Electrickery

A new preamp

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This is about a preamp I made for personal use with the Home Made Busking Amp. but it will work happily with any amp or PA system. It works fine with our Behringer B208D for example.
It is all contained in a 2″ x 4″ die-cast box which can be attached to the mic stand (I use a niece of an old motorcycle inner tube) or simply laid on the floor.
It is powered by a 9V PP3 battery.
It takes about 1.2mA from the battery when in use, slightly more if the clipping LED operates. Read more

Home Made Busking Amp

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I play in Tin Taxi, an acoustic duo
We do some busking and also the occasional spot in various locations.  This is a description of the amp I made.
We had been using a VOX DA5 for busking.  It wasn’t bad. It had a guitar input with tone control and lots of special effects which we didn’t use , a single mic input with a volume control and an aux input with no control at all. The sound was good, but it was not really ideal for an acoustic duo. But it had a nice enclosure and a nice speaker, so I used those. Read more

Testing Lead Acid’s

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I have four old lead acid batteries stored in the garage.
All of these batteries have been retired for some time but I keep them in the garage and charge them up every 3-6 months.
This is the technique I used to measure the capacity of these batteries:-
Charge the battery fully on my Ctek charger
Connect a load across the battery designed to take around 25% of the battery over 4-5 hours (based on the C20 capacity of the battery)
Disconnect the load and leave the battery overnight.
Measure the open circuit voltage and use this to deduce the state of charge.
From the state of charge and the known drain, calculate the capacity of the battery.
To be honest, I don’t know if this is a sound method, but it seems logical to me. Read more

AA Battery testing

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This is simply about how I tested a bunch of old AA rechargeables.
As it is quite possible we may get some power cuts this winter I decided I may want to make use of some old batteries we have. It actually adds up to quite a bit of energy storage.
Before retirement I was a professional photographer, and I did a lot of weddings and events.  I used a Nikon SB800 flash units which take either 4 or 5 AA batteries.  After some trial and error I settled on Panasonic Eneloop batteries.  These hold their charge for a really long time in between charges, so after a shoot, I could recharge the batteries, and they were ready for the next time.  Read more

Lights for power cuts

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Power cuts are quite possible this winter. Whatever the cause, we will have to deal with it. We are not badly placed. Our gas heating won’t work as the pump is electric, but we have a multifuel burner in the living room which should keep the chill off. We have stocked up with fuel just in case. Our cooker works from gas and all we need is a box of matches as the igniters won’t work.
Rather than being completely reliant on candles and torches on phones I thought it may be a good idea to have a couple of battery powered lights. But I wanted bright ones powered from 12V batteries. Read more

Finally – battery charging

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When I replaced the PDU with my version I did not bother with a battery charger.  As we never had a hook up, there was no point But last week we spent a few days on a campsite – with a hook up!!! Maybe we are getting old. 

We didn’t really need it, but I reckoned on a campsite nowadays you have to pay for a hook up whether you use it or not, and so it’s best to use the site’s electricity rather than my gas for heating.  We also found out, after nine years ownership, that the hook up also heats the water. This is good but there does not seem to be any control of the water temperature and its gets very hot.
The little solar panel kept the battery charged, but I thought it would be good to be able to charge the battery conveniently from the mains. Read more

One more battery for the road

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The Varta was 4 years old.  I had got the feeling it was a bit down on capacity, but it’s a bit immaterial. I managed to flatten it by leaving it for a few weeks with a light switched on.  I must have inadvertently left it on when we unpacked the van from a previous trip. Unfortunately the weather has not been good, and the solar panel with a few hours daylight per day could not compensate for the light on 24 hours per day. Read more

Microphone Phase switcher

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Why a phase switcher?

We busk with two mics.  We are typically 3 feet apart and the mics are around 1 foot in front of each of us.
We use only on busking amp with a single speaker.
Feedback occurs when the sound from the speaker reaches the mics in sufficient volume to be recycled and amplified. Read more

Damned Technology

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Back in 2014 when I first did my calculations I estimated that phones, tablets, and computers would take an average of 14AH a week while were out and about at festivals and on holidays.
Things have changed in five years.  The technology items have got more power hungry and we find that we use the van a lot to visit folk so we spend a lot of time sitting in it. So we use more power demanding technology more often – a classic double whammy. Read more