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The Multi Amp aka Dynalo Mk2


spritzer
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2 hours ago, Pars said:

Adapter boards that I layed out and were in one of the GBs.

I think you could just plug them into a 14 pin socket with no lead bending, but if I recall correctly, one of the JFETs would be backwards. No big deal on the Toshibas, at least according to John Curl. I presume the Linear Systems would be OK as well.

Yeah, the Source and Drain can be swapped. Useful in optimizing layouts.

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The killer, however


Ok. This one?
https://www.ebay.com/itm/8-X-NEC-2SK163-2SK163L-2SJ44-2SJ44L-AUDIO-FET-/383673522014?_trksid=p2349624.m46890.l49292

All part of rip off Britain.


Politicizing and nationalizing are sad.
Mostly the same if i try to buy lateral FETs from British's Profusion.
All those jfets and mosfets are the last of Mohicans and it's even more sad.
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16 hours ago, Pars said:

Adapter boards that I layed out and were in one of the GBs.

I think you could just plug them into a 14 pin socket with no lead bending, but if I recall correctly, one of the JFETs would be backwards. No big deal on the Toshibas, at least according to John Curl. I presume the Linear Systems would be OK as well.

Cheers, Pars - will go swim through the Dynalobal gerbers until I find it :) 

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6 hours ago, Bespav said:

 


Ok. This one?
https://www.ebay.com/itm/8-X-NEC-2SK163-2SK163L-2SJ44-2SJ44L-AUDIO-FET-/383673522014?_trksid=p2349624.m46890.l49292



Politicizing and nationalizing are sad.
Mostly the same if i try to buy lateral FETs from British's Profusion.
All those jfets and mosfets are the last of Mohicans and it's even more sad.

 

First the link. Chinese - what do you reckon the chance of obsolete sand from China being genuine?

And second - What exactly are you saying? Please very carefully clarify.

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Can anyone advise on removing the little PCB at the bottom of the kgdynalobal_v9 Gerber file? 

jlcpcb.com asked me to remove it to avoid errors and I haven't a clue...

Is there a version without the little PCB at the bottom?

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  • 1 month later...

hi! i would like to share my work with you. i am working on a small susy dynalo but with grlv psu and much better cooling capacity. also i will change the pzta tranzistors with toshiba 2sc2881 and 2sa1201 because they do not heat as much as pzta for some reason, and they are smaller (sot 89). it is a work in progress. for now i only developed an amp (one channel) and psu section without anything else. 

in following pictures you can see one amp channel and psu with meanwell switchers feeding the grlv (maybe i will put a transformer). bottom side of the pcb has exposed copper (large white spots) which will make contact with case to have more thermal mass. as you can see, there are lots of vias and they connect top and bottom part of pcb around output transistors to increase thermal surface. size of one channel section is 42x87 mm, and psu section is 98x61 mm. so i plan to fit finished project in 150x150mm case. i am a student so it will take time to build this thing, and of course a lot of hard earned money :D . i hope you like it! 

pictures:

https://drive.google.com/drive/folders/1x2SQcV86kyMJL18twtRnseKntS9kgVBa?usp=sharing

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  • 1 month later...
On 5/12/2021 at 12:38 PM, johnwmclean said:

Another one in blue this time,

Congrats, John, looks very nice and clean! Can you do a quick compare to your newly finished CFA3, which one do you like more and which J-FETs ended you up using? 

Edited by starcat
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  • 2 weeks later...

Anyone tried the Dynalo Mk2 through-hole with Xicon 273 resistors? All the RN60Ds are 100ppm where the Xicon 273 are 50ppm, 1/2w... and cheaper as well.

Edited by starcat
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  • 5 weeks later...
  • 2 weeks later...

I've bought from NAC for shipping to the UK. They have no minimum order charge, unlike my supplier in the UK (Micross) who without warning imposed a UKP200 minimum order charge (plus shipping plus VAT). Happy I was not, and let them know, vociferously.

Buying Linear Systems parts from NAC was straightforward, with very reasonable shipping to the UK, and with very nice personal service. Five star.

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  • 3 weeks later...

hi! i have a balanced diy dac with output capacitors to block dc component. can i connect the dac to ss dynalo without capacitors? dac has a dc bias of 2.7V per output. i know for single ended this is not an option, but im not sure for balanced...

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  • 3 weeks later...

Well, two years later, I'm thinking about finally finishing up a Mini Dynalo build. Last time I was working on it, I stuffed the boards but failed to solder the on-board regulators (even though I used a stencil with solder paste, I still suck at such fine hot air work). I picked up the AMB sigma78 and sigma79s, and noticed they mismatch the U5 and U7 areas on the PCB. U5 and U7 have holes for 5 pins, but the regulators have 3. It looks from photos others have posted that the outside pins are ignored. What's up with the extra holes on the board?

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