(1 customer review)

World Designs HD3S Headphone Amplifier


World Designs HD3S Headphone Amplifier is simple but effective circuit using ECL83 valves running single ended in a headphone amp that can be bought as a kit or pre-built.



World Designs HD3S Headphone Amplifier

A beautifully simple, yet sophisticated, stereo headphone amplifier design using ECL83 valves. The unit works directly from any source and includes headphone impedance matching for optimum results from your favourite headphones. With the current interest in high quality headphones driven by the portable audio revolution, this is the right product to get the best from them. Until you try a good quality headphone amplifier in place of the  headphone sockets on most portables and amplifiers (where they are, in most cases, an afterthought  to increase the feature count) you do not realise what you are missing.

The circuit utilises twin high specification E/I transformers output that will drive any headphone load from 16 ohms to over 300 ohms depending on how the secondaries are configured, switched by DIP switches for easy re-configuration. The HD3S is a single-ended design, with the power pentode wired up in triode configuration for that added purity, and is as quiet as a mouse.

Read the full review of this headphone amplifier in Hi-Fi World, where it was awarded top marks or see the summary on our Reviews

HD3S is available either as a kit or pre-built for Standard and XL version.

External dimensions: W220 x D314 x H82mm. Weight 3.6kg

Additional information

Weight 5 kg
Dimensions 56 × 56 × 17 cm
Build Option

Standard Kit, Standard Pre-Built, XL Kit, XL Pre-Built

1 review for World Designs HD3S Headphone Amplifier

  1. Vince

    Got a pre-built World Designs HD3S Standard Kit

    The World Designs HD3S headphone amplifier’s sonic character can be described with the following:
    Black background – Testing with Focal Elegia and Clear, both fairly sensitive headphones (105 and 104 db respectively), shows that the amplifier has no hum, even when the volume pot is turned to 100%.
    Classic tube warmth – Compared to my solid state Phonitor XE, this amplifier is characteristic of other tube-based amplifiers as it delivers a relaxed presentation. Excellent for longer listening sessions.
    Treble is crisp and tonally ‘just right’ without exhibiting sibilance. Almost as good as my Phonitor XE, which costs 3 times the price of the HD3S!
    Mid-range is clean and not overpowered by an overemphasised bass bleeding into the mid-range.
    Bass and sub-bass is taut and impactful – particularly with my planar magnetic Hifiman HE-1000 V2’s (my favourite pairing with this amp). Never sounds artificial or bloated.
    Excellent micro-detail retrieval – I listen to this amplifier at low to mid listening levels (between 8 am and 11 am on the volume pot) and the detail retrieval is excellent to my ears.
    Like all other tube amplifiers, one to two hour warm up will have this amplifier sounding optimally.

    Despite the understated look, if you look closely you will notice that the build quality of the chassis is exceptional:
    Brushed and chamfered aluminium front plate with machined logo and accented with four chrome plated screws.
    Chrome volume control knob with a machined grove, so you can clearly see where the ALPS volume pot is set at.
    Two millimeter thick black painted sheet metal chassis with numerous vent holes punched to ensure more than enough ventilation for the two ECL83 tubes.
    Gold plated line in/out RCA connectors.
    Quality electrical components.

    Some other great qualities about this headphone amplifier:
    Impedance matching for headphone – achieved by taking off the top cover and arranging dip switches in combinations as stated in the manual as well as a sticker within the chassis itself. There are four selectable ranges so it covers practically all headphones out there. This ensures that you can optimally match the output impedance to your particular headphone(s).
    Line in/out ‘loop-through’, so it can sit between a DAC and Preamplifier/Integrated amplifier. This is convenient because you won’t need to plug and unplug the HD3S in and out of your hifi system, and coupled with its understated and clean look, it will blend into most hifi racks.

    Overall this is an exceptional headphone amplifier. It can hold its own against my Phonitor XE, despite costing 3 times less than the Phonitor! In kit-form, this headphone amplifier gives other kits a run for their money. Especially when you factor its sonic character and exceptional build quality. Highly recommended!

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