Well, I think you're right about converting these little Wharfedales to infinite-baffle / sealed-box.
I've plugged the ports in the 9.0's more tightly (although not hermetically).
With the lightly-packed open-cell bungs there was still a trace of 'chuffing' from the ports when I cranked up bass sine-waves which has gone, and I immediately found that I had to turn up the Lepai/JPW sub to maintain the bottom-end.
Better, definitely, but I'm not sure that I'd do this without the sub to boost the < 60Hz stuff.
Now to replace the 2200pF reservoir cap in the Lepai.
I use single conductor 22AWG Cu wire for speaker wires, Ag plated to save the CU from the heavy Teflon jacketing. Cu and Teflon argueThe bare ends tarnish, so, I cut then off every year, or so. The freshly peeled new ends still look brand new. I bought a fifteen pound reel of scraps, over a decade ago. I have not made much of a dent in that reel. A "sound" investment.
My switching power supply wall wart delivers 12.75 V to the LP-2020A+.
It was really noisy.
I have now spliced in a C-R-C-R-C-R-C-R-C-R-C-R-C "Pi" filter into the wires from the wall wart to the LP-2020A+.
It is now a bit quieter. And delivers 9.48 volts and 300 mA.
9.48V*0.3A = 2.8 watts to the chip.
2.8 watts * 80% worst case efficiency is 2.25 watts to the speex.
That is ~96 dB on my woofers at 430 Hz. crossover point, to ~80dB at 30 Hz @1W/1M.
It sounds OK.
C-R-C-R-C etc'. Caps and resistors?
I assume you're using full-range folded-horn speakers of c. 112 dB/W?
Try Panasonic FR (upright mount), or FC (side mount with bend leads). Many audio DIYers prefer FC but FR has higher ripple current and lower impedance.
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No problem...
5600uF should be sufficient. I encountered problem of amp shutting-off halfway if I use a higher value cap (such as 6800uF). Here is why I don't understand how some people can still use a 10,000uF cap.
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I notice the Lapai's board is marked for a larger cap (a 3300pF, presumably) than the 2200 on mine.
Can an even bigger one than 3300 be mounted?
No problem...
Cross-post!
So a 5600 will fit? ( I was thinking maybe 4700).
With Panasonic FR (Length: 25mm), you can fit upright. You will have the bend the leads and fit sideway with FC (Length: 36mm). Some branded 4700uF caps (such as Nichicon, Elna, BC and certain Panasonic models) will NOT fit upright.
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Replacing Lepai reservoir capacitor ...
Again, thank you.
(I've titled the post to assist with searches - this is useful, basic info for dilettante modders like me).
Again, thank you.
(I've titled the post to assist with searches - this is useful, basic info for dilettante modders like me).
No problem. You might want to add a 220nF (that's nanofarads!) polyester cap parallel to the reservoir cap to help filter the irregularities from power source.
For me, I solder the small cap BELOW the mainboard, directing under the reservoir cap across its terminals. This helps save space.
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That would be quite small?
Could it be mounted under the PCB (soldered to the legs of the reservoir cap, poking through the board)?
ETA>>
You're too fast!
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No need to poke through. Just under the mainboard, solder across the legs of the reservoir cap will do.
If you use a Panasonic 220nF (0.22uF) TF polyester cap, it measures 7.3 v 4.5 mm.
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Yep - that's what I was saying.
However, assuming my Lepai is going to carry on as an amp for the woofer, it probably wouldn't benefit from it.
But now I'm wondering about the Indeed TA2020S which is, basically, what's providing most of the audio-band via the Diamond 9.0's.
Maybe it could benefit from this cap (assuming it isn't already present)?
ETA >> the Indeed has a 4700uF cap.
Nah... This small capacitor is cheap! Just add it while you still have a hot iron in case you decide to use the Lepai solo again.
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You're quite right, I was thinking 'theoretically' instead of practically - if I'm going to be replacing the reservoir cap anyway, why not do both mods!
What do you think about the Indeed (or the various other TA2020 iterations - Muse, Sure, Topping, SMSL) - would they benefit from it?
I am quite sure it will. Usually, these small tweaks may have just been ignored during production to save some costs. One small cap may not cost much but adds up once it goes into mass production.
that cap is too small
There were people who tested these small cap in parallel with larger one, they showed in order to make difference, the smaller cap need to be 20% value of the main cap, which in most case impractical. Lower value cap is for different purpose, mostly for EMI, not for filtering supplies.
There were people who tested these small cap in parallel with larger one, they showed in order to make difference, the smaller cap need to be 20% value of the main cap, which in most case impractical. Lower value cap is for different purpose, mostly for EMI, not for filtering supplies.
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