[KC-130]

To expand the conversation a bit, I have a brief comment on the difference between using the Hugo 2 alone (as both DAC & Amp) and adding the MKii Amp downstream.
The Hugo 2 has no problem delivering the power expected of a quality SS Amp. I've accidentally observed this on occasion by setting the Hugo 2 in Line Out mode while forgetting my headphones were plugged into the Hugo 2 rather than the target external Amp... painful.

More to the point, the Cayin Amp greatly improves the SQ of these elements over the Hugo 2 alone:
- Depth: The soundstage is granted a greatly improved front-to-back definition which, to me, is what engages my internals below the shoulders.
The deeper the soundstage, the more I sense the musicality flow southward through my sternum. This is where I find the Amp produces what my headphones may lack.
- Separation: Even listening to a performance with minimal instruments (e.g, Patricia Barber's jazz rendition of 'My Girl') I physically glance around the room as though I'm spotting the band members; and that's a natural reaction to most all of the music I play through the Cayin Amp.
- Clarity: With the Hugo 2 alone I find that the 'expected' sound of the instruments is not nearly as distinguished. For example, in an instrument heavy performance it's a challenge to discern the identity of the bass... is it an upright bass or is it an electric bass ? The Cayin Amp adds the extra nuance, via thump or slam, that paints a clear image of the source.

I'm sure that if I were left alone on a deserted island I would appreciate having just the Hugo 2... but in the comfort of my listening room, I prefer adding the MKii.

 

[Andykong]

Just picked up a HA-1A Mk2 unit. A few comments (after a couple of hours listening with the stock tubes).

• With HiFiMan HE-560 phones (planar, 45 ohm, 90dB sensitivity): This thing sounds spooky good, with extremely wide soundstage. No evident background noise. Impedance switch setting only makes minor difference. (These are the primary headphones I plan to use with the HA-1A Mk2.)

• With Sennheiser HD-540 II (300 ohm, 94dB): Overall presentation is quite good. But there's a low level background noise (that's neither hiss nor 60Hz hum) audible with no music playing. Noise is lessened somewhat at 6-32 ohm setting, but still detectable. This noise isn't particularly loud (or unusual) for a tube amp, and it's not audible with music playing, but it's puzzling, considering that HD-540 sensitivity is only 4dB higher than the HiFiMan. (The noise difference seems to be greater than a 4dB increase would indicate.)

• With Audio Technica ESW9 (25 ohm, 104dB): Noise is too evident to make this a viable headphone for this amp. (I didn't expect it would be, but figured I would try it anyway.)

• Preamp outputs (to 25 wpc DIY gainclone power amp with nearfield bookshelf monitors): Holy crap! Dynamic, and friggin' holographic. And with no music playing, there's no detectable noise. It's dead quiet even with my ear right up to the speaker drivers.

This raises a few questions regarding why some noise might be present in the headphone output but in not the preamp output:

• I assume the 12AU7 driver tubes are in the circuit for both headphone and preamp outputs. Is that correct?
• And, more significantly, I assume the EL84 power tubes are NOT in the preamp output circuit. Is that correct?
• Is there something else in the preamp output circuit that could impact this issue?

I've got some 12AU7 tubes on the way, so I'll try rolling those to see if they impact the sound quality (and possibly noise). But so far, I'm impressed with the sound of this amp.

A bit puzzled by the background issue when connected to a Senn HD-540II, I have two HD-540 Gold in my cabinet, 600ohm and 300ohm, I don't recall background hissing with my HA-1Amk2, but I was using Golden Lion 12AU7 in my personal unit. I'll have to retrofit the stock tube back to HA1Amk2 and try again some time later to verify this.

Try switching to 600ohm, lets see if the background hissing is lowered at 600ohm setting.

With ESW9, if you really want to use it with HA1Amk2, get a IFI iEMatch, this should tame the background hissing significantly. Unfortunately, IEMatch is only available in 3.5mm, so it should work with your ESW9 but not sensitive headphones with 6.35mm.

You assumption is correct. There are certainly other things that might cause higher then normal background hiss. As KC-130 has suggested, RF interference is a possibility, and using interconnect and power cord with good shielding will help. You can also conduct a small experiment by unplugging all cable and only connect one source to the HA1Amk2 with on pair of interconnect, this close reduce the open loop possibility which tube amplifiers are more sensitive than SS amp.

 

[Andykong]

To expand the conversation a bit, I have a brief comment on the difference between using the Hugo 2 alone (as both DAC & Amp) and adding the MKii Amp downstream.
The Hugo 2 has no problem delivering the power expected of a quality SS Amp. I've accidentally observed this on occasion by setting the Hugo 2 in Line Out mode while forgetting my headphones were plugged into the Hugo 2 rather than the target external Amp... painful.

More to the point, the Cayin Amp greatly improves the SQ of these elements over the Hugo 2 alone:
- Depth: The soundstage is granted a greatly improved front-to-back definition which, to me, is what engages my internals below the shoulders.
The deeper the soundstage, the more I sense the musicality flow southward through my sternum. This is where I find the Amp produces what my headphones may lack.
- Separation: Even listening to a performance with minimal instruments (e.g, Patricia Barber's jazz rendition of 'My Girl') I physically glance around the room as though I'm spotting the band members; and that's a natural reaction to most all of the music I play through the Cayin Amp.
- Clarity: With the Hugo 2 alone I find that the 'expected' sound of the instruments is not nearly as distinguished. For example, in an instrument heavy performance it's a challenge to discern the identity of the bass... is it an upright bass or is it an electric bass ? The Cayin Amp adds the extra nuance, via thump or slam, that paints a clear image of the source.

I'm sure that if I were left alone on a deserted island I would appreciate having just the Hugo 2... but in the comfort of my listening room, I prefer adding the MKii.

Hugo2 should offer superb transparency when use as an all-in-one unit, but if you were using a headphone that prefer high current output, adding HA-1Amk2 will definitely help.

On the other hand, your observation also tells us one thing: specification is not always that important with tube amplifier. I am pretty sure Hugo2 has impressive channel separation figure in its specification, adding HA-1Amk2 will definitely lower the channel separation from system point of view. If this is a pure solid state system, lower channel separation will most likely produce a less satisfactory instrument separation (more cross-talk), but in you were using a tube amplifier, that will be a different story completely.

I hope your sharing will provide more insight to potential tube amplifier users, trust your ears, not the specification data, you must listen to it in person before you can appreciate the level of fidelity offered by a tube amplifier with lower-specification.

 

[Orang_sabar]

I hope your sharing will provide more insight to potential tube amplifier users, trust your ears, not the specification data, you must listen to it in person before you can appreciate the level of fidelity offered by a tube amplifier with lower-specification.

I really agree with this statement.
But there is condition that we can't try an amp before we buy. So I understand that some people will have to trust a specification sheet or a review article, before they buy an amp.

 

[Bostonears]

A bit puzzled by the background issue when connected to a Senn HD-540II, I have two HD-540 Gold in my cabinet, 600ohm and 300ohm, I don't recall background hissing with my HA-1Amk2, but I was using Golden Lion 12AU7 in my personal unit. I'll have to retrofit the stock tube back to HA1Amk2 and try again some time later to verify this.

Try switching to 600ohm, lets see if the background hissing is lowered at 600ohm setting.

With ESW9, if you really want to use it with HA1Amk2, get a IFI iEMatch, this should tame the background hissing significantly. Unfortunately, IEMatch is only available in 3.5mm, so it should work with your ESW9 but not sensitive headphones with 6.35mm.

You assumption is correct. There are certainly other things that might cause higher then normal background hiss. As KC-130 has suggested, RF interference is a possibility, and using interconnect and power cord with good shielding will help. You can also conduct a small experiment by unplugging all cable and only connect one source to the HA1Amk2 with on pair of interconnect, this close reduce the open loop possibility which tube amplifiers are more sensitive than SS amp.

Hi Andykong,

Thanks for your comments. I think I have now resolved the issue, and I believe it had to do with the Input Selector switch. Previously, I had only used the CD input. (The Aux input still had the plastic covers on its jacks.) To try to troubleshoot the noise, I was using the highly sensitive AT ESW9 headphones (with nothing connected to the RCA input jacks). Listening closely, I could make out two components to the noise: a low pitched grumble, which increased the higher the impedance setting on the front switch; and a faint high pitched hiss, which increased the higher the volume knob was turned up. The hiss (presumably from thermal noise) was less prominent, and what I would expect from any tube amp, since it was barely audible with the volume knob in a normal listening position.

Then I switched the input selector to the Aux position, and the low pitched noise immediately dropped off considerably, leaving only the faint hiss. And when I switched the selector back to CD, the low pitched noise remained reduced. Now I can switch back and forth without experiencing a problem. I think there might have been some contamination on the contacts in the Input Selector switch. The only time I hear the low grumble now is for about 20 or 30 seconds when I first turn on the amp, then it fades out. (I'm guessing that's from the power regulation tube warming up.)

Not sure why the original noise issue didn't affect the Preamp Outputs. (Maybe something to do with different grounding for the Pre Outs?) In any case, amp noise is now low enough that I can use the Senn HD540 II with the impedance switch at 151-300 ohms without abnormal noise. And I can even use the ESW9 at the 8-32 ohms setting without a noise problem (although the HA-1A Mk2 is way too powerful to have practical range on the volume control with those cans).

I think I'm now good to go with this amp. (It's fantastic with the HiFiMan HE-560.) And I really appreciate that a Cayin company person responds to concerns stated here on Head-Fi. Keep up the good work. (And maybe have somebody check those Input Selector switches at the factory.)

 

[Andykong]

Hi Andykong,

Thanks for your comments. I think I have now resolved the issue, and I believe it had to do with the Input Selector switch. Previously, I had only used the CD input. (The Aux input still had the plastic covers on its jacks.) To try to troubleshoot the noise, I was using the highly sensitive AT ESW9 headphones (with nothing connected to the RCA input jacks). Listening closely, I could make out two components to the noise: a low pitched grumble, which increased the higher the impedance setting on the front switch; and a faint high pitched hiss, which increased the higher the volume knob was turned up. The hiss (presumably from thermal noise) was less prominent, and what I would expect from any tube amp, since it was barely audible with the volume knob in a normal listening position.

Then I switched the input selector to the Aux position, and the low pitched noise immediately dropped off considerably, leaving only the faint hiss. And when I switched the selector back to CD, the low pitched noise remained reduced. Now I can switch back and forth without experiencing a problem. I think there might have been some contamination on the contacts in the Input Selector switch. The only time I hear the low grumble now is for about 20 or 30 seconds when I first turn on the amp, then it fades out. (I'm guessing that's from the power regulation tube warming up.)

Not sure why the original noise issue didn't affect the Preamp Outputs. (Maybe something to do with different grounding for the Pre Outs?) In any case, amp noise is now low enough that I can use the Senn HD540 II with the impedance switch at 151-300 ohms without abnormal noise. And I can even use the ESW9 at the 8-32 ohms setting without a noise problem (although the HA-1A Mk2 is way too powerful to have practical range on the volume control with those cans).

I think I'm now good to go with this amp. (It's fantastic with the HiFiMan HE-560.) And I really appreciate that a Cayin company person responds to concerns stated here on Head-Fi. Keep up the good work. (And maybe have somebody check those Input Selector switches at the factory.)

Thanks for your kind consideration.

I did mention in a previous post that

The first 60 second after power up, the tube amp might sound very strange, something like out of tune if you are listening to a connected headphone when you press the power button.

The sound should sound normal after that, but it'll take around 15 minutes before the tubes become completely stable.

So if you "hear the low grumble now is for about 20 or 30 seconds when I first turn on the amp, then it fades out", then it is likely a warm up problem.

Although the two inputs (CD and AUX) are supposed to be identical, I prefer to AUX input for no reason, it just sound a little bit more transparent to me, so I use AUX as my primary input, and maybe that's why I didn't recall any abnormal behavior. I'll pay attention to that and report your observation to our Engineer.

 

[Pictograms]

Hi Andykong,

Thanks for your comments. I think I have now resolved the issue, and I believe it had to do with the Input Selector switch. Previously, I had only used the CD input. (The Aux input still had the plastic covers on its jacks.) To try to troubleshoot the noise, I was using the highly sensitive AT ESW9 headphones (with nothing connected to the RCA input jacks). Listening closely, I could make out two components to the noise: a low pitched grumble, which increased the higher the impedance setting on the front switch; and a faint high pitched hiss, which increased the higher the volume knob was turned up. The hiss (presumably from thermal noise) was less prominent, and what I would expect from any tube amp, since it was barely audible with the volume knob in a normal listening position.

Then I switched the input selector to the Aux position, and the low pitched noise immediately dropped off considerably, leaving only the faint hiss. And when I switched the selector back to CD, the low pitched noise remained reduced. Now I can switch back and forth without experiencing a problem. I think there might have been some contamination on the contacts in the Input Selector switch. The only time I hear the low grumble now is for about 20 or 30 seconds when I first turn on the amp, then it fades out. (I'm guessing that's from the power regulation tube warming up.)

Not sure why the original noise issue didn't affect the Preamp Outputs. (Maybe something to do with different grounding for the Pre Outs?) In any case, amp noise is now low enough that I can use the Senn HD540 II with the impedance switch at 151-300 ohms without abnormal noise. And I can even use the ESW9 at the 8-32 ohms setting without a noise problem (although the HA-1A Mk2 is way too powerful to have practical range on the volume control with those cans).

I think I'm now good to go with this amp. (It's fantastic with the HiFiMan HE-560.) And I really appreciate that a Cayin company person responds to concerns stated here on Head-Fi. Keep up the good work. (And maybe have somebody check those Input Selector switches at the factory.)

So do you not get any of your weird noise with the EDW9 or your hiss is just loud enough to cover it? (I’m just curious) or do your HD540 just amplify a specific frequency so you hear it more?
I was reading the info on a tube website and one comment they made was it’s a good idea to slightly twist the tubes in the socket to make sure the pins have made full contact, since many tube returns ended up not being noisy just missing sitting perfectly.

 

[Pictograms]

It’s also not the same but I was testing all my headphones and iems the other day and discover the my VE smalls 24ohm 117db sensitivity allow me to hear hum, no other of my iems allow me to Hear it even more sensitive ones... very strange I assume it amplifies one specific frequency more than the others.
Switching the 12DT5 tube takes it away but o find it so strange that it’s only audible with one set of iems.

 

[Bostonears]

So if you "hear the low grumble now is for about 20 or 30 seconds when I first turn on the amp, then it fades out", then it is likely a warm up problem.

Although the two inputs (CD and AUX) are supposed to be identical, I prefer to AUX input for no reason, it just sound a little bit more transparent to me, so I use AUX as my primary input, and maybe that's why I didn't recall any abnormal behavior. I'll pay attention to that and report your observation to our Engineer.

I don't consider noise during warm up of a tube amp to be a problem. It's just the tubes warming up, and as long as it's gone during listening, that's fine.

As far as I can tell, the two inputs now sound identical. They just didn't when I first started using the amp. As I speculated in the earlier post, it might have been due to some contamination on the Input Selector switch contacts.

So do you not get any of your weird noise with the EDW9 or your hiss is just loud enough to cover it? (I’m just curious) or do your HD540 just amplify a specific frequency so you hear it more?

The ESW9 headphones are very sensitive headphones (primarily intended for use with low power portable devices), and revealed the noise more obviously. Now that the "problem" with the Cayin seems to be fixed, I don't hear the weird noise with the ESW9 when the amp is set to the low impedance range appropriate for those headphones. I only hear it when the impedance setting is increased (increasing the amp gain), but I wouldn't use such a setting with those headphones. Previously, the noise was very evident at any setting. In any case, the ESW9 are too sensitive to use on a regular basis with a high powered desktop amp like the Cayin.

The HD540 and HE560 are more typical of the type of headphones likely to be used with the Cayin amp. The HD540 are more sensitive than the HD560 (by 4dB in their specs), and it's possible that the HD540 are even more sensitive at the specific frequency of the noise. But perhaps more importantly, the HE560 are low impedance planar headphones which require a lot of current (but not much voltage), whereas the HD540 are high impedance dynamic headphones that require a lot of voltage (but not much current), and that distinction might be why the noise was more evident on the HD540. But both of them are now fully usable without any evident noise, other than the typical faint tube hiss when the volume knob is turned way up, beyond the normal listening range.

 

[Pictograms]

What Dac is McDermott everyone using with this amp?
I’m currently using the Chord mojo but thinking about an upgrade.
I have found myself setting on the Jan military pre amp tubes after switching between Northern Electric,Tung sol, and stock.
The Northen Electric have a very similar sound to stock but have more extension especially treble, giving a very clear sound.
The tung sol and Jan are similar to each other. Both are less mid focused but have great separation and very fast attack/decay... maybe less tubey?
The tung sol have a nice relaxed bass while the Jan are very tight with great slam and I find it pairs very nice with the Mojo.

 

[Pooh in japan]

Has anyone tried with hd820 ?

 

[Pictograms]

So anyone still keeping tabs on this thread?
I have a strange issue with hum and hope someone may have any ideas...
With my more sensitive headphones Beyer T90 and VE zen I am getting hum which is barely audible at the lowest ohm setting but goes up drasticlly with each ohm setting.
It does not change with volume level and is only audible with quiets pre amp tubes.
I have checked for ground loops and moved my amp around the house and tested at different times of days.
Does this sound like a normal amount of hum?

 

[project86]

This seems pretty normal as far as the increase in hum as you switch to higher impedance settings. That's been my experience across various amps from different brands so nothing unique to Cayin.

I will have to try some more sensitive headphones with the HA-300 to see how it does.

 

[Bostonears]

You might try a different 12DT5 tube

 

[Pictograms]

I’ll give some other 12DT5 tube a go, but as long as it’s not indicative of a real issue I’m not really bothered.
Anyone have a good source for 12DT5 tubes? Where I have bought in the past don’t stock them.

Thank you both!