SYMEF amplifier

[Jay]

Hehe what is the next shot, Leach amp?

[Nico Ras]

Originally Posted by padamiecki

lucky you
the first long shot
and got it

Usually every first thing you make and it sort of works is the greatest thing ever.

[OnAudio]

Originally Posted by drowranger

OK I will change the wattage of that resistor to 1/2.already finished working for the chasiss and will assemble the second channel .it will be very easy for me coz I already tested the first channel and made it working.and parts already complete.next week I will post pictures and thank you for this wonderful amp.NO HUM completely silent.natural sound also.after this i really like your preamp and want to pair this to your Symef.

the SYMEF is really worth for the shot.no regrets.my first diyaudio amp.

regards,
joel

Hi Joel,

I am glad you like it and have good experience with it as well as positive feedback. Keep us up to date and thanks for contributing to advancement of the state of the art.

The preamp is still cooking . You could try one of the possible builds.

Enjoy the break between Christmas and new year . Hope you are having a good time. Happy new year.

kind regards,

Harrison.

[drowranger]

actually im building amps. for a long time but this is the first design i tried in this forum.symef amp is very good .like harrison said that it should be pleasant i have been listening in high volume no preamp just dvd and the amp.well the highs are soft but sharp and really like the mids specially you can hear the guitar plays very clear and also the low end its there.even though im using tower speaker.i have already build optimos and sloan's favorite bjt design and also the basic ef harrison symef surely can compete with other amps.im not being exaggerated but i already listened to it.

I'm only on vacation for 36 days and i know that i need time to finish it.hopefully before i go at least i finish it 90% .transformer is my problem i need torroidal.i have used an L bracket because my heatsink is divided into three per each side.I need to thermally coupled it.

before I leave will post again picture for those who are interested.

thanks harrison my dad likes it too.I said to him that you are the engineer who wants to prove something in this forum,and you have a point.your formula works.

happy new year to you harrison and to all of you guys.

by the way the other amp besides the symef in the picture.I only want the power supply and the speaker protector inside is sloans favorite bjt design.

[drowranger]

life is short so I make sure I dont want to miss a thing.

if you will use a power supply of 50 volts remember to change the wattage of two resistors. 4.7k is the value and change it to 1 watt.

cheers,
joel

[OnAudio]

Originally Posted by drowranger

symef amp is very good .like harrison said that it should be pleasant i have been listening in high volume no preamp just dvd and the amp.well the highs are soft but sharp and really like the mids specially you can hear the guitar plays very clear and also the low end its there.even though im using tower speaker.i have already build optimos and sloan's favorite bjt design and also the basic ef harrison symef surely can compete with other amps.im not being exaggerated but i already listened to it.

thanks harrison my dad likes it too.I said to him that you are the engineer who wants to prove something in this forum,and you have a point.your formula works.

happy new year to you harrison and to all of you guys.

Hi Joel,

Good to hear the amplifier met its objectives. Am glad your dad likes it too . Your work is very neat. The formula does work . Happy new year too.

Just a few more questions...

Have you listened to any rock and roll ? The guitar does answer for that category somehow .

How does piano music sound ?

Have you listened to any of these artists : Whitney Houston, Celine Dion, Mariah Carey ?

kind regards,

Harrison.

[drowranger]

hi harrison,yesterday I checked my two amps optimos and see if the wirings are still ok coz I have this tradition every new years eve I played songs very loud instead of playing with firecrackers. then I got this urge to compare the optimos from symef.

I thought sloans amp is the best that I have assembled.symef surely beats optimos in listenning test.maybe because symef parts mostly are original specially the driver and output transistor.and maybe also the mica capacitors I have used.symef has greater bass and mids are more detailed.same speaker and player I have used and same artist also.

I attached picture of my two optimos amps with supply of 72 volts dc/rail.

right now im working again on chassis and making pcb for speaker protector and power supply will post picture within this week

regards,
joel

[OnAudio]

Originally Posted by drowranger

hi harrison,yesterday I checked my two amps optimos and see if the wirings are still ok coz I have this tradition every new years eve I played songs very loud instead of playing with firecrackers. then I got this urge to compare the optimos from symef.

I thought sloans amp is the best that I have assembled.symef surely beats optimos in listenning test.maybe because symef parts mostly are original specially the driver and output transistor.and maybe also the mica capacitors I have used.symef has greater bass and mids are more detailed.same speaker and player I have used and same artist also.

I attached picture of my two optimos amps with supply of 72 volts dc/rail.

right now im working again on chassis and making pcb for speaker protector and power supply will post picture within this week

regards,
joel

Hi Joel,

Happy new year and thanks for the feedback

kind regards,

Harrison.

[drowranger]

hi Harrison,

I have already fix the high dc offset value from 50mv to 4.4 mvolts.I have change the differential transistor from bc557 to mpsa92.bc556 is not available on my source so I tried bc557 but its not a good decision due to high dc offset value.

you are right in your simulation it shows 10mv but in real world much lower up to 4mv.and also I have change the decoupling capacitor fro 33uf to 220uf even at full volume no hum can be heard.

as you can see my input or signal wires is not shielded and no need coz the amp.is quiet and also used copper tube as spacer for the pcb and connection of my star gnd. to chassis.

in listenning test, surely it has beaten my carver receiver .I have used a behringer mixer with low ,mid and high contol and to control the volume of the signal because I did not put a volume contol on the amp.I compare the symef to my carver coz it has also high ,mid and low contol.

symef turned my tower speaker(yamaha) sounds like a big speaker.voice of the artist sounds big and the bass is very good even at low volume.I really like the mids and lows of this amp. thats why its sounds very natural to me.

thank you so much for this amplifier.I am very satisfied with this amp.it is really worth of my money,time and energy.Now my worries are over the amp. is working and sound is excellent.sadly I'm going back on sunday morning and vacation is over.as you can see there is still a lot to finish on this amp..Pcb for the power supply,transformer and some paint job.

thanks, harrison .I do love your symef amp. now.It is a treasure!


regards,
joel

[OnAudio]

Originally Posted by drowranger

hi Harrison,

I have already fix the high dc offset value from 50mv to 4.4 mvolts.I have change the differential transistor from bc557 to mpsa92.bc556 is not available on my source so I tried bc557 but its not a good decision due to high dc offset value.

you are right in your simulation it shows 10mv but in real world much lower up to 4mv.and also I have change the decoupling capacitor fro 33uf to 220uf even at full volume no hum can be heard.

as you can see my input or signal wires is not shielded and no need coz the amp.is quiet and also used copper tube as spacer for the pcb and connection of my star gnd. to chassis.

Hi Joel,

Thats good news about the offset. I am glad you debugged it.
The 33uF is supposed to keep a grip on the high frequencies, however if the 220uF is quality enough it may also suffice.

About the hum, you have played a major role also in doing the pcb and layout right, pat yourself on the back.

Originally Posted by drowranger

in listenning test, surely it has beaten my carver receiver .I have used a behringer mixer with low ,mid and high contol and to control the volume of the signal because I did not put a volume contol on the amp.I compare the symef to my carver coz it has also high ,mid and low contol.

symef turned my tower speaker(yamaha) sounds like a big speaker.voice of the artist sounds big and the bass is very good even at low volume.I really like the mids and lows of this amp. thats why its sounds very natural to me.

Thank you for this insightful information. Go even further, visit your local hifi store and pit that amplifier against the best in the world

Originally Posted by drowranger

thank you so much for this amplifier.I am very satisfied with this amp.it is really worth of my money,time and energy.Now my worries are over the amp. is working and sound is excellent.sadly I'm going back on sunday morning and vacation is over.as you can see there is still a lot to finish on this amp..Pcb for the power supply,transformer and some paint job.

thanks, harrison .I do love your symef amp. now.It is a treasure!


regards,
joel

Thanks to you too . Well, they say there is a time for everything under the sun. You will get to finish it and also get to make a few more for your friends.

kind regards,

Harrison.