JoaMat

Touch screen to the right. Who needs Pokémon?

I’ve had a great time the last couple of weeks building the mini Dynalo designed by Kerry. Here is the Dynalo with a finished (almost) board. Side panels from Modushop, internal height 40 mm. Front and rear panel are copper clad boards milled myself and the top cover is an aluminum net for better ventilation. Now, this amplifier turned to be a very nice one, so I started to modify it for my own personal preferences. I want a small portable amplifier to be used in my garden under a cheery tree - resulting in this. Switching power supplies, all connectors at the rear panel and some other stuff not needed removed to give room for Raspberry Pi 3 with a HiFiBerry DAC+ Pro on top. Changed front panel (easily done with a mill and copper clad board) and rear panel has two holes for connectors for the batteries and a wlan antenna. Today I got a heat sink for the output transistors. Below is a picture showing them, they are just resting on some soft pad – have to figure out the best way to get them fastened. I don’t think the sinks are needed but they are very much preferable. Many thanks to Kerry for an excellent work.

Bought from Elfa in Sweden. Sorry, but I can’t find them on Elfa now. I’m sure you would find some similar if looking around.

This maybe? I use this type of terminals. Better isolated to the board.

Me to find that blue plastic water can very interesting. What worries me most is why Vikings like Soren and me are more interested in plastic head phone stands than the head phones???????????????

need more bananas…. balanced out.

and some bananas...

Poor man front panel.

Output transistor on bottom side thermal connected to case via Bergquist soft pad? (Brainstorm - to many drinks last night)

Running the Mini Dynalo as I did above need heat sinks. Measured 250 deg. Fahrenheit. I believe Kerry and Kevin have some modification in mind.

20V and 0.46A, twice. About the same power as T2 output stage. In the palm of your hand.

So far, got them in February this year, the EML 20B-V4 have treated me well. But I don’t think I know enough to judge their overall quality and reliability.

Well, I’m running out of ammunition. Blind shot, could it be the 12V Zener that’s the problem? One way to proceed is George’s advice. Also want to quote Kerry, from The ultimate DIY? A Stax SRM-T2!

Nice build indeed. Really like the look of the power switch, espacailly with darker background. Glad you are going for KGBH. Now 20% off. Join the RASS movement.

If 17V at pin 3 (katode) 10M90S and 1.77V cross 4.7K resistor than you probably have almost 0V at the emitter of STN9360. My next long shot is at the STN936.

Long shot, but a flipped 1N4007 cross STN9360 will probably give the same result as you have.

Great, will it cure excessive terrorizing posting as well?

Amazing how good he is at getting responses!

Great you found the opto servo working well. In my Grounded Grid I’ve omitted offset trimmer and its associated resistor and that works great. For time being I consider the opto servo as the preferred one.

Indeed, a really nice upgrade! I use old chassis for new boards. I even desolder components and move them to the new version/board. That way I keep number of amplifiers constant, an agreement with my partner.

and big eyes.

Wow! I also want one.

An IR remote volume control. Not built today, but brought it out in daylight today after four years. Need a volume control for AMB y3. Might work a little bit more with, it looks like …… .

Just a coincident - bought some of those for experiment from an eBay guy from United Arab Emirates.

Happy Birthday!!