but you need to establish if it is.
Hello again, just wanted to follow up on my last post.
Its been some time but I actually sent Quicksilver’s Mike an Email the day I made the previous post and he replied within hours, very politely and helpful.
Obviously the amp couldn’t be properly diagnosed without taking it apart but based on the information we had Mike told me that I have one of the earliest units of the QSHA which would have this exact hum that I get on higher sensitivity headphones.
After the initial run of these amps Mike redesigned the amp to lower the Hum as much as possible on the newer units by Improving the shielding on the output transformers and some circuitry changes.
My unit can be redone with these changes with a cost of around $300, but since im in south Mexico sending the unit on a round trip to California would cost around $400 all and all.
The amp is really good and I can still use it with my planars and higher impedance cans with 0 noise. I even got some nice Amperex and Telefunken for it, I can take it to Mike’s for way less by crossing the border myself, but im not really sure if I should invest those $300 (maybe more with the tariffs) or save that money for the Trafomatic Head 2 that Id like to get.
The other issue was the that one of the sockets had a malfunction, it probably got loose by having too many different tubes plugged in and out; which Mike told me how to fix by myself, leaving the amp off overnight and wedging a needle in between each tube socket pin and the edge of the socket as to close the pins down and make a nice tight fit for the tube which worked like a charm.
Props to Mike for making such a nice amp, Im not sure if ill get it upgraded but im definitely enjoying it with many headphones still.
Hey guys, has someone here tried the Susvara on the Quicksilver?
I am asking because i understand that theoretically it doesn’t have enough power to properly drive the Susvara, i was expecting to notice a lack of dynamics and possibly even clipping or distortion, but i can’t hear any of that.
Actually, what i am experiencing is a very good synergy between the two. I can tell the OOR has better bass control, but the Quicksilver’s bass is still great.
My listening levels are around 85dB to 90dB with no EQ.
It probably has plenty, despite internet discussions that claim the Susvara needs Watts of power, if you do the math 1W is lots more than it needs, you can run one off a Schiit Magni, with plenty of volume, and no clipping (I’ve done it). It doesn’t sound particularly great of the Magni, but that’s not a function of power.
While I will admit that generally more powerful amps tend to work better with the Susvara, that isn’t at least directly a function of power or current for that matter, you can do the math and determine that
The argument will degenerate into headroom, with people claiming they need 20dB headroom and the numbers do start to get into Watts with that but it’s just not true 20dB of headroom would be 10x louder peaks than the average. 3 or 4x is is a lot more likely.
But at 120dB’s you do really need 5W while going deaf.
If you instead say only need 110dB’s which would still be way more than you probably want, you still only need 1/2W.
Exactly why some amps perform better with the Susvara, I don’t honestly know, but it’s not specifically power or current delivery as a lot of the internet would suggest, at least not in any obvious way.
It may be just that more powerful amps will have different distortion profiles, when outputting a fraction of there designed power, or it may be that amps with more gain have higher slew rates, and perhaps that has some impact, or perhaps the nature of the ultrasonic ringing on an amps output is different when signals are small.
What you are stating matches what i am hearing. The part which still makes me wonder is the extra headroom for proper dynamics specially in the lower end.
I guess using the quicksilver for softer genres and for acoustic is 100% fine, but MAYBE if listening to something busy and bass heavy at around 90dB will cause the Quicksilver to not have enough headroom for the necessary dynamic swings in the lower range (i have read those can go up to 110dB if listening at 90dB).
Amplifiers basically just change one voltage into another one based on gain. Where power comes in with clipping is that the maximum output volume is gated by the power supply maximum volume and the current available in the output stage. It either has enough for the given load or or clips, busy has nothing to do with it.
For dynamic drivers Bass frequencies do, make a difference, less so for planars since they have relatively constant impedance.
There is an impact in tube amps where the voltage swings are around the supply voltage and they are relying on stored energy in the output transformer, but that’s captured in the bandwidth of the Amplifier.
And the stuff you’d probably listen to loud will almost certainly have less dynamic range.
You MIGHT see a classical recording with +20dB peaks over it’s quiet passages, but your not likely to listen to the quiet passages at 90dB’s. Your average rock track is going to be more like 5-6dB’s and something recorded in the 90’s it might only be 1 or 2dB peaks because of the excessive use of compression in those recordings.
Short version don’t over think it, if it isn’t obviously clipping and it sound good just listen to it.
Tube amp clipping is also a lot less offensive than SS clipping.
Another question for Quicksilver owners who also have the Utopia OG.
How is the noise floor for you with this pairing? I can 100% hear some constant noise and i am wondering if it may be something in my chain or if that is expected from this amp + headphone pairing.
I don’t have the Quicksilver, but I can tell you I have owned/own exactly 1 tube amp where the noise floor is not discernable on the Utopia. I couldn’t get the DNA silent, I can’t quite get the Viva silent only the EC is silent.
The Utopia is just very sensitive, and you almost always get some very quiet hum.
I actually added an output attenuator to my own 2A3 amp to drop the noise floor below audible and that has DC heaters and a separate power supply.
It wasn’t dead silent, but it wasn’t distracting for me to where I was bothered by it. It really will depend on the tubes you use, the quality of the power coming in, and the rest of the chain as well. Also I do think it may change depending on the quality of the utopia cable being used since some do change the impedance and sensitivity a bit (sorta, spitballing since I noticed some slight changes there but not fully sure why). Can echo with other comments here that most tube parings are not 100% silent
The noise is almost certainly EMI from the power transformer, there is only so much you can do to shield it in a small box.
On the DHT amps I quoted it’s more likely a combination of EMI and heater noise.
On my 2A3 amp it’ll be ground noise.
The MySphere 3.1’s are even worse offenders for being too sensitive on some amps FWIW.
I should add the two that did NOT have noise were the Radu and Eddie Current Studio B. If i pause the music with headphones on the EC sounds like everything was turned off its so silent.
Thanks for the responses guys, yeah it sounds like there is nothing really wrong in my chain then.
I only notice this background hum when there is no music playing, like if i connect and then disconnect the Utopia, it becomes clear there is a background noise there. I may try a impedance adapter, see how it sounds with that.
