Forum upgrade to SMF 2.1.2, still working on re-theming.
Started by THChrist, December 28, 2010, 11:02:15 PM
Quote from: J M Fahey on December 29, 2010, 05:31:52 AM Hi tchrist.Those are interesting ideas, very experimental and quite far from a finished product.Not bad as a concept, but the waveforms he shows are SS type , not tube type, so the main object of getting so complex and expensive (just ask for a quotation on his output transformers) is not achieved.No te rompas la cabeza contra una pared.Just build a tried and true chip amp, from 5 to 150W; *or* a real tube one; again from 5W to 100W, and experiment with the preamp, stomp boxes, etc.Good luck.
Quote from: phatt on December 29, 2010, 07:52:50 AMHello tchrist,Not sure where your heading but I agree with JM Fahey's last post. 8|That stuff is Way to complex for little benifit as a tube power stage will still be better. I did have a listen to the clip, Turning the knobs did little to effect any real change in sound.Also a servere lack of bass but that's a matter of taste.A note on tube preamps ,, it's a dog chase tail thing as the real benifit of Valves is in the power stage not in the preamp stages.So if you want to throw money at something then build a Valve power stage and leave all the tricky complex preamp stuff for SS. Cheaper and Easier to fault find for the hobby types.These days anything with an AX7 inside a preamp will sell.IME, Complex valve preamps are no better than what can be done with transistor/chip circuits.Sure if money is no object then go nuts but the cost is significantly higher with Valves.Phil.
Quote from: teemuk on December 29, 2010, 07:34:19 AMI don't know... to me at least the MicroPA output looks pretty much like one coming from a generic tube amp: somewhat rounding up on the clipping onset and it even features the same type of crossover/blocking distortion mechanism due to shifting bias point. But, I think those scoped waveforms are either from running to a resistive load or the amplifier's response stays fairly linear regardless of load impedance. So the mechanism where amp's gain interacts with a reactive load is not showing up in there. Otherwise, it pretty much nails the "PP tube power amp thing".
Quote from: J M Fahey on December 29, 2010, 04:10:16 PMHi tchrist.I'm not "clashing" with our friend teemu's opinion (far from it), because I simply didn't even *look* at the "small" Fet amp, just went straight to the "big" one, where I saw no curve bending, bias shifting, etc. at all, at least in the scope images posted by the author.All I saw there is a little top rounding, *very* easy to get by far simpler means.And the "tube artifacts" are generated in a far better way by the excellent Transtube circuit.Maybe driving a real world speaker things change.Differences of *opinion*? Sometimes yes, and that's good, or the World would be quite boring.If you can get that transformer wound for such a low price, and build the amplifier, go for it, and post results here.Happy Xmas and New Year to everybody, y felices fiestas para ti.
QuoteNot bad as a concept, but the waveforms he shows are SS type , not tube type, so the main object of getting so complex and expensive (just ask for a quotation on his output transformers) is not achieved.Just build a tried and true chip amp, from 5 to 150W; *or* a real tube one; again from 5W to 100W, and experiment with the preamp, stomp boxes, etc.Good luck.
Quote from: crane on January 19, 2011, 04:56:22 PMI was also wondering if KMG would be so nice and post some more info about winding those nice output trafos for his FET power amps...
QuoteUnfortunately i have articles about trnsformer calculations only in Russian.