The Multi Amp aka Dynalo Mk2

[JoaMat]

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

[kevin gilmore]

customized case is what I was thinking of.  I have the tools, what I don't have is enough time at the moment

I have had the previous version running at 300ma on now for at least 6 months 24/7 no problems

[RudeWolf]

Well, we might as well manufacture the case to be fully sealed and fill it with mineral oil.

[joehpj]

And when it starts to leak.......

4 hours ago, JoaMat said:

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

Sounds like a plan. A thick case will do the rest.

[kevin gilmore]

well that is a better idea than that magic pixie dust that the one company fills its stupidly priced cables with... and then leaks white shit everywhere

[JoaMat]

Poor man front panel.

[kevin gilmore]

use black magic marker to make it all black, then add some messed up funky logo's

plenty of room to add flying piece of shit kobicon output connector

[purk]

Please don't add the Kobicon...that jack is just pure sad.  How about a 3.5 mm mini TRRS jack?

[JoaMat]

and some bananas...

[wink]

Very agricultural......  

[JoaMat]

need more bananas….

balanced out.

 

[Kerry]

Yeah, I was curious what you wanted to the bananas for.

[cspirou]

Could the Dynalo be used as a preamp instead of using the unbalanced/balanced board? I'd like to wire the output to a switch so I can choose between headphone output and balanced preamp output.

[spritzer]

The Dynalo is a pretty great preamp but just watch the gain. 

[mwl168]

I second Birgir's comment.

In fact, a friend of mine like the Dynalo as a preamp so much he uses it as his main preamp in his speaker system and asked me to build him another SS Dynalo for his headphone use.

[JoaMat]

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.

Edited August 30, 2016 by JoaMat

[Kerry]

Amazing :)

[GeorgeP]

^want! Just needs a touch screen so you can stream over wifi.

[JoaMat]

Touch screen to the right.

Who needs Pokémon?

[gepardcv]

This is fantastic!

Time for a mini-Dynalo board group buy?

[JoaMat]

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.

 

 

[poks999]

Are there any gerber files for the rev-c board that AMB used to make/have? I've been looking to build a dynalo and I really like the one board solution, but I can't find them anywhere. Would it be easier to just find the version9.zip pcb's somewhere and go from there?

[Pars]

Dan Gardner was the one who actually did the Rev. b and Rev. c boards. He isn't on head-case, but you might be able to contact him on that other site (you know the one). I don't think I ever had the gerbers and I don't know if Kevin ever did or not. Dan might still have them. I think his user name there was dgardner, but I could be mis-remembering.

[GrindingThud]

On August 12, 2016 at 7:30 AM, kevin gilmore said:

I have had the previous version running at 300ma on now for at least 6 months 24/7 no problems

Does this version run the same, or does it dissipate more?  I'd like to build this small one but don't want to get in deep until the the heat/sinking is figured out (if sinking is really needed).

[poks999]

2 hours ago, Pars said:

He isn't on head-case, but you might be able to contact him on that other site (you know the one). I don't think I ever had the gerbers and I don't know if Kevin ever did or not. Dan might still have them.

Got it. Honestly, I'm now just looking for the easiest way to get the pcb, since I'm rather excited reading so much to getting to work on the project. Thanks for the help!