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The Multi Amp aka Dynalo Mk2

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Hi all :)

UPDATE: never mind, I found em! Internet Archive to the rescue!

I'm thinking of rolling my own PCB for this. Does anyone have the schematic for the non-Mini version? I don't need the power supply, just the amplifier section. I've been through the whole thread and the links all seem to be dead. The images I did find are too blurry to make out. 

Thanks a ton!

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Hi All,

I am looking at building a dynalo SMT/SMD system, balanced in / balanced out. I have been through this thread back to front as well as the staxmafia thread etc. I think I have got the most recent gerber files (dynalobal17) as well as the schematic (kgdynalobalssproduction.PDF) and I have started building a BOM but have stumbled on a few things that I was hoping some may be able to assist with?

  1. Looking at a few comments, all resistors are 0805 size but I am not really sure of current size etc (have shot for 200mw .1% 25ppm at the moment).
  2. The schematic does not line up with the pcb with regards to the caps - the schematics only shows 3 (from memory) whereas the pcb shows as many as 12 documented with values - is there an updated schematic? Or am I using an outdated gerber?
  3. There appear to be a couple of caps on the PCB that have no values - any hints? (see attached pics) Or are these for something else?
  4. Is there a bom available anywhere? I see reference to a xls in a few placed but cannot find the file - am scratching my head on what caps, trim pots, part size for SMD transistors etc
  5. Is this project no longer active / am I barking up the wrong tree? It looks like a great project, but maybe there is a newer project I should be looking at?

Cheers,

Ben

 

Screen Shot 2020-06-27 at 4.15.41 PM.png

 

Screen Shot 2020-06-27 at 4.15.26 PM.png

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I'll take a stab at your questions. I haven't built the full size SMT Dynalo, but have built a few of the mini Dynalo's, which are pretty much all SMT.

  1. The resistors for the mini are all 0805 with the exception of the 20R, which were 1206. Vishay TNPW 0.1% 25ppm were used for most. I'm not sure on sizes for this version however.
  2. Kevin's schematics typically do not show power rail bypassing on them. Follow the board values.
  3. These appear to be LEDs and not caps. Kevin normally specs 1.7V red LEDs, such as Liteon LTL-307ELC.
  4. I don't have a BOM for the full-size SMT version.
  5. This project is still a very valid amp. Some would suggest the current feedback amp (CFA-2 or CFA-3), and I might concur with that opinion.

Be sure to use the golden reference power supply (GRLV) as well, as it is very good and makes a difference.

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Thanks for the pointers Pars - I had overlooked the LED's on the Schematics (too many hours staring at the screen!)

I will take a look at the CFA projects and see which way I go. I was going to use either the GRLV of a sigma22 power supply, the sigma 22 is easy as there are kits available "off the shelf" but kinda makes sense to go with the GRLV to keep everything the "same"

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I've been using a pream based on the ubal/bal and four cfa for my headphones. 

It is one of the amps I feel most satisfied. 

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