JoaMat

Wanted! Anyone willing to sell me a balanced digital attenuator board? or two?

Wow, absolutely amazing!

I consider my T2 to be absolutely silent. I can't hear any noise, might be because my old ears though.

May I help? Q1/Q3/Q13 - MMBTA56 Q2/Q4/Q14 - MMBTA06

Happy birthday!

Superb. And it has your signature… one could see from far distance that it’s a John William McClean coming, something like Mercedes S Class.

Kerry, how long time does your machine need to mill the amplifier top plate?

Nice!! Especially the form of top plate at the screws against the heat sinks.

Could it be the LT1021 that is the problem? It's supposed to be 10 volts as long as the regulated voltage is some 20V or higher.

I want to add that I use the Raspberry with piCorePlayer and a iPad with iPeng and Squeezepad apps. I’m very happy with the piCorePlayer and the iPad apps - Internet radio (I listen to BBC3 HD every day) Tidal, ripped things on hard disk, Met Opera, Berliner Philarmoniker. Pretty magic, isn’t it? Everything works terrific until batteries fade.

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.