1.0The Audio Peoplehttps://theaudiopeople.com.vn/viadminhttps://theaudiopeople.com.vn/vi/author/admin/rich600338<blockquote class="wp-embedded-content" data-secret="PhmupbkdvC"><a href="https://theaudiopeople.com.vn/vi/product/cayin-ha-2a/">Cayin HA-2A</a></blockquote><iframe sandbox="allow-scripts" security="restricted" src="https://theaudiopeople.com.vn/vi/product/cayin-ha-2a/embed/#?secret=PhmupbkdvC" width="600" height="338" title="“Cayin HA-2A” — The Audio People" data-secret="PhmupbkdvC" frameborder="0" marginwidth="0" marginheight="0" scrolling="no" class="wp-embedded-content"></iframe><script> /*! This file is auto-generated */ !function(d,l){"use strict";l.querySelector&&d.addEventListener&&"undefined"!=typeof URL&&(d.wp=d.wp||{},d.wp.receiveEmbedMessage||(d.wp.receiveEmbedMessage=function(e){var t=e.data;if((t||t.secret||t.message||t.value)&&!/[^a-zA-Z0-9]/.test(t.secret)){for(var s,r,n,a=l.querySelectorAll('iframe[data-secret="'+t.secret+'"]'),o=l.querySelectorAll('blockquote[data-secret="'+t.secret+'"]'),c=new RegExp("^https?:$","i"),i=0;i<o.length;i++)o[i].style.display="none";for(i=0;i<a.length;i++)s=a[i],e.source===s.contentWindow&&(s.removeAttribute("style"),"height"===t.message?(1e3<(r=parseInt(t.value,10))?r=1e3:~~r<200&&(r=200),s.height=r):"link"===t.message&&(r=new URL(s.getAttribute("src")),n=new URL(t.value),c.test(n.protocol))&&n.host===r.host&&l.activeElement===s&&(d.top.location.href=t.value))}},d.addEventListener("message",d.wp.receiveEmbedMessage,!1),l.addEventListener("DOMContentLoaded",function(){for(var e,t,s=l.querySelectorAll("iframe.wp-embedded-content"),r=0;r<s.length;r++)(t=(e=s[r]).getAttribute("data-secret"))||(t=Math.random().toString(36).substring(2,12),e.src+="#?secret="+t,e.setAttribute("data-secret",t)),e.contentWindow.postMessage({message:"ready",secret:t},"*")},!1)))}(window,document); //# sourceURL=https://theaudiopeople.com.vn/wp-includes/js/wp-embed.min.js </script>https://theaudiopeople.com.vn/wp-content/uploads/2025/10/HA-2ABlack_01.jpg15001500If HA-6A and HA-300 MKII were amps you would argue for, HA-2A is the one that’s impossible to argue against. Building on HA-3A‘s success, Cayin Audio again wrapped a single-ended Class A NOS tube amplifier into a compact A4 size for the desktop … but reduced size, weight and cost at the same time! HA-2A does that, but it’s no OTL pussycat despite its reduced size and weight. More than anything, Cayin’s baby of the bunch brings the benefits of output transformers designed and built in-house to meet the power requirement demands of modern headphones – both planar-magnetic and dynamic, high or low impedance. [See Product Desc. For More] Flexibility might be the first topic discussed with the lightweight and compact HA-2A, but compromise in quality was never an option. Headfonics say “HA-2A is a very endearing and well-equipped compact tube amplifier for space-conscious audiophiles”. Cayin’s point-to-point wiring is de facto again for signal integrity, and HA-2A’s EI core output transformers surpass even HA-3A’s, extending signal out to 50Khz. That frequency extension up high will already yield great improvements in HA-2A’s mid-range and treble compared to HA-3A, with Cayin’s latest preserving phase response in the human hearing range that much better for superior sound-staging, dynamics and imaging precision. Mixing fidelity that was once the domain of Output Transformer-Less (OTL) amplifiers in the same desktop footprint as iDAP-8 and iDAC-8, with actual power – all while reducing in price – is a true feat of Cayin.  The sense of value doesn’t stop there, with premium New-Old Stock (NOS) valves – US-production Amperex ECF-82/6U8 driver and 17BF11 power tubes from the 1950s – included. Operating the ECF-82/6U8 only as a triode unlocks load line and soft-clipping functions at the drawing board. Their presence at the voltage gain stage is significant, where the majority of an amplifier’s final sound signature is defined. HA-2A’s novel implementation of the composite designs of both these driver and power tube types make for very interesting transfer characteristics and distortion curves. Still, linearity is a given through the holy grail of bias operation, even at this price point, while tube voltages allow for large operating points. Measured distortion is below even the threshold of HA-2A’s bigger HA-6A and HA-300 MKII brothers.  And any distortion will be of the even-order variety expected of single-ended Class A amplifiers, for a smooth, warm and holistic sound. In there is Cayin’s promise – for low cost of entry, weight and size, the flagship trappings of HA-2A are impossible to deny. Class A bias, high tube operating voltages, low capacitances, even-order harmonics and premium EI core output transformers ensure HA-2A gets mentioned over similarly-priced solid-state competitors, and even higher-priced tube alternatives. Even its power transformer is a loosely-wound EI core for greater AC line performance over a conventional toroid, avoiding saturation more naturally plus the negative effects of the latter’s high magnetic flux and coupling between primary and secondary windings. Even for those shopping with limitations to size and weight, HA-2A’s power supply is fully regulated and absolutely sounds like an offering without limitations. Particularly if Audio-Technica, Sennheiser and ZMF Headphones are your typical port of call.  As for those without space or weight constraints, make the HA-6A and HA-300 MKII your first candidates, or view Cayin’s other offerings here and our other desktop amplifiers here.