@Bruno. Best wishes from a very happy customer (UcD180ADs). I progressed from tubes to class D via a little Sonic Impact...........ah the clarity.
Your latest efforts have me intrigued. I like the way you take the time to answer questions in a no-nonsense manner. UcD is good engineering.
Your latest efforts have me intrigued. I like the way you take the time to answer questions in a no-nonsense manner. UcD is good engineering.
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Hello,
You spent some recreative days hopefully.
80mW mean 79dB SPL in a 90 dB SPL/1W speaker, quite well to be heard, when switched on or off. As it is at my UcD180-amp without using the on/off control pin and at the PSC2.400, which uses the control as I believe. I can tolerate that short click although it could be less noticeable.
The 12" Woofers in the PSC driven monitors show at least 1mm (outward) offset after switching on. This is much worse because this shifts the operating point significantly, causing unnecessary Bl(x), Kms(x) and L(x) distortions just around the operating point in the "small signal" range.
50mV (not specified for UcD400 OEM) should show at the B&C 12NDL76, 4.5 Ohms, 18N/A, 3N/mm (Klippel data) negligible 0.01mm offset. It seems to be significantly more. I did not measure the offset voltage though.
Cheers, Timo
Thank you, that you aren't. 😉
You spent some recreative days hopefully.
80mW mean 79dB SPL in a 90 dB SPL/1W speaker, quite well to be heard, when switched on or off. As it is at my UcD180-amp without using the on/off control pin and at the PSC2.400, which uses the control as I believe. I can tolerate that short click although it could be less noticeable.
The 12" Woofers in the PSC driven monitors show at least 1mm (outward) offset after switching on. This is much worse because this shifts the operating point significantly, causing unnecessary Bl(x), Kms(x) and L(x) distortions just around the operating point in the "small signal" range.
50mV (not specified for UcD400 OEM) should show at the B&C 12NDL76, 4.5 Ohms, 18N/A, 3N/mm (Klippel data) negligible 0.01mm offset. It seems to be significantly more. I did not measure the offset voltage though.
Cheers, Timo
No, it isnt. When talking about power the math is like this:
Decibel - Wikipedia, the free encyclopedia
Decibel - Wikipedia, the free encyclopedia
Of course, I was wrong, thanks.
The clicks are well audible however, in particular because of the HF content.
The Klippel measurements for the interested
The clicks are well audible however, in particular because of the HF content.
The Klippel measurements for the interested
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In any case, it's DC, so the result is not SPL but a tiny amount of woofer cone excursion.
Is there any drawbacks attaching the amp module direct to the woofer magnet? (Magnetic stray field intermodulation, fatiguing failures etc?)
If no, you may afford the very length of 5 cm Audioquest Everest 😉
If no, you may afford the very length of 5 cm Audioquest Everest 😉
@tiki could you measure the DC offset on the PSC and let me know?
@wilbur-x I wouldn't do that. The inductor could get biased. According to an industrial customer of ours the've actually had failures caused by the amp module being to close to the magnet. The amp module at the time wasn't ours but I see no overriding reason why ours shouldn't suffer as well.
@wilbur-x I wouldn't do that. The inductor could get biased. According to an industrial customer of ours the've actually had failures caused by the amp module being to close to the magnet. The amp module at the time wasn't ours but I see no overriding reason why ours shouldn't suffer as well.
Hello Bruno,
of course, I'll do that when my son will be back in his rehearsal room.
Thanks!
Cheers, Timo
of course, I'll do that when my son will be back in his rehearsal room.
Thanks!
Cheers, Timo
some people go to lengths to minimize vibrations and my guess is that at a woofer's magnet those aren't quite negligible...
Currently I'm using a 15 dB L-pad at the input of the Ncore module. Is it possible to lower the gain in the same way as with the UcD modules ? If so - how?
Not much has changed since http://www.hypex.nl/docs/appnotes/gain_appnote.pdf
Gain is 4.17*(1+2*Rf/Rg). Rg=1.2k, Rf=2.2k. Rg, as noted in the bugs section of the data sheet is not marked (will be in the future), but it's called R141 and it's the one furthest to the left of the input connector. The maximum gain reduction you can get is 13.4dB, which is when you remove R141 altogether.
Assuming of course that there is enough gain to adequately drive one's speakers is there any advantage to higher or lower gain for the ncore modules? For example, would anything sonically be sacrificed by lowering the gain to get a more fine grained volume control?
The amp certainly isn't going to get worse if you decrease gain (other than SNR it's not going to get better either).
SNR is largely determined by the source I would guess.... thats one of the reasons I use that L-pad.
Ok, then I will remove R141 and end up with 25.8 - 13.4 = 12.4 dB gain. Nice.
Ok, then I will remove R141 and end up with 25.8 - 13.4 = 12.4 dB gain. Nice.
Ok, R141 removed with success, although SMD is difficult for us who have a solder iron the size of a sledgehammer.... how about let R141 be a regular through-hole resistor to make a bit more user-friendly?
I've got 2 reasons not to.
1) Have you ever removed a leaded resistor from a 4-layer board? Are you sure it's easier than SMD?
2) It wreaks havoc with the magnetic sensitivity (or lack of it). Because of the fairly enormous currents running close by the whole layout is done differentially with minimal loop area. A leaded resistor would introduce almost as much loop area as all the rest. The change in distortion would be clearly measurable.
It's not that hard anyway. I usually have a 3mm wide tip on my soldering iron unless I need to do a lot of smd. Put a dollop of solder on either end of the part you want to remove. Then either heat both ends at the same time by holding the tip along the part and touching both solder droplets at once or alternately heat the ends until the part comes off. It'll stick to the iron so wipe it off straight away so you can keep it. Then clean off the excess solder with wick (strong preference for the "chemtronics soder wick" brand, the rest is rubbish) and finally remove the flux with a tissue and acetone. It'll look like the part has never been there.
1) Have you ever removed a leaded resistor from a 4-layer board? Are you sure it's easier than SMD?
2) It wreaks havoc with the magnetic sensitivity (or lack of it). Because of the fairly enormous currents running close by the whole layout is done differentially with minimal loop area. A leaded resistor would introduce almost as much loop area as all the rest. The change in distortion would be clearly measurable.
It's not that hard anyway. I usually have a 3mm wide tip on my soldering iron unless I need to do a lot of smd. Put a dollop of solder on either end of the part you want to remove. Then either heat both ends at the same time by holding the tip along the part and touching both solder droplets at once or alternately heat the ends until the part comes off. It'll stick to the iron so wipe it off straight away so you can keep it. Then clean off the excess solder with wick (strong preference for the "chemtronics soder wick" brand, the rest is rubbish) and finally remove the flux with a tissue and acetone. It'll look like the part has never been there.
1) I have, its fairly easy using a solder pump. The solder points are usually bigger as well, easier to hit with a big solder iron and my somewhat shaky hands... but there is always a risk of damaging the PCB.
2) Whow... 🙂
Thanks for your tip on how to remove SMD parts. I'll try that next time!
2) Whow... 🙂
Thanks for your tip on how to remove SMD parts. I'll try that next time!
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