Symasym5 modifid circuit

[space2000]

hi, i am not good in electronics as all of you. i need help for this circuit design. at first i got it from Symasym5 then went to pavel site to have this modofied circuit design. i have build it. now i have modified by adding one more power transistor 2sc5200 and 2sa1943. i circled the design. do you think it is correct way to adding power transistor in parallel? i have posted the pic.


thank you.

[DVBjunky]

Hi,

may I ask why do you not building the symasym designs of MikeB, AAK, Pavels Mod or others?

I did build several symasyms with Onsemi and Toshiba Transistors based on the "ready for build" design of these people.

Believe me....the only design with better audio quality but less power output is Roenders Amp (heavy modification of the symasym with other design elements).

A well build symasym with MJL 4281 or NJL 0281 will beat any "commercial non-DIY amp" up to the 2000 Dollar price tag.

But, if you want to another "mod", well......I just tried to avoid unnecessary work.

best regards

Alan

[space2000]

hi, thank you for your comments.

actually here in singapore not easy to find those MJL 4281 or NJL 0281 parts. so i used 2sc5200, i know it is not good as those mjl. here is easy to find 2sc5200 and cheap too...only $8 a pare. this is the reason i used this. i am not good in amplifier or electronics, but i like those are hi class amp. honestly tells you, i had one amp that was pioneer, now not working. i used that casing and heat sink to buid one amp. the sound is good but i wanted to use more power to bost my speaker.

i am not so familier with those amplifier. just few days ago started to search to build my own a hi end amp thats all.


thank you.

[h_a]

This is a bipolar design. Depending on your choice of driver transistors and their idling currents, you may run out of base current in demanding situations.

If the driver heatsink is up to it, you can crank up the current, however you should know what you're doing ;-)

I'm sorry that I cannot give you more details as I'm do not know the Symasym well enough.

All the best, Hannes

[Andy L. Francis]

Space2000, your circuit modification should work. Build it.

[Mas Penk]

quote :

hi, thank you for your comments.

actually here in singapore not easy to find those MJL 4281 or NJL 0281 parts. so i used 2sc5200, i know it is not good as those mjl. here is easy to find 2sc5200 and cheap too...only $8 a pare. this is the reason i used this. i am not good in amplifier or electronics, but i like those are hi class amp. honestly tells you, i had one amp that was pioneer, now not working. i used that casing and heat sink to buid one amp. the sound is good but i wanted to use more power to bost my speaker.

i am not so familier with those amplifier. just few days ago started to search to build my own a hi end amp thats all.

thank you.

As far as I Know there is a branch of Onsemi on Singapore. Have you tried them ?

Here the web : http://www.onsemi.com/PowerSolutions...ountryCode=SGP

and Here is the address :
ON Semiconductor
25 Serangoon North Ave 5
#03-10 Keppel Digihub , Singapore 554914
65-6555-8260 (tel)
65-6482-4794 (fax)

Because I also hope that someone can find NJL0281D in SG...

[Andy L. Francis]

2SC5200/2SA1943 should work fine in the circuit. I can't belive they would really sound worse then the ON MJL devices.

[MikeB]

Space2000, the extra pair is added correctly. But, the sc5200 are also tough devices (if genuine). Unless you plan to drive ugly <4ohm speakers and/or increase supply voltage above +/-36v, you can go with a single pair.

Andy, the Toshibas sound absolutely fine. But in my taste the MJL(W)0281/0302 sound even better. I haven't heard the mjl4281 yet.

Mike

[PeterLeest]

Originally posted by DVBjunky
Hi,

I did build several symasyms with Onsemi and Toshiba Transistors based on the "ready for build" design of these people.

A well build symasym with MJL 4281 or NJL 0281 will beat any "commercial non-DIY amp" up to the 2000 Dollar price tag.

Alan

Hi,

I build the original Symasym with MJL3281A/MJL1302A, another one is a revamp of an old Parasound HCA-800II to a Symasym variant using 2SC5200/2SA1943, +/-50V from the existing power supply.

They sound quite different even though they shared the same circuit skeleton. It is like some girls are pretty and some are not but equally attractive though they eat the same food.

The 5200 has stronger bass, whereas for 3281, the treble is more refined. You have to try out to see which one suit you

[space2000]

hi, my transformer have three line out, which i can get easily +v, -V and gnd but my power supply only 34-0-34. how can i get higher volatge like 68v with -v, +v and gnd?

if we add 34+34 then should be 68v but amplifier need +v,-v and gnd.
thank you.