a list of hobby projects I am doing in my "spare" time... updated April 2013

Hobby projects are those things that I do that are a 'total waste of my time' and don't directly help me pay the rent in any way... `they only cost me money and time'... and so on. Despite the costs and lack of immediate remunerative payback these little projects can still be good - but trying to explain and rationalize why, to others, and even myself sometimes, is most often a useless exercise. So... I invite you to laugh at my folly if you like. You can be glad that you don't feel a need to do these things or, if you do feel similar compulsions, you can can take comfort in the fact that you are not alone. For what it's worth, I'll tell you, the reader, that I am not inviting anyone to starting communicating with me about these things, unless this communication can be clean and efficient. I already have too many people calling and emailing for free advice, free help, free, free, free and I really, really, I mean it, really, do not have time for too much free.

project name:

604's and Big Reds:

I own two pairs of Big Red studio monitors. These are speakers manufactured by Audiomarketing Ltd. and sold into recording studios in the 1970's. They used Mastering Labs crossovers and 16 ohm versions of Altec 604 Duplex loudspeakers called "E2"'s (essentially an E2 would be a 604-16G is such a thing existed, or a 604-16HP). I've had one pair of Big Reds that I have used forever and maybe five years ago I bought second pair to keep as a backup since I actually rely on these.

I've been looking at what I need to do to keep these speakers happy and useful (a user-definable term) and in the process I compiled info on Altec 604's and related speakers and associated crossovers. I made a page about 604 and variants which I update as I get new or better, more correct, or less wrong, info.

I recently cycled the pair of E2 speakers I've been using through Great Plains Audio to be restored and that worked out GREAT! I also sent them a single 604-8G to have them fix up and that is back and working like new. Eventually I will find a mate to it... but not at eBay prices.

On a related and parallel track... I picked up a pair of Altec 612 cabinets with 604-E speakers and N-1500A crossovers in them. The plan for these is to restore them to as close to stock as possible. 604's in those silvery-gray 612 utility cabinets were what everyone had been using for years by the time I started working in studios in NYC. I am curious as to just how good pair of these, cleaned up and properly working, can sound.

MDM-4 nearfields:

I have a number of pairs of original MDM-4 Near Field speakers stashed in nooks and cranny's all over my shop/studio space. I have a pair up and running in my home studio. MDM-4's are the original nearfield speaker designed by E.M. Long Associates and manufactured by Calibration Standard Instruments in the mid-late 1970's. Some years ago I spoke with Ed Long about replacement parts. He sold me the last of what he had for these speakers. Afterwards I sourced additional replacements for the woofers, which were still being made. The original H.F. driver is no longer made. It was a, roughly, 3" paper cone tweeter with a closed back cover. I have not found anything close to an exact replacement for this. The crossover is a parallel design with single pole HP and LP filters (a series cap feeding the tweeter, a series inductor feeding the woofers.

I have been evaluating several tweeter replacement candidates. I'm not really happy with the results so far but eventually I will figure this out and apply that upgrade to all my MDM-4 speakers that are no longer original or functioning properly.

Klipsch Cornwall and Heresy:

I have a pair of Klipsch Cornwall's in our extended Kitchen and a pair of Heresy's sitting in the shop. I bought some nice wood veneer for the Heresy's a few years ago but have not gotten the "round tuit" that I need to get that to progress. I think that is because I have no place to put them right now.

In the meantime I have looked at the crossovers and such. I discovered that the squawker and tweeters in these and most other Klipsch from this era are crossed over with series networks using iron core inductor(s), what seem to be AC motor run caps, and an autotransformer with various taps for the mid and high drivers. The autotransformer is cool because it deals with level correction and does some impedance conversion so the drivers appear to the input cap as higher impedance loads and thus changes the RC so that cap can be smaller and have different turnover points for each driver... pretty neat once I realized how it worked. In some ways this is better and certainly more efficient than using loss networks with R's to account for differing and higher efficiencies in the horns vs the woofer... and better coupling from the drivers back to the amplifier - there R no are's.

I recently rebuilt my Cornwall B-3 crossovers, changing two of the three caps (the original 70µF cap sounded and measured better than currently available and affordable bi-polar electrolytic crossover caps - so for now it stays. I upgraded the autotransformer to a newer and larger core'ed version. I was going to change out the inductors to something theoretically better but, as I advise anyone doing rebuild, upgrade and modification work, one step at a time. I did have to change out the tweeters in the Cornwall's because the magnet structure in one of the K77M drivers that were original to these speakers failed... and it's common failure in that version tweeter - the glue breaks down and the pole piece shifts. It's not really fixable unless you have the right tools and a lot of patience. Crites sells a replacement that works fine so I bought and installed a pair.

Vintage Klipsch fans should check out:

Since the Cornwalls got put back together... they sound like Cornwalls and, as I describe it, "they soooo horney!". I will eventually have to get some EQ in place to smooth them out a little or do something about that midrange squawker horn itself. I had read up on a sort of hybrid between the Cornwall and LaScalla ... the LaScalla has a better horn and the Cormwall has a better sounding low end. There is a hybrid that Crites has been promoting called a CornScalla that looks interesting. Lately I have been doing some design work for a friend of mine and this took me into some fairly serious investigations regarding compression drivers and horns so we'll see what if anything I do with that as applied to these Cornwalls. They sound fine... I may just build a little passive EQ network to put ahead of the amplifier to dip out the midrange honk.

Next Steps: get the Heresy's done, replace one of the tweeter diaphragms. These have the original round-backed Alnico K-77 tweeters and I popped one - probably by hot plugging something that made a big bang with the speakers up. Some years ago I bought the replacement diaphragms which are no longer made but did not put them in. I swapped in some other speakers so priority was low. So fix the tweeters, glue the veneer down (since I gave Constantines a good chunk of money for it already). ... and at some point I have to do something with the cosmetics on the Cornwall's as they are utility black and, prior to living in my Kitchen they spent many years in a studio as playback/talkback speakers... and... grill cloth and maybe I'll hunt down some old brass Klipsch badges if I can get them at a reasonable price. ...this is a sickness... but at least it's harmless.

turntables and cartridges:
sorting out the aggregation:

I have a bunch of turntables and the cartridge situation is getting a little chaotic. I currently have three Revox B791/795 turntables that I like quite a lot. One of these died. I have a service manual and intend to make that work again. I really need only two working turntables in the house for day to day playing and digitizing lp's. I have various other turntables though, like Dual 1019's with conical styli for playing and transcribing '78's. My dad has Technics SL-7's, an SL-10 and some others... I need to sort all these out, ditch what does not work or is not useful and fix what is useful. I'm still doing inventory, looking for replacement styli for V15-III and IV and making determinations re the cartridge pile that includes Grado (with the "long horn" mod), Ortofon P-mount, Stanton, Technics (205CMK3 in both P-mount and standard mount versions), Sumoko (Blue Point p-mount) and a variety of other Shure cartridges like M97's, M78's and such...

Next Steps: have to find out where I am before I know where I'm going

FM radio and tv:

I have a deep fringe antenna on the roof and the house is exactly 50 miles due North from Columbus Circle in Manhattan. There are hills and trees all around. Up until analog tv went away I was getting free off air tv and that was fine for getting PBS and the main networks. I bought a couple digital to analog tv converter boxes but those gave me nothing so I had to bend over and take DirecTV like a man.

I hate the fact that I am paying forty bucks a month just so I can watch the news. I had no choice after 9/11 for a time but I shut it off after the transmitters were going full power again and had been doing fine, except for complaints from the kids, which I am pretty good at ignoring. We have FIOS for phone and internet access but FIOS-TV did not roll out in time. The cable company near us seems to be populated by some of the stupidest people I have ever talked to and the service is terrible... and it's the same great steaming heap of crap for the same money anyway. My dad has has FIOS-TV and I can see that this is really no better content-wise though it is a few bucks less in the basic package. DirecTV at least has decent service and a great website so I can avoid talking to idiots.

As it is now, the roof antenna is useless for TV but works great for FM Radio, which we listen to. The goal of this project is to clean up the antenna distribution in the house, ditch the existing preamp that is deep inside the house and get a new preamp or head amplifier to mount right on the mast. I have an antenna rotator but it's in it's box in the basement... kind of useless where it is. So... when I find that perfectly round tuit I'll take the mast down, install the rotator and a new head-amp and raise the mast a couple feet in the process... then run the control cable down and clean up the in-house distribution. I'll try the converter boxes again as well as the one HD TV we have to see if we get any free tv but I doubt that will be successful.

The in-house distribution will be reutilized so the antenna has it's distribution to the various radios around the house (Living Room, Kitchen, Office, Studio, my Electronics Workbench, Bedroom... we have a lot of radios). The TV distribution will become separate and take the modulated analog outputs from the one DirecTV box I am willing to pay for and distribute that to a couple secondary TV's.

Next Steps: figure out the head preamp and have it on hand with whatever it wants for a power supply; make sure I have enough rotator control cable on hand; figure out where the rotator control box will live...

and so on...

and there is more... things like rebuilding old chainsaws and, sadly, a lot more audio related things... I don't have time for all of these things so I'll never run out of things to do