I use mine with 4 ohm speakers and what I do is apply a HF shelf EQ from 12khz on up and they sound great and measure flat to 18khz - the limit of my speakers. Measurements in the Nautaloss thread. They may sound better with 10uH but I am happy with my stock ones. Seeing how you had a bad experience swapping the coils I would give them a listen first for a good period of time. I think the MA drivers have more air on top than TC9FD so you may be just fine.
half the 10.2 impedance could be 22uH with 0.82uF, cutoff frequency is low, 26.5 Khz
10uH with 0.39uF cutoff frequency a little high 57Khz, no problem with these speakers I think and could be better, but not with 60Khz smps probably (those did exist and maybe still do?)
(enclosure does have an influence on impedance, but MA units are measured in a box I believe, so could be closer then infinite baffle impedance???)
(both capacitors are normal values for Panasonic polyprop's with 7.5 mm leadspacing)
Hmmm... Maybe.
The coil swap went fine. I was able to remove the originals without lifting the pads and I tinned all surfaces before making the connections. There was nothing iffy about any of it. Yet the board is seemingly dead. Based on the fact that it sounded horrible when I got it, and the fact that it ran so bloody hot I can only conclude that it was defective. I did get one enjoyable evening out of it, though, which is puzzling. Perhaps the wine helped.
I'm not too eager to buy any more right away. In the long run I'd be better to get in on the GB and do a dual-mono build with proper components.
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I'm planning to use my Yj blue/black board with a pair of Markaudio alpair 10 drivers, and want to optimise the output filter for this driver.
I've read and read again the calculations but still get lost a bit.
The part i don't understand is the driver's impedance value.
The Alpair 10 for example has a nominal impedance of 7.2 ohms (DCR but that rises to around 26 ohms at 40khz.
Which one should i plug in to find the right output filter componenet values? At what frequency should imoedance be taken?
Thanks
I've read and read again the calculations but still get lost a bit.
The part i don't understand is the driver's impedance value.
The Alpair 10 for example has a nominal impedance of 7.2 ohms (DCR but that rises to around 26 ohms at 40khz.
Which one should i plug in to find the right output filter componenet values? At what frequency should imoedance be taken?
Thanks
Hi all,
I've been running my yj blue board for a month now, overall very pleased.
I've connected up my 8ohm transmission line speakers and they are lacking in low bass, mid bass is strong.
Is the stock blue board cutting the low frequencies?
What is the damping factor, I think my speakers require high damping and current instead of watts?
Many thanks
Ian
I've been running my yj blue board for a month now, overall very pleased.
I've connected up my 8ohm transmission line speakers and they are lacking in low bass, mid bass is strong.
Is the stock blue board cutting the low frequencies?
What is the damping factor, I think my speakers require high damping and current instead of watts?
Many thanks
Ian
Outputfilter will have a dampening behavior below selected impedance and a peaking behavior above. (A Zobel on the speaker would create a near constant impedance, with constant impedance phase behavior of speaker also is better, some speaker designers say you always need to correct impedance, Mark Fenlon will say any part added need to be very high quality not to ruin most/some of his work on these speakerunits).
A 10 ohm filter can have some peaking noticable. Human ears I believe are most sensitive between 2-3khz???, with these units you could start there too, 12 ohm maybe. A standard 22uH/680nF filter should sound better then a standard 10uH/680nF filter (Alpair10). The 22uH filter will have limited peaking like TI suggests is allowable, till around 10 ohm, the 10uH filter limited peaking range stops at 6.5ohm, so excessive peaking in entire frequencyrange.
10 ohm 22uH 220nF outputfilter 51khz cutoff frequency will have limited peaking till ~18 ohm
12 ohm 22uH 150nF outputfilter 61khz cutoff frequency will have limited peaking till around 21 ohm
10 ohm 33uH 330nF, 34khz
12 ohm 33uH 220nF, 41khz
bigger value inductors have little less THD.
You put in calculator half the impedance and double the capacity.
A 10 ohm filter can have some peaking noticable. Human ears I believe are most sensitive between 2-3khz???, with these units you could start there too, 12 ohm maybe. A standard 22uH/680nF filter should sound better then a standard 10uH/680nF filter (Alpair10). The 22uH filter will have limited peaking like TI suggests is allowable, till around 10 ohm, the 10uH filter limited peaking range stops at 6.5ohm, so excessive peaking in entire frequencyrange.
10 ohm 22uH 220nF outputfilter 51khz cutoff frequency will have limited peaking till ~18 ohm
12 ohm 22uH 150nF outputfilter 61khz cutoff frequency will have limited peaking till around 21 ohm
10 ohm 33uH 330nF, 34khz
12 ohm 33uH 220nF, 41khz
bigger value inductors have little less THD.
You put in calculator half the impedance and double the capacity.
Thanks for the reply Irribeo, especially that this has been askled numerous times already.
So if I understand you correctly.
From the options you have presented, the best to go for is:
- 22uH and 220nf
Is that right?
So if I understand you correctly.
From the options you have presented, the best to go for is:
- 22uH and 220nf
Is that right?
Don't know about best. Better then 10uH filter and same time, not totally different, no areas where filter obviously has dampened behaviour (where impulses are limited). Maybe you have inductors in mind you want and they are only available in 29uH etc etc etc
Today I did some mods to the YJ red board.. I removed the volume control and soldered on new smd input caps very close to the chip(2-4mm). When listening to the amp I quickly noticed that the ringing/harsness were totally gone! I did the same mod to the yj black board yesterday with the same results. If anyone has the same experience with their board please share it!
What did you exactly do with the black board, what caps, values? Pic. by chance? Thx!
Jadran, I used 50V 1uF X7R smd(surface mounted) on the inputs. It takes some soldering skills to make it work so be warned. Theres a diy cooling fin above the smds now so I can't photograph it unfortunately. I just traced the existing input paths to figure out where to put the 4 caps even closer to the chip. I scraped of the cobber to make 4 open loops and soldered the caps over the cut traces. I have put on bootstrap caps too but that didn't help nearly as much as the input placement change did!
I use my 3116 with MA 10.3 drivers as well (love those MA drivers). Current filter is 15uf/680nf - don't find any harshness or peaking I can detect.
The 15uf were what I had to hand (from an old 41hz T-amp that blew up on me) and I just left the existing caps in place. May change the caps to a lower value tho.
irribeo, I think you have already provided a link to a calculator but I had trouble making it work.
Hi irribeo,
Using this calculator Butterworth Pi LC Low Pass Filter Calculator for 16khz and 12ohm I get values of 44uh and 307nf. I know because this is BTL you 1/2 the inductance so 22uh. However from this site Understanding output filters for Class-D amplifiers | EE Times I read "Because the capacitance across the load is now the series combination of the two capacitors for BTL outputs, each capacitor needs to be twice the value calculated for the low-pass filter so that the total capacitance will be correct." This results in 600nf rather than the 150nf you stated. What am I doing wrong?
Using this calculator Butterworth Pi LC Low Pass Filter Calculator for 16khz and 12ohm I get values of 44uh and 307nf. I know because this is BTL you 1/2 the inductance so 22uh. However from this site Understanding output filters for Class-D amplifiers | EE Times I read "Because the capacitance across the load is now the series combination of the two capacitors for BTL outputs, each capacitor needs to be twice the value calculated for the low-pass filter so that the total capacitance will be correct." This results in 600nf rather than the 150nf you stated. What am I doing wrong?
does it make a difference that the two caps are not directly in series, but there is (at least) a speaker (and the associated R/L/C) separating them?
different for inductors because they sum in series regardless of interposing R/L/C ?
No, I don't know, just something I gathered from another discussion years ago.
different for inductors because they sum in series regardless of interposing R/L/C ?
No, I don't know, just something I gathered from another discussion years ago.
Now I read at another site "At the cost of additional components, a balanced 2-pole filter (the recommended approach) is effective in reducing EMI emissions. Each inductor value is half that of Figure 3. " Fig 3 was single sided this comment relates to BTL. Which is correct?
Just thinking, caps in series the values are additive so logically you need to 1/2 each caps value to get to the original value.
So, now I have answered my own question (I think!), to use the 15uh coils I have, at 12ohm I get a 100nf cap but this is at 88khz. Is that too high to be effective? Or 75khz if I assume 10ohm.
Just thinking, caps in series the values are additive so logically you need to 1/2 each caps value to get to the original value.
So, now I have answered my own question (I think!), to use the 15uh coils I have, at 12ohm I get a 100nf cap but this is at 88khz. Is that too high to be effective? Or 75khz if I assume 10ohm.
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The speaker doesn't separate them, both caps go to earth so effectively in series.
Nah, I have it the wrong way round, the value is halved in series, sorry I am getting myself very confused here.
hi,
just curious, I have a visaton gf200, it's a dual 4ohm voice coil speaker.
from the manufacturer specs. D.C. resistant is 2.9ohm each. parallel is 1.4ohm.
tpa3116 datasheet suggests minimum load is 1.6ohm.
my questions, is it safe to connect this speaker 1.4ohm to tpa3116 PBTL at <20v?
not sure it will have any advantage using 2 x tpa3116 PBTL connect to each voice coil.
just curious, I have a visaton gf200, it's a dual 4ohm voice coil speaker.
from the manufacturer specs. D.C. resistant is 2.9ohm each. parallel is 1.4ohm.
tpa3116 datasheet suggests minimum load is 1.6ohm.
my questions, is it safe to connect this speaker 1.4ohm to tpa3116 PBTL at <20v?
not sure it will have any advantage using 2 x tpa3116 PBTL connect to each voice coil.
You are correct, I halfed the capacitor values and I should not have for BTL BD modulation type filter, only to get to (single)capacitor value in BTL AD modulation type filter (like the STA508 filter I was trying to make equal to tpa3116 filter).
So for tpa3116 filter capacitor values I mentioned should be doubled: like 10 ohm filter 440nF 22uH fc 51khz limited peaking till 18 ohm
12 ohm filter 440nF 33uH fc 41khz limited peaking till 21-22 ohm
Also for earlier posts regarding cogitechs double alp10's capacitorvalue need to be doubled too.
You don't need to half inductorvalue for single ended calculator, don't need to change capacitor value (for BD we have here) just need to half impedance for single ended calculator.
Good you saw that!!!!
I found the simple reason for the non working LL1540 input transformer: it is dead 😡 .
As I wanted to try one channel first, i thought I've made a mistake, but after installing the second one it worked flawlessly. I listened to mono yesterday and I like very much what I am hearing, although it is not the full picture.
I used my second board for this, which is almost stock except 2 Panasonic FM near the chip, but stock coils.
But it sounds better than my other modified board with better coils, great clarity and detail over the whole musical spectrum. A tiny bit of harshness now in the treble, but this should be a question of changing coils and caps, as I have 8 ohm speakers with 10uH coils there should be some peaking in high frequency.
Definitely worth doing, if you have some transformers around...
As I wanted to try one channel first, i thought I've made a mistake, but after installing the second one it worked flawlessly. I listened to mono yesterday and I like very much what I am hearing, although it is not the full picture.
I used my second board for this, which is almost stock except 2 Panasonic FM near the chip, but stock coils.
But it sounds better than my other modified board with better coils, great clarity and detail over the whole musical spectrum. A tiny bit of harshness now in the treble, but this should be a question of changing coils and caps, as I have 8 ohm speakers with 10uH coils there should be some peaking in high frequency.
Definitely worth doing, if you have some transformers around...