[xTelepathetic]

Sounds like my set-up, (on a lower budget):

1) Little Dot MK9. Very tubey sound that I enjoy, but it gets Super hot, right out to the volume knob. If you pause the music and jack the volume, there is a loud hum. In the regions I listen at, I don't hear anything except sweet music.

2) Schiit Valhalla 2. Crisp and clear sound, with a bit of thickness. But I would not call it very tubey at all. I like it in rotation with the MK9. Going back and forth is fun.

And tube prices aren't bad with either unit (6SL7's and 6922's).

I don't suppose you want to try a weird Cayin HA-1A MK2 that may or may not be possessed LOL

In all seriousness, I think it's awesome how different tube amps can vary in sound and how different tubes can impact it as well. You seem to have a good setup going, with one tube amp for fun and another for purer listening. I'm not familiar with the Little Dot MK9, but the Valhalla 2 is a nice-looking tube amp. All of Schiit's gear is pretty nice looking tbh. I may get a cheaper audio stack to take to work and I am really looking at Schiit for that

 

[donkashyap]

I don't suppose you want to try a weird Cayin HA-1A MK2 that may or may not be possessed LOL

In all seriousness, I think it's awesome how different tube amps can vary in sound and how different tubes can impact it as well. You seem to have a good setup going, with one tube amp for fun and another for purer listening. I'm not familiar with the Little Dot MK9, but the Valhalla 2 is a nice-looking tube amp. All of Schiit's gear is pretty nice looking tbh. I may get a cheaper audio stack to take to work and I am really looking at Schiit for that

Between the Valhalla 2 and the Ha1a mk2 which do you think will be a better pair up for 800S.

Price difference for me is 80$ ( Valhalla 2 is cheaper)

 

[xTelepathetic]

Between the Valhalla 2 and the Ha1a mk2 which do you think will be a better pair up for 800S.

Price difference for me is 80$ ( Valhalla 2 is cheaper)

I haven’t tried either the 800S or the Valhalla 2, but I really liked the HA-1A when it worked. The adjustable output impedance allows for 5 different listening experiences. The Valhalla 2 is an OTL tube amp while the Cayin is not, so I would say the Cayin can be used more easily with other headphones like planars and still sound good. Imo, the Cayin would be a better amp, but I haven’t compared against nor used the Valhalla 2

 

[martas38]

I had the HA-1A problem that the EL-84 power tubes started hissing early. Three months and that was it. I bought TAD EL84M tubes and the problem is solved. They are copies of Soviet tubes for the army.

https://www.tubeampdoctor.com/en/el84m-tad-tubes-premium-matched

 

[donkashyap]

I haven’t tried either the 800S or the Valhalla 2, but I really liked the HA-1A when it worked. The adjustable output impedance allows for 5 different listening experiences. The Valhalla 2 is an OTL tube amp while the Cayin is not, so I would say the Cayin can be used more easily with other headphones like planars and still sound good. Imo, the Cayin would be a better amp, but I haven’t compared against nor used the Valhalla 2

Yeah I’m more inclined towards the HA-1A too. Trying to work a deal out as the seller doesn’t want to ship. Hopefully a friend can pick it up.

 

[xTelepathetic]

Interestingly, I have since tried with some more headphones and found the noise floor to be significantly reduced. My findings are as follows:

The ZMF Aeolus that I have paired horribly, with LCD 3s and 2Cs fairing only slightly better. Lots of static and hiss present. A pair of Ether Flow 1.1s I have has virtually no noise. Aside from the headphone differences, I wonder if this could be a result of the cables as well. Using a 1/4" drummer cable on the Ether Flows, which is markedly thicker than that cable used for all other headphones. Also to note is that the DCA drummer cable jack is gold-plated, while the others are silver. Could this impact the noise or just a random coincidence? Additionally, powering 2 headphones at the same time (IE Ether Flows and Aeolus, LCD 3 and Aeolus, ETC) reduces the noise and hiss present problematic headphones but kills their tubiness and makes the sound much more flat and boring. Essentially back to square 1 now, as it could still be an amp issue, a headphone issue, or a headphone cable issue.

 

[r343]

Interestingly, I have since tried with some more headphones and found the noise floor to be significantly reduced. My findings are as follows:

The ZMF Aeolus that I have paired horribly, with LCD 3s and 2Cs fairing only slightly better. Lots of static and hiss present. A pair of Ether Flow 1.1s I have has virtually no noise. Aside from the headphone differences, I wonder if this could be a result of the cables as well. Using a 1/4" drummer cable on the Ether Flows, which is markedly thicker than that cable used for all other headphones. Also to note is that the DCA drummer cable jack is gold-plated, while the others are silver. Could this impact the noise or just a random coincidence? Additionally, powering 2 headphones at the same time (IE Ether Flows and Aeolus, LCD 3 and Aeolus, ETC) reduces the noise and hiss present problematic headphones but kills their tubiness and makes the sound much more flat and boring. Essentially back to square 1 now, as it could still be an amp issue, a headphone issue, or a headphone cable issue.

Made some observations when owned HA-A1 (brand new!)

1. When fed with unbalanced RCA signal amp will ground loop causing hissing, RCA isolator fixed this, other way is to plug RCA output from HA-A1 to some other amplifier

2. It Hums with every headphone to some degree, no matter if source is plugged or not or volume pot is to zero or not, turning impedance knob to higher will increase intensity of the hum, hum can be eliminated by using very insensitive headphones or buying gain reducer like IFI IE match.

3. If touching or knocking amplifier physically causes ringing like noise to either channel of headphones, one or more tubes is faulty, in my case it was EL84 power tube.
Fully healthy tubes won't exhibit noise even when amplifier is physically touched.

 

[xTelepathetic]

Made some observations when owned HA-A1 (brand new!)

1. When fed with unbalanced RCA signal amp will ground loop causing hissing, RCA isolator fixed this, other way is to plug RCA output from HA-A1 to some other amplifier

2. It Hums with every headphone to some degree, no matter if source is plugged or not or volume pot is to zero or not, turning impedance knob to higher will increase intensity of the hum, hum can be eliminated by using very insensitive headphones or buying gain reducer like IFI IE match.

3. If touching or knocking amplifier physically causes ringing like noise to either channel of headphones, one or more tubes is faulty, in my case it was EL84 power tube.
Fully healthy tubes won't exhibit noise even when amplifier is physically touched.

I tried plugging the Cayin RCA out into another amp and it did not help the hiss. Interestingly, the Cayin is dead silent when used as a preamp. This leads me to believe that it is definitively an issue with the headphone outputs or the pairing to headphones and their corresponding cables. As Fuches noted the amp behaved perfectly, and I was able to get near silent playback with my Ether Flows, I am leaning towards a headphone pairing issue/cable issue.


A Redditor was kind enough to loan me a Morley Hum Exterminator and it did not help to further reduce some of the background noise.

 

[mbphotox]

Can you increase the gain from the Line signal you feed it?
With my tube amp, it greatly helps to reduce the noise if I just increase the gain from the input signal so that I don't have to crank the volume on the poti too high.

 

[xTelepathetic]

Can you increase the gain from the Line signal you feed it?
With my tube amp, it greatly helps to reduce the noise if I just increase the gain from the input signal so that I don't have to crank the volume on the poti too high.

Volume has very little effect. The bulk of the noise for me comes from headphone pairing and output impedance selection

 

[ChristoT]

I had a similar problem although not so one-chanelled, in so that I would get a really high noise floor, like a hiss that was audible on quiet music also. The way I fixed it was by insulating the rca outs for the preamp function of the Cayin. I did move it about the house to no real effect, but when i plugged an rca cable to the preamp out and then into my Atom amp, the Cayin went completely silent. I discovered it by accident, as I was using it as a preamp with my Atom and just wanted to see how different the sound is - plugged the headphones in the Cayin with the Atom connected to it and there was zero hiss. Silent. So that's how I use it now, just keep an rca cable from the preamp out of the Cayin plugged into any input on my stereo amp that I don't use. So I don't know, that may be worth a try also.

Amazing finding. Thank you so much for sharing, Lubak! I just attached a RCA from the preouts of HA-1A Mk2 to a spare DAP that I keep around but no longer use and it cleaned up the hiss entirely. I keep the DAP off and detached from power at all times. Btw if there’s nothing at the opposite end of that RCA, it adds a lot more noise, so, as always, one should be careful when messing with the contacts of sensitive amps. If I listen very carefully, I can still detect some low, barely audible hum, but it may have been there before too, just now it’s more noticeable with all the hiss gone. I’ll try some tube rolling, maybe it’ll clean that up, too. Once again, thank you for sharing, Lubak. Love the gathered collective wisdom of the Head-Fi community!

 

[BMGRO]

A very interesting find indeed! As soon as I tried it, it went to dead silent. Simply amazing! A huge thank you to @Lubak for figuring this one me out!

 

[ChristoT]

Guys, has anyone managed to completely get rid of the noise floor of the HA-1A MK2? So far I’ve reduced the initially strong hiss to practically nonexistent, but there’s still a quiet low hum left. Nothing to worry about but can’t help but to think it may be just as solvable as the hiss issue, with the right treatment. I noticed a few posts throughout this tread the amp being referred to the amp as “dead silent” but I couldn’t tell if it was meant literally or as in “pretty quiet for a tube amp of this price range”. Any actually dead silent HA-1A MK2 out there? Your feedback is much appreciated.

 

[jerick70]

Guys, has anyone managed to completely get rid of the noise floor of the HA-1A MK2? So far I’ve reduced the initially strong hiss to practically nonexistent, but there’s still a quiet low hum left. Nothing to worry about but can’t help but to think it may be just as solvable as the hiss issue, with the right treatment. I noticed a few posts throughout this tread the amp being referred to the amp as “dead silent” but I couldn’t tell if it was meant literally or as in “pretty quiet for a tube amp of this price range”. Any actually dead silent HA-1A MK2 out there? Your feedback is much appreciated.

Hi @ChristoT I wanted to give you my experience with tube amps. I really don't think you are going to find a tube amp that is totally quite. Tubes are noisy and are going to give you some noise. I've tried really hard to find one at all price levels and still I have gotten some noise. I even talked to a custom tube amp maker and a tube preamp maker and they said they couldn't do it. The way that I've dealt with it is use headphones and speakers that a less susceptible to the noise. I've noticed that headphones like the Audeze LCD-2 and DCA Expanse have a lot less noise from tubes compared to something like a Fostex TH-909 or a Hifiman HE1000. I still get some noise but it is a lot less prominent. I've pretty much given up trying to find totally quite tubes. I run quite a few tube amps right now and when the noise is bothering me I switch to a solid state amp like the GS-X MKII. Only sure fire way to make sure you're not going to get noise..

My two cents.

 

[ChristoT]

Hi @ChristoT I wanted to give you my experience with tube amps. I really don't think you are going to find a tube amp that is totally quite. Tubes are noisy and are going to give you some noise. I've tried really hard to find one at all price levels and still I have gotten some noise. I even talked to a custom tube amp maker and a tube preamp maker and they said they couldn't do it. The way that I've dealt with it is use headphones and speakers that a less susceptible to the noise. I've noticed that headphones like the Audeze LCD-2 and DCA Expanse have a lot less noise from tubes compared to something like a Fostex TH-909 or a Hifiman HE1000. I still get some noise but it is a lot less prominent. I've pretty much given up trying to find totally quite tubes. I run quite a few tube amps right now and when the noise is bothering me I switch to a solid state amp like the GS-X MKII. Only sure fire way to make sure you're not going to get noise..

My two cents.

Thank you for the reply. I think you’re totally right. Cheers!