irf to n or not to n
I am ready to purchase some IrfP044 Mosfets for the Aleph-x (low power ver). It seems there is a choice btween No N and N type with what seems to me to be a trade off between less capacitance with the N type but more thermal resistance. My feeling is as long as the device is heatsinked proprely It would be more advantages to take less capacitance. Any thoughts ?
J
I am ready to purchase some IrfP044 Mosfets for the Aleph-x (low power ver). It seems there is a choice btween No N and N type with what seems to me to be a trade off between less capacitance with the N type but more thermal resistance. My feeling is as long as the device is heatsinked proprely It would be more advantages to take less capacitance. Any thoughts ?
J
Nixie,
The Aleph-X design already has compensation caps on the feedback that create a low pass filter a little above 20kHz. That and the balanced operation more or less make HF noise a non-issue for these amps. I live at the bottom of Seymour Mountain where RF intensity is very high, and my Aleph-X's have no problems whatsoever with it.
Also, the 044 version is preferred for ower powered version as they don't eat up as much of the rail voltage compared to the 240's or 244's. The 044's sound ever so slightly darker, but still ever so resolved.
Cheers, Terry
The Aleph-X design already has compensation caps on the feedback that create a low pass filter a little above 20kHz. That and the balanced operation more or less make HF noise a non-issue for these amps. I live at the bottom of Seymour Mountain where RF intensity is very high, and my Aleph-X's have no problems whatsoever with it.
Also, the 044 version is preferred for ower powered version as they don't eat up as much of the rail voltage compared to the 240's or 244's. The 044's sound ever so slightly darker, but still ever so resolved.
Cheers, Terry
metalman said:
Has anyone used IRF 144's? I used them in my Aleph30 with great success. Just wondering if anyone has experience using 144's with the HiFiZen boards from the GB a couple of years ago. How would the sound differ from the 044's or 240/244's for an under 40watt AlephX amp?
Thanks!
-David
As you go to the higher voltage parts the transconductance
decreases (higher voltage doping gives greater resistivity)
and you subjectively see more bottom, but somewhat at
the expense of the top end. This is reasonably subtle, but
is exacerbated by using IR input P channel devices. For this
reason, the Harris or Fairchild input P channel parts are even
more important.
decreases (higher voltage doping gives greater resistivity)
and you subjectively see more bottom, but somewhat at
the expense of the top end. This is reasonably subtle, but
is exacerbated by using IR input P channel devices. For this
reason, the Harris or Fairchild input P channel parts are even
more important.
I am wondering if anyone can help me. I have a problem with my aleph-x. Here is the schematic. I am using 4 devices total per side. 22.5vdc and about 2.5 amps per side. It seems to bias up where it should, and I have about 4.5v on r1 and r51. I can get dc down to a ok level and every thing seems to be ok. The problem is when I give it a signal, I can just barley hear sound out of a speaker. I thought the output protection might be on but the bipolars are off. Any ideas where to look next?