Does it matter if I use the IRFP 240 vs. the 140? My kit came with the 240 and it appears they are interchangeable. I plan on replacing the power brick with a higher voltage linear supply at a later date and going to a larger chassis as necessary. The DIY store does reflect the following difference but I am not sure that I understand how this difference impacts the build.
The 140 has a lower voltage (100v) vs the 240, but this is offset by the higher transconductance and higher current rating. As long as the supplies are less than +/-50V or 100V single-ended, I think it’s a slightly superior part.
The 140 has a lower voltage (100v) vs the 240, but this is offset by the higher transconductance and higher current rating. As long as the supplies are less than +/-50V or 100V single-ended, I think it’s a slightly superior part.
If you use your ACA in the "Bridged Mono" mode as it is called on the back panel of ACA 1.8, there is an error in the design that has been discovered. It is documented in posts 12084, 12085 and 12087 of the original ACA thread: https://www.diyaudio.com/community/threads/amp-camp-amp-aca.215392/
Fixing this flaw requires just changing one resistor on the back panel and will give you a couple more Watts output. It doesn't affect Stereo, Parallel or Balanced Modes.
If you dislike the Odd order distortion in the Bridged Mono mode, I have a mod that will make your ACA sound more like it does in the Stereo Mode, only louder.
Fixing this flaw requires just changing one resistor on the back panel and will give you a couple more Watts output. It doesn't affect Stereo, Parallel or Balanced Modes.
If you dislike the Odd order distortion in the Bridged Mono mode, I have a mod that will make your ACA sound more like it does in the Stereo Mode, only louder.
I found that with the mods that I liked the single stereo amp more than either of the bridged modes. There was more transparency than the parallel mode and I did like the tonal balance better than the bridged. So I am running a single amp from dual 36v supplies with FQH44n10's. Very interested to hear you mod for the bridged mode to see if some of what I like in the stereo amp can be preserved while increasing the headroom.