ECN Forum Forums Photo Discussion Forums Electrical Nostalgia Vibrator Supplies??

I know a young guy that makes tube guitar amplifiers.

And here's a guy who built a ***DIGITAL CLOCK*** with them....
http://www.eldocountry.com/projects/tubeclock.html

Wow! Now that is a project built for sheer love of doing it. I guess a lot of people would say "Why bother?" when you could just buy a quartz LCD clock module for less than $10, but that would miss the whole point of the exercise!

And I love Nixie tubes. I have an old Solartron digital meter with them sitting in a cupboard -- one of those projects I'm going to "get around to" eventually.

Nixie clock!! Too cool!!

Kind of like this homebrew computer keyboard.

I have a lot of projects, but I couldn't ever imagine having enough time on my hands for either of these!

"I think vacuum-operated wipers are still used on buses."

Generally, busses are diesel powered. diesel engines lack a throttle plate, and therefore have no manifold vacuum. to make up for this, they have a vacuum pump which is driven by the accessory belt. the vacuum pump is able to generate vacuum at any RPM, so if some buses do indeed use vacuum operated wipers, they should work just as good as their electric counterparts and not have the issue of not working when during acceleration like what happens vacuum operated accessories on a gas engine.

Not only were cars equipped with 6-volt systems, many, especially British cars, had positive grounds. I used to do car stereo installs, back when 8-tracks (and even 4-tracks) were king.

There were converters that could convert 6 volts to 12 volts, and even positive ground to negative ground. Some brave people got around this by isolating the stereo chassis from the car body metal.

The reason they switched to negative ground systems is that the ignition spark is more efficient than with a positive ground system, because the spark jumps the other way.

Yep, the positive-chassis survived into the 12-volt era of the early/mid-1960s on many British models. Remember this was still very much the age of the dynamo too; alternators didn't become common on cars until a few years later.


I knew a guy in a village where I lived once who changed his car about as often as other people change their socks! Every time he had problems with moving all his radio/tape/CB gear across, just on negative-chassis versions.

Then came the day that I opened the door to find him standing there with a CB set in his hand, the "aroma" of burned-out circuit-board tracks being obvious even without removing the covers. He'd just acquired an old early-1960s Ford Anglia and hadn't realized that it was positive ground. (Nor did he realize that a CB set doesn't need a 35A fuse inline!)


I think I did that with one transceiver. I ended up spending a lot of time playing with capacitors to get the live chassis at "RF ground."

In addition to vibrator supplies, another method of getting plate voltage for tubes in mobile applications was a device called a dynamotor.

Looked like a small electric motor, with no external shaft. Inside, it consisted of a low voltage DC motor and a high voltage DC generator on a common shaft. Almost as noisy as a vibrator supply electrically (and mechanically they sounded like a jet engine winding up !), but they did away with the need for rectifying the output voltage.

Some SSB ham transcievers (Heathkit and Collins for sure, probably others) of the late tube era had transistorized mobile power supplies available as options. A separate box that would convert 12VDC into 800VDC for the final tubes, as well as various bias voltages, etc.

That reminds me: If you're interested in this older stuff, keep a look out for the "Basic Electricity" and "Basic Electronics" series of books which were published by Van Valkenburgh, Nooger & Neville Inc. in the 1950s/60s.

They were written originally as instructional materials for the U.S. forces, and include operational descriptions of vibrators and dynamotors, as well as many other topics. There were editions re-written into "British Commonwealth" English and terminology as well, which may well have found their way to Australia and New Zealand. Public libraries might be able to get hold of them. Well worth a read.

I love tubes for amps. I have so bought so many non-functioning tube amps over the past 5 years. Most just had a bad capacitor, bad transformer (which I would usually replace with several transformers for the different voltages), or were just junk in the basement. I have an old Bogen challenger 60W PA amp I use for my bass. It uses 807's as the output stage tubes. It was $5, plus $10 to repair, and $30 for a speaker cab, and I spent $25 more for various parts to make it a 120W amplifier. It sounds a whole lot nicer than my $300 solid state amp head. I have also built some nice marshall clones, about $100 to build, sold all 5 of them for about $300 each.

The only bad thing is since I use solid state diodes for the power supply, I have to integrate a delay in it so the tubes don't get hit with power until the filaments warm up. I enjoy putting old-tech things to new uses. I have a cap/resistor meter with the old cat's eye tube (dont remember the tube number right off) that my grandfather gave me. It's pretty accurate.

I've never really found a solid state amp that I like. I only use them for vocal amps and PA amps for live gigs.

I just wish I had some original 12AX7s. The ones I have are Svetlana's, and they don't sound all that great. Used USA brand/European tubes usually sound better than new svetlanas.