[Sampajanna]

What are differences in MK2?

 

[Whitigir]

Ohhh, now I see, all the transformers are custom made by Cayin in house! I thought they were from off the shelves components. That is very interesting to know, but there are also some very high-end, expensive transformers out there too. I wonder if anyone have already been upgrading their amplifier yet LOL!

 

[puffmtd]

I will own this.

 

[dadracer2]

What are differences in MK2?

There is a new improved volume controller, which due to a lack of availability of components is the cause of the delay in larger numbers being made, as far as I know. Not aware of any changes in the circuit itself. The 300B and 6SN7 are now from a different maker again due to availability, the TJ Full Music 300B is no longer made so Cayin have changed it for a Gold Lion 300B and the 6SN7 is now a modern Tung Sol GTB. There may be other changes but that's al I have seen mentioned on the forum.

 

[Palyodgree]

When made available I will sell my mk1 for the MK 2 just for the black chassis, it’s sooo sexy in black besides it will match my other black components.

 

[Andykong]

3. Transformer Coupled Balanced Driven

HA-300MK2 is a transformer coupled SETA. The output from the 300B output tube will drive a pair of proprietary output transformers which support both headphone and speaker outputs. If the 300B triode tubes are the spirit of the HA-300MK2, the output transformers are the flesh and blood of the amplifier. Cayin believes in this design. While there are different types of vacuum tube amplifiers in the market, we stick with transformer couple whenever possible, and that means literally all our desktop tube amplifiers are transformer coupled.

One of the frequently asked questions regarding our tube headphone amplifier is whether our XLR-4 and 4.4mm phone output are genially balanced driven, or are they “fake” balanced for convenient only since our tube amplification circuit are single-ended.

We understand the preference towards balanced headphones in Personal Audio hobby. For transformer coupled design, it is fairly straight forward to support both single-ended and balanced driven in the same circuit because our amplifiers are transformer coupled.. In simplified terms, balanced amplification is all about feeding opposing polarity signals to the left and right transducer. In the case of transformer-coupled speaker amplifier, in regardless of single-ended or balanced tube amplification, it will deliver + and - output to the left and right speaker terminals in order to drive a pair of speaker properly, and these L+, L- and R+, R- output from output transformers are in fact equivalent to a fully balanced output already.

When we apply this to headphone application, balanced headphone amplification is feeding opposing polarity signals to the left and right ear-cup of your headphone (in regardless of whether there is a dynamic driver or a planar inside). Likewise to the example I quoted above, we can achieve that through a specific method to wind the transformer so that the positive polarity (aka "hot") and negative polarity (aka "cold") are driven in opposite directions, hence deliver a fully balanced output from a single-ended tube amplification circuit. In other word, both single-ended and balanced headphone output are "original" output from the transformers, we don't take the single-end output and then convert it into balanced through wiring. .

HA-300MK2 offers two balanced headphone outputs: 4.4mm and XLR4 respectively. From what we observed, XLR4-terminated headphones are almost exclusively full-size headphones but 4.4mm terminated headphones cover a wider range including low impedance high sensitive portable friendly headphones. For these reasons, we decided to optimize the 4.4mm and XLR4 headphone outputs separately. The XLR4 output is a full-fetched output from output transformer while the 4.4mm winding is a level-matched, lower noise, lower power output with the same audio performance, making it more suitable for portable headphones. For instance, at LOW headphone impedance setting, the XLR4 output delivers 2 watt per channel and the 4.4mm output delivers 1.4 watt per channel, roughly 70% of XLR4 only.

Since the 6SN7 and 300B circuit are operated in single-ended, HA-300MK2 will convert XLR balanced input into single-ended before feeding the signal to 6SN7 and this will involve a pair of input transformers. Since the inputs are low voltage line level signal only, these input transformers are very compact and can easily hide between the balanced input connectors and the 6SN7 circuit. Although the RCA single-ended input will skip this conversion process and we might anticipate that the single-ended input will sound better than the balanced input, the conversion from balanced to single-ended is a lot simpler than doing it the other way round. As a result, adding the input transformers in the signal path is hardly audible but at least we don’t have to worry that we need to provide a balanced input into to achieve better performance from balanced headphone output.

 

[Andykong]

4. Impedance Matched Headphone Outputs

One of the very useful feature of Cayin vacuum tube amplifier is the impedance matched headphone output. HA-300 provides three headphone impedance settings, and the amplifier will optimized its output to handle the headphone loading according to the specified headphone impedance. Each impedance matched output is an independent secondary winding from the output transformers. The impedance settings are:

	Recommended for​	Target Impedance (XLR4 and 4.4mm)​
Low (L):	8Ω~64Ω​	32Ω​
Medium (M):	65Ω-250Ω​	64Ω​
High (H) :	251Ω~600Ω​	300Ω​

The recommended range is not designed as a linear coverage because headphones don’t spread across the impedance linearly. For instance, I can only recall two headphones (HD660 and HD700) between 120Ω-250Ω. While the ranges are identical to the original HA-300, we have revised the target impedance to accommodate the latest norm of low impedance headphones.

Matching headphone impedance should produce a natural sound with well-defined bass reproduction. This is our recommended starting point but not necessarily your preferred sound signature, so you can start with the nearest setting to your headphone and then experiment with other settings. To enhance your experience with impedance matched headphone output, please compare your headphone impedance with the target impedance in the previous table. If your headphone impedance is in the middle of two target impedances (e.g., 50Ω), then both setting are consider appropriate and you can select the settings according to your preference (or music genre at different playback session).

Since the impedance ratings of dynamic headphones are varied across the audible frequency range, the impedance matched headphone output will only have nominal effect. However, if you are using a planar headphone, setting appropriate headphone impedance might cause bigger implication. The impedance of your planar headphone is supposed to remain constant across the audible frequency range.

Please do not confuse headphone impedance matching output with gain control in Solid State amplifier. Although higher headphone impedance will deliver higher output power, but that’s because we are driving the amplifier at a harder load. Gain control is one of the biggest different between Solid-state and Vacuum tube amplifiers. You can adjust the gain ratio in SS amp to alter the output power, but you won't find gain control in an all-tube amplifier. The HA-300MK2 has two stages of amplification (6SN7 and 300B) and output transformers. None of these allow us to adjust "gain ratio" like a solid state amplifier. Therefore H/M/L headphone impedance setting is technically different from High/Mid/Low gain control in solid state amplifier. The headphone impedance setting will introduce bigger change to sound signature than changing the gain of a solid state amplifier.

Back to Transformer

To summarize, the output transformers of HA-300B are extremely complicated because we need a pair of Multiple Winding Output Transformers that takes cares of three headphone outputs (6.35mm, 4.4mm, XLR4) at primary winding, and supports three impedance matched headphone outputs, plus one set of speaker output, at secondary winding.

We should all notice by now that transformer plays a vital role in transformer coupled vacuum tube amplifier. The design and implementation of transformers become an important part of our product tuning. The choice of transformer core, specification of copper wire in different parts of winding, and the winding instruction will affect the performance and sound signature of our product. This is a critical core competence that will maximize our product development capability, extend our product life cycle and enhance our operate efficiency.

Given Cayin’s scale of operation and devotion to build high quality tube amplifiers for our customers, Cayin bite the bullet and incorporated a small transformer plant in our facilities. We design and wind all the power supply and output transformers of our tube amplifiers in-house. This will allow the R&D department to have total freedom in specifying the winding instructions for our products, and we have total control on the material and craftsmanship on the transformer of our tube amplifiers.

 

[bdjul]

@Andykong thank you for such an interesting information. I noticed that rated output were changed. Balanced Xlr output becomes the most powerful one, when in old ha-300 it was single ended 6.3.

 

[Andykong]

Live action at CanJam Singapore today. Our Singapore partner Zeppelin setup HA-6A and HA-300MK2 sharing the same source, visitors can compare the two tube amplifier side by side.

 

[dadracer2]

Hi @Andykong will you have a partner at Can Jam London in July do you think? It would be delightful to have a chance to hear these new products.

 

[Andykong]

Hi @Andykong will you have a partner at Can Jam London in July do you think? It would be delightful to have a chance to hear these new products.

We have worked with AMP3 in one of the CanJam London, but their main focus are portable products. @PhilW, not sure if Audio Concierge is active in CanJam London.

 

[dadracer2]

Thanks Andy I will give them a call and see.

 

[Loftprojection]

This is the most beauty amp on the market, so sexy in black.

Is the volume control still a 24 step attenuator? I would have loved it if a remote would have been added this time, specially since this beauty can drive speakers. Amp designers seem to think all we are all sitting at an office desk with the amp at arm distance.

 

[Andykong]

This is the most beauty amp on the market, so sexy in black.

Is the volume control still a 24 step attenuator? I would have loved it if a remote would have been added this time, specially since this beauty can drive speakers. Amp designers seem to think all we are all sitting at an office desk with the amp at arm distance.

We replaced the volume to JRC MUSES72320V electronic controlled analog volume controller with 41-steps ALPS balanced potentiometer. Unfortunately the HA-300MK2 didn't support remote control.

 

[Sampajanna]

Can make users just upgrade the volume control?