On some Pass schematich, the inrush thermistor, is connected in series with the hot line, and in other it's connected to safety earth. I don't know what's best in the F4. ?
I also think, its something to do, with the PSU, so i atteched a link, i will use.
LINK
Hope you don't mind cviller
Jesper.
I also think, its something to do, with the PSU, so i atteched a link, i will use.
LINK
Hope you don't mind cviller
Jesper.
I leave it to NP or someone who has built the F4 (anyone?) to comment.
But another thing worth mentioning is panel fuse holders: Be careful to solder the leads so it is NOT possible to get a shock when changing fuses. This means connecting the "hot" lead to the rear terminal of the fuse holder.
ALso, always use mains fuses. The large fuse box fuses are dimensioned after the house wiring, e.g. 15 A, and will probably not blow if the equipment fails. However, the equipment in the best case may be destroyed, in the worst case catch a fire and/or hurt/kill someone.
RK
But another thing worth mentioning is panel fuse holders: Be careful to solder the leads so it is NOT possible to get a shock when changing fuses. This means connecting the "hot" lead to the rear terminal of the fuse holder.
ALso, always use mains fuses. The large fuse box fuses are dimensioned after the house wiring, e.g. 15 A, and will probably not blow if the equipment fails. However, the equipment in the best case may be destroyed, in the worst case catch a fire and/or hurt/kill someone.
RK
When Pass has a thermistor to ground in most of his schematics; It is being used where a connection to ground is necessary, but the small resistance of the thermistor will break a potential ground loop.
The thermistor is not necessary... a straight ground is ok.
When it is in series with the primary it may be necessary - due to inrush..
This is how I understand it.
The F4 manual states that when in mono balanced operation one can attain 100w into 8 ohms , I assume no less as it isn't quoted..
If I were to attempt to run a 4 ohm load in balanced mono, could I lower the rails on each module to - say +-18v ....? I'd use irfp140/9. If so would I not still be near that same ~100w mark safely ? would I want to lower the source resistors to keep the bias current up?
Thanks!
If I were to attempt to run a 4 ohm load in balanced mono, could I lower the rails on each module to - say +-18v ....? I'd use irfp140/9. If so would I not still be near that same ~100w mark safely ? would I want to lower the source resistors to keep the bias current up?
Thanks!
mpmarino said:
thank you master
Oh, but if I may?......
Do you object to lowering the rails a couple volts, due to the fact that I have lower voltage trafos up the -ss? What would you consider the minimum before we have to start to make changes? I'd ask about the irfp140 but I already know the answer.
Thanks
Recent discussions on the Aleph-X builders thread involving Nelson Pass and others indicate that 1) a small amount of single ended bias can produce an audible improvement in a complementary follower output stage and 2) that this SE bias can be added passively.
In the F4, connecting a 100 ohm 20W-25W power resistor from the output node to V- would add approximately 5W of SE bias and would be cheap and easy to try.
Perhaps someone who has built an F4 could be talked into trying this and reporting back (Steen?)
Cheers,
Graeme
In the F4, connecting a 100 ohm 20W-25W power resistor from the output node to V- would add approximately 5W of SE bias and would be cheap and easy to try.
Perhaps someone who has built an F4 could be talked into trying this and reporting back (Steen?)
Cheers,
Graeme
