Does the ESR affect sound quality and/or efficiency/heat (do these pass output current?)
Also curious about your opinion on use of electrolytics as blocking caps on the input; did you change those?
Is this correct? What about R8, 120k?
This is important to me so I can properly calculate a passive shelf filter to correct an issue with my L/R speakers.
I'm confused on the correct values for the main caps, shown on p.21 fig.25 here
http://www.inductor.com/irf/iraudamp7s.pdf
If my rudimentary understanding of circuits is right, they're CP7 and CP8.
I wonder why they're "CP" and not just "C", and why they're printed in red and have asterisks in front of the 470uF.
http://www.inductor.com/irf/iraudamp7s.pdf
If my rudimentary understanding of circuits is right, they're CP7 and CP8.
I wonder why they're "CP" and not just "C", and why they're printed in red and have asterisks in front of the 470uF.
They are inverse the amplifier circuits, there are many material are described in content.
Before I ignore this, in the capacity of the capacitance on use size, 22 UF is more reasonable.
So we don't have to change it.
My question is not about the 22uF value, it is whether it is advisable to use a nonpolarized electrolytic capacitor for an AC audio signal.
I thought that crossover distortion wasn't an issue for class D because they don't construct the output waveform from two halves like AB designs, but then I came across this:
Is this true for the IRS2092-based modules?
If so, what is the freq of this alternating idling current?
The only evidence is a small bump at 20W in some of the THD+N vs. power graphs, but curiously only in one channel.
Is this true for the IRS2092-based modules?
If so, what is the freq of this alternating idling current?
The only evidence is a small bump at 20W in some of the THD+N vs. power graphs, but curiously only in one channel.
It's probably the self generated 400Khz frequency that is used as part of the Class D design..
I've just ordered a set of L25D's to power my 8R woofers and I'm building twin linear power supplies with a dual secondary 700VA transformer... Is there a point where supply capacitance would be considered overkill or perhaps even counterproductive? I have 40,000uF currently available for each board.
There must be a point of diminishing returns for power supplys but I very much doubt it would be counter productive.
The L25D looks great! I'm still waiting for the resistors I need to change on my l20d's in order to make them run safely at about 85V.
@ ljm would I be able to change components on the L25D to make it suitable for this voltage as it looks very tempting!
The L25D looks great! I'm still waiting for the resistors I need to change on my l20d's in order to make them run safely at about 85V.
@ ljm would I be able to change components on the L25D to make it suitable for this voltage as it looks very tempting!
Building a capacitance multiplier may be more effective cost- and space-wise.
Elliott Sound Products - Linear Power Supply Design
Srcoll down to the "Capacitor Value" section and give it a read.
Srcoll down to the "Capacitor Value" section and give it a read.
check for markings.. (you might need a magnifier), he might not be able to tell you since he's the designer, and not involved with the sales..
If you have a power supply you can use, you can also measure the zener's to see which one's are which as per "Testing Zeners" on this page
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4 zeners are still on the tape:Have the tape IS 5V6 .
4 came individually ,separate IS 15V.
Note of anode
Well, I finally got my L20D amplifier assembled and it's sounding good!
I am using a recycled DVD player chassis, and I haven't finished tidying the wiring yet, but here is where I am at:
I'm using a ConnexElectronics SMPS300R, with 2 extra Elna 18000uF filter caps between them and the boards. I had originally ordered an A350SMPS, but it had a problem when I first tested it. Cristi offered to upgrade to an SMPS300R as a replacemant.. slightly less wattage, but made to provide +-60V to better suit the L20D, and its running very well.
The L20D boards are almost currently stock, except for the addition of heat sink compound (didn't ship with any, as others have said), and I have replaced the small stock bypass capacitors with 1200uF low ESR capacitors as well.
Only had it running for a few hours... but it sounds GOOD. Not as quiet as some amps, but more than quiet enough (hiss with ear near the waveguide, not audible away from the speakers). And this is all just as first fired up, with no fine tuning of the layout.
Power use for the pair of modules measured with steplight power meter is 12W idle.
I am using a recycled DVD player chassis, and I haven't finished tidying the wiring yet, but here is where I am at:
I'm using a ConnexElectronics SMPS300R, with 2 extra Elna 18000uF filter caps between them and the boards. I had originally ordered an A350SMPS, but it had a problem when I first tested it. Cristi offered to upgrade to an SMPS300R as a replacemant.. slightly less wattage, but made to provide +-60V to better suit the L20D, and its running very well.
The L20D boards are almost currently stock, except for the addition of heat sink compound (didn't ship with any, as others have said), and I have replaced the small stock bypass capacitors with 1200uF low ESR capacitors as well.
Only had it running for a few hours... but it sounds GOOD. Not as quiet as some amps, but more than quiet enough (hiss with ear near the waveguide, not audible away from the speakers). And this is all just as first fired up, with no fine tuning of the layout.
Power use for the pair of modules measured with steplight power meter is 12W idle.
@ zog666 that looks like a sweet set up
Must admit during the short tests iv done these amps do sound good!
Running 86v rails
I have changed the components LJM suggested but the resistor next to the voltage regulator on the heat sink (changed from 2k2 to 3k 1 watt) runs very hot still.
maybe change to 2 or 3 watt?
Must admit during the short tests iv done these amps do sound good!
Running 86v rails
I have changed the components LJM suggested but the resistor next to the voltage regulator on the heat sink (changed from 2k2 to 3k 1 watt) runs very hot still.
maybe change to 2 or 3 watt?