Simple Symetrical Amplifier

[shaan]

Initially installed a 5.6pF ceramic their. Treble okay.

Then I placed a 10pF ceramic. Treble okay.

Then placed 100pF/2KV. Treble okay.

Now it's 22pF. Treble okay.

470pF? Don't know.

edit: No audible RF modulation noise in any of the above cases, even with my standing-wave RF exciter turned on.

 

[shaan]

Which of the Grounds in the schematic need to be connected to the Signal Ground?

The one closest to the ground supply connector, as short as possible. No 10ohm elevation is used.

 

[naf]

Dear Shaan/LazyCat
How about replacing BD139/140 with SC3423/2SA1360/? i found it in my local store.
is there any part to change?

thanks

 

[naf]

Here it is my complete shaan's SSA peeceebee...

 

[shaan]

Here it is my complete shaan's SSA peeceebee...

GORGEOUS!

 

[shaan]

Dear Shaan/LazyCat
How about replacing BD139/140 with SC3423/2SA1360/? i found it in my local store.
is there any part to change?

thanks

Checked the specs for them. 3423/1360 should be okay.

Edit: You may need to re-drill the holes for the VAS bjts a little wider. Like the ones for the electrolytic capacitors.

 

[Lazy Cat]

Dear Shaan/LazyCat
How about replacing BD139/140 with SC3423/2SA1360/? i found it in my local store.
is there any part to change?

thanks

2SC3423/2SA1360 are very good transistors for VAS, but they have Ic max=50 mA, so VAS bias current should not exceed 15 mA to have some reserve to max collector current limit.
Also current gain of 2SA/SC is linear only to some 20 mA than it drops rapidly, but for the VAS purposes in SSA they should work without any modification.

 

[naf]

Checked the specs for them. 3423/1360 should be okay.

Edit: You may need to re-drill the holes for the VAS bjts a little wider. Like the ones for the electrolytic capacitors.

Ok, thank you Shaan i'll redrill holes for VAS.

 

[naf]

2SC3423/2SA1360 are very good transistors for VAS, but they have Ic max=50 mA, so VAS bias current should not exceed 15 mA to have some reserve to max collector current limit.
Also current gain of 2SA/SC is linear only to some 20 mA than it drops rapidly, but for the VAS purposes in SSA they should work without any modification.

Thank you very much LC for complete explanation, i learn something new.

 

[shaan]

Hi naf.

Do you use FeCl to etch the PCBs?

 

[naf]

Hi naf.

Do you use FeCl to etch the PCBs?

yes, i use FeCl to etch my board

 

[ersa191]

Here it is my complete shaan's SSA peeceebee...

Hi naf, with what did you coat PCB?

 

[de Ocampo]

Here it is my complete shaan's SSA peeceebee...

was it silver coated? have you done it manually? It looks like factory coated...very refined!

 

[naf]

Hi naf, with what did you coat PCB?

I coat using immersion silver

 

[naf]

was it silver coated? have you done it manually? It looks like factory coated...very refined!

Thankyou,
yes it's silver coated. all peeceebe process have done manually.
i enjoy all processing step. it's Do it Myself .

 

[masood]

dear shan,
p[lz also share me with the copper side of this peeceebee.
yours ever masood

 

[masood]

dear shan ,
i have 2 pair of mosfet 2sk1058 and 2sj162.so i want to use them in single hi-fi amplifier do you have such type of amplifier circuit and pcb detail plz send me if you not mention .sorry to bother you.
thanks masood

 

[Salas]

Thankyou,
yes it's silver coated. all peeceebe process have done manually.
i enjoy all processing step. it's Do it Myself .

Are you doing actual silver nitrate bath electroplating?

 

[de Ocampo]

I saw one DIYer silver coating his pcb in You Tube , it looks complicated though mixing these 3 types of chemicals, it looks like a chemist job

Naf, what is this immersion silver you mentioned, can this product be purchased locally? I have read silver nitrate is very expensive.

 

[TonyTecson]

electro-less plating is the process used...you can inquire from jewellery shops near your place...