Projekat: SVAJA

[Bocko]

Slike sa strane 7:

[Aleks]

Hvala ti! Ja sam skoro sve to pogubio, imao sam i ja data meltdown, ali nije crkao nego sam formatirao pogrešnu particiju pri nekom prekombinovanju hard diskova... nije mnogo otišlo, al skoro sve iz Hi-Fi foldera...  

[Zen Mod]

[Bocko]

Kada se već "digla" stara (datumski) tema, ima na velikom forumu unapređena verzija, od strane Juma člana, (naš Sipi), link: 

https://www.diyaudio.com/community/threads/25w-class-a-amp-with-lateral-mosfets.183482/post-8133809 

 

 

[zerowaf]

Hvala ti!  

[Bocko]

Nema na čemu, i saam sam zainteresovan da uradim i poslušam ovaj uradak, nije previše komplikovan aaa lateralci se krčkaju već duugo u ladici  

Ukoliko neko odluči da iskopira Juminu pcb, mere su 75x40mm, neka slobodno postavi ovde

[Bocko]

Kopiran tekst sa velikog foruma, by Juma, ukoliko neko nema pristup tom forumu: 

Juma:

I designed and built a new version of this amp too. Now the VAS is cascoded and CCS loaded, output cap is included in feedback loop, OLG is higher, especially at high freq. (hanks to TMC - C8, C10, R18) .
Output symmetry (half of the supply voltage at Sources of Q2,Q4) is set by P1.
Output stage bias is set by voltage drop on LED D1 :

• white LED drops 2.8V which translates into 400 mA bias
• blue LED drops 3.3V which translates into 600 mA bias
• green LED drops 2.0V which translates into 200 mA bias

The result is much cleaner, more refined and precise sound
I attach schematic, layout (75 x 40 mm, copper side view) and picture of the built amp.


There are two discrepancies in previous post:
- P1 is present in schematic but not in the PCB layout.
PCB has the voltage divider only : R1 (18k in actual build) and R10 (68k) without P1 which I left out because symmetry was fine in prototype model - adjustment wasn't needed.
- D3 and D4 are serially connected and they are placed on PCB as one component. 

(see Juma post 334. He didnt use pot on PCB. He just used resistorm which was fine for him.)