The Multi Amp aka Dynalo Mk2

[JoaMat]

Take a look at this 3M product. 3m8810[1].pdf

I use it and I'm confident it will hold the heat sinks safely in place.

Edited April 22, 2017 by JoaMat

[mypasswordis]

17 hours ago, JoaMat said:

Take a look at this 3M product. 3m8810[1].pdf

I use it and I'm confident it will hold the heat sinks safely in place.

Interesting, thanks! What heatsinks are you using? 

Found a more manageable size than a full roll: http://www.mouser.com/ProductDetail/Adafruit/1468/?qs=sGAEpiMZZMsMyYRRhGMFNiXkQBm6C%2fDzTH5xAw3Ul9o%3d

[Skooby]

I refer a mechanical mean to keep the heatsinks on, easier for serviceability.  I modified mine a bit with an extra heatsink to provide a conductive mean to transfer the heat to the chassis.  The extra heatsink contacts the top plate once it's screwed on.  The BJTs get real hot (John said of 74C sounds right).  Radiative/convective heat transfer via the heatsinks in the small chassis space may not be enough.  Try someway to get the heat to the chassis... 

    

[JoaMat]

I like the way Skooby attachs the heat sinks.
 

2 hours ago, mypasswordis said:

Interesting, thanks! What heatsinks are you using? 

Found a more manageable size than a full roll: http://www.mouser.com/ProductDetail/Adafruit/1468/?qs=sGAEpiMZZMsMyYRRhGMFNiXkQBm6C%2fDzTH5xAw3Ul9o%3d

It’s a Fischer SK 81 - 100 x 37.5 x 15 mm. Found it  at a local dealer. Cut it in two halves and it fitted quite nicely.

 

I also use an aluminum net for top cover. Heat sink or nor the heat has get out of the cabinet. At 74 degree Celsius the PTZA06 is good for some 450 mW.

[mypasswordis]

Found these on ebay, almost same size as your heatsinks at 45x35x18... did some quick measuring with ruler, looks like may work though lengthwise it is a little too exact. Maybe someone can find one with 50mm length 

Edit: 

Also, anyone know if doing outboard TPS regulators with heatsinks can dissipate more than doing it on board? I want to use the same power supply to power the ubal to bal SMD boards from the most recent group buy

Edited April 23, 2017 by mypasswordis

[sbelyo]

On 4/3/2017 at 7:10 AM, ang728 said:

Finished assembling this,pretty comfy color

 

 

 

 

I want one of these cases...  dang

On 2/18/2017 at 11:18 PM, congo5 said:

 

and I find these very hard to solder:

I was going to ask my dad if he could run my boards through an oven at work.  is that with a heat gun?

[congo5]

yes

if you mean hot air / liquid flux

$31

http://www.ebay.com/itm/YOUYUE-Hot-Air-Gun-Rework-Station-SMD-Solder-Soldering-Digital-3-Nozzles-858D-/162327338780?hash=item25cb769f1c

[Skooby]

That's one fine soldering work on the QNF chip, sir!  Ruined two boards, getting 3rd and 4th boards for another attempts.  Damnit, this ain't rocket science!

(*** if you can't get the QFN on.  No sweat, just get the AMB Lab off-board/pre-soldered regulators! ***)

My problem is getting just the "right amount" of solder on pins and pad.

 

Edited May 3, 2017 by Skooby

[congo5]

18 hours ago, Skooby said:

problem is getting just the "right amount" of solder on pins and pad.

yes that is what I found also

just a light coating or its a problem

so you might tin it and wick some off

the outside can and should be redone with a small tip  iron.

the kester flux I have dries up too early and gets  sticky so that doesn't help

haven't found any really good flux for this yet

paste might work better here but don't have any

recommend checking for shorts before power, I lost one that wasn't checked

with practice and the right tools this can be done many times with out damage to the board

preheating is a good Idea, even to 150F helps

toaster oven-candle warmer-heating pad-light-something

[mypasswordis]

Be careful and check datasheets as some SMD components are only rated to spec with 3 or so reflows, they get slightly worse after put through each thermal stress cycle

Edit: forgot to add that you can buy a stencil of just the QFN package, make sure to do that first and then hand place the rest of the components near it before you reflow with hot air

Edited May 3, 2017 by mypasswordis

[congo5]

Yes I use kapton or aluminum tape to protect what's nearby

good point

[mypasswordis]

I can confirm the heatsink does in fact barely fit. Waiting on more parts and still deciding what to do about the power supply...

[cspirou]

I found that MPSA06/56 is available. Can they be used in place of MPSW06/56 for the through hole version?

[cspirou]

Never mind. I found this comment by KG

 

[mwl168]

I believe this was discussed before. MPSAx56 has lower power rating and is pin-compatible. IIRC, one datasheet I read lists both together.

[masamoto]

It's Alive  Very happy with the sound still testing different bias but loving it already.

[mypasswordis]

Please let us know what you end up with. I am using 15V rails and 301 ohm resistors and it sounds fine so I never bothered to try anything else. 

[Rossliew]

Dear all, is it possible to have a tubed version of the SuSy dynalo?

[spritzer]

No, that would be something Cavalli would try...i.e. rather stupid and sound like shit. 

[wink]

3 hours ago, spritzer said:

No, that would be something Cavalli would try...i.e. rather stupid and sound like shit. 

Woo - hoo...!

[masamoto]

On 14.5.2017 at 9:57 PM, mypasswordis said:

Please let us know what you end up with. I am using 15V rails and 301 ohm resistors and it sounds fine so I never bothered to try anything else. 

I run 20v with 270R right now giving me 15ma sounds about right.

This weekend is a long weekend here so I will get to compare more.

I was going to get a case first but that seems to take longer than expected.

I looked around and will be going for this case.
http://www.fischerelektronik.de/web_fischer/en_GB/cases/M1.01_M1.04/Shell-%2C extruded assembled cases%2C desk consoles and Euro cases/PR/G100/$productCard/parameters/index.xhtml
I sent them the design and measurements and it comes down to about 60 for a case.

Is that a good price? I never ordered custom cases. Dimension W 250mm*H 70mm*D 220mm.

[mypasswordis]

^ oops, forgot to answer. Yes it seems like a good price? Especially for a custom. 

A new Dynalo mini has been born (probably, I haven't tried with headphones yet). Was measuring 72 C on the regulators and 89 C on the output transistors so I threw heatsinks on everything. Now measuring about 62 on the fins of all three 

Edit: spoke too soon, it stabilized at 70 C

Edit 2: I was planning on using the PS for the ubal to bal boards also but everything is running on the absolute ragged edge already so that won't work. I need to move the heatsink for the regulators out away from the switchers anyway. 

Edited July 21, 2017 by mypasswordis

[Helium]

On 23.09.2016 at 1:52 AM, kevin gilmore said:

final board file for the transportable just posted

http://gilmore.chem.northwestern.edu/boards/SSDynalo-v1-4.zip

this is Kerry's work, very amazing

 

What is exact board dimension of this PCB?

On 02.11.2016 at 4:45 AM, Kerry said:

I did a small update on the mini board to add a pad on the opposite side of the on board regulators.

Here's and updated view...

Hi Kerry. Is SSDynalo-v1-4.zip from Kevin's depository the latest gerber?

SSDynalo-v1-4.zip

EDIT: Found, never mind.

Edited September 6, 2017 by Helium

[cspirou]

I believe is 6.8" x 4.8". The length I'm sure of but the width is a bit fuzzy, although I know it's under 5".

For the PCB there is also a TKD version because the Alpha pot is not the easiest to source.

[Helium]

Yes, it's 4,8 x 6,8, and latest rev is 1.5.

What's input impedance of 'portable' Dynalo? If it's low, then problem is that 5K RK27114 Alps hard to source, even on Ebay (they seem to disappear completely).