SYMEF amplifier

[Lazy Cat]

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Dont expect to find the formula there It will be published soon

I wonder what are you waiting for? Some universe planets alignment, full moon in third quarter or ...?

 

[OnAudio]

Hi Adam,

Thank you for the files. The middle one is a no no. The bottom one looks promising. I don't know how long the proofing process will take but will get back to you.

kind regards,

Harrison.

 

[OnAudio]

Hi Lazy Cat,

The processes involved in getting such things done is lengthy. But its coming..

kind regards,

Harrison.

 

[drowranger]

It actually works...

Harrison, have you ever built, measured or heard any of the audio projects that you so keenly promote and want others to spend money and effort on to see if they actually work?

Padamieki, there are many amplifiers on this site that are excellent and works. Why not try a proven working design. Look at SSA for instance or any of APEX offerings.

I have posted measurements on idle current(46mv) and dc offset(4.4mv and3.9)which Im sure this is much lower than most of the amps. that were featured here.And operate the amp. at 52 volts

Assemble it first according to his design then get back to him if your not satisfied.I did not spend to much time comparing Symef amp. to my carver receiver, instantly I noticed the difference.I have read your analysis about symef and spend to much time comparing it to your amp.

Question: Did Symef equally or surpassed your amp? coz if not I,m sure you will not put yourself to stress.accepting reality is hard but when you do it will save you time.

regards,
drowranger

 

[PauloPT]

Hi!

I'm very intrigued about this amplifier. There's an aura of mistery and secrecy around it. The THD spectrum looks very nice! I'm tempted to build it. But why 2 amps - the SYMEF and 1DIFFQC? How different are they soundwise? Did the secret formula arrived to 2 different results? Is there a BOM for the SYMEF? Can I use Joyel's PCB from post http://www.diyaudio.com/forums/solid-state/198500-symef-amplifier-17.html#post2886765 #161? Can I use 2SC5200/2SA1943 for outputs? Is the prefered version the one with MPSA92 for the small bipolars? Could I use BD139/140 instead of MJE340/350 without compromising the sound? Should I build it? Sorry about all these questions...

Thanks.

 

[PauloPT]

I'm sorry to have bombarded the thread with so many questions. To late to edit...

I think I'll build the SYMEF. I just need some guidance through the process.

 

[OnAudio]

Hi PauloPT,

Drow has done a meavelous job with the PCBs. Not only that he has shared his experiences which are very valuable. Do not hesitate to use his setups. If you can get the BC556B or KSA992, Drow has been very helpful when it comes to PCB requests.

The original actually uses TO3 devices. Alex designed a nice PCB, I am still looking forward to him constructing the amplifier and giving us feedback. However flat packs have proved successful under Drows setups. I have been looking forward to Tinituss' progress using the flat packs.As such I believe small mods can be accommodated.

If possible why not try both the SYMEF and 1DIFFQC ! Wouldn't it be a surprise if you cant tell the difference ? Exactly how do our ears work ?

kind regards,

Harrison.
http://www.diyaudio.com/forums/members/tinitus.html

 

[OnAudio]

Hi PauloPT,

It is with great pleasure that I welcome you to the club.

kind regards,

Harrison.

 

[PauloPT]

If you can get the BC556B or KSA992

I can get BC556B. I can also get MPSA92 but not KSA992. I think I'll use the BCs.

However flat packs have proved successful under Drows setups.

I have some 2SC5200/2SA1943 asking to be used.

If possible why not try both the SYMEF and 1DIFFQC !

That's a good ideia! But tell me, do they sound different to your ears?

It is with great pleasure that I welcome you to the club.

The pleasure is mine! Thank you for sharing your design!

 

[drowranger]

post 134 for pcb using bc556

Toner transfer will be easy for you co'z I made tracks and pads much wider and bigger.That is the method I used.I prefer you should print using printer(laser) than copier because it will give you much better result. Pdf form is in standard size.

If you are using mpsa92 correct pcb is in post 163.

I have used pcb for bc556b and there is no mistake.just check the value of parts specially the resistor and check also if there's contact between your driver,output transistor and your heatsink. Dont forget to connect the star gnd. of pcb to the chassis.I have used copper tube and serves also as spacer and conductor to my chassis.

set your pot resistance at middle before soldering it to the board.You will be fine,and we will monitor your progress.

How much supply at rail are you going to use?

regards,
drowranger

 

[PauloPT]

I prefer you should print using printer(laser) than copier because it will give you much better result.

I'll use my laser printer. The pdf should be printed mirrored, right?

I have used pcb for bc556b and there is no mistake.

Great! I'll go for bc556b.

How much supply at rail are you going to use?

I'm not sure. I have with me 2 transformers that I could use. They're both 300VA. One gives me 25Vac (+-36V dc rails) and the other is 35Vac (+-50V dc). Which one do you recomend?

,and we will monitor your progress.

Great! I'll post pictures as I go.

 

[drowranger]

I think its not mirrored...

I should post the copper side not in mirrored.I'll check my files.

regards,
drowranger

 

[drowranger]

no problem about trafo...

just mind the capacitor voltage, 63 volts will do fine.will try first the 25vac after amp. has no problem then will shift to 36vac.and we have to change the two resistor to 1 watt when supply is 50 vdc

about pcb layout it should not be in mirror because its a toner transfer method.mirrored pcb layout can be use in presynthesized boards using light.

I will check and find the layout I will post it today

regards,
joel

 

[PauloPT]

I said mirror because the "SYMEF" word is printed straight and when you iron the paper on the board the words will be reversed.

 

[drowranger]

ok...

its good that you remind me.I uploaded before the copperside in mirror image and forgot those who want to use the toner transfer method.

here it is now and goodluck to your amp.

regards,
joel

 

[PauloPT]

parts

I'm puting together my shopping list for parts and I need some help with it:

All resistors are 1/4W except the 2 4.7K that are 1w, right?

The trimpot is 2k?

The 33uF have to be tantalum, can't they be Al electrolytic?

the small 8.2pF hard to get, can't it be 8pF or 10pF?

For now it's all my doubts.
Thanks.

 

[Nico Ras]

As the African sun was rising and warming the bowels of the earth. Lions were stretching themselves ready for another day a day full of great expectations. Nico had just had breakfast, he was longing for this day...on this day he would get to plug in the SYMEF and listen. He had finished the project late at night.

When the first tones came through, Nico sat up, paused and took a deep breath, he listened a long time. Nico finally moved over to his laptop and logged onto diyaudio and started typing ...................................................................

....to be continued

We don't have laptops in Africa, we bang with sticks on hollow tree trunks, besides the messages are real time. A second benefit of the noise is that it keeps the lions and other wild animals away from you house in the trees.

 

[PauloPT]

We don't have laptops in Africa, we bang with sticks on hollow tree trunks, besides the messages are real time. A second benefit of the noise is that it keeps the lions and other wild animals away from you house in the trees.

How do you interface the hollow tree trunk with the internet? What's the bandwidth you're getting? Is it a big trunk? I always thought you used desktops in Africa...

 

[drowranger]

the rest is 1/4 watt...

R9-R12=5watts
R13&R14+2watts
R27&R35=1watt
pot. is 2k
only input capacitor is tantalum (I used polypropylene)
33uf (decoupling cap.at supply rail) is electrolytic(mine I used is 220uf/100v electrolytic)
for 8.2pf,8pf will be fine-I used 10pf(mica capacitor beco'z 8pf not available)

regards,
joel

p.s. check capacitor polypropylene at rs component-panasonic part#ECWF2W475JA

 

[Nikos]

Nice work
but you have tested the amp with osc and gen.
any square wave test 1-10-20 khz
regards Nikos