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 Post subject: musical bicycle
PostPosted: January 15th, 2025, 12:35 pm 
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Joined: March 2nd, 2013, 2:43 pm
Posts: 227
Location: Potomac, MD
Some of those in the DIY group already know about me having made an indoor bicycle trainer that generates the electricity needed to run an audio system. I have recently changed the system from CD based to LP. And with this I needed a new amplifier with phono. So I thought I would share this amusement with the rest of the group. First and foremost to anyone who thinks they are paying too much for power, they should try to generate their own power. Believe me, for the amount of power you get for pennies you will have to work really hard if you had to generate that with your own body. I summarize the components that I have made with a series of pictures. To run this system I need to supply an average of 60 watts going into the inverter. There are additional losses not counted here in the generator and mechanical chain linkages that my legs need to generate. I would estimate these additional losses at around 20% of the power delivered.

First is a general view showing a protective bag with noise-absorbing materials. Second picture gives a back view with the two chains and generator. If I pedal at 85 RPM on the cranks the generator spins at around 1500 RPM. The generator is 3-phase and I run it typically at around 70 volts output, but the useful range I use is 50 to 100 volts depending on my leg speed. A front-mounted display, not shown, shows amps, volts, watts, and energy in watt-hours. Next a view of the amplifier. This is a 6 wpc ZOTL complete with tube phono section. I could have made the pedaling easier by making this SS, but I needed a challenge physically and mentally to make the most efficient TUBE amp I could. The output tubes are 6DL5/EL95 types. The plate-to-plate loading is around 73 k for an 8-ohm speaker. The ZOTL can do this whereas it would not be possible to wind a full-bandwidth output transformer to do this. The average plate voltage is 560 V The next picture gives a view from the front where the amplifier and turntable are shown.. Next up is the inverter. This is a custom made unit with crystal frequency control and a low-distortion 120 V sine wave output. It can regulate from 50 volts in to over 100 volts in. Finally, a large energy storage bank of capacitors is needed. This gives an important fly-wheel effect to the pedaling. Without this the pedaling is very jerky.


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File comment: General view
general view.jpg
general view.jpg [ 387.33 KiB | Viewed 6288 times ]
File comment: Chain linkages
back.jpg
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File comment: amplifier close-up
amplifier.jpg
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 Post subject: Re: musical bicycle
PostPosted: January 15th, 2025, 12:38 pm 
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Joined: March 2nd, 2013, 2:43 pm
Posts: 227
Location: Potomac, MD
I had to break this up into two picture sets.


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File comment: amp and turntable
front to left.jpg
front to left.jpg [ 328.6 KiB | Viewed 6285 times ]
File comment: Inverter
inverter.jpg
inverter.jpg [ 328.98 KiB | Viewed 6285 times ]
File comment: Energy storage capacitors
energy storage.jpg
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 Post subject: Re: musical bicycle
PostPosted: January 15th, 2025, 12:48 pm 
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Joined: July 24th, 2015, 4:17 pm
Posts: 1778
Location: Parkville, Maryland
[quote="dberning"]Some of those in the DIY group already know about me having made an indoor bicycle trainer that generates the electricity needed to run an audio system. I have recently changed the system from CD based to LP. And with this I needed a new amplifier with phono. So I thought I would share this amusement with the rest of the group. First and foremost to anyone who thinks they are paying too much for power, they should try to generate their own power. Believe me, for the amount of power you get for pennies you will have to work really hard if you had to generate that with your own body. I summarize the components that I have made with a series of pictures. To run this system I need to supply an average of 60 watts going into the inverter. There are additional losses not counted here in the generator and mechanical chain linkages that my legs need to generate. I would estimate these additional losses at around 20% of the power delivered.
To complete the "full on" DIY project how about incorporating your scratch-made tape recorder? That way I run a referendum to have you voted as the ultimate DIY hobbyist second to none. :handgestures-thumbupleft: :obscene-drinkingcheers:

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 Post subject: Re: musical bicycle
PostPosted: January 15th, 2025, 1:18 pm 
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Joined: February 28th, 2013, 3:31 pm
Posts: 1820
As David says pedaling your way to home brew electrical power is a crazy hard thing to do. Many years ago when I was much stronger I went to the science museum in Chicago where they had a bicycle powered generator where you could try to generate 1/4 horsepower or around 185 watts. I was able to do that for only a very short time before I gave up. Also, the same problems arise when trying to use a home generator. I have a 22KW backup generator for my house that runs on propane and I figured that running it for three days would cost me more than a months worth of energy from my utility Peco not counting the maintenance on the generator. Puts things in perspective.


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 Post subject: Re: musical bicycle
PostPosted: January 15th, 2025, 2:30 pm 
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Joined: July 24th, 2015, 4:17 pm
Posts: 1778
Location: Parkville, Maryland
tomp wrote:
As David says pedaling your way to home brew electrical power is a crazy hard thing to do. Many years ago when I was much stronger I went to the science museum in Chicago where they had a bicycle powered generator where you could try to generate 1/4 horsepower or around 185 watts. I was able to do that for only a very short time before I gave up. Also, the same problems arise when trying to use a home generator. I have a 22KW backup generator for my house that runs on propane and I figured that running it for three days would cost me more than a months worth of energy from my utility Peco not counting the maintenance on the generator. Puts things in perspective.

If you'll recall -- David lives(d) on his bicycle. His legs are well developed for long-distance cycling. So any part of his "home-bicycle-generator" project is not a surprise. LOL!

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 Post subject: Re: musical bicycle
PostPosted: January 15th, 2025, 4:17 pm 
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Joined: February 19th, 2017, 9:43 am
Posts: 535
David - you never cease to amaze me!

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 Post subject: Re: musical bicycle
PostPosted: January 16th, 2025, 9:08 am 
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Joined: December 14th, 2013, 2:19 pm
Posts: 993
The solid state world has Nelson Pass. We have David. We both win!


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 Post subject: Re: musical bicycle
PostPosted: January 16th, 2025, 11:45 am 
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Joined: July 24th, 2015, 4:17 pm
Posts: 1778
Location: Parkville, Maryland
Stuart Polansky wrote:
The solid state world has Nelson Pass. We have David. We both win!

10-4 :handgestures-thumbupleft:

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