SYMEF amplifier

OnAudio · 2011-11-19 5:38 pm

drowranger said:
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 · 2011-11-19 5:45 pm

drowranger said:
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 · 2011-11-19 5:49 pm

OnAudio said:
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 · 2011-11-19 6:16 pm

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 · 2011-11-19 6:19 pm

drowranger said:
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 · 2011-11-20 10:49 am

c6 to 100uf

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 · 2011-11-21 4:03 am

drowranger said:
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 · 2011-11-21 5:35 am

using ksa992 and bc556b

OnAudio said:
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 · 2011-11-21 12:22 pm

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?

An externally hosted image should be here but it was not working when we last tested it.

AndrewT · 2011-11-21 12:32 pm

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.

OnAudio · 2011-11-21 7:19 pm

drowranger said:
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.

Hi Joel,

Nice progress.

In reference to your schematic and layout

For Q3 and Q4 only: if you cant find the KSA992, Use BC556B or BC556C. If you cant find BC556B or BC556C use 2N5401. That is their order of preference for Q3 and Q4.

Let me get you right...for the rest of the small signal transistors you are planning to replace MPSA92 with 2N5401 and MPSA42 with 2N5551 ? That is OK.

Kindly consider using nothing less than tantalum for C10 and C11.

kind regards

drowranger · 2011-11-22 11:22 am

change trimpot

quadtech said:
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?

An externally hosted image should be here but it was not working when we last tested it.

it varies in differential transistor used.ksa992,bc556b and 2n5401 priority in order.

regards,
joel

drowranger · 2011-11-24 5:29 am

found mistakes on pcb design

I have finished making one pcb and have to edit today the pcb for small mistakes I made.sorry for the low resolution I'm using cellphone.

regards,
joel

drowranger · 2011-11-24 7:47 am

corrected tracks on bc556b pcb

drowranger said:
I have finished making one pcb and have to edit today the pcb for small mistakes I made.sorry for the low resolution I'm using cellphone.

regards,
joel

I have edited the pcb and also widens space of transistor driver pads suitable for toner transfer.In my experience having thick toner on photo paper and pressing the iron hard tends the toner to expand and fills the spacing between pads and tracks.and also check components pads vs pads vs tracks(clearance).

regards,
joel

p.s. will use this for the other pcb and post result on saturday.

OnAudio · 2011-11-25 2:44 pm

nice progress

Hi Joel,

Nice progress.

Cheers

drowranger · 2011-11-26 9:24 am

result for bc556b pcb post

I change my prevoius work with this latest layout for bc556b co'z I want the name SYMEF on my pcb.Next is to remove unwanted copper and make list for parts to be purchased.

regards,
joel

p.s. this layout is very suitable for toner transfering I have made the pads bigger and put enough cleara

nce.

OnAudio · 2011-11-29 4:06 pm

progress report

Nico Ras said:
I will make an attempt at yours after our summer holidays kick off in less than a month. Thank you.

Hi Nico,

Hows your progress with this 'beauty'

coming along

kind regards,

Harrison.

Nico Ras · 2011-11-29 5:19 pm

Sorry OnAudio, I have discarded the idea, sorry mate. When one has achieved your goal it is a futile exercise to go round in a circles, it results in the same conclusion.

I listen and enjoy the music and experience what the artist intended. Listening to equipment would never satisfy anyone but audiophiles.

An audiophile would be critical of a live performance and complaining that their Peevey amps does not sound like Marshall amps or the guitars should have been a Gibson not a Yamaha or that the Rolling Stones should have sounded like the Beatles.

OnAudio · 2011-11-29 8:05 pm

Nico Ras said:
Sorry OnAudio, I have discarded the idea, sorry mate. When one has achieved your goal it is a futile exercise to go round in a circles, it results in the same conclusion.

I listen and enjoy the music and experience what the artist intended. Listening to equipment would never satisfy anyone but audiophiles.

An audiophile would be critical of a live performance and complaining that their Peevey amps does not sound like Marshall amps or the guitars should have been a Gibson not a Yamaha or that the Rolling Stones should have sounded like the Beatles.

Hi Nico,

Is all good

Nico Ras · 2011-11-29 8:19 pm

However, I will lurk in the shadows as I have done the past weeks just to make sure I have not missed anything. So one can never say never - really.

SYMEF amplifier

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