RhPf Electronics' Nerd Lab IV Bench gives you the full inside edge on 175 different Diodes of all stripes

The IV BENCH is the second RhPf Nerd Lab resource I cover after the super handy Pedal Tone Maps. Diodes play such an important part in shaping the output of gain pedals in particular. They are of course also used for power management and various other electronic purposes - but our main interest in these is in Clipping Profiles - Vf Forward Voltages and Current Rise. There is another side to these Diodes which is more esoteric - while the Germanium Diodes are typically much better behaved than their sensitive Germanium Transistor equivalents - but there are of course variances and outliers as always! RhPf’s Thomas records a number of values across key Diode types - to give you meaningful Mean and Median aggregates to be able to usefully compare and select appropriate variants.

Probably the most famous application of Diodes is the 1N34A or specifically the 1N34AITT Diode that populates the original Klon Centaurs. For my main visual I focus on the J Rockett Archer Select Klone - which has no less than 7 different Clipping Diode selections onboard - which you can flip between.

Those Diodes are namely OA10 (CV7049), 1N270, 1N695, IN34A, D9B, D9E, and Red LEDs. The IV Bench has references for each of those, bar the 1N695’s, and note that the database has the milspec CV7049 variants of the OA10’s. I also selected 2 other 1N34A varieties just for fun - and you can see the relevant curves for each of those at the top.

If you read my Archer Select Review as referenced above - my favourite 3 Diodes in that are the OA10 (CV7049), then the 1N270, and then 1N34A. I like the 1N695 and D9B the least, while the D9E is a close but lesser alternative to the 1N34A. It’s interesting how the feel and tonality is not always a direct correlation to the graph. Much like with Germanium Transistors in particular - there is more mystery to them than simply Forward Voltage and Leakage values. The OA10 / CV7049 is the softest of that lot, while the 1N34AITT is quite close to that on the graph - but my second choice 1N270 is relatively distant (but not nearly so distant as the Red LED!) - with a relatively slow current rise according to its curve. Note that each Diode has an ’N=X’ value which is the number of Diodes measured to reach that mean - this can range from 1 up to 100, but more typically in the 10-30 range!

These are the key lookup settings  for the IV BENCH :

• [OPEN SEARCH]
• TYPES : All Types / BJT NPN Si / Germanium / LED / NMOSFET Forward / NMOSFET Reverse / Schottky / Silicon / Silicon Carbide / Zener
• SORT : A→Z / Z→A / Vf @5mA↑ / Vf @5mA↓
• CURRENT AXIS : Linear / Log
• [COMPARE] option
• [STACK] option
• [FREEZE] - freeze current curve/s for further comparison
• [ADD TO SELECTION] option
• [EXIT PREVIEW] function
• [FIND 3 SIMILAR (Mean)] option
• [REMOVE ALL] function