Tuesday, 12 September 2017

TDA2030A & TDA2030 Amplifier Observations

TDA2030A & TDA2030 Amplifier Observations - Intro

I have recently built portable battery powered speakers using a PAM8403 and a PAM8610. They are very efficient "Class D" amplifiers and can be run on high volume for hours and hours on one set of AA batteries (1.3ah).

However, I would like more bass! So I have tried this TDA2030A "Class AB" board to see how it compares. The TDA2030A is almost identical to the TDA2030. The former have a slightly higher max wattage rating.

This amplifier can be built on to boards that can handle up to 22V although 36V is achievable in some applications. I was limited to 16V by the capacitors that were installed on my pre built board, purchased from ebay (fluxworkshop).

TDA2030A & TDA2030 Amplifier Observations - Current

This is perhaps the TDA2030A amps most troubling characteristic. It requires 3.5A of current (max current), this means that with anything other than top end AA batteries such as "Eneloop" you will not be able to run this on AA batteries. They would also drain quickly even if you could!

The limiting factor it appears with the use of AA cells is the battery holder box. After testing one of the springs had melted and slumped.. I have read elsewhere that the cheap AA battery holders are only good up to about 1.5A.

So . .  you will need a power supply from the mains. . .or lithium high drain cells or an SLA Battery. Again the battery holder for the lithium cells will have to be good quality.

By comparison the PAM8403 and a PAM8610 draw about 1.0A of current which is ideal for use with AA batteries and cheap holders.

I tried the following batteries:

  1. 6 x AA 1.3ah Uniross Batteries in Holders - Not Good
  2. 5 x 4.5ah NiMh (Battery Pack from Silva Headtorch) - OK
  3. 1 x 12V SLA (Actually LiPO4 but in SLA Type Package - Nominal current 7A) - Fine

TDA2030A & TDA2030 Amplifier Observations - Voltages 

To get good performance out of this amplifier you will need to run it higher than the minimum voltage of 6V, in fact even at 9V the output is distorted and low power. The sound is clean when at low volume (60db), but push past that level and the sound is terrible.

I have read else where that this chip sings better at 22 volts, but I can't try that. I can report that at 15V (SLA fresh off charge) it performs well. Running with no distortion at full volume (70- 75db).

TDA2030A & TDA2030 Amplifier Observations - Heatsink

The board I purchased came with a very small heatsink. It looked small to me, so I salvaged a heat sink from an ancient graphics card and used that. I also applied some thermal paste between the chip and the sink. 

A Larger Heatsink - Perhaps Not Required
The TDA2030A (or TDA2030) as I configured it does not generate very much heat, the heat sink as pictured above get slightly warm to the touch, so a small heatsink, such as the top picture in the post would probably be OK. 

TDA2030A & TDA2030 Amplifier Observations - How Loud

I would estimate 75db, specs say 85db. So specs say around 10 time more than I do! But this is running at 22V instead of 16V.

In comparison to PAM8403 the TDA2030A is louder, but PAM8610 running at 12V and 1A is far far louder. 

TDA2030A & TDA2030 Amplifier Observations - Sound Quality

The sound quality of this small "Class AB" amplifier is pretty good. It has better than the "Class D" Amplifiers that I have tried. 

I would describe the sound from this amplifier as richer, than the other class D offerings. There seems to be more depth to the sound, it is less flat than the Class D amps. 

I am sorry for the subjective nature of this appraisal, but that is the best I can do. 

TDA2030A & TDA2030 Amplifier Observations -  Pros & Cons

Con - If you were build and battery powered portable speaker with this it would like cost 3 x times that of a Class D build because of the battery. 

Pro - Slightly Better Sound Sound / Richness

TDA2030A & TDA2030 Amplifier Observations - Photos

Very Small Package

Large Battery in Webbing Pouch

Bag of Spanners! (Ugly)

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Friday, 8 September 2017

Use Apple Pay Without Passcode

Use Apple Pay Without Passcode - Intro

You can NOT do this!

Despite being able to use my "real" contactless card without a passcode, Apple have decided I am a child, and need to be controlled.

There is a slightly less annoying work around. . . . .  or you could just buy a roll of gaffa tape!

Use Apple Pay Without Passcode - Work Around

First off you need to disable touch ID, it is rubbish anyway, being completely unreliable and denies you access to your phone just when you need it, normally when you are in a rush or in a meeting. 

Go To:

Settings > Touch ID and Passcode

If you do not have a passcode then set one up (Turn Passcode On). When you are choosing your new passcode, you will see small writing "passcode options", here you can choose a 4 digit passcode (like the old days), which will keep you safe without wasting your precious time. 

If you are currently using a 6 digit passcode then you will need to:

Settings > Touch ID and Passcode > Turn Passcode Off

and then. . . .

Settings > Touch ID and Passcode > Turn Passcode On

First Turn Passcode On (Turn On and Off to get 4 digit code)

you will then see the above screen with the "Passcode Options". 

Next we need to minimise the number of times you will be required to input the passcode, which can be got down to about 3 or 4 times day using the below option. 

Settings > Touch ID and Passcode > Require Password

By default this is set to "Immediately" which is really annoying. Select "4 hours" or what ever you feel is good for you.

Choose 4 Hour Delay before passcode is required. 

Use Apple Pay Without Passcode -  Conclusion

So you can now use apple pay, only have to use you passcode 3 or 4 times day, and when you pay. It would be very nice if I only had to use passcode when I paid, but like I say I am child and can not be trusted, thank goodness apple are there to protect me!

If like me you are on and off you phone all day perhaps 50 + times (who isn't) this workaround will allow you to use apple pay, whilst only having enter passcode 2 or 3 times a day. 

I hope this keeps you sane, if all else fails just use some gaffa tape to stick your contactless card to the back of you phone. 

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Illustrator Devon

Monday, 28 August 2017

Bor Yueh BY-201 Front Rack Review

Bor Yueh BY-201 Front Rack Review - Intro

I needed to fit a child seat to the rear of my bike, and wanted panniers for shopping too. So front rack is the route I went. This unlike a "lowrider" rack allows you to use full size rear panniers on the front of your bike.

A few years ago, people would have started talking about centre of gravity, but thanks to the marketing powers of firms like Salsa, "bike packing" sees luggage mounted all over bikes, typically very high up. I am not saying it is good, but it has become more trendy to have an unstably loaded bicycle. So I should not need to justify the whole COG thing.

Update: 06/09/2017

I have tested this rack with a 35kg load. Which consisted of 2 large panniers and a medium sized child. I travelled 10 miles with this load and bumped down curbs, and did some violent steering. All good. So a bit stronger than that 10kg mentioned on the website.

Smallish RAck - Full Size Panniers

Bor Yueh BY-201 Front Rack Review - Fitting

The rack comes with a selection of nuts and bolts for fitting, as well as plates for mounting, and what not. The only criticism here would be that the bolts are all screw driver type bolts and not allen key variants / jobbies.
No Caption - Self Explanatory 

You will require a hole in the fork crown (where the mudguards are bolted on) and also some forward facing rack mounts on the bottom of the forks. I doubt this would fit on to mudguard mounts, although there are some spacers provided which may get this to work.

Bor Yueh BY-201 Front Rack Review - In Use

I have owned one of these a few years ago. They are a good rack. Issues it for 2 or 3 years with no issues. So this is a 2nd purchase, which must count for something.

As mentioned in the intro this puts your luggage above 6" above low rider height. This really doesn't bother me in the slightest, and I can use any of the rear panniers I already have on the front of this bike.

Bor Yueh BY-201 Front Rack Review - Photos

View from Above - Lack of Allen Bolts is a Shame

Fixing are however, Sturdy

Mounting Point at Fork Crown 

PAM8610 Amplifier Review & Build

PAM8610 Amplifier Review & Build - Intro

I was very impressed with my 99p PAM8043 has enabled me to build a small portable speaker for just a few pounds.

Off the back of this success I thought I would build a more powerful portable speaker using a PAM8610, which costs . . . .  £1.99 so still a cheap project.

This is the board variant reviewed.

This more powerful board delivers 15W per channel, and runs on 12v (7v to 15v). I was hoping for more sound, which was delivered, but the quality of sound is far below that of the PAM8043.

PAM8610 Amplifier Review & Build - Power Supply

The 8610 will run on 7 x AA batteries (1300mah) for many hours at a moderate volume. A week's worth of morning and evening listening is achievable on one set of batteries, approx 12 hours. At full volume I would estimate 1 or 2 hours.

(2x15W) 30W / 12V would indicate a 2.5A current requirement, so if you choose a 12V AC adaptor for power probably best to go for 3A as a minimum.

PAM8610 Amplifier Review & Build - Speakers

Many of the more complex boards using the PAM8610 require an 8 ohm speaker. But if you buy the basic board, then you can run a 4 ohm speaker . . .  the more complex boards do not really offer any advantages in terms of performance, although they are easier to use, with no soldering required (provided you have the right connectors!)

PAM8610 Amplifier Review & Build - Sound

The sound was a bit disappointing at first. It is a very mid tone heavy, to the point where it is harsh. Whilst the PAM8043, has a rich sound even when unfiltered this amplifier requires a low pass filter on the woofer, in order to make it listenable.

For example, without a low pass filter, you will require a graphic equaliser to try and remove some of the harsh mid range sound, and having tried this I can tell you it is not a very good option.

PAM8610 Amplifier Review & Build - My Set-Up

This project ended up looking a bit messy, because it had to be reworked so many times, attempting to get the right sound. In the end the addition of low pass filters was the breakthrough, that finished it off. I had tried stuffing the cabinet with wool to change sound, but this was unsuccessful.

The DIY low pass filter was easy to make. I just wish I had thought of it earlier. I had to make sure that the bass / mid range driver and the tweeter were fed separately through their respective filters.

Note size of PAM8610, very small. 

A close up of the amplifier and the wiring, between it and the speaker. The coil, shown below is the professionally made variant. Whilst above right, is a DIY effort that worked adequately.

Amplifier will happily sit on it own wiring, as it weighs next to nothing.
I did not worry about mounting the amplifier to the inside of the cabinet, as the the board is so light, it will sit happily suspended on its own wiring.

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Thorpy's Non-Technical Speaker Crossover Guide

Thorpy's Non-Technical Speaker Crossover Guide


There are plenty of guides around on the web showing how to build speaker crossovers.

However, I found most be a bit mathematical. You will need maths if you a building the perfect set of speakers, but for a functional set, you can use these rough instructions. They worked for me.

Crossovers are normally hidden inside a set of speakers and so unless you are building your own boom box, or set of speakers, you may never have seen one before.

I have taken some of the more simple advice on the web and dumbed it down still further, for those who want to see some pictures, and just have a go.

I have no clue how any of this works. But I have built a boom box, with the below components, some homemade / DIY, and it works. So I would urge you to have a go too.

What does a Crossover do?

If you look at most speakers they have two drivers, a tweeter for treble  (high pitch sound) and a larger driver for mid range and bass (low pitch sound).

What does a cross over do? Well it filters the sound and delivers high frequency sound only to the tweeter, and low frequency sound to the large driver.

Do you need a Crossover?

Sometimes no. Sometimes yes. Most speakers have some form of crossover. But how can you tell if you need one:

Example 1 - A crackly / distorted / snicky sounding tweeter may require a filter to get rid of the low pitch sound, that it is not designed to handle. In this case you would want to filter out low pitch sound, with a "high pass filter", which can be done with a capacitor (see below).

Example 2 - A harsh sounding mid / bass driver that is getting too much treble. In this case you would need to filter out the high pitch sound. This can be done with a "low pass filter", this is done with an induction loop.

What do you need to build a cross over?

Here is a picture of my setup. (I am sorry to say that the capacitor in this picture is covered with glue, so it is a little hard to see. But it is there! Click on the image to make it bigger)

Ugly but Functional

Ingredients - You will need:

  • Soldering Iron & Solder
  • Insulated Copper Wire 2 or 3 Meters
  • Bi-Polar Capacitor 40V +
  • Sticky Tape
  • Glue
  • Chunky Steel or Iron "Core for Inductor"*

*I used the spindle from a industrial motor, but you could use a bit of scaffold pipe, or a big bolt or a piece of broken round file. It has to be iron or steel.

Install a High Pass Filter (also called a "Bass Blocker")

A high pass filter is very easy to install, you will need a bi-polar capacitor.

Polarised or Bi-Polar

Now as a general rule you should choose a capacitor with a voltage above 40V, but the higher voltages will also work, although they offer no advantage. The "uf" can be anything you like, and will probably work OK. Search here.

Just solder the bi-polar capacitor between the positive amplifier output and the the positive terminal of the tweeter. The the tweeter should be "fed" power through the capacitor.

Top Tip: Do not look directly at the capacitor when you power up you system. It may explode if you have chosen the wrong voltage or type (polarised or bi-polar). If you look the other way the bits won't go in your eyes.

Install a Low Pass Filter (also called a "Treble Blocker)

To make your low pass filter (induction coil) take around 2 to 3 meters of door bell wire, or other single cored insulated wire, and wrap is around your chunky steel or iron core. Leave enough spare wire poking out so you have enough to solder it to where it needs to go.

An Induction Coil - Very Techncial

Power needs to be fed to you bass speaker through this coil. So you wire one end to the positive supply from the amplifier and the other to the positive terminal of the speaker. (Scroll back up to the labeled picture to see how)


As mentioned this will not get you a top notch speaker, but it will make a horrible sounding speaker sound OK. 

By example, before installing these DIY crossover coils, I had to have the equaliser on my iphone on bass booster, and the sound was still too harsh.

After installing I can switch the EQ off, and they sound well balanced, I used an induction coil (low pass filter) taken from a professionally made speaker for the left hand side, and my DIY induction coil (low pass filter) on the right hand side. I cannot tell any difference by listening between the speakers. So the homemade one is working it would seem. 

For Reference - This is a professional made induction coil. Note PAM8610 amplifier bottom Right.

For reference I am using a PAM8610 to run this portable speaker, from 7 x AA batteries. The speakers were taken from some low quality active speakers. Also I should point out that you can get a pretty good bluetooth speaker for £30 / $50. So do not spend too much money on this unless you are doing it for fun!

Inside my DIY Portable Speaker

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Wednesday, 16 August 2017

Unstable / Surge Voltage for XL6009 Buck Convertor

Unstable / Surge Voltage for XL6009 Buck Convertor

I am new to electronics, and this small boost convertor has me baffled. It displays some weird behaviour. One sets the voltage using the small brass screw, but then if you watch and wait the voltage climbs from the set voltage, 5 Volts in my case up to 28v or higher. I have also observed the same behaviour when setting the boost converter to 10v.

This has resulted in me destroying a bluetooth amplifier, because after setting the voltage at 5V, and connecting the voltage climbed to 28v and killed the amplifier board (PAM8403).

I am powering the XL6009 board, with a headway 8ah LIfePO4 battery at 3.9V, which is rated for 100A output. So I do not think insufficient power is the problem.

If you have had any joy with this sort of thing O would appreciate some help.

Friday, 14 July 2017

Make a Portable Speaker with PAM8403 Amplifier

Make a Portable Speaker with PAM8403 Amplifier - Intro

Do you have an old speaker or two hanging around in the garage or loft? Would you like to make a kick @$$ portable speaker for just £3 / $6? Left me show you how.

Lets get real here, you are not going to save lots of money you can probably buy a portable speaker, for you iphone or android phone direct from china for £6 / $12, but this way you get to save a trip to the dump, and get some satisfaction.

Old Speaker + £3 = Disco

Make a Portable Speaker with PAM8403 Amplifier - Ingredients

You will need the following ingredients:

  • An old speaker (4, 6 or 8 ohm) lower ohms = more volume.
  • Some wire (door bell, lead from old adaptor. . . )
  • Battery Holder to hold 3 x AA or 3x AAA batteries  
  • PAM8403 amplifier board
  • A drill 
  • screw driver
  • Soldering iron
  • solder
I have gone in to detail regarding the battery holder and the PAM8403 amplifier below.

Make a Portable Speaker with PAM8403 Amplifier - The Amplifier

You can buy the vanilla PAM8403 board on ebay for next to nothing but for a few £/$ more you could get hold of a blue tooth variant. This is useful if you want to use a phone without the 3.5mm jack socket.

There also variants with a volume control, and a smoothing capacitor. This may be worth getting if you do not have a spare capacitor

Bluetooth . . . . . volume control . . . . . or vanilla (normal) the choice to yours.

Make a Portable Speaker with PAM8403 Amplifier - Power Source

The amplifier run on a any voltage between 2.5V and 5.0V. This means you can power it with:

  • 3 x AA batteries
  • 3 x AAA batteries
  • USB power lead from PC or Wall Adaptor
  • 1 x 18650 Battery
  • A USB power bank
I have tried with a USB power lead, and then 3 x AA batteries both worked very well. 

The amp have two channels (left and right) and as far as I know you have to use both channels. You cannot splice the two channels together to make one. 

Make a Portable Speaker with PAM8403 Amplifier - How To

So the old speaker I have had a tweeter (small high frequency speaker) and woofer / midrange speaker. I used one "channel" from the amop for each. I cant remember which way around I put them. 

You will need to remove the cross over if there is one, save the capacitors for re-use.

In order to do this you will need to open up the speaker and, take a wire from either the woofer or the tweeter, you may find that you have a cross over unit in there, you will need to by-pass this so you can create two separate channels. Keep the cross over and carefully remove one of the capacitors for reuse, in a moment. You will need to solder this in to the positive wire of the tweeter. Like this:

Adding a capacitor as above will improve sound quality.

I first tried the amp and speaker together without this capacitor and the tweeter sounded distorted. However, after adding the capacitor all was well. 

The amplifier is tiny. . . note pinky (little finger) for scale.

Next up we need to start soldering all the bits together, if you do not have a soldering iron just buy one. They are useful for all sort of mending and fixing and making. As you can see the PAM8403 amplifier is tiny. And this makes for fiddly soldering, you can only use thin wire as the holes are too small for thick wire. 

Wiring is simple. . .but fiddly!

So for simplicity I house the wiring in a surface mounted junction box on the rear of the seapker, I had one of these spare in the garage. But you could actually just put all of the wires inside the speaker if you wanted to. Although it would be more fiddly to work on. 

3 x AA Battery Holder - £1.99

This cheap battery holder from ebay has a built in switch (counter sunk). I screwed it on to the rear of the speaker. With 3xAA batteries in side in produced 4.5V, good quality rechargeable batteries are preferable to disposable, as they hold a higher charge for longer, so voltage stays are close to the optimum (5V) as possible. 

Toggle switch. . . if you like.

I also added a toggle switch that I had as it is a nicer switch to use, than the one on the battery holder. You can also use a piece of cord, rope or strapping as a carry handle. 

Carry Handle

Make a Portable Speaker with PAM8403 Amplifier - Performance 

The sound level of the finished speaker (4 ohms / 4.5V ) is approximately 60 - 70 decibels. You cannot really have a normal conversation in the same room. As a 35+ year old man, I find it unpleasantly load at full volume.

There is quite a lot of midrange and high pitch sound, and perhaps some more bass would be a good, but overall for a piece of hardware that cost 99p, and is the size or a postage stamp it is amazing . . almost alchemy in terms of its performance. 

This is a fun, low cost project that I have enjoyed doing, and I would urge you to do the same if you require a speaker of this type rather than buying some other hard to recycle item from china.

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Thursday, 13 July 2017

Living with iOS 9.3.5 on an iPhone 4S

Living with iOS 9.3.5 on an iPhone 4S  - Intro

I have been avoiding upgrading my iOS since iOS 7. However, on wednesday night I drank too much red wine and upgraded, because an app I wanted to use requires iOS 9 or higher.

What a mistake to make. My snappy adequately fast phone was rendered sluggish and virtually useless. So what can I do?

Living with iOS 9.3.5 on an iPhone 4S  - Down-Grade - NO WAY

Apple must know that older devices will not run there newer iOS properly, and hope that the performance of iOS 9 on older devices will force people to upgrade. For this reason they do not offer a way to downgrade your iOS. 

There is one exception, and that is 6.1.3 which is still "signed" for use on the iPhone 4 (not 4S). There is 3rd party software avaiable to do this, if you have iOS 9.3.4, but not for iOS 9.3.5.

So this is impossible for 9.3.5.

Living with iOS 9.3.5 on an iPhone 4S  - Jail-Break - NOOOO WAY

This is also not possible, iOS 9.3.5 is not jail-break-able.

Living with iOS 9.3.5 on an iPhone 4S  - Re-Install and Performance Mods - WORTH A SHOT

This is the only way left for people, and I think by following the below steps you can claw back the usability of you iphone 4S.

9.3.5 Reinstall

  1. Back-Up Your Iphone (Use iTunes)
  2. Reset (Settings > General) Choose (Erase All Content and Settings) 
  3. Restore from Back Up when Done.
Note: This freed up a lot of storage space for me. Despite having most the same apps and music on the phone after restore. Perhaps the old iOS is not deleted from the phone when it is upgraded?

9.3.5 Performance Mods

Do the following:
  1. Turn Off Animations (Settings > General >Accessibility)
  2. Turn Off Transparency (Settings > General >Accessibility)
  3. Turn Off Back Ground App Refresh (Settings > General)
  4. Enable Low Power Mode (Settings > Battery)
  5. Delete All Unwanted Apps (Hold Down Any App Icon Until Wobble)

Living with iOS 9.3.5 on an iPhone 4S  - Conclusions

APPLE! It should not be like this, serve the customer please. If I want to install Windows 3.1 on my PC I can. . . . this means I do not have to send my old PC to india, for kids to dismantle, and go to early graves with lead poisoning. . . there is a moral element here!

Every time you make a new iphone there is also a carbon cost, it is no good prattling on about how considerate you are in you CSR reporting if your belligerent attitude towards legacy hardware is causing mountains of E-Waste, and unnecessary Carbon Emissions. You know global warming, that thing that Trump Ignores. . . but then he is a pretty good guy after all.   

Illustrator Devon

Tuesday, 11 July 2017

Daphon GA-1 Amplifier Review

Daphon GA-1 Amplifier Review - Intro

WHo wants a new blue tooth portable speaker when you can use a chunky black box, attached to your phone with a cable? I appreciate that this is a guitar amp, but I also thought it might be good for playing music through. . . . .turns out NOT. It is not even a very good amp, and yes I am considering the fact it is small and runs on batteries.

Daphon GA-1 Amplifier Review
A nice looking amp with a quality feel. . . . 

Daphon GA-1 Amplifier Review - Battery

This GA-1 takes a 9v power pack (LR6) what a faff that is , why not 6 xAA? That would be so much cheaper and easier. So that is a really annoying feature. Considering the amps performance (low) then you need to keep the battery in prime condition to deliver good sound, otherwise more distortion, and there is PLENTY of that any way.

Daphon GA-1 Amplifier Review BAttery
Really? That is the best battery option you could think of?

Daphon GA-1 Amplifier Review - Sound Quality

Terrible. There is something to be said for it small size, and if you are playing in your bedroom or maybe at a BBQ in the woods. . . . but the sound quality is so so poor, its hardly worth having. Using it a speaker for say music from an iphone is a terrible idea, as the sound distorts at an incredibly low volume. 

The Insides let this amp down. . .badly

Daphon GA-1 Amplifier Review - Insides

Inside the amp we see the board is centered around a panasonic (AN7142) 0.9W chip. This is well below the advertised 2W output, or leagues away from 5W max output touted.

Now I am not a electronic guy, but you can get amp chips that support 5W. So what have they done in there? Whatever they are doing it certainly looks as though the internals could be better.

A low power chip may be to blame for the terrible sound?

Daphon GA-1 Amplifier Review - Manufacturers Blurb

This is the blurb straight from daphon:

Portable Performance Amp

A perfect beginner guitar amp or a busker's best friend. Because of it's battery power you can have amplification wherever you are. The amp has the capacity to produce decent volume and you have control over your sound through tone control. Flick the drive button for a crunchy overdrive. Also suitable for microphones, though an impedance transformer is recommend for best performance.

Hours of Fun on a Single Battery

Runs on a single 9 volt battery (the rectangle type) that can last many hours depending on volume, can also be powered by a 9V ac adapter. The amp is 20cm / 16cm / 8cm in size and a headphone output is included for silent playing.

Music On-The-Go

Also a great portable music speaker. Just plug in your Mp3, Ipod or Discman via the input and you can have access to music wherever you go.

Daphon GA-1 Amplifier Review - Dimensions

Dimensions: 20cm x 16cm x 8cm
Weight: 1.2kg
Maximum power output: 5W
RMS power output: 2W

Daphon GA-1 Amplifier Review - Conclusions

A well built case a solid feeling controls, let down by very poor quality internals.

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Thursday, 29 June 2017

Schwalbe Dirty Harry BMX Tire Review

Schwalbe Dirty Harry BMX Tire Review - Intro

These are a cheap BMX tire from Schwalbe. However, do not be fooled by the price, this is an excellent tire that could be used on folding bikes, kids bikes as well as BMXs and have an excellent building quality and a good multipurpose grip. It comes in 20" (406) variant only, and is 1.95" wide.

Schwalbe Dirty Harry
Not Just for BMX

Schwalbe Dirty Harry BMX Tire Review - Grip

The tread pattern is ideal suited to street riding, loose gravel riding, and dry dirt. Where it quickly comes undone is claggy mud, where the closed block tread pattern quickly clogs. The tread pattern is also quite shallow, this is advantageous in that the "knobs" do not flex when under load but a disadvantage as they clog more readily. 

Schwalbe Dirty Harry
Tread Pattern Looks Flash and is Good for All Except Thick Mud

The rubber compound is SBC (Schwalbe Basic Compound) as used on early Big Apple Tires and is perfectly adequate, although not as good as some of their high end compounds. 

Schwalbe Dirty Harry BMX Tire Review - Build Quality 

These are a moderately high quality tire. But is has one blinding feature that most other BMX tires do not have, a kevlar puncture protection belt (Kevlar Guard). This is an excellent feature, and will stop punctures from just about anything, except hawthorns. 

Side View

The TPI is s little low if you want to carry large loads, but for normal riding is is very good. These have a soft feel when riding when compared to a very high TPI tire such as the Eclat Ridgestone.

Tread Deatil

Schwalbe Dirty Harry BMX Tire Review - Conclusions

A cheap reliable tire form a quality brand, with excellent puncture protection. A tread pattern suitable for all sorts of surfaces. . . .whats not to like?

Thursday, 8 June 2017

Informal Tender or Sealed Bids - Buyer's Guide

Informal Tender or Sealed Bids - Buyer's Guide - Intro

I am not an expert. But we have recently bid on a property using the Informal Tender or Sealed Bids process, and here are some observations which may be useful to you.

Informal Tender or Sealed Bids - The Property's Price

This is set by the estate agents to generate interest in the property, so it is likley to be below the actual value of the property.

You could complicate things here my trying to work out how much the property is worth. But the really the simple fact is, it is worth whatever you are willing to pay for it.

You don't really like it? - Bid 20% below  Price

You really want it? - Bid as much as you can afford*.

*I did look at some other similar properties nearby and this confirmed my suspicions that the property was under priced. For example if you are looking at a 3 bedroom terrace house for £180,000, and most property that are similar  sold recently for £220,000, then this will give you some idea of the level of bid that could be placed. Remember if you bid too much the mortgage company will find that the property is over-valued, and likley not lend you the money to buy it.

Informal Tender or Sealed Bids - How are the Bids Decided

Price would be a major factor with the buyer likley accepting the highest offer.

However, if to similar offers are received, then the buyer will likley choose the offer that which does not rely on chains or borrowing.

A chain free cash buyer would be most favourable, although I have read on line that cash buyers are not always the first to be picked.

Informal Tender or Sealed Bids - How to Bid

Ask the estate agent for a Informal Tender form or proforma, for you to fill out. If they do not have one then include the following information in a letter:

  • Title - Subject to Contract Informal Tender
  • For - The Address of House you wish to Buy
  • Your Name (s)
  • Your Address & Other Contact Details 
  • Is your offer and ability to proceed dependant on another property? Yes or No
  • If yes give details. 
  • Level of borrow you anticipate.
  • State of agreement regarding borrowing i.e. Agreement in Principal. 
  • Name of your Solicitors
  • Other things you think might be relevant. 

Informal Tender or Sealed Bids - When to Bid

You are hopefully delivering a envelope or an email to your estate agents.. . . . . . 

If the people running the tender are less than honest then it does not matter when you submit you bid, as the process is rigged. In this instance it may be advantageous to submit your tender at the last minute, so as to give the organiser less time to react.

If the people running the tender are honest, then nobody will see you bid other than the honest organiser and the vendor, so it does not really matter when you submit your bid.

Informal Tender or Sealed Bids - Can You Bid more than Once?

Yes, just submit a revised offer if you think you may have bid too much or too little.

Informal Tender or Sealed Bids - Have You "Won"?

You will normally find out within 1 or 2 weeks after the closing dates for bids. It may be that if you are the second best bidder, and the first best bidder withdraws then you might be in with a chance.

This is was the case when we bid, we were "significantly lower" than the winning bid, but for what ever reason they pulled out, and we are now buying the house! 

Friday, 26 May 2017

L1e-A Type Approval - Missed Opportunities

1 - L1e-A Type Approval - Missed Opportunities - Intro

The L1e-A class of vehicle is at at present described in European Directive 168/2013, at the moment there is no way of obtaining UK type approval for this vehicle. If you built a 15 mph 1000w ebike it would need to undergo the same inspection process as a Motor Bike.

But for now let us imagine that the DVSA had the resources to publish a list of requirements. If they followed the requirements set out in European Directive 168/2013, then the below list (Chapter 2) would be required, and uptake of the L1e-A vehicle class would be minimal. 

If we are to release to full environmental benefits of electrically assisted pedal cycles then we must allow a higher power rating under existing EAPC regulations, whilst maintaining current 15mph speed limit. 

If one has to tax and insure these higher powered, but low speed (15mph) vehicles what is the incentive in operating one? One may as-well opt for a "real" motor bike or a car.

In my various emails shared with the Department for Transport (Chapter 4) no reason for the current 250w limit has been given, the USA have a 750w limit which has been in use for over a decade. 

In short this could be a very useful, zero emission, transport solution. We need to clean up our air, we need to reduce our carbon emissions. 1000w 15mph EBikes and ETrikes could take over many of the jobs that Small Vans and Car currently do in our cities. 

Passengers . . .
. . . post. . . .
. . .  or freight.
Most of these heavier cycles are popular in the "low countries" such as Belgium and Holland. In the hilly UK, if these pedal powered vehicles are to be success then we will need a 1000w power limit on an assisting electric motor.  

2 - L1e-A Type Approval - Missed Opportunities - Requirements

L1e-A - Horn

You will not need am audible warning device. AKA a Horn.

L1e-A - Brakes

According to UNECE Reg. 78 unless the vehicle weighs less than 35kg. In which case normal bike brakes will be OK.

Rim widths must be kept under 45mm to avoid stopping distance requirements.

L1e-A - Endurance

Needs to be able to last for 5 years. Which bits this applies to I do not know, likley the frame I should think. 

L1e-A - Lights and Signals

A headlamp, a side reflectors, pedal reflectors. Headlights can be switched automatically or manually. No rear light is required.

This is rather silly. A rea light is one of the most important safety features on a bicycle. . . . the mind boggles.

L1e-A - Saddle

A normal bicycle saddle.

L1e-A - Tires

Normal bike tires provide loaded weight is below 150kg, and the tires are less than 67mm in width. This translates to 2.35" cycle tires being OK, which is pretty wide. 

L1e-A - Anti Tamper

The vehicle user should not be able to alter the vehicle speed above 15mph, with (i am guessing) an off road switch or similar.

L1e-A - Vehicle structure integrity

Must conform with EN 14764:2005. This is a bicycle standard realting to "City and trekking bicycles." So if you are converting a modern bike of the correct type then it should comply. However, this standard does not apply to:

"It does not apply to mountain bicycles and racing bicycles, tradesman's delivery bicycles, recumbent bicycles, tandems and bicycles designed and equipped for use in sanctioned competitive events."

L1e-A -Passenger handholds and footrests

These are not required. However this would suggest passengers are allowed. . . 

L1e-A - Registration Plate / Number Plate

10cm by 17,5cm space is required for mounting. This is annoying. This is large un-aerodynamic thing to fit on to a bicycle. 

L1e-A - Kick Stand

Yes you need one of these. A kick stand, or two foot stand for example. 

L1e-A - Propulsion Unit performance

This is a little complex, and will depend on the type of system. If a pedal assistance system then there are standards to be met (EN 15194:2009 &  UNECE Reg. No 8)

L1e-A -Electric energy consumption and electric range

There are no minimum range requirements. 

3 - L1e-A Type Approval - Missed Opportunities - - Conclusions

One of the great joys of owning a ebike is the lack of legislative burdens. No tax, no insurance, no requirement to wear a helmet. . . . 

The L1e - A category has the potential to revolutionise inner city transport if implemented correctly and sensitively. But if regulators are too heavy handed this form of vehicle will be relegated to an obscure and underutilized form of transport. 

4 - Type Approval Requirements L1e-A - Letters to DfT

I have had various contacts with the the Department for Transport. I would rather see this L1e-A bracket included under EAPC regulations.

Letter 1

An initial enquiry, brought boiler plate response. So . . . my response.

I think in the days before the world wide web, the response may well have been a useful one. But it is repetition of information that I have already read, and already have access to. It is all very well to choose 250 watts as a maximum power rating, but I fear this figure has been chosen at random with no true understanding how an electric motor works.

How will this be enforced? – We have a enforcement system that measures speed, not power.

Practicality? – Would you place a power limit on a Tractor?

Worthy Contribution? – A moderately fit rider can produce 800w power when cycling. 250w as an addition is rather small.

I summary I am trying to investigate why this 250w figure has been chosen. I would like to think there was some science behind it somewhere. . . . but I have a strong suspicion it was plucked from the air.

DfT response to Enquiry on why current limit is 250w.

Directive 2002/24 made type approval compulsory for all two wheeled motor vehicles,  except powered cycles not exceeding 250 watts. 
Unfortunately we have no detailed information on why that threshold was chosen. It may  have come from a prior threshold in an EU country where such cycles were common eg  Netherlands.

Letter 2 - Higher Power for Low Speed EBikes 

My Letter - Enquiring About Power Increase

Now that we are leaving the EU could we open a dialog on how best to increase max allowable power on pedal assisted EVs? To be clear 15mph speed limit would be maintained, with increased assistance level and torque.

Since our last communication we have heard that diesels will likely be banned in cities, and I think it is likely that electrical assisted vehicles can fill this gap.

With the price of electric cars and vans being inhibitive for most, I think now is the time to investigate this possible review of the EAPC regulations. Here are some links to some vehciles that would benefit from a change to the regulations: 

For Passengers



For Cargo



Surely this is worth looking at? We have an air quality and emissions mountain to climb in the next decade and this can only help. . . .

Dft Response to Increasing 

Thank you for your e-mail of 27 April concerning electrically assisted pedal  cycles (EAPCs). I have been asked to respond as I work in the Department  for Transport’s cycle policy team and lead on EAPCs.

As we are currently in the pre-election period, known as purdah, new policy  decisions cannot be taken until after 8 June when a new Government will  have been elected.

You may be aware that prior to the beginning of the purdah period detailed  guidance on compliance issues affecting certain EAPCs was published on the  Department for Transport’s website. For ease of reference here is a link to  the guidance.

My response to This

Thank you very much for you informative response. I had seen a draft of your linked document last year, I am worried that if these slow, low powered cycles are grouped with motor vehicles that the added administrative burdens will prevent their uptake.

I have recently read that there is a directive 168/2013 that introduces the category L1e-A for type approval. That is a 15mph top speed but with a 1000w power allowance.

This is exactly the type of bicycle I think that would prove useful for passenger and load carrying, and would provide a real alternative to cars and vans. Especially in hilly areas, were the current 250w allowance does not contribute meaningfully.

These types of cycle would also allow individuals and businesses to opt for zero emissions transport at a fraction of the cost of an electric car. This would accelerate the inner city air quality improvements required of the UK, whilst adding to the fitness and wellbeing of those using the cycles.

I believe that the DfT are updating type approval regulations at present, I would ask that the L1e-A category is merged with the EAPC regulations. I am of the opinion that attempts to classify these cycles as motor vehicles would severely restrict there up take, and thus limit the myriad of positive effects that they would bring for those using them, and air quality.

Finally, it is very difficult to enforce a system based on power ratings, at present our enforcement system favours speed as an enforcement mechanism, which most police can measure easily. If a bicycle is limited to 15mph, then there is very little point in having any more than 1000w power, any more and it is surplus to requirements. 

Environmental Permit Applications  

Desktop Study

Monday, 8 May 2017

Thorpy's Grass Track Dilly Cart Build

Thorpy's Grass Track Dilly Cart Build - Intro

This is a brief write up of the dilly cart / box cart that my kids and I have built for the National Trust, Landhydrock, Dilly Cart Race. I am not racing in the kart, instead my wife, and two daughters are entering because I enjoy building things, but not driving.

The race is a grass track race, and as such the rolling resistance is quite high. For this reason the race organisers suggest the use of 24" wheels or bigger.

Normally a box cart, or dilly cart track is paved in some way, and on these tracks a smaller 20" BMX wheel will serve you well, they have more spokes and are generally stronger.

I chose large wheels, because I think it will be annoying if the cart does not roll well. I think my kids will use the brake quite a lot, and not gauge the track ahead very well in terms of the momentum, required. Bigger wheels will reduce the likelihood of stalling on a grass track. So that is why I think the bigger the better even if you are not out to win.

Watch the length. 2.5 meters is soon used up!

Thorpy's Grass Track Dilly Cart Build - Specifications / Rules

For Landhydrock, Dilly Cart Race 2017 the carts have to meet the following requirements, unlike many cart races, you only need 3 wheels, which makes things a lot easier in terms of steering!

  1. Carts must have a minimum of three load bearing wheels.   
  2. We recommend a wheel size minimum of 24 inches, as you will be racing on a grass track.  
  3. Carts must have effective steering. 
  4. Carts must have effective brakes. 
  5. Carts must fit within the following dimensions:  

  •     Maximum length 250cm, 
  •     Maximum width 150cm, 
  •     Minimum track width 60cm 
  •     Maximum weight of vehicle, ballast and driver 150kg. 

  1. Carts must not have any sharp edges, glass or loose parts.   
  2. Carts will be examined before racing, and any carts considered  dangerous or unsuitable for the course will not be allowed to race.   However, inspection does not constitute a warranty of safety.   Drivers are solely responsible for the safe construction and operation  of their vehicles. 

Wonky but Functional

Whilst I found the width allowance to be very generous, you will have the watch you length. The 26" wheels add a lot of length as there are approx 60cm front to back so there is 1.2 meters straight away. The pictured cart is 2.4 meter long approx.

Thorpy's Grass Track Dilly Cart Build - Ingredients

Two bikes will provide moist of the stuff you need, they will have mounts for brakes, wheels, and other handy bits saving time and trouble. To summarise, try to get hold of two old mountain bikes. The recycling centre is a good place to start, where you could get 2 bikes for £20.

To Weld or Not to Weld?

If you buy a welder, then I am pretty sure you will be able to learn to use it pretty quickly. A cheap gasless mig welder can be had on ebay for £120. A welder is such a handy thing to have, by the time you have spent £50 on an alternatives such as epoxy, rivets or bolts etc. then  you may as well make the investment.

If you were to building from wood, that is OK.  I have done this before and the results are not as good. And even then we used some welded parts for brackets etc. I have seen some good wooden carts built with wheel barrow wheels, but with larger wheels it become more difficult.

Extra Tubing

The best source for cheap tubing I have found is electrician's conduit which you can get from any plumbers store or electrician store. Not B&Q, somewhere like plumb-base. It come is 3 meters lengths so unless you have roof rack, take a hacksaw with you.


You will need something to make the seat, this could be a canvas only deck chair type thing, or as I have done a plyboard jobby with a bit of cushioning (roll matt).

Foot Rest

This could be wood, tubing of net / mesh as used in pictures.


I used water based exterior paint, with an undercoat. It was left over from our front door. Metal paint would do a better job, but it is very smelly (high VOC content) and I wanted my kids to help paint it.


I am just using the tires that came on the bike. But you could opt for fatter tires with a shallow tread if you were really keen.


Ballast is a heavy lump of something that you attach to the cart to make is go quicker. Heavier thing have greater momentum, and so speed gained down steeper sections will be maintained through flatter sections.  I am not putting ballast in the cart, I just want my family to have a nice day and I am not bothered about winning. If the dilly cart were to tip over with 25kg or 50kg of ballast in side then I do want a family member underneath that kind of fast moving weight.


Hopefully you can use the brake son the bike. A front wheel break is not ideal as there will not be much weight of the front wheel, causing it to skid easily, at which point the steering will stop working! Not ideal.

1 Break on one side of the rear, will cause a little skewed, when braking, but is an ok option, if you have time then brake both rear wheels.

A very simple solution is a ground bearing break. Pull up a handle and a piece of wood hit the ground slowing the cat in the process.

Thorpy's Grass Track Dilly Cart Build - Design

Perhaps this should have come before ingredients. . . . . 

HAVE FUN. Do not worry too much about your design, unless you enjoy that part of it. Just try to keep the wheels aligned, and think about the human that has to fit inside the dilly cart. A good way would be to sit on your garage floor and draw around you required seating area, with a permanent marker. Then build the cart around this. 

Two Bikes Stuck Together make the Job Easier

Make sure the cart is strong enough. I will test out our dilly cart before I put my kids in it. I am double the weight of my wife, so I consider that an adequate test. 

So many things in life are prescriptive, why not just make it up as you go along!

Thorpy's Grass Track Dilly Cart Build - Extra Bits

Some extra bit s that might be considered . . . . . 

  • Flags 
  • Streamers 
  • Roll Bar - Stops youngsters getting squashed.
  • Horn
  • Spokey Dokeys
  • Spoiler
  • Mudguards - Stop debris front front wheel going in eyes.