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Lottery DIY Sony VFET pt 2 (N-Channel) - assembly by Mighty ZM


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Postovano na Big Diya

https://www.diyaudio.com/community/threads/lottery-diy-sony-vfet-pt-2-n-channel-assembly-by-mighty-zm.385977/

mrzi me da prevodim, copy paste

Coverage of  assembling one Lottery amp for my dear Friend, way of paying back for valuable help he gave in some of my endeavors

He's extraordinary busy in last several months, so ......

Amp No. 122, member tunasto here, @vinko on Baby DIyA

Let's start with schematics - I like when schematics are present

 

 

 

 

simple schm.pngFE schm.pngOS schm.png

DIY SONY VFET pt2 shrinked.pdf

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While at schematics, let's cover few things ( I already posted in origin thread about this amp), so let's repeat:

well, I'm always amused studying Papa's schematics, from any imaginable reason .... mistakes being one of them :clown:

original, drawing mistake marked, mistake fixed, simple remedy for better AntiBigBadaBoom at speaker out; there is no mistake at Papa's pcb, it is just on drawing

now - last schm - in this moment already tried and proven, results are:

edited delay circ is working flawlessly - no visible move of cone neither at power On nor power Off

only if you are powering it Off reluctantly, slowly operating the switch , there is movement of cone, but slow and gentle - and even that one is not audible

same behavior when leaving power switch ON, and doing power operation with mains cable of switcher - Nada during power On, gentle roll of cone with powering Off

will post plenty of pics and some text, in separate thread

maybe next evening

and yes, really dunno how delay circ operated in original, didn't tried it at all; but I'm used to change Papathings just for sport - hard to make it better, easy to make it in different way :rofl:

FILTER, DELAY.pngFILTER, DELAY, drawing mistake.pngFILTER, DELAY corrected.pngFILTER, DELAY ZM.png

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OK; thermal issues

some facts:

T bars came in Papa's arrangement, with approx 4mm Dia holes
TO3 isolator pads are silicone thingies, I don't like those above 15W or so per device; gone for Mica + quality goop
T bar is having bowed side which is going to meet heatsink; see sketch; some lapping - water-sand paper on thick glass is problem solver
heatsink is bowed as all extruded heatsink of this profile are bowed; see sketch; no problem when you arrange adequate force with screws - not the case in this case; will rectify that

 

1 what's bowed.png

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solving thermal issues; see pics, pretty much self-explanatory

whoever did arrange with Modushop guys assembly with M3 screws is not having enough mileage with all things mechanical/thermal; not blaming a guy at all, I know that this wasn't operation made by professionals and outcome is still extraordinary

that's exact reason why I'm posting this, to help Greedy Boyz in proper finishing and to feed my own OCD

fact is -these 4pcs of M3 screws needed to be M4 and additional 2pcs of M4 are necessary

only that way , with lapped T Bar, there is enough squeezing force at disposal to get rid of air gap between T Bar and heatsink

2.jpg3.jpg4.jpg5.jpg6.jpg6a.jpg7.jpg8.jpg9.jpg10.jpg11.jpg12.jpg14.jpg15.jpg

13.jpg

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Still in mechanical realm, sort of

Again post-Pa dealing gone wrong - Pa did arrange 2 pole switch, while hole on back side is for one pole, one pole in kit;

Again no blame from my side ; I did enough mistakes that I know from where they are invoked, rest of life is not enough to learn how to prevent them :rofl:

I had a bag of proper 2 pole switches

paper masking tape, calipers, files, patience

1.jpg2.jpg3.jpg5.jpg4.jpg6.jpg7.jpg8.jpg9.jpg

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Still on back side of amp

Mean Well switcher PSU is of good quality, but I don't like flimsiness of DC connector, neither male nor female one

Good ole 5-pin XLR is certainly better; I would like Calt Stecker being on cable, Heiss Stecker being on amp, but didn't had Heiss one ....... anyway , I did stay with original topology - Heiss Stecker on cable

superblingy drill and edge reamer, no need to be overly precise, XLR is covering all

I didn't even hop to my vertical drill, done it with hand-accu one

useful tip for soldering pin-equipped connectors - always mary male one with female one - no bending of pins in plastic, due to heat

 

1.jpg2.jpg3.jpg4.jpg5.jpg6.jpgCUNNING TRICK.jpg

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Rest of pics

Observe - there are some trick which can make your life easier:

-Cone head temporary screws ( aligning, no scratches round holes)
-align brackets with back side of heatsinks, no warping of back plate in that case
headless screws for front plate; how to unscrew and orient bottom to mount washers and nuts and tighten them
wiring done with one heatsink, bottom and back plate screwed together; then mounting second heatsink, soldering wires, then mounting front
one or two pads are close to screw nuts; marked on pics; either use plastic washers or metric screws/nuts ( smaller than enclosed ones) or be brave as MZM - I did bend integral star washers, was stubborn to use Papahardware

dunno - I did forgot something for sure , but you'll ask; it's not Rocket Science anyway

there are probably few redundant pics, but - hey - web space is cheap nowadays

 

IMG_20220428_165828.jpgIMG_20220428_165908.jpgIMG_20220428_165912.jpgIMG_20220428_170853.jpgIMG_20220428_170901.jpgIMG_20220428_202849.jpgIMG_20220428_202903.jpgIMG_20220429_215659.jpgIMG_20220429_215709.jpgIMG_20220429_220949.jpgIMG_20220429_220956.jpgIMG_20220429_221157.jpgIMG_20220430_180547.jpgIMG_20220504_193529.jpgIMG_20220504_193534.jpgIMG_20220504_193539.jpg

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Facts

-PSU 36Vdc
-Iq one channel 1A76, second channel 1A8; was thinking to alter that to 1A6 by the Book, but who cares - more the merrier
-Output node set by the Book - to 14Vdc
-Ambient Temp 20degC
-VFet Case 66degC
-Mos Case 59degC
-T Bar Temp at exact mid between two TO3 50degC
-Heatsink Temp at outer side, between fins, exactly between M4 Allen head screws 44degC
-1R5 at channel pcbs 99degC (Papa is FAB, no clearance)
-3R3 at PSU pcb (ZM is Chicken, 2mm clearance) 88degC
-JFets 44degC
-Switcher case , placed on edge at bench 37degC

-no noise, no hum

-It sings; forgot to take a picture :rofl:

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Napisano (izmenjeno)

ZM diy amp assembly 101! :D 

Znaš da je netko sjajan kad sve što radi izgleda lako. :oke:

Izmenjeno od zerowaf
Super slova...samo krivo raspoređena
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Quote

-Switcher case , placed on edge at bench 37degC

 

Mean Well switcher od 36Vdc/150VA

 

ladan

msm taman za decicu - to sad moderno na Big Diya

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decije bolan

:smesna:

 

zezam se - moze to korektno da radi, kao sto ovo i radi korektno

Nele je krenuo sa ovom serijom pojacivaca- jos onomad od ACA - na nacin koji je neverovatno uspesan po pitanju masovnosti i popularizacije 

zahvaljujuci tome sto se koriste cigla ispravljaci nema komplikacija sa ozicavanjem mreznog napona, maltene pola mehanike je izbegnuto, sastavi ga i pionir od 12godinica uz pomoc nekog iskusnijeg

i sto je naveci fazon i kvalitet - biranim designe-om se dobija da to svira neverovatno dobro za ulozene novce i ulozen trud - trci u krug oko ne znam kolko skupo placenih komercijalnih proizvoda

 

msm, daleko bilo da je to my cup of tea, ali cilj misije je itekako postignut

ovaj ampic svira ko avijon ....... nije dzaba Lottery Amp

 

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A pa da, ja pitam a pravio sam ACA sa switcherom - nego davno bilo zaboravilo se :D

Lepo bre mnogo, šta da rečem. Ponosni vlasnik po drugi put uboo loterry :oke:

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