I'm relatively new to the Class A world.
In the Aleph 4 with 12 x IRFP244's per channel. What is the power dissipated by each device. Common sense would say that at Vcc = 48V and Iq = 400mA, the Quiescent dissipation will be 19.2 Watts. What will the dissipation be at Full Power ?
Looking at several DIY builds and the genuine article, I have clearly missed something as they all have enormous heatsinks and still run fairly hot.
In the Aleph 4 with 12 x IRFP244's per channel. What is the power dissipated by each device. Common sense would say that at Vcc = 48V and Iq = 400mA, the Quiescent dissipation will be 19.2 Watts. What will the dissipation be at Full Power ?
Looking at several DIY builds and the genuine article, I have clearly missed something as they all have enormous heatsinks and still run fairly hot.
I've opted for the Aleph 4 as I intend to use single ended RCA inputs. The threads indicate that the Aleph X is tricky to stabilize unless a balanced input is used ??
I keep on harbouring on about heatsinks because my ML333 clone cooked over £60 of transistors. In this case it was partly my fault, the thermal contact between the transistors and the ally back plate was through SilPads (never again) and the back plate didn't have thermal grease between itself and the heatsinks. After correcting the heat issues and repairing the blown components I still had to reduce the bias from 1.25A to 1.0A. It now runs at a happy 55 - 60C depending on the British weather.
The question is, is my ML clone running in Class A ? With Vcc at +/-65V and Iq at 1.0A its probabaly in Class A at most normal listening levels. It certainly sounds exceptional against my Arcam AVR280 using an Arcam CD36 front end, Chord Chorus interconnects and a Tantalum Resistor Stepped Attenuator. I'm starting to question the speakers though. I'm using B&W 602s3's with QED QUDOS silver cables.
I keep on harbouring on about heatsinks because my ML333 clone cooked over £60 of transistors. In this case it was partly my fault, the thermal contact between the transistors and the ally back plate was through SilPads (never again) and the back plate didn't have thermal grease between itself and the heatsinks. After correcting the heat issues and repairing the blown components I still had to reduce the bias from 1.25A to 1.0A. It now runs at a happy 55 - 60C depending on the British weather.
The question is, is my ML clone running in Class A ? With Vcc at +/-65V and Iq at 1.0A its probabaly in Class A at most normal listening levels. It certainly sounds exceptional against my Arcam AVR280 using an Arcam CD36 front end, Chord Chorus interconnects and a Tantalum Resistor Stepped Attenuator. I'm starting to question the speakers though. I'm using B&W 602s3's with QED QUDOS silver cables.
I've just missed the EDIT time limit. I was using the Arcam AVR280 in Bi-Amped Mode, the ML is used in Bi-Wired Mode. The ML clone still sounds outstanding against the Arcam. The Arcam was re-capped by CPA-Acoustics at a cost of nearly £500, so it is much better than a factory standard version.
BINGO - Managed to buy 7 off RS type 0.45K/W heatsinks for £40 off e-bay.
The intention is to build a cube with the 8th heatsink being replaced by a connector panel. The whole thing will be about 400mm x 400mm x 180mm(H).
I'm trying to find threads regarding the choice of capaitors to use in an Aleph 4 build.
The intention is to build a cube with the 8th heatsink being replaced by a connector panel. The whole thing will be about 400mm x 400mm x 180mm(H).
I'm trying to find threads regarding the choice of capaitors to use in an Aleph 4 build.
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