Yes, slow progress! Too much party, not enough work 
Got some nice little details still to add to the front. Have to finish wiring & connect PCM / BMS. Little shockmount electronics board seems to work well when bolted down!
Can anyone spot the silly mistake? 🙁 Measure twice cut once, etc...
Got some nice little details still to add to the front. Have to finish wiring & connect PCM / BMS. Little shockmount electronics board seems to work well when bolted down!
Can anyone spot the silly mistake? 🙁 Measure twice cut once, etc...
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
A little confused by this equation (far from an electrical engineer!) Can you clarify what is meant by Zi? Is this the capacitor? (I know Z as inductance...)
Also, is there anyway to make this 2nd order or higher? I am a little uncomfortable using such a low slope! 🙂
PLLXO:Okay, I'll look into them.
Still doesn't make it any clearer to be honest. The quote mentions a capacitor, not in equation. There is also a resistor & impedance in the equation, but only one on board at input.
I thought that changing the capacitor would have affected the HP?
Unless I'm missing something really obvious!
Ta
Still doesn't make it any clearer to be honest. The quote mentions a capacitor, not in equation. There is also a resistor & impedance in the equation, but only one on board at input.
I thought that changing the capacitor would have affected the HP?
Unless I'm missing something really obvious!
Ta
The input impedances with 20dB, 26dB, 32dB, and 36dB gains are 60k, 30k, 15k, and 9k ohm. Equation is correct.
Okay, so I work with these:
Input impedances with 20dB, 26dB, 32dB, and 36dB gains are 60k, 30k, 15k, and 9k ohm
&
f=1/(2*Pi*Z*C)
Makes sense now 🙂
Input impedances with 20dB, 26dB, 32dB, and 36dB gains are 60k, 30k, 15k, and 9k ohm
&
f=1/(2*Pi*Z*C)
Makes sense now 🙂
yes equations are nicer if your own calculations match the given ones🙂 btw blueblack board standard is set to 26dB (30k)
Tiny capacitors ! 180nF for the 60Hz HPF, 3.6nF for the 3KHz HPF (for 6db/oct filter, 15K impedance)
I am concerned about the PLLXO. Using a gain resistor of 60k (required to be >50k for 12db/oct), the voltage multiplier (10x) is too low for full driving of the amplifier from LM1036 (1V output). Seems I need a 15K impedance for happy drivings?
Can anyone confirm this is an issue? Thanks.
I am concerned about the PLLXO. Using a gain resistor of 60k (required to be >50k for 12db/oct), the voltage multiplier (10x) is too low for full driving of the amplifier from LM1036 (1V output). Seems I need a 15K impedance for happy drivings?
Can anyone confirm this is an issue? Thanks.
So, fine tuned the port today, ended up at 78Hz 🙂
Impedance sweeping showed up a few panel resonance nasties too (both on impedance graphs and audibly). Will need to make some braces between adjacent panels....
Not so worried about the 6dB/oct filters now I've hit each driver with some power, the faitals seem to handle unfiltered abuse quite happily. Will try them first them go from there.
Question: Can anyone tell me why there are two gainsetting resistors at 100k & 20k? And why there are two 1uF input capacitors??
With thanks,
Impedance sweeping showed up a few panel resonance nasties too (both on impedance graphs and audibly). Will need to make some braces between adjacent panels....
Not so worried about the 6dB/oct filters now I've hit each driver with some power, the faitals seem to handle unfiltered abuse quite happily. Will try them first them go from there.
Question: Can anyone tell me why there are two gainsetting resistors at 100k & 20k? And why there are two 1uF input capacitors??
With thanks,
The chip has + input for left and right and - input for left and right, differential. So there are 4 inputcapacitors and when using a single ended source the plus ot minus input capacitor gets connected to ground.
Gainsetting is done by a voltagedivider. Chip senses voltage upon startup and selects gain. If you remove the 100K for example you will notice chip selects 20dB gain (60k inputimpedance), you will notice you have a 6dB less gain, if source is high output it will give you more room for volume control, if source is low output it will limit maximum volume.
Gainsetting is done by a voltagedivider. Chip senses voltage upon startup and selects gain. If you remove the 100K for example you will notice chip selects 20dB gain (60k inputimpedance), you will notice you have a 6dB less gain, if source is high output it will give you more room for volume control, if source is low output it will limit maximum volume.
Okay, I see. So I need to replace all 4 capacitors. (Two sets of 180nF, two of 3.6nF). Can you answer why they are different sizes? Seems some people in the TPA3116 thread just replaced the big ones..
And I'm sorry, but I really don't understand the explanation of the gainsetting. I understand potential dividers, but fail to see how a single 100k resistor results in a 60k input impedance?
Thanks,
And I'm sorry, but I really don't understand the explanation of the gainsetting. I understand potential dividers, but fail to see how a single 100k resistor results in a 60k input impedance?
Thanks,
We have sound !! Working with batteries and all !
Well, kind of. There are a few issues......
Pictures up soon 😀
Well, kind of. There are a few issues......
- The side with the 3nF capacitor is now dead.. Can anyone offer any suggestions on why? (Isolated down to that particular channel) I'll start having a fiddle with the amp over the weekend when I get the chance.. It does however create an impressive amount of static!
- - Holy mother of pop ! Anyway to stop the 'squeek', 'squeel', 'pop' or 'bang' when it's all turned off?
- - 12v regulator on the LM1036 got a bit smoky.. Also need to investigate..
- - Inrush current trips the battery management protection. Can anyone suggest a way to get around this? Google search turned up using a PTC?
Pictures up soon 😀
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How much bulk capacity is in the system? Tripping the battery protection should not occur with this system, as there is "no" load at all at startup.
There definitely is something wrong with your setup. Is this happening also with LM1036 disconnectected? Maybe the step-down is broken down, which would explain the blown 12V regulator.
There definitely is something wrong with your setup. Is this happening also with LM1036 disconnectected? Maybe the step-down is broken down, which would explain the blown 12V regulator.
Getting there! Hopefully the last of the 'in progress' posts.
From last time:
1. Seems I blew a channel of the TPA chip. Replaced the chip and it's alive again!
2. This bang .. Solved .. See why below
3. ^ Same
4. ^ Same
So, what did I do? Remove all circuitry aside from a small storage capacitor between the LM2596 and the LM1036. No idea what it was in the LM1036 PSU circuit, but no longer any mad inrush or 5A trips! Kept the PTC after the battery anyway.
It's sounding sweet ! But, I am clearly at the limit of the TPA chip at 25V. When VCC=25.2V, there is some kind of protection inside the chip that activates at (very) high volume.
Man, this amp has no problem driving the cones well past Xmax 😱
Last of the messy pics, before it's all neatened up with decent photos!
From last time:
1. Seems I blew a channel of the TPA chip. Replaced the chip and it's alive again!
2. This bang .. Solved .. See why below
3. ^ Same
4. ^ Same
So, what did I do? Remove all circuitry aside from a small storage capacitor between the LM2596 and the LM1036. No idea what it was in the LM1036 PSU circuit, but no longer any mad inrush or 5A trips! Kept the PTC after the battery anyway.
It's sounding sweet ! But, I am clearly at the limit of the TPA chip at 25V. When VCC=25.2V, there is some kind of protection inside the chip that activates at (very) high volume.
Man, this amp has no problem driving the cones well past Xmax 😱
Last of the messy pics, before it's all neatened up with decent photos!
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
You may want to add a subsonic filter, to reduce xmax at frequencies the enclosure can't do. (Helps to save some power and protects the speakers from an acustical short)
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