The Multi Amp aka Dynalo Mk2

[johnwmclean]

Still hand solderable right?

[nopants]

haha if you guys put it that way I'm convinced, doesn't take much

I'm pipe dreaming here but it you might be able to squeeze the attenuator if you move the psu to a separate box. then you have the linear dps option a la Justin

[kevin gilmore]

of course its hand solderable.

you just have to find the right set of hands. preferably robotic.

[JoaMat]

and big eyes.

Edited July 12, 2016 by JoaMat

[RudeWolf]

Save for the smaller regs, everything else should be manageable. Just keep the parts from flying off the table.

[jowls]

Holy balls, this looks awesome!

[TMoney]

Any chance of a Mjolnir Audio version of the mini at some point, @spritzer?

[jowls]

3 hours ago, TMoney said:

Any chance of a Mjolnir Audio version of the mini at some point, @spritzer?

Isn't the market for a transportable balanced amp already covered? 

 

A Mjolnir version of this would be insta-buy...

[spritzer]

It's something I could look into.  I'm going to build one and see how I like it. 

I'm slowly working on a full size version of the circuit so that takes precedence at least for a while. 

[kevin gilmore]

4 hours ago, jowls said:

Isn't the market for a transportable balanced amp already covered? 

not a fully balanced fully differential fully discrete one that i know of.

[Kerry]

One week turn around... Not bad

Here's the board with 2oz copper.  I still need to finalize the BOM and get an order in.

 

[spritzer]

Excellent!!    The small box of volume pots should be there shortly. 

[luvdunhill]

For the two heatsinks that have faces that attach to the board, perhaps remove the solder resist on the top side?

[Kerry]

That's a possibility for the next round.  The ones from ebay have solder mask on the back.  We're going to be dissipating under 1W for each sink and I think it will be ok, but it is a question that will be answered shortly

I took a look at the ones that AMB is doing sig78xx/79xx.  I'm unclear whether he has mask on the back side.  Lots of good data on the forum regarding temperature rise for various power levels / heat sinks.

 

[Mister X]

Quote

I took a look at the ones that AMB is doing sig78xx/79xx.  I'm unclear whether he has mask on the back side. 

Assuming "the production boards" are the same as the σ78 prototype I have....there is solder mask on the back side but the vias are exposed.

 Which could cause a short if an insulating pad were not used and the (proposed) exposed thermal pad on the PCB is grounded and extends past the outline of the TPS7A4701/TPS7A3301 regs.

[Kerry]

I got the parts in this afternoon and had a chance to start stuffing.  Here's the back of the board.  A couple of things wrong.  The holes for the IEC inlet are a bit small.  I can drill them out since all the traces are on the bottom.  The other more important issue is I used the wrong size QFN-20 pattern for the regulators.  Luckily I have an off-board option that I'll be using on this version.  I ordered a couple of sig78/79 regulators from AMB's site.

I can test the rest of the board so I will continue stuffing.  Should be done tomorrow night.

 

[Kerry]

Almost there.  I've got one channel dialed in and working on the second. 

 

[GrindingThud]

OMG, must build this.....

[wink]

Can we buy one on ebay...? (Ducks head and runs for cover......   )

[nopants]

yeah I'm definitely interested in building this, gorgeous

[purk]

superb really!!

[cspirou]

Just joined this site specifically because of this amp. This project simply looks awesome. I would really like to build the mini version with SMPS but I don't trust myself to solder surface mount components yet so I'll probably end up doing the original version that started this thread.

I have a couple questions. Is there any measurements posted for this amp? Is there a performance hit when using the Dynalo SuSy in a single ended configuration vs a basic Dynalo?

[HemiSam]

Pure sexy, Kerry!  Please keep the pics coming  

HS

[jowls]

This looks great. The form would be ideal for me 

[cspirou]

I am looking at kgdynalobal5 and kgdynalobal9. Version 9 looks like an SMD version and version 5 is a through-hole version. Was the SMD version developed because parts are scarce for the through-hole version? Do I assume that performance is nearly identical for both versions?