There are two versions of the Iron Pre: Balanced / Differential and Single-Ended.  Builders of the balanced version can select balanced or single-ended for each input.  The boards include not only the “iron-based” gain stage, but also a shunt-regulated PSU section, and a relay-based input switching section.  A total of 5 inputs are supported.  Each kit also includes a “Twister” board for input selection.  The balanced version is intended to be built as a dual-mono project.

You can read more about it here:

• What's Wrong With The Kiss Boy?
• Iron Pre Essential Kits for the diyAudio Store register your interest

What Will You Need To Complete The Project?

We have both an essentials kit and a supplemental parts kit.  There is no “complete kit or completion kit”.  It includes the parts that are generally more difficult to source and/or may have longer lead times. 

Many people customize their builds.  However, if you purchase the bundle, you’ll likely need:

• Power transformer(s) – 20VA minimum, 36VAC CT or 2x18VAC
• Input attenuation – Potentiometer(s) / Muses / Autoformer Volume Control (AVC) Note – If an AVC is chosen, it is used in place of the signal transformer.  You can find details in the KISS thread.
• Chassis. Modushop / HiFi2000 has excellent custom chassis specifically for the Iron Pre:
  • Single Ended Chassis
  • Balanced Chassis
• A few passive components, LEDs, wiring, etc. depending on your personal preferences.

With the new V.4 SMD update, it is important to know that the supplemental / completion kits have changed also.  For details, please see post #1 of the Iron Pre discussion thread if you have a V.3 or previous completion kit and you'd like to use it with your SMD essentials kit.

What if I have questions?

This project is intended for intermediate to advanced DIYers.  However, many novice builders have achieved success.  This kit, along with yet another sensational pictorial build guide from 6L6, makes this project more accessible to a variety of builders.  If you need additional support, members have posted a number of BoMs, shopping carts, and parts lists in the forum thread.  The Mighty Zen Mod is ever-present and kindly offers support and a quick wit.  Other forum members are available to lend a hand and provide ideas for the never-ending list of options to customize your project to fit personal tastes and needs.  And yes, it will drive an F4.

Note - The SMD version of the Iron Pre includes pre-matched and installed JFETs.