#151
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I first measured the voltage gain and then built a couple of in-line attenuators to pad the class D amplifiers by the required 4.5dB. A secondary issue can be the reactive load that results at the crossover frequency from uncoupling the bass from the mid-treble section of the crossover. To avoid my class AB amplifier seeing a very capacitive load I went to the trouble of designing and installing a conjugate matching network which connects in parallel with the load, so it has zero effect on the signal other than creating a more resistive load for the amplifier. Adding this network had a far greater effect (subjectively) than I was expecting. Obviously for the better. See results below. The matching network keeps the phase angle within +/- 30 degrees. Last edited by Art Vandelay; 11-19-2019 at 03:52 AM. |
#152
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So if one uses the 8Ω output taps, how much current can the amp then deliver at say 3Ω (a B&W's minimum impedance) ? McIntosh does not specify. In addition, using output transformers leads to a relatively low damping factor; hence the amp can not truly control the speakers. There are amps which can deliver the current required by the speakers regardless of the actual load impedance. Example: Accuphase A-250 nominal Class A 100W@8Ω / 200W@4Ω / 400W@2Ω / 800W@1Ω And their damping factor is >1000 @8Ω (i.e. their output impedance < 8mΩ !) |
#153
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Fwiw, Stereophile's review of the new 462 reveals very impressive performance overall. https://www.stereophile.com/content/...r-measurements |
#154
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#155
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Unless they have 16 KT88s.
__________________
Main Equipment: Kharma Elegance dB11-S, JL Audio F113v2 X 2, Block Audio Line & Mono SE Amplification, Bricasti M21 DAC, Antipodes Kala K-50 Server, Clearaudio Performance SE. Satisfy tonearm & Maestro Wood MM cartridge. Power: Shunyata Everest 8000, Sigma XC v2, Sigma NR v2, Block Audio PCs, Defender, ADDPowr Wizard Grounding: Shunyata Altaira CGS - 4 X Alpha CGS cables, Network : Supra Cat 8+, Twin (Nenon) Modified Buffalo GS2016 Switches, Keces P3 LPSU, Cables: Wireworld Platinum 8 USB, Wireworld Platinum Eclipse 8 Speaker cables, 6M & 1M Tubulus Concentus ICs, Other:Two PSI Audio AVAA C20, Multiple GIK products, Stillpoint Apertures, Stillpoint Minis and Ultra SS, Three 20 Amp lines, Furutech GTX - Gold outlets, Adona Rack |
#156
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Dang I had to look than one up
Im not an engineer!!! Plus, Ive never used tubes except when my stepdad plays with his antique radios of which he has literally hundreds. His particularly proud of his Awater Kents. Last edited by Wised; 11-19-2019 at 12:15 PM. |
#157
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I must admit that a pair of Accuphase A-250 Class A monoblocks cost substatially more than an MC462. However I do consider them as one of the very best matches for my B&W 800 D3. Stereophile (see link from Art Vandelay) measured the heatsink temperature of the MC462 after one-third power for 30 minutes into 8 ohms at 158.6°F (70.3°C). So MCs never get hot? Last edited by meltemi; 11-19-2019 at 07:57 PM. Reason: spelling |
#158
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Im glad accuphase is one of the few manufacturers that state distortion at different impedances the majority dont.. Last edited by Wised; 11-19-2019 at 04:15 PM. |
#159
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For me that is the best choise.
Last edited by Masterlu; 11-20-2019 at 07:46 PM. Reason: Enlarge photo |
#160
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Awesome set up! Any issues blending in the DB1D?
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