Analog Electronics Music

Co-workers Bring New Projects

One of the best parts of working with others interested in electronics is having similar hobbies: namely, electronics and music.  And even though I have similar hobbies, I never really brought them up in conversation with co-workers (believe me, some of the stuff I have done pales in comparison to some of the people I work with). However, in the past few weeks it has really paid off talking about my non-work work, both for my personal hobbies and for things to write about that interest me.

Tektronics 425M Oscilloscope:

A few months back I had mentioned how I blew up my Wurlitzer 200 and needed to start troubleshooting it for possible problems. I also lamented the fact that I didn’t have a scope to look at waveforms when I finally got the DC characteristic where I want them. Fast forward to a few weeks ago and a friend and co-worker mentions that he had a scope that he had purchased on eBay but was DOA. Apparently it broke in the midst of shipping and he didn’t get charged by the seller. He also bought a working scope later and intended to fix this one, but never got to it. As such he was clearing out room and offered it to me, a truly generous offer.

The scope itself is a dual channel, 100 MHz scope. It is a military version of the scope so it possibly has better spec’d parts (but I haven’t looked into this  too much).The main problem is that the beam does not render any images onto the phosphorescent screen. Other than that, it is supposed to work fine. Time will tell on the other components.

The interesting  thing about the older analog scopes is that many of them can be repaired by non-professionals. More accurately, they can be repaired by individuals not employed by Tektronics because the schematics are available, the components are large enough to replace quasi-easily and there aren’t proprietary ASICs you have to order from the OEM. One notable fixer-upper of all old things Tektronics is Jim Williams, applications engineer for Linear Technologies and electonics writer (my favorite thing about him is that he lists his 84 Tek scopes at home when he writes his own bios at the end of books or articles). All of these things lead to some analog engineers being die-hard fans of analog scopes. They also like that analog scopes never introduce sampling errors or glitches. This is less and less of a problem with new digital scopes on the market and yet the analog vs digital battle rages on (at least in my mind).




  1. Get the front panel working
  2. Use it to troubleshoot any remaining hum and sound issues on the Wurlitzer 200
  3. Use it to aid me in creating a simple waveform generator (perhaps a buffered output from a computer?)
  4. Use it to troubleshoot issues that arise with the organ and other projects surrounding it

Hammond M3 Organ:

Another co-worker and I were discussing music one day and I mentioned my work on the Wurlitzer. He happened to mention how his wife would be very pleased if he would sell their organ; I was similarly pleased. I’ve been a fan of Hammond Organ in Soul Jazz and Jazz music (thanks Evan and Trevor) a while longer than I’ve been collecting the instruments used by them (thanks Noah).

The organ came to me in good shape sound wise; a little bit of hum but all of the keys are in really good shape and the drawbars work great. No Leslie speaker for now but the person who sold it to me says he might be able to sell me his model 900 eventually. I will also try and get one on my own in the mean time to see if I can’t get a better model (Model 122 or 145). The cosmetic condition of the organ is poor but I don’t think it would have as much character if the thing was squeaky clean. I also plan to possibly chop the organ at some point (put it into a smaller, transportable case) so the cosmetics don’t really matter.

Hammond M3 Organ Side

Hammond M3 Organ Front


  1. Get the organ oiled and hum-less
  2. Successfully replace and re-bias the tubes on the main amplifier
  3. Build an external amplifier and cabinet to increase the sound output
  4. Create sound effect pedals to modify the sound output of the organ to my liking
  5. Document the internals of the tonewheel mechanism
  6. Chop the organ into a transportable case (less than the original weight of 250 lbs)

So these are some of my projects for the summer and possibly extending beyond into the rest of the year. I really look forward to working on two pieces of spectacularly engineered equipment. While I won’t be redesigning the equipment or doing much beyond touching up some of the worn out components, I hope to learn from the internals of these pieces of equipment and use them in future projects.

Do you have any ideas to build off of what I have listed here? What kind of projects are you working on this summer? Let me know in the comments!

Analog Electronics Life

Happy Holidays

I’ve been a bit more of a Grinch this year than I am usually at Christmas/Festivus/Hanukkah/Kwanzaa/etc. I think part of it is my worries about the economy and the rest is because I think the buying of presents is good intentioned, but kind of a waste. Once I get past my own soapbox, I often find that I end up with some thoughtful gifts from the ones I love. Let’s get to the part where I am thankful for the gifts I did get:

  1. A book — My gf was kind enough to listen to me complain about being an analog engineer and not having one of the most important books on my bookshelf. She got me Troubleshooting Analog Circuits by Bob Pease. Up until the past few months I never knew who Bob Pease was until an experience co-worker turned me onto his and Jim Williams’ writings. I admire both of them for their extensive experience in the field of Analog Engineering and their friendly, down-to-earth writing style (something I try to emulate). The “Troubleshooting” tome is well known as a guide on how to specifically move towards pinpointing issues in an analog circuit. I look forward to reading it and applying it. I also hope to post a book wishlist/review list in the near future.
  2. Tools — My parents understood that people trying to fix up a house and make it more energy efficient require tools to do so; they got me some great tools. I’m sure those tools will help me fix all the mistakes I make in the house too. I have also decided that Lowe’s/Home Depot/Etc are the Toys R’ Us of the “older kids”.
  3. A Chord Organ — This is a gift from previous owner of the house I bought to me…because they left it in the attic. It turns out this is a “Magnus Serenade”, and so far it has been pretty hard to find any information on it.  I believe that it is a simple chord organ, similar to the other Magnus models. The idea is that you activate reeds or sets of reeds with keys or buttons (respectively) and then an electronic blower forces air across them to produce a sound. Really it’s like a big accordion (without the back pain). I haven’t had a chance to pull it out of the attic to try it out yet, but if it does not work, it will give me another opportunity to work on old musical instruments. The video I’ve included below is a similar model of chord organ…not the best sound, but definitely unique.

Magnus_Serenade_1 Magnus_Serenade_2

I hope everyone had a great holiday and I look forward to continuing to post in 2009!

Analog Electronics Learning

Great resources for learning about analog electronics

I am absolutely floored by the internet every single day. I often wonder to myself if given the proper linking, guidance and mentoring, whether schools are even necessary any more (maybe the different methods are exactly what we need). This would of course also require some strong drive to learn and a whole lot of time on your hands, not to mention eyes that can bear reading computers screens all day. But I think it is possible; Some schools have even offered up their entire course catalogs online.

Me? I’m an information glutton. I will get 10 books from the library just because I get so excited about them, even if I only have time to read 2. As such, I thought I would clue everyone in to the absolute wealth of information on analog technology on the web. Most of the information you are going to find will be in the form of application notes (basically a cookbook on how to use a particular circuit). But sometimes you will find actual courses and training. I’ll be sure to list these first.  If you know of any other great resources, please leave them in the comments section! Enjoy!

National Semiconductor – The Analog University. Forget saving the best for last, this is by far the best resource I have found to date. There are full length courses that would make MIT blush.

Texas Instruments – This site has information on the entire spectrum of design from learning a concept, picking parts, creating the design and then simulating it.

Linear Technology (link 2) – These are app and design notes from one of the more robust companies out there.  There are also some great articles, some by none other than the great Jim Williams. See other work by Jim here.

Analog Devices (link 2) (link 3) – Analog devices is a monster supplier and has a lot of resources at their disposal. This allows for some great learning content. The links listed include the AnalogDialogue, a nice forum for analog discussion.

Here are some others with mostly app notes, but don’t discount them:

Maxim Semiconductor

ON Semi

Silicon Labs

NXP Semiconductor (formerly Philips Semiconductor)

That’s all I have for now in terms of online resources. I think I’ve maybe gone through about 2% of everything available, so I’ve got some reading to do!

On a side note, I’d like to welcome readers from the Motley Fool! Thanks for coming and feel free to take a look around!