Very good article.
P.S: there is a small (not important) error on page 2, the terms Common Source and Common Gate are swapped. (last line, first colum)
P.S: there is a small (not important) error on page 2, the terms Common Source and Common Gate are swapped. (last line, first colum)
Very nice article , Thanks!.🙂
There is only a complaint: I can't see where P5 is😱I guess it is P4😀
There is only a complaint: I can't see where P5 is😱I guess it is P4😀
Very nice indeed, and new stuff to build too.
A nice mosfet test jig 😀
Thanks alot Nelson 😎
/Hugo - 50.000 views by now.
A nice mosfet test jig 😀
Thanks alot Nelson 😎
/Hugo - 50.000 views by now.
Practical Mosfet Testing for Audio
Wonderful piece, NP. I hope this one makes it into the Zen anthology.
Wonderful piece, NP. I hope this one makes it into the Zen anthology.
I really enjoyed the article! Thanks Nelson.
Was anyone else surprised by the amount of distortion being measured? Is this why all Pass gear seems to use some feedback?
Was anyone else surprised by the amount of distortion being measured? Is this why all Pass gear seems to use some feedback?
Some Pass products use feedback globally, some do
not - we deal with each on a case by case basis using
practical subjectivity as the primary basis for the decision.
If you think Mosfets have lots of distortion remember that
these were not particularly presented as low distortion
examples. If you want to see some awful looking tube or
bipolar curves, I can come up with some.
😎
not - we deal with each on a case by case basis using
practical subjectivity as the primary basis for the decision.
If you think Mosfets have lots of distortion remember that
these were not particularly presented as low distortion
examples. If you want to see some awful looking tube or
bipolar curves, I can come up with some.
😎
I understand what you are saying about mosfets compared to other devices. I was just surprised to see 10%+ distortion at a 5V amplitude. I was planning on building an amplifier where all the voltage gain was handled by an irf610, with no global NFB. It doesn't look like such a good idea now. 
how hot can you safely and sensibly run an irf610, assuming you have proper heatsinking? Also, isn't it a trade off with circuit gain, since you are lowering all the impedances? Thanks for the help.
I like to keep the chips below 75 deg C. Actually I like to keep
them a lot lower.
As to how you set this up, that's really dependent on the
design. When looking at distortion specs, though, keep in
mind that the distortion at the lowest levels is the most
important, or as we say, "The First Watt is the most important"
pass - owns a company called First Watt that will be releasing
product soon. Muuuhahahahahahaha....
them a lot lower.
As to how you set this up, that's really dependent on the
design. When looking at distortion specs, though, keep in
mind that the distortion at the lowest levels is the most
important, or as we say, "The First Watt is the most important"
pass - owns a company called First Watt that will be releasing
product soon. Muuuhahahahahahaha....
nothing turns up on Google...
is this where the Aleph might turn up again?
Or more modestly priced Pass gear??
hmmmm... sounds cool though
is this where the Aleph might turn up again?
Or more modestly priced Pass gear??
hmmmm... sounds cool though
When looking at distortion specs, though, keep in
mind that the distortion at the lowest levels is the most
important, or as we say, "The First Watt is the most important"
How can this be applied to practical reality?
I mean how do we factor this into the total system if say we have hi sensitivity speakers or bi/tri amping with say the Aleph or XAleph modules?
Do we bias as high as we dare (and keep and eye on supply rail ripple) or pick a power output level that will satisfy the optimum level for lowest distortion?
Mr Pass , Can you suggest any guidelines for deriving lowest distortion?
macka🙂
mind that the distortion at the lowest levels is the most
important, or as we say, "The First Watt is the most important"
How can this be applied to practical reality?
I mean how do we factor this into the total system if say we have hi sensitivity speakers or bi/tri amping with say the Aleph or XAleph modules?
Do we bias as high as we dare (and keep and eye on supply rail ripple) or pick a power output level that will satisfy the optimum level for lowest distortion?
Mr Pass , Can you suggest any guidelines for deriving lowest distortion?
macka🙂
Thanks for the advice. I looked at the data sheet for the IRF610. The power dissipation is rated at 36 watts with a 25c case temp. With a sink resistance of 2.2 C/W (I have these around) + 1C/W case to sink resistance, I would end up with about a 32 C rise (case temp, 10W on the device). This would derate them to about 26W. So, could I get away with running them at 10watts? How long would they last? Would that be enough to get the distortion down, and the bandwidth up (40V@.250A)?
I understand about the first watt being the most important, but doesn't the amp tend to sound "congested" on peaks when the distortion goes up so much at these higher levels?
I can't wait to see your new company's products! These wouldn't happen to use vacuum tubes, would they?
Thanks again.
I understand about the first watt being the most important, but doesn't the amp tend to sound "congested" on peaks when the distortion goes up so much at these higher levels?
I can't wait to see your new company's products! These wouldn't happen to use vacuum tubes, would they?
Thanks again.
It should hold up for a long time at 10 watts.
Regarding congestion on peaks, it depends. Since we don't
have your schematic here to speculate with, there's not much
I can say.
(Maybe you want to look into some nice efficient speakers)
No tubes on the horizon.
Regarding congestion on peaks, it depends. Since we don't
have your schematic here to speculate with, there's not much
I can say.
(Maybe you want to look into some nice efficient speakers)
No tubes on the horizon.
Hi Ya Nelson,
Hate to bust your chops, but any idea on when the passive balanced preamp and electronic crossovers articles will be out.
V~
Hate to bust your chops, but any idea on when the passive balanced preamp and electronic crossovers articles will be out.
V~
