With all the distractions this week, I’m not quite as far along as I would have hoped. But all the top plate wiring is done, the power supply sections are complete, and the 6AS7 power stage is complete.
Continue readingMore SET Progress
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New Content
I just posted the project page for the 12AU7 “Color” Preamp which I completed a couple of months ago. Why don’t you go check it out.
SET Wiring Coming Into Focus
I really haven’t had as much free time this week as I thought I would. But, in spite of other tasks taking priority, I’ve managed to get the iron for the SET all wired into the top plate.
Continue readingGood Progress in 6AS7 SET Assembly
I managed to make good progress on the assembly of the 6AS7 SET today. In addition to getting all the hardware and iron mounted in the chassis and on the top plate, I’ve actually started wiring.
Continue readingA Little Progress
I managed to eke out a little time to work on the 6AS7 SET top plate this afternoon. I didn’t get a lot done but at least I’ve finally started.
Continue reading6AS7 SET Assembly Begins
After many delays and distractions I have finally finished the 6AS7 SET chassis and have begun assembly.
Continue readingGetting Organized and About Those Jigs
I currently have a couple of major projects on the workbench and a few other minor tube circuit investigations underway. When this happens I find myself pulling things off of shelves, moving other things around, and generally creating quite the mess until I’m having problems finding just about anything. When this happens I generally step back and take some time to get everything organized again. But this time, I wasn’t quite prepared for what I found.
Continue readingProgress on Several Fronts
It’s been a productive few days. Two different amp projects are coming along nicely and today I’ve reached a milestone.
Continue readingVolume Controls and High Frequency Response
These last few days I’ve been working on the driver stage and overall schematic for the new 6L6 SE-UL amplifier. While drawing up the schematic yesterday, I inserted a 250kΩ volume control at the input without much thought. While performing some preliminary analysis, I realized my mistake.
Continue reading6AS7 SET Chassis Is Almost Complete
For the last few days I’ve been applying oil to the SET chassis. It now has four coats of oil, cured and buffed out. There’s only one decision left for the chassis.
Continue readingEveryone Makes Mistakes
Today I was once again reminded of the perilous state of human fallibility and the risks of personal hubris. The cost of today’s lesson? One ruined KT-88. And a little smoke in the office.
Continue readingThe Morning SET Swap
This morning as I sat down in my office to check email and the like, I looked over at the amp in the corner of the room and made a snap decision. It was time to perform a SET swap.
Continue readingOverlapping Projects and Getting Things Done
This afternoon I’ve been working on another amplifier project. This particular one is the 6L6 SE-UL for which some readers have been looking since I published my Optimization of the 6L6 SE-UL page back in March of 2019. I recently realized that it had been three years since I published that data set and that it was probably time for me to get the project started. So this afternoon I’ve been investigating driver stages for the amp.
Continue reading6AS7 SET Finally Starts to Move Forward
It looks like the weather has finally broken here at CascadeTubes and spring has arrived. Yesterday, the 6AS7 SET chassis got its first coat of oil. The purple heart used for this chassis is definitely much deeper in tone than that used on the The 6DJ8 Headphone Amp.
Continue readingLine Level Isolation Transformers – A Lesson Learned
About a year ago my television display died and I was forced to buy a new TV. I had been using the Lacewood V2.0 amplifier for the sound system and, when I plugged in this new TV, it formed a bad ground loop with the amplifier, introducing a nasty hum. This was not an insurmountable problem. I simply dug through my parts closet until I found a little line isolator I had built about a decade previous for some project I was working at the time. I installed this isolator and the problem went away. But that’s not the end of this story.
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