This little amp turned out to be lounder and punchier than I thought it would. This lead to experimenting with different output transformers and negative feedback before finishing it. It has plate-to-plate and global negative feedback. Audio tubes are Winged "C" 6F3P, and the rectifier is a JJ ez81. OPT's are from Musical Power Supplies, which I painted. The Antek power transformer is mounted underneath the top-plate of the Hammond chassis. The circuit is built on a blank project board I found on eBay.

Comments

• Twang
• 15 June 2017 at 02:02PM
• Nicely done. schematic available?

• vvelt
• 15 June 2017 at 04:16PM
• Hi, the schematic came from this forum thread:
  
  http://www.audiokarma.org/forums/index.php?threads/se-6v6.307681/
  
  It's the revised circuit for the 6BM8 down the page. I made up the CLCRC supply and added 33k from the OPT's to pin 8 (cathode). This helped improve the sound of these transformers. I first tried the amp using a variety of OPT's without the additional feedback and it performed great depending on the quality of the iron.

• CrystalRF
• 13 July 2017 at 03:15AM
• Nice. How much did all of this end up costing you? Do you have an excel BOM? :-)

• vvelt
• 14 July 2017 at 04:33PM
• Hi, I don't have a BOM per se. Some parts I had on hand but I spent about $150 on new parts and tubes, close to $100 on the chassis, and just over $100 for the OPT's. It always seems to add up quickly.

• steinkare
• 3 September 2017 at 10:20AM
• Hello.
  
  Where did you buy the pcb?
  A very nice amp!
  
  Steinkare

• vvelt
• 18 September 2017 at 09:12AM
• Here is a link to the pcb. The one I just bought is colored blue but is otherwise the same as pictured.http://www.ebay.com/itm/Universal-prototyping-PCB-for-Tube-Amplifier-Preamp-7Pin-8pin-9pin-Tube-Socket/171337457609