[r343]

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.

You can probably remove background hum with gain reducer like IFI IE Match, also use lowest impedance setting on HA-A1 to further reduce hum.

If you connect HA-A1 to USB DAC it will most likely cause ground loop because amp has build in PSU and connection to amp is unbalanced RCA.
Ground loops makes you hear PC mouse movements, gpu and other unwanted noises trough headphones.

Ground loop is different than humming sound with the amp.
to get rid of ground loop you can

- connect DAC with SPDIF input from PC to get rid of USB noise
or
- connect RCA outputs of HA-A1 to other device
or
- Attach RCA ground loop isolator between DAC and RCA cables to HA-A1. This one i do not recommend because it will worsen audio quality and is audible.

I've had HA-A1 MK2 and Feliks Echo Mk2.

Feliks Echo Mk2 was dead silent without hum even with sensitive Focal Utopia and Fostex TH900 but hum aside i think HA-A1 Mk2 had more robust sound.

*edit*
If you physically "knock" amp with finger and get ringing like noise trough headphones you have faulty tube, fully working tubes don't exhibit any noises even when amp is touched.

 

[ChristoT]

You can probably remove background hum with gain reducer like IFI IE Match, also use lowest impedance setting on HA-A1 to further reduce hum.

If you connect HA-A1 to USB DAC it will most likely cause ground loop because amp has build in PSU and connection to amp is unbalanced RCA.
Ground loops makes you hear PC mouse movements, gpu and other unwanted noises trough headphones.

Ground loop is different than humming sound with the amp.
to get rid of ground loop you can

- connect DAC with SPDIF input from PC to get rid of USB noise
or
- connect RCA outputs of HA-A1 to other device
or
- Attach RCA ground loop isolator between DAC and RCA cables to HA-A1. This one i do not recommend because it will worsen audio quality and is audible.

I've had HA-A1 MK2 and Feliks Echo Mk2.

Feliks Echo Mk2 was dead silent without hum even with sensitive Focal Utopia and Fostex TH900 but hum aside i think HA-A1 Mk2 had more robust sound.

*edit*
If you physically "knock" amp with finger and get ringing

 

[ChristoT]

I’ll give the iFi IE Match a try. Thanks for the input.
I also found interesting your point about the ringing sounds from the tubes when the amp is lightly knocked. I did this test immediately after purchasing the amp and back then there was no such issue at all. Tried it again now and this time the ringing sound is clearly audible. I guess I’ve somehow messed up some of the tubes. Though, if I don’t knock it, and besides the relatively low hum, the amp sounds great.

 

[r343]

I don't think you have messed up with the tubes, they just wear out eventually and start ringing.
One of bigger power tubes went out surprisingly fast.

You can find faulty tube by swapping tubes left/right and listening if ringing noise switches side, one pair at the time.

 

[ChristoT]

I don't think you have messed up with the tubes, they just wear out eventually and start ringing.
One of bigger power tubes went out surprisingly fast.

You can find faulty tube by swapping tubes left/right and listening if ringing noise switches side, one pair at the time.

That's a great advice. Thanks!

 

[martas38]

Tube ringing is a feature. It is normal. This phenomenon is called the microphone effect of tubes and every lamp has it. Some less, some more.

 

[muths66]

What a sweet sounding.

 

[muths66]

Just managed to bought a pair of used heerlen ecc82. Sound fantastic.Too bad label pretty gone.

 

[ChristoT]

Went back to Psvane on amp section vs Gold Lion I had in for a short while...just felt the Lion made things darker/fuzzier as well as adding more body/warmth...Natural vs warmish I'd say now, with better imaging and tighter sub-bass..smoother slightly extended highs. Pricey tubes, (circa $200 for the 4 in UK) but worth it.

I have no idea which brand would be 'next level' after Psvane and what they could bring to the table over these....

Did you find the PSVanes a bit noisy? Recently I picked up a set of PSVane Art Series and actually quite liked their accentuated sound signature and extra bass slam, but they also brought this rustling noise- like crumbling paper or maybe be a bit like a scratchy vinyl record. The same setup gets dead silent with the Gold Lions back in, so I presumed it must be the PSVane tubes. How did you resolve the noise issue?

 

[Lohb]

Did you find the PSVanes a bit noisy? Recently I picked up a set of PSVane Art Series and actually quite liked their accentuated sound signature and extra bass slam, but they also brought this rustling noise- like crumbling paper or maybe be a bit like a scratchy vinyl record. The same setup gets dead silent with the Gold Lions back in, so I presumed it must be the PSVane tubes. How did you resolve the noise issue?

No issue..dead silent !

 

[stefsant]

hallo everyone, I just got the used Cayin HA1a-MK2 and I really like it. It's quiet and works perfectly. However, I noticed a detail that I ask other owners for clarification on. Aside from the 12au7s, the other tubes on the right side seem completely turned off. I don't know if it depends on differentiated wear of the all original valves, on the circuit or on a defect. The previous owner told me it has always been this way. It actually sounds good and I've tried all modes and connections. Can anyone give me any information on this? I would like to attach some photos but I don't know how.

 

[dpump]

Are you are talking about the light that should light up under each tube and the ones under the right tubes aren't on? It's a known problem that these lights fail. All 5 of mine light when I first turn the amp on, but a little later 2 of them go out. Won't have any effect on the sound if any of the lights aren't on. I wish I could disable all 5 of mine but there's no way to access them.

 

[martas38]

Did you find the PSVanes a bit noisy? Recently I picked up a set of PSVane Art Series and actually quite liked their accentuated sound signature and extra bass slam, but they also brought this rustling noise- like crumbling paper or maybe be a bit like a scratchy vinyl record. The same setup gets dead silent with the Gold Lions back in, so I presumed it must be the PSVane tubes. How did you resolve the noise issue?

PSVane 12AU7 Art Series are very noisy and malfunction after a while. I thought I had a problem in the Cayin, and the service said the amp was ok. After switching to other tubes, the hiss disappeared. I like the sound of the PSVAne, but they are not reliable and I won't be using them again.

 

[stefsant]

Are you are talking about the light that should light up under each tube and the ones under the right tubes aren't on? It's a known problem that these lights fail. All 5 of mine light when I first turn the amp on, but a little later 2 of them go out. Won't have any effect on the sound if any of the lights aren't on. I wish I could disable all 5 of mine but there's no way to access them.

Thanks for the reply. Exactly those, the lights under the valves. In fact it sounds great and is very quiet for a tube. The only technical problem is some blowing and some small noise that can be heard every now and then on the right, without music. I think it depends on the valves. The amplifier has the original ones rated by the owner as 70%. It arrived perfectly packaged in the two original boxes.

 

[stefsant]

Hello, I would like to change the valves starting from 12au7. I'm torn between taking two ecc82 GF1 Blackburn NOS mullards directly, or starting by having a bit of fun with tube rolling, with cheaper tubes. My question is if I mounted two RCA 5963 (12AU7-ECC82) NOS Grey, would I already have an improvement over the stock tubes?