SYMEF amplifier

[OnAudio]

Originally Posted by drowranger

I have check the supplier the smallest casing is 26mm x 13mm it takes up the space of the whole input filter circuit.capacitor is metallised polypropylene is there any other way for this?

p.s. can i use metallised polyester or uncoated MKTpolyester capacitor and rating is 63volts?
regards,
joel

Hi Joel,

C8 Could be 4.7uF 16V NP . C6 100 uF 6.3V NP (you can get rid of the diode) unless there are any objections

kind regards

[OnAudio]

Originally Posted by drowranger

pin configuration of bc 556 is cbe while mpsa92 is ebc.im planning to use 2n5401 and compatible to the board i have design.is this fine also?

Hi Joel,

Your progress and work is looking soo beautiful . You can use the 2N5401, however what you are creating looks promising that is why I even suggest using KSA992 if you can lay your hands on it

kind regards

[OnAudio]

Originally Posted by OnAudio

Hi Joel,

Your progress and work is looking soo beautiful . You can use the 2N5401, however what you are creating looks promising that is why I even suggest using KSA992 if you can lay your hands on it

kind regards

This suggestion is for Q4, Q3 on your schematic

[OnAudio]

Hi Joel,

Some suggested voltages

C1 200V
C2 100V
C3 100V
C4 100V
C5 6.3V
C6 6.3V
C7 35V
C8 16V
C10 63V
C11 63V

kind regards

[AndrewT]

Originally Posted by drowranger

can i use metallised polyester or uncoated MKTpolyester capacitor and rating is 63volts?

50V or 63V or 100V polyester or terephthalate or mylar. any of these will be far better than any electrolytic. All will be smaller than MKP, all will be cheaper than MKP.

You could go down to 2u2F or 3u3F.
2u2F gives up 2octaves of sub-bass. Might be worth trying that. You like the result.

[drowranger]

I retain the diode just in case it will be needed.I found 4.7uf metallised polypropylene rated 250 volts for c8 this is the lowest voltage rating.Also change the layout.check again if this is final.

[OnAudio]

Originally Posted by drowranger

I retain the diode just in case it will be needed.I found 4.7uf metallised polypropylene rated 250 volts for c8 this is the lowest voltage rating.Also change the layout.check again if this is final.

Hi Joel,

Checked the schematic, looks OK.

Cheers

[drowranger]

Originally Posted by OnAudio

Hi Joel,

Your progress and work is looking soo beautiful . You can use the 2N5401, however what you are creating looks promising that is why I even suggest using KSA992 if you can lay your hands on it

kind regards

I change pcb layout for ksa992 and for bc556b.does bc556b superior than 2n5401.it looks like ksa992 is hard to find but will try to get it.

regards,
joel

p.s. now I can start for the pcb.

[quadtech]

Joel, very PCB designs are really nice.
Can I suggest you add pins to allow mounting this style of
multiturn trimpots too for more flexibility?

[AndrewT]

That pic shows 3 inline pins.
Add a 4th hole/pad for the offset pin version.
This can be important when one wants the trim rotation direction to achieve the expected effect.