J Rockett Delivers the Ultimate Klon Experience with its new Archer Select Overdrive - with a Selection of 7 Superior Clipping Diode Options Onboard

J Rockett’s Archer series is rightly lauded as being one of the very best takes on the Klon Centaur circuit since it was introduced in around 2014. There has been a variety of editions over the years - Silver, Gold Ikon and Jeff - and including my own favourite Steve Stevens Signature Rockaway Archer edition from 2017 - with its 6-Band EQ.

Controls - Output, Ground Lift Switch (for DI Output), Treble, Gain, Clipping : 1N270 / 1N695 / 1N34A / D9B / D9E / Red LEDs, Clipping On Footswitch, OA10 On Footswitch.

So the concept for the Archer Select is to load it with every essential one of those rare NOS Germanium Diodes - including the most typically used 1N34A and D9E varieties - and with the Mullard OA10 as the J Rockett default Diodes of choice. Bill Finnegan has often stated that 1N34A Diodes with around 0.35 Vf (Forward Voltage) were the ones that he chose as a preference for his Klon Centaur - after testing a wide variety of Germanium Diodes at that time.

So when you hit the ’On’ switch of the pedal you get the default Mullard OA10 Diodes, and then the left-hand ’Clipping’ footswitch flips the circuit over to whatever option is selected on the Clipping dial - which takes you through 5 further Germanium varieties - and with the last option being Red LEDs :

• 1N270
• 1N695
• 1N34A
• D9B
• D9E
• Red LEDs

It’s a little like taste-tasting 6 of the finest ever vintages of one of the greatest wines ever produced. Each tickles your tastebuds in the right way - and has its own very finely nuanced character - while protracted sampling of those delights will inevitably make it difficult to distinguish some of the finer points of difference between each of those. 

A key indicator for Diode Function and impact - is their Forward Voltage (Vf) measurement - which for Germanium Diodes most typically sits within the 0.25-0.35 Vf range, and for Red LED’s is a much higher 1.7 Vf.

• OA10       (c. 0.23-0.24 Vf)
• 1N270      (c. 0.268Vf)
• 1N695      (c. 0.25-0.275 Vf)
• 1N34A      (c. 0.27-O.35 Vf)
• D9B          (c. 0.26-0.28 Vf
• D9E          (c. 0.257Vf)
• Red LEDs (1.7Vf)

(These values are taken from various web resources - so take them as aproximate)

So the higher the forward voltage - the louder the output typically - while Germanium devices and components are always somewhat temperamental and even the exact same designation of parts from the self same batch can vary enormously. Similar to finding the right hFe value for the Germanium Transistors that go into a Fuzz Face circuit.

Meaning that when you buy a batch of Germanium parts - you need to test each one individually to make sure that it outputs within the correct range for that application. Testing different parts even from the same manufacturer and batch can result in a huge variation of outputs - often by as much as 1 Volt difference - so these decimal place variations rather result in very subtly colouring differences to the output. Each Diode type renders very slightly differently - while you need very sharp ears to distinguish between them on occasion.