I am keeping this journal for my own record. There is no new engineering in this project. This is just my own journey while building my first tube amp.

Major milestone achieved today. I finally took the plunge and cut the aluminum. I am very happy with the results. Each and every part fits perfectly.

I planned this project around Front Panel Express. I used their tool designing and redesigning the lay out until I was confident in my layout and fit. Problem is FPE is expensive. Then I saw some comments from other builders that the edge FPE leaves is not really finished. I went searching for a more cost effective solution. I landed on cutting using WaterJet while searching for local CNC shops. There is a company in Toronto close to where I work www.pva-enterprises.com that has an advanced waterjet cutting machine. I exported my FPE file and sent it in for a quote. Given I need a left and a right panel for the 2 mono's I got them to cut both panels...

I have had a few people ask for the CAD files and software for the ADAU1442 DSP. I have tried uploading the whole lot as a series of ZIP files - I hope this works OK.

There are a few things that warrant comment, and if you try to untangle this lot, I am sure a few questions to me. Feel free to ask away...

Comments:
- The sigmastudio file is simply there to generate the code for the DSP. All the actual values for filters etc are calculated by the microcontroller under user control.

- SigmaStdio generates a bunch of export files, my software uses the *.h files, both to load the DSP code, and also to get the addresses in the ADAU1442 of registers for biquad coefficients etc. The microcontroller code pretty well loads these in straight, but there is a tiny bit of tidying up the sigma generated files first...

- The microcontroller is a PIC18F4560 (from memory) the CAD file has a PIC18F5420 in the schematic - these are pin...

The most disruptive audio technology since the CD, since the advent of stereo actually, is ... the iPod. You can lump in mp3, iTunes, and digital distribution in there if you want, but it’s the iPod, the physical device, which has more than anything re-defined what we think of as an audio system in the twenty first century. Shelves of physical media and a playback unit, or, if you preferred, broadcast content, has been displaced by a handheld, personal, portable jukebox. The audio component system of the 1970’s (media, sources, preamp, amp, speakers) has faded into obsolescence, replaced by powered speakers, headphone amplifiers, desktop audio, compact “speakers+amplifier” systems the ubiquitous "dock" fronting a traditional amplifier-speaker system.

Audio is missing the front end.

Because it isn’t an iPod, I’m sure of that. Its day is done. No, it's pretty clear to me that the front-front end of the future is settled: Its the internet. The cloud....

I think I may be getting it..?? (well something anyway). I have been living happily with the 3w ECL86 amp (current output reigned in by feedback) for some months, and am accustomed to its sound now. A friend has recently returned my Class A hybrid digital amp and I thought I would try it out again. I instantly noticed a sort of grungy ness and colder “transistory” sound, even though this is a no feedback design with a transistor emitter follower output. It is curious how the little IB two way speakers don’t like transistor amps.

I got to thinking about current output amplifiers, I was intrigued a few months ago by some comments on an article in the EE times Consumer audio: Is accurate sound overrated? where the poster "Cookie Jar"  stated “One day on a whim, I hooked up my distortion meters to the actual speaker terminals of my living room stereo, and I was in for a rude awakening. The distortion readings were a couple of orders higher than for...

The Nexus 7 is cheap. I paid 19,800 yen for my 16 GB model, shipping and tax inc., and it came with 2,000 Yen credit to buy apps and movies and such in the online Google Play store. And yes, its plastic, even the silver metallic trim around the edge is just a silver-coated plastic part. It is solid, however; sturdy, well-built, and good-looking. The back is covered in grippy, dimpled rubber that feels like leather. The screen is a little dim, but high resolution (800x1280) ~220pi, pretty to look at and easy to read.

With a 7" screen and default portrait orientation the device is closer in spirit to a large smartphone than a small tablet. A giant, wi-fi only smartphone. It's a handy size for reading paperback-format books, comics, and news articles, but not so hot for magazine format publications and A4-formatted journal articles. Browsing the web is generally fine, but the experience varies widely depending on the individual layout of the web page. As you might expect,...

Over the past few weeks I continued to build out and test the power supplies. I really am pleased with the decision to make each supply as a module that can be fully developed and tested outside the box.

After the success with the first supply for small tubes, I moved on to the power tubes. After abandoning the large Sangamo can caps, I ordered in 8 2200uf snap in caps.. 2 per rail, 4 per monoblock. After they arrived I realized that these things are pretty big. The question was how to securely mount them. I settled on another wood block so they can be mounted securely under the chokes. As before, I mounted them through the wood using some silicon cement. There are some nice mills wire wound bleeder resistors. The B+ power supply design calls for a single center tapped 230v transformer. I had scored 2 pairs of 120v 500va Toroidal transformers. I must admit it took a lot of research and a couple of helpful posts before I was sure that I really had this figured...

recently aquired Realistic HK-210/Acrosound Stereo 120 amplifier. would like to restore but can not locate schematic or operating/owner's manual(instructions for biasing tubes). does anyone have schematic and/or manual or direct me where i can be find them?

Well, as mentioned elsewhere checked out the first proper show we've had in decades, and in hindsight it has been a very worthwhile, educational experience. Not because I heard magic audio I've never heard before, but, because I then browsed a collection of other people's thoughts and takes on the various sounds heard at the event, on another, Australian, audio forum.

Which showed me that people are in very different spaces, as regards to what is considered, "proper sound". Obvious of course, but it still throws one, makes one question one's ideas and thinking on matters ... for a split second, at least ... :)

My personal take on the show is that there has been a very discernable improvement in the standard, or average, quality of sound of a normally assembled system which has had only a minimal amount of tweaking applied to optimise it. Problems that were obvious in previous such efforts were far less apparent, you didn't want to run screaming from...

This is a place holder for information regarding an East Coast DIY audio gathering.

Stay Tuned...

Here are some pictures of the Power Supply that CRT and myself designed for use with the F5T and F6Convertible design. It is meant to be both compact, have adequate capacitance, and be able to use the recommended MUR3020W or similiar diodes. They are 2mm thick boards with 3OZ copper thickness.

(Updated boards take now 40mm wide caps and are larger measurements below and new pics)



Boards measure 108mm wide x 192mm long. The diode boards are 35mm x 54mm each.









...