now you're clearer and I can agree
still , I would leave countries from that
proven vendors - non proven ones
that's for me effective differentiation
Hi James,
I may be interested in the boards, if you still have them I'll send a PM.
Best
Nigel
I have bought quite a few of the Jims Audio eBay LU1014. I run them through my curve tracer and they are genuine.
Be aware that these kinds of parts have wide variance. The threshold Vgs may be quite far away from some other random sample.
I did receive two dead parts and Jims Audio replaced these two dead devices.
You should spend some time looking at the characteristics of the parts. If you want some help, send me a PM.
Looking at the bom C8 is 1uF, considering is I parallel with 15000uF and 220uF I suppose that is possible to use a 10uF 100VDC Sprague V-735P that I have on stock. Eventually, I will change them in the future If I'll experiment.
F3 in progress - Couple of pictures
Hi All,
I got my F3 up and running in temporary chassis. Plan is to tweak it a little and then put the pcb and heatsink arrangement in something that looks a little more attractive than plywood scraps. Boards are by Peter Daniel; thanks to jameshillj for those, and for several parts. I've been listening to it for a while; sounds great. The heatsinks are from Heatsink USA, and they get pretty hot, but the hand test suggests I'm fine. (I can hold my hand on the top of them indefinitely, although it's a little uncomfortably hot.)
Power supply is the old Apple tower with the blue LED. That's been done for a while; information is at this other thread if anyone is interested.
CLC power supply for F3 in Apple computer case
The other two Apple towers are monoblock F5s I did a while ago. (OT: These still need finishing touches, like blue LEDs. There's space to put chokes in them to switch from CRC to CLC in the power supply, although I'm not sure when I'll get around to it. There's always something more urgent...) These are powering woofers in a bi-amped system; the F3s are to power the tweeters, although in the future I might use them elsewhere.
I mounted the LU1014Ds by soldering to little copper heat spreaders, as suggested in several places here on diyaudio. This seems to have worked well.
The only thing that really went wrong was that I killed two of the little jfets while measuring them to calculate the value of R5. The legs on them are pretty fragile, it turns out. This means the jfets in the two channels are quite different (one is from Deep Surplus years ago, the other came from jameshillj) and the various voltages are rather different between the two channels. I'm going to listen to it for a while before deciding if I care. Initial impression is that it doesn't matter much, if at all.
Thanks to everyone who's provided information in this thread and elsewhere on the site, and of course to Nelson, as always.
Best
Nigel
Hi All,
I got my F3 up and running in temporary chassis. Plan is to tweak it a little and then put the pcb and heatsink arrangement in something that looks a little more attractive than plywood scraps. Boards are by Peter Daniel; thanks to jameshillj for those, and for several parts. I've been listening to it for a while; sounds great. The heatsinks are from Heatsink USA, and they get pretty hot, but the hand test suggests I'm fine. (I can hold my hand on the top of them indefinitely, although it's a little uncomfortably hot.)
Power supply is the old Apple tower with the blue LED. That's been done for a while; information is at this other thread if anyone is interested.
CLC power supply for F3 in Apple computer case
The other two Apple towers are monoblock F5s I did a while ago. (OT: These still need finishing touches, like blue LEDs. There's space to put chokes in them to switch from CRC to CLC in the power supply, although I'm not sure when I'll get around to it. There's always something more urgent...) These are powering woofers in a bi-amped system; the F3s are to power the tweeters, although in the future I might use them elsewhere.
I mounted the LU1014Ds by soldering to little copper heat spreaders, as suggested in several places here on diyaudio. This seems to have worked well.
The only thing that really went wrong was that I killed two of the little jfets while measuring them to calculate the value of R5. The legs on them are pretty fragile, it turns out. This means the jfets in the two channels are quite different (one is from Deep Surplus years ago, the other came from jameshillj) and the various voltages are rather different between the two channels. I'm going to listen to it for a while before deciding if I care. Initial impression is that it doesn't matter much, if at all.
Thanks to everyone who's provided information in this thread and elsewhere on the site, and of course to Nelson, as always.
Best
Nigel
Attachments
Thanks ZM.
Of course at some point I'm going to have a change from making power amps. F3s are nearly finished, M2 is on the way, and I have another chassis under construction, possibly for an F4, or more likely your new LUDEF thingy. And that LuFo looks pretty interesting, too. This habit may be getting a little out of control! 😀
Of course at some point I'm going to have a change from making power amps. F3s are nearly finished, M2 is on the way, and I have another chassis under construction, possibly for an F4, or more likely your new LUDEF thingy. And that LuFo looks pretty interesting, too. This habit may be getting a little out of control! 😀
Oh, and i forgot to say that after a day of listening I think my system has never sounded better, although there are still more tweaks to be tried. Big fun!
stop thinking
recipe for neverending fun
unavoidable life things will already force you to think, so avoid whenever you can
recipe for neverending fun
unavoidable life things will already force you to think, so avoid whenever you can
I bought the F3 boards in the group buy about 2 years ago, but haven't started on them yet. Today I started reading the F3 manual and the excellent document Carsten prepared.
About 5 years ago, a fellow diyer advertised that he had IRFP044 he wanted to sell. I remembered what Nelson had written in Zen variations 1:
About 5 years ago, a fellow diyer advertised that he had IRFP044 he wanted to sell. I remembered what Nelson had written in Zen variations 1:
So, I bought some. Would it be worthwhile to use them in the F3? If so, am I correct to assume that changing Q2 from IRFP240 to IRFP044 would make the most sense? Or does the Mosfet in this position have little effect on the sound of the amp?
Yeah, I like to characterize the F3 as the LU making music, and all the rest providing life-support for the LU. 😉
Hi all,
As I will probably use F3 to drive a fullrange driver starting at 150Hz, can I replace electrolytic output cap with 2x100uF (paralleled) MKP runcaps (-3dB @around 100Hz)?
As I will probably use F3 to drive a fullrange driver starting at 150Hz, can I replace electrolytic output cap with 2x100uF (paralleled) MKP runcaps (-3dB @around 100Hz)?
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If you're going to have a crossover to implement the 150Hz cutoff that will have caps and you can eliminate the output caps entirely.
I probably will use ACN, but I could go passive for fullrange and add an active filtered woofer (with EQ)
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