Headphone Amplifier Design Nears Completion

The headphone amp design is now complete, all I have left to do is finish adding the dimensions to the drawing.  Then I can input all that information into CAD/CAM to give me ‘.dxf’ files to send to the laser cutter in Exeter.  The cabinet will be of 6mm MDF.

Headphone Amp Inside.

Headphone Amp Inside.

Rather than put the Bluetooth receiver inside the amp, I have provided for USB power output and 3.5mm jack signal input on the top.  This means as Bluetooth develops or is even replaced altogether, there’s still a good chance the new technology can be connected to this amplifier.  It also means many other signal sources can be connected without the need for input switching = more expense to the buyer, more complication and another switch contact for the signal to get through.  So a CD player or computer could be used as the signal source.  Plus the BT receiver can be pulled out and used somewhere else, say in the car – after all; this is all about high end HiFi on a budget.

Headphone Amp Outside.

Headphone Amp Outside.

I now have designs for a low power amp (10W RMS/channel) a mid-power amp, a high power amp, a portable stereo player, a full-range speaker with auxiliary sub-woofer and auxiliary tweeter and a Headphone Amp.  All needs converting to CAD/CAM to get ready for laser cutting so again, I will be gone for a while as I learn how to control the CAD/CAM software and construct all these files.

Posted in Amp Cabinet, Design, Headphone Amp | Tagged , , , , | 4 Comments

Dunya Yunis – Abu Zeluf

Vinyl Album Cover.  Jean Jenkins:  Music in the World of Islam - 1.  The Human Voice

Vinyl album cover:  Jean Jenkins, Music in the World of Islam – 1. The Human Voice

Dunya Yunis is an amazing Lebanese mountain singer. I first came across this song by her when decades ago I bought Jean Jenkins’ ‘1. The Human Voice’ from the ‘Music in the World of Islam’ series.

Later it was sampled by Brian Eno and David Burn’s ‘Regiment’ track on ‘My Life in the Bush of Ghosts’. I very much enjoyed Eno and Burns album but the original vocal will entertain for centuries.

You can find Dunya Yunis singing Abu Zeluf on Youtube here:


And on Spotify for Jean Jenkins:


Posted in Music, Useful Info, Vinyl | Tagged , , , , , , | Leave a comment

Need a Barndance Caller Exeter, Devon?

. . . here’s where to go:


Posted in Construction | Leave a comment

Quick Update

I’m feeling guilty for not saying anything on this blog for such a long time, so will write something quick now.

I took some time off to decorate the sitting room; laying a parquet floor and a vintage looking HiFi system (Amstrong 521 amp with Bluetooth inserted inside and a pair of Olle Mirsch loudspeaker cabinets with Jordan JX92S drivers with tuned reflex port – I’ll add photos later), then it was Christmas, then my usual 3 winter cold viruses in a row . . .

Then next job was to work on the speakers for my office/workshop.  Some couple of years ago I bought a pair of KEF Concertos locally for £80.  Nobody else was interested, I think because the owner’s wife doesn’t like the teak wood look so got him to stain them black.  Staining varnished wood is always going to be difficult and they looked a mess.  Being skint that didn’t put me off and I have tried to strip the old varnish and stain off but not that successfully.  I also discovered that one of them has been dropped at some point and the bottom ‘lip’ at the front had been repaired using rubber solution and a stapler.

I’ve decided that I will paint the cabinets white and have chosen a grill cloth to compliment.  In the meantime I have replaced all electrolytic capacitors with polypropylene versions (adding around 1Ω for every 10µF to compensate for the lower ESR, otherwise the filters’ cut off points would change) and mounted it on the rear as it now all takes up so much space.  I’ll box the crossovers in before painting and that will reduce the ringing of the lower part of the cabinet; knocking with knuckles from bottom to top reveals a lot of bounce in the bottom half.  It is stiffer at the top because the cardboard tube used for the B110 midrange’s compartment holds the cabinet rigid at that point.

There are some other little tweaks but I’ll go into them when I put some photos up of that project.  The reason for all the work on them?  The sound they make is so easy and listenable, they make my Naim SBL’s seem quite dull in comparison!  They must be around 50 years old but still sound fantastic.  I can totally recommend any speaker that has the KEF B139, B110 and T27 speaker driver combination.

There’s another project hanging around in the background – a friend of mine is into vintage cars and wants a good quality windscreen wiper timer module, so he can delay the wipers on his old Morris Minor.  That design is finished and I’m waiting on finding the right cable lengths before assembly and once we are sure all is good will will put it into production for general sale.

Right now I’m back on the job of designing my HiFi.  I had a great idea, went down the wrong road, realised and am now back on the right path.  I’ll explain . . .

I have a lot of parts that I will no longer be using (due to design change) and we don’t have a HiFi system for our kitchen so I wanted to put these parts together.  I wanted to keep it simple – the only inputs would be Bluetooth for ultimate convenience and a built-in DAC for ultimate sound quality (allowing a computer to be the ‘source’ so delivering high-resolution files to the amp).  Plus the smallest footprint possible for both amp and speakers.  So the design brief; simple, small, great sound quality, reasonable cost.  I then came to the conclusion that many other people would want exactly the same thing – a HiFi system for today’s modern way of living.

So that is what I am doing at the moment, laying out my own amp’s design to get the above; simple, small, convenient, superb quality, affordable.  Here is a picture of the layout drawing as of this morning.  All parts are in place, all MDF panels are mapped out and I am now adding interconnections, thus making it easier to build repeatedly.

Basic Amp Layout Drawing.

Basic Amp Layout Drawing.

You cannot see the dimensions given on this picture but the amplifier will be 141mm high by 307mm wide and 170mm deep (not including another 30mm for the heatsinks and another 15mm for the control knobs).  Output will be 12.5WRMS from calculations so I would say a comfortable 10WRMS per channel in the real world.

The design is totally mono-block, in other words two totally separate amplifiers in the same cabinet with only the earthing being common.  This means signals from one channel with not affect the other channel and visa versa = improved stereo separation.

There are four transformers:

  • one for each channel’s, small signal front end,
  • one for each channel’s output transistors.

I’ve looked at Cookson Gold and believe the design can take the cost of using 0.8mm x 5mm Sterling silver ribbon to connect between each set of output transistors’ reservoir capacitors – you may not be able to understand the importance of this if you don’t make your own amp designs.  Note again that the output transistors get a power source all to themselves so no feedback into the signal source end.

There will also be 2 sets of phono input connections mostly because the PCB caters for a couple extra; it make the unit more useable and because it won’t add much to the final price.  So the full range of inputs to the amp will be:

  1. Bluetooth
  2. Built-in DAC
  3. 3.5mm Jack
  4. 6.5mm Jack (so you can plug an electric instrument in and jam)
  5. Pair of phono sockets
  6. Pair of phono sockets

The speakers will be small full-range units with the option of sub-woofer stands to increase height of the full-range drivers so they sit above the arms of any sofas.  They’ll also add a bit more oomph.

On the drawing above can be seen a large toroid mid-way up on the right.  This is a larger mains transformer than used in the 10WRMS design I am currently working on.  It will allow for 60WRMS per channel output and that will be the next design after this one goes on sale (hopefully sometime this year).

This picture shows the layout of the front panel:

Front Panel Layout.

Front Panel Layout.

Posted in Amp Cabinet, Amplification, cabinet, Construction, Design, Earthing, PCB Layout & Design, Power Amplifier, Power Supplies, Pre Amplifier, renovation, Vintage HiFi Renovation | Tagged , , , | Leave a comment

Shellac gig at The Fleece in Bristol, 7th October 2017

My friends and I went to see this gig last Saturday. It was amazing.

Before going in, we had a quick beer and then went to an Italian restaurant. After chatting a while about Shellac, Todd Trainer came past and said hello – he’d been sitting behind us and could not help overhearing our conversation.

The guy came across as being really decent and sincere and before he went offered to put us on the guest list. We already had tickets so didn’t need that but it was a generous thought – it is after all, how they make a living. We all really appreciated it.

He’d let us know roughly when they were going on so we had another beer and then went to the gig. I am a photographer (as in I like to take photos – no more) and although not a pushy one at all I thought this was an opportunity not to be missed so I slowly slide between gaps to get right to the front. I’d like to say a big thanks here to all those that let me do that, everyone was really kind and let me through. I hope you enjoy the photos enough to feel it was worth it.

Todd Trainer of Shellac, The Fleece, Bristol, October 2017.

The gig was just great, I took loads of images, all in black and white and the music was awesome, totally awesome. Steve Albini, Todd Trainer and Bob Weston seemed like they’d had a good time and came across as professional, open and honest, sociable and above all – kick-ass musicians. Thanks guys.

This Liquiphonics account at WordPress has become squashed together with my photography blog ‘matalimages’ and my blog for my friends poetry ‘geoffspoetry’ – Google did that, the b*’s 😉  Don’t know how it happened. So you may know how to get to my Shellac photos but in case not, here are some links:

Liquiphonics HiFi on Facebook (22 images):  https://www.facebook.com/profile.php?id=100010561183725

Liquiphonics HiFi’s WordPress Blog (30 images):  https://matalimages.wordpress.com/

Posted in Music, Useful Info | Tagged , , , , , , | Leave a comment

Goodbye Walter Becker

I got into Steely Dan after coming across the stunning album cover for ‘Countdown to Ecstasy’.

Steely Dan's 'Countdown to Ecstasy' album cover.

Steely Dan’s’Countdown to Ecstasy’ album cover.

Their music was a variation on the Americana mix of jazz, rock, blues.  It had style, humour and a crisp, clean sound – they were really fussy when it came to sound quality.

Their music led me on to Donald Fagen’s; I love ‘The Nightfly’ and ‘Sunken Condos’ but I never even thought that the other half of the band could have his own solo albums.  I’ll need to have a listen to them.

Sadly, Walter Becker has now gone and far too soon at the age of only 67.  Thanks for the fun Walter.

Here is an interesting post about Steely Dan’s track ‘Deacon Blues’ and why it is used as an audiophile standard for comparing HiFi equipment (thanks to Graham for pointing me in this direction):


Posted in Music | Tagged , | Leave a comment

Clean Mains Connections = Good Sound

I recently bought a second-hand tuner, an Akai AT-550.  The condition of the mains plug pins was the worst I have ever seen.  Even though the connections pass relatively high voltages, they still need to be clean or sound quality will be affected.  I am particularly fussy about the earth pin connection.  Here is a picture of the tuner:

Akai AT-550 Tuner.

Akai AT-550 Tuner.

To clean the brass pins of corrosion and dirt, I use a fibreglass stick but sandpaper or even a knife can be used.  If you have the confidence, it’s worth taking a look inside the plug to make sure all three connections are good and that the fuse connections are not corroded or lose.  This shows the plug:

Showing the mains plug earth pin badly corroded.

Showing the mains plug earth pin badly corroded.

Showing the mains plug earth pin partially cleaned.

Showing the mains plug earth pin partially cleaned.


Showing the mains plug earth pin fully cleaned.

I cleaned all three pins, not just the earth and when finished, they were all shiny.

If anyone needs an explanation of how to connect a mains plug properly, please do ask me and I will upload a post showing how to do it – not everyone knows.

Posted in Useful Info | Tagged , , , , | Leave a comment