You need to see the graphs of Denon PMA-800NE. I do not trust the THD graph of the Polish site.
[Polish] Denon PMA-800NE - Wzmacniacze stereo | Testy w Audio.com.pl
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With some mods/tweaks and... we have a good base to work with. For example, add a RF/EMI filter. Schaffner 9244B
How to clean the DC at mains. And ripple too.
An externally hosted image should be here but it was not working when we last tested it.
or discrete with much more attenuation.
EMI/RFI/Common Mode Filter – assembled and tested PCB | ATL Audio Ltd.
https://www.audiocircle.com/index.php?topic=153802.msg1751490#msg1751490
An externally hosted image should be here but it was not working when we last tested it.
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You know none of those harmonics are audible to anyone? Well noone whose ever had their hearing measured 🙂 Perhaps you are special? Find out with a double-blind listening test.
If > 90 dB this harmonic profile is audible. At 60 dB without any doubt, and much more with complex recordings -> so much harmonics clouded the sound.
At 80 or 90 dB it will depend on each person and their system. And recording quality, very important. If you listen to modern commercial music, so badly recorded, you do no need to spend a lot of money in the audio system, and it will not matter if they are at 60 dB or more than 90 dB.
That is the great current problem, the lousy use of the best current technology, with the creation of very low quality musical products. I do not talk about musical tastes but about the recordings quality.
At 80 or 90 dB it will depend on each person and their system. And recording quality, very important. If you listen to modern commercial music, so badly recorded, you do no need to spend a lot of money in the audio system, and it will not matter if they are at 60 dB or more than 90 dB.
That is the great current problem, the lousy use of the best current technology, with the creation of very low quality musical products. I do not talk about musical tastes but about the recordings quality.
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I am in the process of building this kit and am to the point where I test the transformer and Power Supply. It is supposed to read 72ish volts from the PS PCB, but I am getting 164ish. Any ideas on what I might have done wrong?
I built this kit and checked all along the way and had no issues. Stop now and get in touch with Dan at Akitika, he will give you great customer service and troubleshoot your issues with you...do not continue until you have this issue resolved.
I did, and he is great responding past 9pm. Turns out...my batteries were dying in my MM and giving crazy readings. New Duracells- all is good now- back to final assembly.
I am 8 hours into break in, and the GT-102 is definitely a great bang for the buck. Excellent instructions, and Dan is awesome! However, actually bought this to drive the bass woofer on some bi-amped 3 way bookshelves. Maybe it will kick in but right now- the bass is less in quantity and clarity compared to my VTA70 (which almost half the wattage...3x the price). I bought this for tighter and more authoritative bass than my tubes. Anyone have any thoughts on it getting better over time, or mods? Thanks in advance!
My two cents.
With only one chipamp LM3886 by channel, better loudspeakers with minimum impedance is near to 8 Ohms than 4 Ohms if you want bass.
If you add a subwoofer(s) then it is not a problem with 4 Ohms. If sub with electronics as Direct Servo, better idea.
But first you can use a good soft PEQ to add low frequencies. To spend you will always be on time.
With only one chipamp LM3886 by channel, better loudspeakers with minimum impedance is near to 8 Ohms than 4 Ohms if you want bass.
If you add a subwoofer(s) then it is not a problem with 4 Ohms. If sub with electronics as Direct Servo, better idea.
But first you can use a good soft PEQ to add low frequencies. To spend you will always be on time.
I built the GT-102, along with Elekit Tu-8200 and 8340. I'm using full range drivers. I find the GT-102 to have really tight, punchy bass (I like it) and the tube amps seem to have a deeper sounding bass (I like it). I drive the GT-102 with the PR-102 pre-amp and when I want more bass I just kick on the tone controls.
Curiosity finally got the best of me and I built one to give as a gift. The build was a lot of fun; the instructions are top notch.
I was really happy with the final product. It sounded great and I ended up, like one review I read, going through a ton of songs listening to it because I just didn't want to stop.
Now that it is gone I really miss it and I haven't switched back to any of my prior amps I used in that room because they just aren't as good as it was. I would put the DIY M2 above it for sound and my DIY SE tube amp (both well over twice the price) but beyond that the handful of chipamps and other small amps I've tried weren't close.
I will likely end up building another sometime.
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I'm no good at short term A/B testing. I have to listen to each for awhile and the one I prefer will show itself by my listening to it more often. So, someone send me a Luxman so I can compare 🙂
I was taking a look. Indeed, single supply and a tricky regulator (72V).
Edit: notice how they used a small capacitor after the bridge (C7), and how the raw voltage is much larger than the regulated voltage, at idle (it will sag quite a bit under load). This works well, I've tried it. Smaller transformers sound better to me and this sort of regulator is well suited, with the large cap (C6) as close to the output stage as possible.
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Active bridges are useful for reducing diode dissipation (and reducing dropout voltage) in Class A amps where current flows are high and continuous. For Class AB amps where quiescent current flows are rather low, the added benefit of lower thermal dissipation is not as important given the added complexity and cost of active bridges.