Just Speccy 128k

The very first thing I want with in review series is Just Speccy 128k.

Just Speccy is ZX Spectrum 128k clone done by Piotr Bugaj known as zaxon. Piotr is well know maker of many interfaces for ZX Spectrum, Amstrad and many more computers also making own clone of ZX Spectrum 128k and Amstrad CPC6128. I have both of his clones – but today I will dig only into Just Speccy 128k.

My edition is yellow board issue 3 as I know Piotr had plan to make just 10 units but it has ended in over 200 units until now.

Actual design consists as for me as complete and almost perfect solution for Speccy fan that needs modern make work horse.

JustSpeccy 128k

  • clone of ZX Spectrum 128k
  • RGB output
  • stereo AY sound
  • build in DivMMC interface working with ESXDOS
  • build Kempston joystick port
  • NMI (to be connected as button – on my board I have used reset button from ZX Spectrum + case and two wires) to bring ESXDOS menu, save snapshot etc.
  • price: 119 GBP for full assembled board.

Honestly what more you may wish? HDMI output? Well, TK Pie and ZX HD is solution for that. I would vote for solution to bring Microdrive, floppy drive and DivMMC to one platform allowing to backup from older storage systems and tape level compatibility.

Let’s see how it works.

After fire up the JS128 we see for a moment startup screen when we see the unit starting, recognizing the SD card, showing ZX Spectrum copyright screen, pressing NMI button and loading ESXDOS and then startup screen as for real ZX Spectrum.

Actually after 16 seconds we are in the game. How. Try it on modern console like Playstation 4 Pro 😛

If we want to connect it to modern TV – or old Samsung Syncmaster 710MP in my case – we just need Scart/Euro input which that’s to backward compatibility most of modern TVs still have.

On the JS128 side we need to connect both RGB output plug and audio output that is MIC socket (yes, I know it was always misleading for me – but MIC is output from Spectrum and EAR is input port to load ie from the tape) and that cable lead is included with assembled version of JS128.

For FullHD recording I use HD Video Converter and then Avermedia Game Capture HD II – within this setup JustSpeccy128k works flawlessly and shows both great sound and video output.

comparing JS128 and real/oryginal Spectum computers

16k/48k/plus version

  • RF output, can be easy modded to have composite output but can be as external additional interface as TK Pie or ZX HD
  • no AY sound (can be as external additional interface) just beeper
  • no storage interface but can be added (external DivMMC).
  • no Kempston joystick port but can be added (from 10 GBP for used old interface towards 20 GBP)
  • zaxon is offering DivMMC with AY stereo sound, two slots with microSD cards, Kempston Joystick port for 50 GBP.
  • no way to upgrade 16k/48k model to 128k model without buing that 128k unit.

Adding that all to old rubber or plus ZX Spectrum we are coming close to sell price of JS128. Still it’s 128k clone so let’s compare it with 128k and 128k +2/3 units.

128k toastrack

  • no storage
  • ULA128
  • RGB output, RGB switching on modern TVs is possible with more complicated cable lead (with powering SCART/EURO)
  • no stereo sound without modding or external unit
  • no joystick port but can be added as external unit
  • has MIDI/RS232C ports

as above – DivMMC with stereo AY, joystick port and microSD card slots gives it modern breath, however to use is everyday I would suggest doing some mods that will secure overheat inside aspecially ULA chip and of course recap (replacing several capacitors).

128k +2/+2a/+3

let’s divide it a little bit. Grey +2 with built casette deck is last fully ULA128 compatible unit.Black +2A/B/+3 are remade by Amstrad and modified so causing some incompatibilities (most of them were corrected as software/game updates but – these unit are not using ULA128 known from ZX Spectrum 128k).

  • All these units has storage – either casette deck either 3″ disk drive. It’s not modern solution but – still – most of published games are oryginally on tapes.
  • All these units has RGB output. Composite signal can be aquired from them but after some work (ie grey ZX Spectrum 128k +2 needs correction of two transistors as they are placed reversed in factory).
  • All these unit has joystick port but it’s less popular Sinclair standard. It can be modded by simple converter switching pins on DB9 joystick port or you as above buy external interface to have Kempston (Atari, Amiga) compatible joystick.
  • All these units has AY sound, but not stereo. It can be modded to stereo mod internally and as above externally.


JustSpeccy128k and dilema of case for it

Just after getting my own JS128k I felt into dilema of choice of case for it. Cute, small rubber case, maybe paited white and paired with white membrane? Or level up of and more keys after fitting into ZX Spectrum + case? actually tried both. My ZX Spectrum + case is temporary one until I will decide, while that I paired it with PokeMon’s SMD tactile (low force) switches keyboard membrane.

So, what is in package with assembled board version
– TV Scart/Euro lead
– SD card with ZX Spectrum demos and ESXDOS system

So you need case for it (but assume that when someone is placing order for assembled board without case he already has case for it) and PSU (can be grey 128k +2 PSU as it’s 9V 2A).

Zaxon on sellmyretro
Zaxon’s homepage: eightbitclone.com

ESXDOS website

You can take a look and listen how JS128 is within part one of AY battle:


and how Mescaline demo looks on my Just Speccy 128k:

Review Points
  • 10/10
    video output quality - 10/10
  • 10/10
    sound output quality - 10/10
  • 10/10
    features - 10/10
  • 8/10
    price - 8/10
  • 9/10
    support - 9/10



  • kempston joystick interface
    – really wow quality RGB video output thru MiniDIN 8pin connector
    – stereo sound AY with brilliant quality
    – built in DivMMC with SD card slot
    – you can use your 2A 9V grey 128k supply
  • inside we have SLAM ULA128 clone and 128K version ROM.

    fits both rubber key ZX Spectrum 16k/48k and ZX Spectrum 48k+ cases, but need a few cuts and drills to provide all holes for SD card slot, RGB output.


  • no composite output
  • high priced as assembled board and with ZX Spectrum case*
  • no user manual – however I didn’t need it – when I have borrowed JS128 to friend, first question from him was “where is manual”. Piotr, JS128 needs more documentation for the user, even digital one, I know you are more constructor then writer but at this level of informations provided from the maker – this is product for more advanced ZX Spectrum user.
  • *it’s cheaper to get ZX Spectrum 128k +2 but adding all these features that JS128 has will take some money and with case we are about twice of the market value of 128k +2 alone, but having these all 128k and 128k +2/3 units I have to admit I use most of the time JS128 – it has all what I need from ZX Spectrum for everyday frequent using. The price is fair in my opinion but if price is main factor for you – it’s not cheap ZX Spectrum clone.

    User Review
    7.73/10 (11 votes)