KEF Q100, graphs measurements by kimmosto
http://www.diyaudio.com/forums/multi-way/320222-coaxial-drivers-ultimate-speaker-post5381270.html
KEF LS50, graphs measurements by kimmosto
http://www.diyaudio.com/forums/multi-way/320222-coaxial-drivers-ultimate-speaker-post5381146.html
KEF Q100 with only first order crossover. It is more lineal... always.
http://www.diyaudio.com/forums/multi-way/320222-coaxial-drivers-ultimate-speaker-post5381270.html
An externally hosted image should be here but it was not working when we last tested it.
KEF LS50, graphs measurements by kimmosto
http://www.diyaudio.com/forums/multi-way/320222-coaxial-drivers-ultimate-speaker-post5381146.html
An externally hosted image should be here but it was not working when we last tested it.
KEF Q100 with only first order crossover. It is more lineal... always.
KX Amplifier is Born
Hello Bonsai!! Your timing is impeccable, I’m so glad you started this thread for the KX amp. My build is almost completed, the Walnut wood top and front panel need to be fabricated along with placement of switches. In the meantime this newborn is singing away!! Here are a few details: Pair of Antek AS-3224 transformers w/covers Pair of Ripple Eater psu’s This combination gives me final voltages of -28.5vdc/+28.1vdc loaded. The dc offset varies from -5mV to +5mV when the KX is at operational temperature.
The reclaimed heat sinks are large enough to mount both the psu and amp board without a problem keeping the heat dissipation under control even when running at the high side of 28vdc. I do not have experience with your other amplifiers (SX/NX) so unfortunately I can’t compare to them. In my short listening time, the soundstage is very impressive. Music seems to flow from well outside the speaker “box”. The bass is very solid and articulate. Definitely not an amp that should be cranked up in an upstairs apartment, the downstairs tenants might think a thunderstorm is approaching
On my test bench, the speakers are low efficiency 4ohm bookshelf type. I couldn’t hear any hum/noises. Now, I have the KX in my main rig paired with very efficient 8ohm floorstanders and there is a slight hum that’s audible. I’ll have to get that worked out. Thank you Bonsai for sharing a wonderful amplifier project, I’m really going to enjoy this one.
And.... WELCOME BACK!!
Vunce
I can build the amp but can’t flip the pictures, I apologize.
Hello Bonsai!! Your timing is impeccable, I’m so glad you started this thread for the KX amp. My build is almost completed, the Walnut wood top and front panel need to be fabricated along with placement of switches. In the meantime this newborn is singing away!! Here are a few details: Pair of Antek AS-3224 transformers w/covers Pair of Ripple Eater psu’s This combination gives me final voltages of -28.5vdc/+28.1vdc loaded. The dc offset varies from -5mV to +5mV when the KX is at operational temperature.
The reclaimed heat sinks are large enough to mount both the psu and amp board without a problem keeping the heat dissipation under control even when running at the high side of 28vdc. I do not have experience with your other amplifiers (SX/NX) so unfortunately I can’t compare to them. In my short listening time, the soundstage is very impressive. Music seems to flow from well outside the speaker “box”. The bass is very solid and articulate. Definitely not an amp that should be cranked up in an upstairs apartment, the downstairs tenants might think a thunderstorm is approaching
On my test bench, the speakers are low efficiency 4ohm bookshelf type. I couldn’t hear any hum/noises. Now, I have the KX in my main rig paired with very efficient 8ohm floorstanders and there is a slight hum that’s audible. I’ll have to get that worked out. Thank you Bonsai for sharing a wonderful amplifier project, I’m really going to enjoy this one.
And.... WELCOME BACK!!
VunceI can build the amp but can’t flip the pictures, I apologize.
Attachments
I saved the article: http://www.medleysmusings.com/kef-q100-drive-unit-testing/ now the site is out.
KEF-Q100-drive-measurements-by-medleymusings.zip, 740 KB:
http://maty.galeon.com/WP-imagenes/kef-q100/KEF-Q100-drive-measurements-by-medleymusings.zip
KEF-Q100-drive-measurements-by-medleymusings.zip, 740 KB:
http://maty.galeon.com/WP-imagenes/kef-q100/KEF-Q100-drive-measurements-by-medleymusings.zip
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Ripple Eater PSU / Capacitance multiplier.
Simple Ripple Eater PSU for the sx and kx-Amplifiers
http://hifisonix.com/simple-ripple-eater-psu-for-the-sx-and-kx-amplifiers/
For me it is very important to clean the noise because I suffer from a terrible electrical grid at home. I was struck by the Capacitance multiplier / Ripple Eater PSU. Together with my gadgets it can be the definitive solution to my problems, I think/hope.
Each time I managed to lower the noise, the soundstage increased, the details and music filled the room more.
Simple Ripple Eater PSU for the sx and kx-Amplifiers
http://hifisonix.com/simple-ripple-eater-psu-for-the-sx-and-kx-amplifiers/
Harmonics
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.
For me it is very important to clean the noise because I suffer from a terrible electrical grid at home. I was struck by the Capacitance multiplier / Ripple Eater PSU. Together with my gadgets it can be the definitive solution to my problems, I think/hope.
Each time I managed to lower the noise, the soundstage increased, the details and music filled the room more.
You set Distance to 3 meters (10 Feet).
Inside a domestic room, the Critical Distance is more like 3 or 4 feet, ~~1 Meter. Closer, SPL rises; further, and SPL hardly drops, due to reverberant field "filling" the room.
The direct sound at 3 meters will indeed be 88.2dB SPL, but the *total* sound at your ears will be 6 or 8 dB higher, ~~95dB SPL.
All good points - perhaps something to consider for a future spin of the board. That said, I've not had any problems on the 10 or so kx and sx board sets I've personally built, or had any reports of problems on any of the other builds. Re the 'OMG' diodes, I've popped the supply fuses on the sx-Amp quite a few times during development without issue (the OP devices are hugely overrated on the recommended supply rails). I guess however the case would be different if one of the OPS transistors were to fail.
Overshoot - ok - we can split hairs over it but not an issue in use and remedied with a change in resistor and/or cap if someone believes its objectionable. In practice its a non-issue.
Have you looked at some of the square wave plots on Stereophile (tube and solid state)?
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Hello Bonsai!! Your timing is impeccable, I’m so glad you started this thread for the KX amp. My build is almost completed, the Walnut wood top and front panel need to be fabricated along with placement of switches. In the meantime this newborn is singing away!! Here are a few details: Pair of Antek AS-3224 transformers w/covers Pair of Ripple Eater psu’s This combination gives me final voltages of -28.5vdc/+28.1vdc loaded. The dc offset varies from -5mV to +5mV when the KX is at operational temperature.
The reclaimed heat sinks are large enough to mount both the psu and amp board without a problem keeping the heat dissipation under control even when running at the high side of 28vdc. I do not have experience with your other amplifiers (SX/NX) so unfortunately I can’t compare to them. In my short listening time, the soundstage is very impressive. Music seems to flow from well outside the speaker “box”. The bass is very solid and articulate. Definitely not an amp that should be cranked up in an upstairs apartment, the downstairs tenants might think a thunderstorm is approaching
On my test bench, the speakers are low efficiency 4ohm bookshelf type. I couldn’t hear any hum/noises. Now, I have the KX in my main rig paired with very efficient 8ohm floorstanders and there is a slight hum that’s audible. I’ll have to get that worked out. Thank you Bonsai for sharing a wonderful amplifier project, I’m really going to enjoy this one.
And.... WELCOME BACK!!
I can build the amp but can’t flip the pictures, I apologize.
Wow - quite a build Vunce!
Trust it goes well and you'll have it up and running shortly. Once you have finally wired it up f you still have noise issues we can sort it out. Remember to twist the power cables from the transformer to the PSU board, and from the PSU to the amplifier boards. Same for speaker terminals to amplifier boards. Keep input cables well away from power supplies and associate wiring.
Schaffner FN 9244B IEC inlet filter
Vunce, I can see a RF/EMI IEC inlet filter in your DIY. Which?
Years ago I was researching about it and those who had better specifications were those manufactured by Schaffner, and by far. I have a few in my two systems.
Schaffner FN 9244B 3A
https://www.schaffner.com/product-storage/datasheets/fn-9244/
* B = medical
Vunce, I can see a RF/EMI IEC inlet filter in your DIY. Which?
Years ago I was researching about it and those who had better specifications were those manufactured by Schaffner, and by far. I have a few in my two systems.
Schaffner FN 9244B 3A
https://www.schaffner.com/product-storage/datasheets/fn-9244/
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.
* B = medical
Usually I listen them in near field, in phase, with music from my computer. But other times, when some songs produce an adrenaline rush, I need to get up and go around the room, directing the orchestra.
An example of a r: https://www.audiocircle.com/index.php?topic=153802.msg1672876#msg1672876
To compare speakers I think it is better to do the calculations at a 3 m of distance and random phase.
About 65 dB continous. Tracks with DR15 -> 80 dB.
For security, I prefer make the calculations with 80 dB continous -> I want/need amp+speaker at 3 m: 95 dB
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Thank you fellas for the kind words. The KX sounds fantastic. But, I’m again battling with noise issues coming from the LED recessed lighting in my
house
It seems that some of my builds are more “tolerant” and some are not to this issue, but not this one. As long as I’m in total darkness everything sounds great, as soon as the lights are turned on a horrible BUZZZZ can be heard 10 feet away from the speakers!!
I understand this really is no fault of the KX-amp and has to be dealt with before any critical listening. It’s very frustrating.
house
It seems that some of my builds are more “tolerant” and some are not to this issue, but not this one. As long as I’m in total darkness everything sounds great, as soon as the lights are turned on a horrible BUZZZZ can be heard 10 feet away from the speakers!!
I understand this really is no fault of the KX-amp and has to be dealt with before any critical listening. It’s very frustrating.
New lights (LED) have a SMPS transformer. More of them are cheap and noisy and they fail to comply with the strict European regulations in this regard but they continue to be imported.
Before were the small appliances (radio alarm), then the chargers of the phones and now the new lights -> the electricity grid is getting dirtier.
To this we must add both electric motor that violates the regulations.
Try to change the RF/EMI filter or to make a cable with one and connected to the amp. Better with a Schuter connector.
Note: I am sorry by the new off-topic, Andrew, but I hope you are understanding.
![URL]](/community/proxy.php?image=http%3A%2F%2F%5BURL%5Dhttp%3A%2F%2Fmaty.galeon.com%2FWP-imagenes%2Fhard%2Fcables-Schaffner-filter-Wurth-ferrite-150Khz-IEC-C13-Schurter-from-ATL.jpg%5B%2FURL%5D&hash=2f3dc7bc420181ea6d74a1bf65037239)
Before were the small appliances (radio alarm), then the chargers of the phones and now the new lights -> the electricity grid is getting dirtier.
To this we must add both electric motor that violates the regulations.
Try to change the RF/EMI filter or to make a cable with one and connected to the amp. Better with a Schuter connector.
Note: I am sorry by the new off-topic, Andrew, but I hope you are understanding.
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@maty tinman - kindly learn how to attach the image files properly!
