It was brought to my attention that I had not posted photos of the pair of speaker cabinets that I am building for this project. Each cabinet holds a single 12" speaker. I do not yet know if they will be partially open back, closed back, or rear ported. I have built two other cabinets like these, using other wood and methods of joinery. This design was copied from a Roland VGA-5 combo amp because the materials available dictated it. The 3/4" construction-grade plywood is not preferred material. But I found an uncompleted card table project in an abandoned rental house I was cleaning out for a real-estate agent. So here it is. The dye was mixed with denatured alcohol as a carrying or delivery agent. The dye applying is now complete for both cabinets. I am now applying a finish.
Sunday, October 8, 2017
Looks finished doesn't it? As the last 3 photos show, it is not finish. All of the elements have been mounted. My effort will slow down a bit now. I hope to complete the wiring and testing by the end of the year.The 12AX7 on the left side of the chassis is the only planned preamp tube at this point. Phase inverter is in the middle near the bias adjustment potentiometer. The open tube socket near the phase inverter is an auxiliary, just in case I can't get proper gain from the single preamp tube. Only recently did I learn that I don't have four 1614 tubes, but two with the other two being steel-cased 6L6. Rectification is by bridge as you can see. On the left of the rear chassis, is an octal socket (with pig tail inserted). This was in the chassis when I pulled it from the Conn organ, and I decided to leave it in to be used as HV read points. I wound up with two different capacitor holders. The silver colored one is preferred but I haven't found a second one yet. Brian can you help? So what is the funny bulb near the front of the chassis, you ask? That is something I've been working on for a while. I've named it the "hydrophonic ambivalator". The specifics of its function are secret, but I will say that it enhances the sound of the amp by adding to the ambiance. I added a mix of turret boards and solder points since the entire preamp hasn't been worked out yet.
Monday, September 25, 2017
Sanding, priming, and top coat are now complete. The top coat is actually engine block paint, and it is actually FORD BLUE. Next I will begin attaching all of the chassis-mounted components. I hope to complete this by the end of October this year. We will see.
Thursday, August 31, 2017
Sunday, May 7, 2017
It's been two years since I last posted here. I've started a new amp project. This one will involve combining the Fender Twin Reverb power amp, with the Sunn preamp used in their Sorado, Sonic II, 200s, and Sonic I-40. An additional twist will be the use of 1614 tubes in place of the 6L6. I am using a chassis I took from a Conn organ. In the photos here I've mounted the power and output transformers. No measuring for everything else.
Sunday, April 19, 2015
|Chassis after letter stamping|
|schematic showing feedback removal|