The discussion on tube testers and their usefulness (or not) got me thinking about my own tube testing needs and how I go about it. I already have a solution for octal power tubes with the 7S base pinout which I’ve mentioned before. But what about those ubiquitous signal triodes I seem to use in almost every project? What should I do about them?
Continue readingSo 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 readingAs 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 readingI get a lot of questions from people looking at my website. Most questions are about the posted projects or requests for recommendations for test equipment. However a topic which comes up regularly is about vacuum tube testers. The questions range from simple a “Should I buy one?” to complex requests for information on types, operation, “accuracy” and the ever present question “Are they worth it?”. Unfortunately, the topic is actually much more complex that most people realize.
Continue readingI 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 readingTo 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 readingBack 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 readingThis last week I was thumbing through my very dogeared copy the RCA RC-30 Receiving Tube Manual. I was not looking for anything in particular but just browsing and a data sheet for a particular tube caught my eye; the 6DQ5 Beam Power Tube. The only description was “Glass octal type used as horizontal-deflection amplifier in color and black-and-white television receivers”. As I began looking through the specifications I began to wonder how I had missed this tube up to now.
Continue readingIt’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“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 readingI’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 readingIt’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 readingFor me, it really started about six years ago. I had been using an iPod for a while before that, but the real transition took place sometime in 2015. I had been notified that I was moving cross country for work and things were getting boxed up and ready. All my CDs and vinyl were carefully packaged up for the move. I was left with an iPod and my computer for playing music. That was when I started my slide into bad musical habits.
Continue readingI often get emails and pictures from builders that have built some of the projects I’ve posted here at CascadeTubes. I like seeing all the different ways that people have taken what I provided and modified it to put their own spin on the project.
Continue readingThe Christmas break saw me very busy with tasks other than amp building. So the new SET is a little behind schedule. In spite of it supposedly being a “quiet” Christmas with just immediate family, I ended up tackling several small projects which I had been putting off and I helped my daughter move. And of course I was back at work this week as well. Now that doesn’t mean that I got nothing accomplished, it just means that things are progressing slower than anticipated. This is where I’m at:
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