[Andykong]

Can't wait for a review of the Mk2 to be posted.. I think I heard from someone in another thread (similar product) a post where they implied they will be getting one for review to compare with that said similar product.

https://www.head-fi.org/threads/feliks-audio-envy.960600/post-16866722

Yes, Headfonics will be the first review site with HA-300MK2. We shipped the amplifier out on 12 March, unfortunately the amplifier was idled at Shenzhen for two weeks because of the lockdown from 15 March, otherwise @marcusd should be working at a first contact review of HA-300MK2 already. The amplifier is still finding its way out of China, we need to exercise our utmost patient on this one.

 

[bdjul]

@Andykong Andy, in black this amp is simply stunning. Can you tell me please, does new ha-300mkII improve on the hum sensitivity?

 

[Z_Showmaster]

Someone tried his Empire Ears Hero CIEM out the 4.4mm and reported no hiss.

 

[Andykong]

Someone tried his Empire Ears Hero CIEM out the 4.4mm and reported no hiss.

Thanks for the update, this is exciting.

When I talked to our Lead Engineer Chen for the reason behind different output between 4.4mm and XLR4, he did mention several time that the 4.4mm phone out optimisation has taken IEMs into consideration, he has reduced the output and improve the SN ratio at the same time, making some the HA-300MK2 applicable to selected IEM. We didn't have the luxery to test out the HA-300MK2 with a lot of IEMs, so I didn't include this in the Transformer Coupled Balanced Driven section. I just checked, the Empire Ear Hero is 105dB/mw @ 1kHz and impedance is 17.6 Ohms @ 1kHz, this is a very good starting point for HA-300MK2 with IEM, let's stay tune on this subject and find out if the HA-300MK2 is indeed IME freiendly.

 

[Andykong]

@Andykong Andy, in black this amp is simply stunning. Can you tell me please, does new ha-300mkII improve on the hum sensitivity?

Yes, we did something along this line. If you look at the opening post at page #1, you can notice two highlighted features,

• Custom make silica gel shock absorber as anti-shock buffer between critical tube components, chassis mainframe and tube socket, remove microphonic of 300B DHT effectively and provide quiet and realistic playback from sensitive headphones.
• Minimize interference by reinforcing shielding of transformers, effective circuit layout and optimized circuit design

The new design works great in our setup, but we need to test this in user setups before we can determine the effectiveness of the new design.

 

[Sampajanna]

Yes, we did something along this line. If you look at the opening post at page #1, you can notice two highlighted features,

• Custom make silica gel shock absorber as anti-shock buffer between critical tube components, chassis mainframe and tube socket, remove microphonic of 300B DHT effectively and provide quiet and realistic playback from sensitive headphones.
• Minimize interference by reinforcing shielding of transformers, effective circuit layout and optimized circuit design

The new design works great in our setup, but we need to test this in user setups before we can determine the effectiveness of the new design.

Can MK1 users upgrade the volume control?

 

[Mobiustereo]

As a owner of the ‘regular’ 1st gen. HA-300, I can only say wow! I can’t imagine how they could improve on this already amazing amp. Wish I could attend!!

 

[Whitigir]

Can MK1 users upgrade the volume control?

You don’t like stepped attenuator? Anyways, it should be pretty simple to do such things, and a good question for Cayin

 

[Andykong]

Can MK1 users upgrade the volume control?

This will involve changing the stepped attenuator to JRC MUSES72320V + ALPS attenuator, the JRC is a electronically controlled analog volume chip, it is installed on the main ciruict board, so from factory point of view, you need to replace the main PCB in order to gain access to the JRC volume chip. Unfortunately the MK2 circuit board is not a 100% direct compatible to the version 1 circuit board. In other word, this is not possible.

 

[Whitigir]

This will involve changing the stepped attenuator to JRC MUSES72320V + ALPS attenuator, the JRC is a electronically controlled analog volume chip, it is installed on the main ciruict board, so from factory point of view, you need to replace the main PCB in order to gain access to the JRC volume chip. Unfortunately the MK2 circuit board is not a 100% direct compatible to the version 1 circuit board. In other word, this is not possible.

Ah! My bad! I thought MkIi was still point to point soldered, and perhaps a daughterboard of the JRC volume control in places.

 

[111MilesToGo]

I read that the stepped attenuator in the original HA-300 is a little issue, too few steps, volume coming up too fast. The HA-300 MkII improves on that. My question is: Does the HA-6A have this same issue as the 300 MkI?

 

[Andykong]

Ah! My bad! I thought MkIi was still point to point soldered, and perhaps a daughterboard of the JRC volume control in places.

All the tubes and discrete components are still point to point soldered.

 

[project86]

I read that the stepped attenuator in the original HA-300 is a little issue, too few steps, volume coming up too fast. The HA-300 MkII improves on that. My question is: Does the HA-6A have this same issue as the 300 MkI?

It's funny - as far as I know the HA300 and HA-6A use the same stepped attenuator volume control, both with 24 steps. But having used both, I feel like I experienced less issues with finding an ideal volume match when using the HA-6A. I don't know exactly why that might be but I have two theories.

1) the HA-6A can switch from Triode to ultra-linear mode, and also gives options for running different tubes. So I am more likely to choose options that harmonize with my chosen headphones, and thus operating within the best volume range already.

2) I tried the HA300 first, and then the HA-6A. To some extent I probably got used to it, and found it less troublesome just based on pre pre-existing knowledge/experience. I did find that using a DAC with quality volume control can help fill the gap - adjusting by a few notches on the DAC side is usually imperceptible in terms of SQ degradation, and can often get things precisely where you want them.

 

[Yggy]

I have bookmarked that HD250 and noticed it was sold at base price, I was wondering whether you have pulled the trigger. HD540 are well known and collected by many, but HD250 are very low profile and didn't draw any attention, so they are hard to find because a lot of users don't know this item has resale value. Yes, 600 ohm LInear one is very rare.

I got my HD250s AK. I’m pretty sure they are 600 ohm but they don’t have the 300 ohm stamp on the cup. Lovely sound. Similar sound to HD540 but fuller bass and more intimate. I replaced the pads and foam disks with the new old stock HD430 pads I got with my HD540. Look much tidier now.

 

[Palyodgree]

Thanks for the update, this is exciting.

When I talked to our Lead Engineer Chen for the reason behind different output between 4.4mm and XLR4, he did mention several time that the 4.4mm phone out optimisation has taken IEMs into consideration, he has reduced the output and improve the SN ratio at the same time, making some the HA-300MK2 applicable to selected IEM. We didn't have the luxery to test out the HA-300MK2 with a lot of IEMs, so I didn't include this in the Transformer Coupled Balanced Driven section. I just checked, the Empire Ear Hero is 105dB/mw @ 1kHz and impedance is 17.6 Ohms @ 1kHz, this is a very good starting point for HA-300MK2 with IEM, let's stay tune on this subject and find out if the HA-300MK2 is indeed IME freiendly.

Andy will there be a price adjustment for the Mk2 ?