Hi dear i've just bought that fantastic board.
I've also bought a toroidal 500VA 36vac.
The problem i've notice is the weak bass. It is quite strange, but this fact makes the amp sound really bad. it is not realistic!
Looking around in varius forum I've red about some fun that mod this board, changing input caps, adding or replacing some filter caps in the power rail. However seem that the problem still exists. The revision i've of this board is the last. I've just send an email to hifimediy, they told me that the problem i have is not real: in their opinion the board works well. They told me that the last revision has STA516b the last revision (2014) of the power chip.
Anyone that have the board is able to help me?
I've to apologize to my bad English, but i am italian..
Thanks to all in advantage!
I've also bought a toroidal 500VA 36vac.
The problem i've notice is the weak bass. It is quite strange, but this fact makes the amp sound really bad. it is not realistic!
Looking around in varius forum I've red about some fun that mod this board, changing input caps, adding or replacing some filter caps in the power rail. However seem that the problem still exists. The revision i've of this board is the last. I've just send an email to hifimediy, they told me that the problem i have is not real: in their opinion the board works well. They told me that the last revision has STA516b the last revision (2014) of the power chip.
Anyone that have the board is able to help me?
I've to apologize to my bad English, but i am italian..
Thanks to all in advantage!
For sure, but when you connect them in antiphase, their will be lack off bass because of cancelation.
Much luck, i'm out.
Much luck, i'm out.
Hello.
What type power supply are you using ,if unregulated conventional what are the filter cap values.
Small low value filter caps can kill off bass
What type power supply are you using ,if unregulated conventional what are the filter cap values.
Small low value filter caps can kill off bass
Hi, sorry for the delay! However the power supply rail is standard. I've not increese the caps! what do you think? should i add a 10000uF cap?
First try doctormords suggestion. You would not be the first to have reversed phase. It could be an error on the amplifierboard. It takes no time to try it.
If you stay in between speakers and get more bass if you walk left or right, then you definately have a phase issue. The bass should not change much if phase is correct.
If you stay in between speakers and get more bass if you walk left or right, then you definately have a phase issue. The bass should not change much if phase is correct.
I've just test! It is not a phase problem. But I see that could be a power supply problem! I've changed the supply caps around STA516b! And add 2200uF as close as possible to sta516. But problem seems not solved! I've used an equalizer to adjust the sound. +6db 32Hz and +4db 100Hz and the soud finally changed. Bass is present and well responsive. So the problem seems to be an atteniation on low frequencies.. Why? What could be? I'm not sure about LP filter in the final.. The quality should be very good! And the input cap as well. i cant understand what is happening!
What impedance is the woofer? I think the T4 is designed for 8 ohm, and only have half the power in 4 ohm.
That could be a problem. Measurement show around 5 ohm at 20Hz 50 Hz and the range between 150Hz to 300 Hz is below 5 ohm.
Is your toroid 2x36 volt 36-0-36 or single 36 volt.
2x36 rectified will be at the limit for that chip I think, and only ok for 8 ohm. If you have a 2x20 volt laying around (VA rating is not important for testing), you could try that. It should give better performance for lower impedance. hifimediy also writes that this board is for 8 ohm only (but its another chip than the one you mention)
Is your toroid 2x36 volt 36-0-36 or single 36 volt.
2x36 rectified will be at the limit for that chip I think, and only ok for 8 ohm. If you have a 2x20 volt laying around (VA rating is not important for testing), you could try that. It should give better performance for lower impedance. hifimediy also writes that this board is for 8 ohm only (but its another chip than the one you mention)
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