header image
Welcome to Sophtamps.ca
Written by Administrator   
Saturday, 19 November 2005

Sophtamps.ca was created out of pleasure. I wanted to build all tube amplifiers but I didn't have enough experience to feel confident about building tube amps that run on high voltage. I still wanted to build an all tube amp.

My first try was to build a hybrid amp using a starved plate 12AX7 into an LM386. Although the results were remarkable to me, it was still hard for me to fully tweak the sound of it (mainly due to the opamp).

After that, I started seeking more information on using tubes at low voltage. I found the lxh2 amp. This amp is supposed to have a very nice power tube distortion (it uses 2 EL84 at low voltage). It used a quad opamp setup to drive both tubes. Alas, the schematic was ascii and hard to read. Furthermore, the web page was recently taken down. UPDATE: The LXH2 site is back up with the ascii schematic. Click here to access the main site. Navigate to extremely low power tube amp for the lxh2 schematic.

During that same period, I came to discover "space charged" tubes. These tubes were developed at the end of the tubes life cycle and were meant to used in tube car radios. These tubes WERE designed to run at 12V (as opposed to using tubes at 12V that were meant to be used at over 200V).

You will find on these pages, my various toyings with these tubes. Right now, the bulk of the information can be found in the schematics page. Currently, only my designs are hosted here. As more and more people start to use these low voltage tubes, I entend to host other people's low voltage tube designs.

Happy reading!


Schematics on this site and projects (even the low voltage projects) on this site deal with voltages that can KILL YOU.  If you should choose to work with high voltage tube products or circuits, you agree to assume any and all associated risks.  If you are not qualified to work with high voltage electronics, please seek help from a qualified engineer or technician.


23-JUN-2006 Traynor YBA-1A modifications. Click here for the details.
13-MAR-2006 Completed my derailment amp! Click here for the details.
13-JAN-2006 Published the design for the 30V amp. Click here for the details.
24-SEP-2005 Added tube data for the superior instruments TW-11 tube tester. Click here to go to the tube data.
08-JAN-2005 Update 12AL8 schematic making it a high gain amp. Click here to go to the updated schematic.
Last Updated ( Sunday, 08 April 2007 )