It’s been a tense couple of days waiting for the patina to set on the 6AS7 SET top plate. But I just placed the copper on the chassis and it looks great!
Continue readingMuch Better Patina This Time
4
Tag Archives: SET
That Didn’t Go as Planned
Regardless of how much planning you do and how many test runs you accomplish, sometimes things simply don’t go as planned.
Continue readingThe SET Moves Forward
With the return of some more normal weather here I got the chance to work on the SET chassis today. Specifically I got the bare copper plates chemically treated for the patina for which I was looking. They look good. Or, more accurately, they look just the way I imagined when I first thought of doing this. I’m very happy with the results.
Continue readingTriode Test Jig Progress
The weather has finally returned to normal here and I got to spend a little time in my shop today. I decided that I wanted to be able to finish the base of the SET and my new triode test jig at the same time. So I needed to get going on the test jig base.
Continue readingTalking about SETs
With my shop temperature hovering around 38°F (≈3°C) and with the outside temperature hovering around 20°F (≈-7°C) I though that today might be a good time for a little “inside” amplifier discussion. And today’s discussion is about SETs; BIG ONEs.
Continue readingA 6AS7 SET Option
One more thing concerning Front Panel Express; with a tie in to the SET project. Just as an experiment, last night I opened Front Panel Designer and duplicated my 6AS7 SET top plate design. Now that I’m familiar with the software it took less than an hour to complete.
Continue readingUpdate on the SET Chassis
So I’ve been playing with the copper tarnish/patina process and I think I’ve got it figured out. After doing lots of small parts with various approaches I’ve learned enough to start the amp pieces. Among the things I’ve learned is that the washing process both before immersion in the chemical bath and after tarnishing while washing off the chemicals is very important. I’ve also learned that an even buff with a steel wool is better than taking the copper to a high gloss shine. And finally, the initial tarnish is very fragile. After doing the bath and letting the piece dry, it really should be left sitting in the open air for between three and five days. After this, the oxide layer toughens up and it can be handled and clear coated.
Continue readingCopper Patina for the 6AS7 SET
As I mentioned back in June, I have been looking at different finishes for the copper portions of my 6AS7 SET amp. At that time I had mentioned that I was interested in a “patina” type finish for the copper. I learned that to many people copper patina means green tones, blue corrosion, and wild colors. I was looking for something more like a tarnished penny look. Something that would make the unit look more like an older piece of equipment. Unfortunately this was to be more involved than I first imagined.
Continue readingOne Last SET Driver Check
I took some time yesterday to perform a performance check on the driver for the 6AS7 SET. As some may recall, this driver was developed and prototyped back in 2015, and brass boarded in 2016, as a driver for the 6336 SET Amplifier. In the 6336 design it uses a 300v B+ to produce a swing of 82V peak to fully drive the big triode. However, in the unique power supply topology of the 6AS7 SET, there are some additional considerations.
Continue readingA Couple of Bad Months
To anyone trying to get in touch with me for the last couple of months, I apologize if I didn’t get back to you. It’s been a couple of bad months.
Continue readingAbout That Bias Point
Back in June, in the Competing Priorities post when talking about the 6AS7 SET, I made the following statement:
I also had another idea this morning which may lead to a little more prototyping work to check out a theory I have (another potential delay). But if the experiment turns out well, I may move bias points around a little on the 6AS7.
Well, I spent this morning with some prototype circuits and a stack of tubes investigating the bias points for the 6AS7 SET power stage. And I learned a couple of important lessons.
Continue readingSometimes Life Gets In The Way
It’s been a month since I posted about the new SET and I just thought I’d let everyone know that I haven’t forgotten about the project. The truth is, as the title says, life has gotten in the way. Most specifically, this month I started on a major project; I’m helping my daughter build a house.
Continue reading“Pecking” at the SET
“Peck”. This is a term with which I don’t expect most tube amp builders to be highly familiar. However, it is a term that is exceedingly important to my work this morning on the 6AS7 SET amplifier. Let me explain.
Continue readingCompeting Priorities
I’m now just shy of ten weeks into my new routine and there are a lot of projects vying for my time and attention. This situation has made it difficult to make serious progress on my 6AS7 SET project.
Continue readingAbout that SET…
It’s been several months since I’ve talked about my new 6AS7 SET and my guess is that some folks are wondering what’s happening. Don’t worry, it’s still in process. However there are some extenuating circumstances associated with the amp’s delay. Let me explain.
Continue reading