I’ve been working on the color preamp over the last few days as I’ve had time. My volume control and output capacitors are supposed to arrive today so it shouldn’t take too much longer to finish it up. However working inside the small chassis is a challenge.
Continue readingSince I’m still waiting for appropriate weather to finish the 6AS7 SET chassis, I’ve been making progress on a small project for the aluminum chassis from the last post. I decided to put together the “Color” preamp from the post a few days ago. This project will make use of one of the Hammond discount power transformers about which I posted a couple of weeks ago. It’s coming along well, but VERY slowly.
Continue readingWhile waiting for appropriate temperatures to paint and apply oil finishes, I’ve been working on a simple preamp project. It’s only a handful of parts and to avoid complications with finishing a handmade chassis, I decided to use a preformed aluminum project box I had sitting on my shelf. I quickly regretted that decision.
Continue readingFor a while now, ever since the “Universal Preamp” was posted on the site, I’ve been getting steady requests for a good tube preamp to provide some color to solid state amplifiers. My initial answer to this problem was to design a good quality cathode follower for the Universal Preamp. There was one problem, the volume control.
Continue readingIgnoring the wood chassis for the time being, I made significant progress on the triode test jig today. I just thought I’d post a quick update. Parts are now mounted and some wiring is underway.
Continue readingI’m working on two projects simultaneously right now; the 6AS7 SET and the Triode Test Jig. In the last couple of days I’ve made progress on both. However now I appear to be at an impasse.
Continue readingIt’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 readingRegardless of how much planning you do and how many test runs you accomplish, sometimes things simply don’t go as planned.
Continue readingAs everyone who’s tried to buy one knows, power transformers for tube projects can be expensive. Even small transformers for small projects. But today I stumbled on a great deal for a small preamp power transformer made by Hammond.
Continue readingWith 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 readingSince I first introduced the concept for the “Universal Preamp” over ten years ago on the DIYAudioProjects forum, there has been almost constant discussion of my decision to place the volume control on the output of the preamp. I have been asked questions about it numerous times over the years. I have also had some “spirited discussions” with some who vehemently disagree with that design decision. Well, I thought it was high time to explain that decision once and for all, and to discuss exactly what this configuration means for preamp performance and output impedance.
Continue readingAs I was going through some things today I stumbled upon an email discussion I had recently on the topic of toroids (i.e. toroidally wound transformers and inductors) and shorted turns. Given the popularity of toroids, and amount of misinformation floating around on the internet on the topic of shorted turns, I thought that a short discussion of the phenomenon was in order.
Continue readingThe 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 readingI have added a side bar widget on the Blog page labeled “ARTICLES OF NOTE”. I decided that rather than having links floating all over the posts and comments, when I found something of interest I’d post the link in this block.
The first item is a web page from the Lampizator site discussing Audio Heresy. I found it fairly humorous.
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.
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