The calculation is calculated on a 1 ohm. The picture shows the output impedance. The correct damping factor calculation was divided into 4 ohms, 4, 8 ohms divided by 8, ect, ect. and calculate the inverse.
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It only requires a basic unregulated power supply as most solid state power amplifier circuits use.
In this case use a 2x25VAC or 25-0-25VAC transformer of at least 200VA for a stereo pair, a bridge rectifier and say 2x4700uF 50V per rail to produce a +/-35v supply. Use more capacitance if you like but I find the above gives good performance.
In this case use a 2x25VAC or 25-0-25VAC transformer of at least 200VA for a stereo pair, a bridge rectifier and say 2x4700uF 50V per rail to produce a +/-35v supply. Use more capacitance if you like but I find the above gives good performance.
Hello,what modification's i need to make to the amp if i want to put another pair of mjl and my power suply is +- 56vd dc(2x56v dc),i made some schematics to see if they are good or not,thank you !
http://http://tinypic.com/view.php?pic=288xbvc&s=5#.Uj8sZYa9WWc
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http://http://tinypic.com/view.php?pic=288xbvc&s=5#.Uj8sZYa9WWc
Image - TinyPic - Free Image Hosting, Photo Sharing & Video Hosting
Image - TinyPic - Free Image Hosting, Photo Sharing & Video Hosting
I built a symasym some years back and I'm considering building another.
I thought I'd change some little things on the original PCB before starting (change the trimmer, remove the fuses, thicken some traces to make it easier to self-etch, etc.) and, one thing leading to another, I ended up in Eagle with a quite different PCB.
So, here it is. Does it seem ok or should I go back to the original one ?
I thought I'd change some little things on the original PCB before starting (change the trimmer, remove the fuses, thicken some traces to make it easier to self-etch, etc.) and, one thing leading to another, I ended up in Eagle with a quite different PCB.
So, here it is. Does it seem ok or should I go back to the original one ?
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The ground pins of C10 and C11 should be as close to the ground connector as possible. You've put them as far from it as you can.
Why not put the reservoir caps along the space behind the power transistors? This would take the small-signal circuitry out of the magnetic loop and decrease radiated distortion. Power ground wouldn't be at the other side of the board so you wouldn't need to run the power output trace through the small-signal section.
Why not put the reservoir caps along the space behind the power transistors? This would take the small-signal circuitry out of the magnetic loop and decrease radiated distortion. Power ground wouldn't be at the other side of the board so you wouldn't need to run the power output trace through the small-signal section.
Thank you for the comments... there's much work on my plate after that.
Some questions in order to clarify things in my mind.
- I had some trouble understanding what you pointed to, as I deleted that jumper by running ground tracks left and right... and then I remembered that the evolution in between 5.2 and 5.3 was precisely the opposite
- I like the idea a lot, especially wrt the magnetic loop.
Some questions in order to clarify things in my mind.
- What's the problem about R7and R29 ? This part is coming straight from the original layout.
- I had some trouble understanding what you pointed to, as I deleted that jumper by running ground tracks left and right... and then I remembered that the evolution in between 5.2 and 5.3 was precisely the opposite
- Well, it was kinda on purpose. C10 and C11 are the reservoir for the small signal circuitry. If I put them close to the ground connector, they'll be connected before the power reservoir caps and see all the charging currents. In a ground bus, isn't it better to have the sensitive circuitry after the big stuff ? Or am I missing a step ?
- I like the idea a lot, especially wrt the magnetic loop.
The ground trace from the reservoirs is a long resistor. The charging currents create a voltage gradient across this resistor. The voltage difference will always be smallest closest to the source. By putting the frontend reservoir ground at the other end, you are injecting rectifier and switching noise into the frontend rails.
This hasn't much left in common with the starting point. I tried having power ground at the middle and keeping the feedback path as short as possible. A bit of a problem to bring the signal to the drivers though... Wires under the board ?
If it isn't worth pursuing, I'll just etch the original board with some little changes (especially put a decent trimmer onboard and add decent test points for bias).
If it isn't worth pursuing, I'll just etch the original board with some little changes (especially put a decent trimmer onboard and add decent test points for bias).
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Anyone here replace the output transistors with 2SC5198 and 2SA1941 like this guy below ?
[Elektronika] Symasym Zibiego II
because i have few pair of this transistor in hand, but worry about will blow it.
any help thanks in advance.
[Elektronika] Symasym Zibiego II
because i have few pair of this transistor in hand, but worry about will blow it.
any help thanks in advance.
There are several versions of Symasym around in Europe and globally here, posted on the forum. They have various common output transistors, mostly TO264. Some PCBs were designed for multiple output pairs, so you really need to consider the specific version and your supply voltages to say whether it will work OK or perhaps be risky with the lower heat dissipation of the smaller package. Given the usually low voltage supplies recommended here, there is likely no problem with 6-8R loads. I'd suggest 2 pairs with 4R loads regardless, though.
Your Toshiba types are similar to 2SC5200/A1943 but in a smaller package, and lower voltage spec. Expect near identical performance as output devices, used within their rating. Since dissipation is less with a smaller case, you need more efficient heatsinking to keep them as cool, if that becomes an issue.
Closer TO3P equivalents are newer 2SC5200N/A1943N and these really look to be the original die, repackaged in T03P form. Anyway, check the Toshiba datasheets out: Transistors | Products | TOSHIBA Semiconductor & Storage Products Company
Your Toshiba types are similar to 2SC5200/A1943 but in a smaller package, and lower voltage spec. Expect near identical performance as output devices, used within their rating. Since dissipation is less with a smaller case, you need more efficient heatsinking to keep them as cool, if that becomes an issue.
Closer TO3P equivalents are newer 2SC5200N/A1943N and these really look to be the original die, repackaged in T03P form. Anyway, check the Toshiba datasheets out: Transistors | Products | TOSHIBA Semiconductor & Storage Products Company
Hi Guys,
I haven't kept up with the evolutions of the Symasym. I built two of them years ago when Carlos first started this thread. One from home etched boards and then another with the group buy boards. I still have an unused pair of the group buy boards that I have thought of populating but I wonder if there have been any significant upgrades that should be incorporated into the build. If any of you have some suggestions I would appreciate hearing from you.
Thanks, Terry
I haven't kept up with the evolutions of the Symasym. I built two of them years ago when Carlos first started this thread. One from home etched boards and then another with the group buy boards. I still have an unused pair of the group buy boards that I have thought of populating but I wonder if there have been any significant upgrades that should be incorporated into the build. If any of you have some suggestions I would appreciate hearing from you.
Thanks, Terry
Would it still have a good sound, just with a lower output amplitude? Or would you get distortions and noise?