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This is the excellent USB power pack I use when I travel.

2 x 2.1amp outputs. 8400mAh capacity.

Two digit Led display shows battery level

 

What SD CARD should I buy?

If you want an SD Card for your camera - these are the ones I use and recommend. 

I'd strongly recommend not to buy any SD cards off ebay - I've heard about too many issues with counterfeit cards - often sold on by unwitting resellers. My inbox regularly gets messages from people who bought a £150 camera then cheaped out and bought a £3 memory card on ebay - Then when it doesn't worth they blame the camera! It doesn't make any sense. Good memory is cheaper than it's ever been - see the links above.

A lot of HD cameras will not work properly with cards larger than 32GB (cards over 32GB are usually SDXC rather than the SDHC standard used by 32GB cards. SDXC cards use the ex-FAT system rather than FAT32 - in short they are a different standard). - so don't just buy the biggest card you can afford - read the specs in the manual to see what it accepts.

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CLASS 10 UHS-1 CARDS (For HD Cameras)

 

U3 CARD (For 4K cameras)

 

 

SPECIAL DASHCAM CARDS

The SD card in a dashcam is re-written over, more frequently than in other types of cameras. Some manufacturers void their guarantee if an SD card was used in a dashcam. So, no surprise, there are special High Endurance SD cards made just for dashcams...here's some.

 

VERY IMPORTANT. These links take you to the product, however Amazon have three different ways of selling. There's Amazon Direct - This means that you are only dealing with Amazon themselves, then there's other sellers that use Amazon's facilities - these show as Fulfilled By Amazon and finally there's Market Place sellers that advertise on Amazon, but operate independently.  I strongly recommend that you only use the first...the Amazon Direct - Sold By Amazon option. Even if it appears that you are paying a couple of £/$ more it is more than likely you are comparing the price of a real item against the price of a fake.

To give you an idea of the extent of the fake goods problem. In a 2016 survey by Apple - 90% of the 'Apple' chargers sold through Amazon - using the other the two methods..which includes the "Fulfilled by Amazon" option -  were found to be counterfeit....90%! 

 
« Bring out the Gimbal | Main | Dashcam Battery pack lets you record whilst parked »
Sunday
Jun052016

Retro HiFi: The DBX Disc

One thing that often comes as a surprise to anyone getting into vinyl for the first time is surface noise. As soon as the stylus touches down on a spinning disc there’s a noticeable background rumble. You could spend thousands in trying to eradicate this, but turn the volume up and you’ll discover that whenever one object scrapes along another, surface noise is inevitable. 
  
The absence of any background noise was one of the things I noticed when I listened to a CD for the first time in 1982. The complete lack of vinyl rumble, or tape hiss between tracks was something that was impossible to miss. A father of a friend who sold BAE aircraft around the world brought a Sony CDP-101 player back from a business trip to Japan. I remember turning the volume way up in order to hear what wasn’t there, just as much as what was.
  
In addition to no surface noise the new CDs had no static cracks and pops, and classical music recordings benefitted from the expanded dynamic range offered by the new format. Other attractions were of course the smaller size, longer playing time, easy track access, and a resilience to dust.
  
It turns out that many of the ‘new’ features available on CDs were already possible with Vinyl, it’s just that most people weren’t aware. Track access, random play and  each side play were all possible with the right turntable. Lesser known is the fact that zero disc noise, CD levels of dynamic range and reduced pops and crackles from dust were all features available on the obscure DBX disc format since the early 1970s.
  
In this video I look at (and listen to) DBX discs for the first time, and I’m shocked with the results. Watch the video below to find out more. 
You can still find old DBX Disc decoders on ebay where you can also find some DBX encoded records. The Discogs marketplace is also a good place to source DBX discs.
  
UPDATE: 
In a (soon to be proved misguided) attempt to placate the angry crowds brandishing pitchforks and flaming torches - HERE IS A DIGITAL RECORDING of the first two minutes of Pramlatta's Hips. 
 
You can hear the needle drop at 2 secs in...the silence after that is the lead in and then the music starts. There has been no manipulation of the recording - it's just phono out from the DBX 224 decoder into the audio in of a Sony HDR-MV1 recording in PCM WAV
  
I still feel that analog audio can only really be experienced in person, not via a digital recording - just like a photo of a oil painting, while all the information is there it's just not the same ...but hey what do I know, I'm just some guy on the internet.

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Reader Comments (38)

I enjoyed the DBX Disc video very much.
In the video, you briefly touch on the subject of Dynamic Range.

You might be interested in these links then about the Music Industrie butchering the Audio CD...
http://www.cdmasteringservices.com/dynamicrange.htm
http://www.cdmasteringservices.com/dynamicdeath.htm
Have you ever come across this as well in your experiments and listening?

Rgds,
Olli from Germany

June 8, 2016 | Unregistered CommenterOlli

Thanks again for this video. It got me motivated to seek out a replacement 224 decoder for the one I owned that vanished in transit. My new old 224 arrived today and I immediately inserted into one of my systems. I'd forgotten how spectacular those DBX encoded discs could sound. Now the hunt for more discs will commence!

June 8, 2016 | Unregistered CommenterDavid F.

Actually those level adjustments are not to set it up so it'll sound the same as the rest of your equipment. They are a vital part of the compression. You need to set it right with the help of a standardized tape/disk so the decoder will know about the point where it doesn't need to do anything. Essentially if you are translating volumes and "stretching" them out, you will have a factor by which you stretch it and a point where the input and the output are the same. This needs to be adjusted.

On internal de/encoders on Tapedecks that's usually no problem as you already have a factory aligned path.

BTW 100 dB of dynamic range were probably rather impossible to reach directly on tape. The range of hearing is just about 60 dB anyhow (on direct contrast, obviously there's more if you leave time for your ears to adapt).

BTW the things to listen for on such noise reduction systems are sounds where the volume changes abruptly. For example plucked string instruments like guitars. The systems work like an automatic gain control which doesn't quite work the full way. Highcom achieves this by having multiple gain control elements driven by the same control signal. They are driven so on the end the level will stay constant. If you now take the signal from after the first gain element, you will get a signal that's "half way" compressed. Essentially you can have the end of the chain on your playback device which will compress it down to zero, and use the inverse of your control signal to get your recorded signal up to the original range again. This would be much more simple to explain with pictures.

June 9, 2016 | Unregistered CommenterChristian Berger

@David F. Whenever I stick my neck out on something and say that it is impressive, I just wait to hear how wrong I am and that DBX sounds awful. I can only relay my own annecdotal experience, which scientifically may be proved to be completely inaccurate. It's especially difficult with audio where there is so much disagreement. So with that said, it's great to hear back from you and know that I'm not imagining it, DBX Discs really do sound great..and I'm happy that this video re-ignited an interest you had in the past.

@Christian Thanks for the information. I'm really just an amateur having fun with tech and don't know any more about things than the average chap in the street. On my decoder the controls do adjust the output levels...if I turn them down it's quiet and if I turn them up it's loud. When I did the direct recording the only way I could prevent the audio from the RCA plugs peaking out the inputs on my digital recorder was to turn down the levels on the dial.

June 9, 2016 | Registered CommenterTechmoan

Just enjoying the heck out of your reviews of old hifi tech. I worked for a couple of audio retail shops years ago, and am still a high functioning audiophile. I really look forward to more of these. The Cantata piece was a hoot. Wondering if you will come across the Seeburg 1000 music system some day.

Another company known for noise reduction was Phase Linear. The "Auto Correlator" was unique, in that it did not require that the source be encoded first. There was some trade off in fidelity as a result. They did however introduce a CX decoder called the model 220, that worked with specially encoded LP records. CX was developed by CBS records, the performance was very comparable to the DBX system. Very quiet with wide dynamic range. I sold a friend one years ago, and I don't think he has quite forgiven me. Turns out, only a handful of CX recordings were ever pressed.

June 10, 2016 | Unregistered CommenterJoe Austin

Whilst I don't have (or probably have any hope of getting) a Seeburg 1000, I do intend to make a video about something that's related to this at some point in the future.

June 10, 2016 | Registered CommenterTechmoan

Hi,
For those looking to purchase a decoder so you can listen to dbx encoded discs, you might want to take a look at the dbx model "21". It will ONLY decode discs and cassettes. Possibly, because it cannot encode, it might be not as expensive as model "224".
Just a suggestion!
Happy listening!!!
Serge

June 16, 2016 | Unregistered CommenterSerge Desaulniers

Great video, as usual! I appreciate the time and effort you put into the editing and sourcing all the elements (again as always) to make it interesting from beginning to end. I am myself also a fan of old technologies and have been devouring your videos for a few months now. Hope your channel grows more and more, you deserve to make a living with this!

June 17, 2016 | Unregistered CommenterFed

Hi, I had posted a comment like this on YouTube but it probably got drowned under all of the usual YouTubeiness. I have two questions, and one comment:

First question: what happens if you try to decode a non-dbx signal through the dbx decoder?

Second question: Could you post a high-quality .wav of the dbx-encoded audio that hasn't gone through the decoder yet? I think it would be interesting to try to reverse-engineer the encoding, just for the hell of it. (I'm guessing it's a digital signal that's encoded at a low level so it's not audible, and the audio you hear when you're not going through the decoder is just there as a preview audio sort of thing, or maybe it's a 1-bit DSSD or the like.)

And the comment: In the video you refer to how most music has only a dynamic range of 3-10dB, and then state that means a 100dB dynamic range on a recording medium is unnecessary. This is an all-too-common point of confusion; the term "dynamic range" actually means multiple things, and in the context of a recording format, "dynamic range" generally refers its signal:noise ratio, which is related to its sampling resolution. In this sense, a dynamic range of 100dB means that it's (probably) equivalent to around 18-bit audio, whereas the "loudness war" meaning of dynamic range is just about the variation in the overall sound power level. These two terms are easily-confused but mean entirely different things, and for example 8-bit audio has a dynamic range of 15dB but you certainly wouldn't want to use an 8-bit WAV file instead of a CD for listening to music. :)

Anyway, thanks for continuing to make these great videos - I've loved learning about all these obscure audio formats and nifty gadgets.

June 21, 2016 | Unregistered Commenterfluffy

1) This question was asked quite a few times under the video in the comments so I put the answer in the video description text box. An abridged version of that answer is;
"A normal record with no DBX encoding played through a DBX decoder sounds muffled...like listening to a speaker through a pillow."
2) I haven't made any more recordings of discs....but there's really no need to experiment with trying to decode the signal, DBX decoders are still quite easy to come by, and there's no need to guess about the way the technology works ...DBX is not a Digital signal, and you can read more about the technology here. https://en.m.wikipedia.org/wiki/Dbx_(noise_reduction). You'll also find more info in the pictures in the article above.

June 21, 2016 | Registered CommenterTechmoan

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