in most cases that's more convenient , than perfect
few general remarks :
Jfets need to be somewhere in range of 8-15mA Idss , but they're biased by CCS , so no biggie there - as long their Idss is greater than bias itself
regarding output mosfets - they can vary from day to night with Ugs , and still perfectly useful for circuit , as long they're matched (upper pair , lower pair , no need for matching lower to upper ) at , hopefully , same current as they're working in amp
I've got mine playing now as I prepare for dinner. I'm going to give it a long good listen after dinner 
First impression is of course, is very good. I'm super happy it just plays music!
I have one issue with shut off, a quick whistle/screech. I don't think it is a speaker smasher but I'd like to get rid of it. I could put in switches at the speaker terminals but that seems clumsy and I'd biet there is a clever way without adding much to the circuits (I'd hate to mess with such perfection)!
Has anyone got a quick solution?
Cheers and many, many thanks!
First impression is of course, is very good. I'm super happy it just plays music!
I have one issue with shut off, a quick whistle/screech. I don't think it is a speaker smasher but I'd like to get rid of it. I could put in switches at the speaker terminals but that seems clumsy and I'd biet there is a clever way without adding much to the circuits (I'd hate to mess with such perfection)!
Has anyone got a quick solution?
Cheers and many, many thanks!
Oh yea, you oughta see my work bench...My first tube amp upon its completion, was like a well planned highway interchange. It was also impossible to service. Tear-down required desoldering and some of that task was nearly impossible. I had to redo most of it; now it looks like this one and I can break it all down into discrete sections as was required, quite a few times, to get it to sound the way I wanted it to.
I promise if I make another Aleph J, with the same pieces of scrap metal, I'll plan the "roads" more neatly.
It sounds better by the hour; can't wait to sip a dark mellow beer in front of it later...
Cheers!
enjoy for now ;
if needed - prior to powering off - pull speaker wires out
in a meantime, while listening da muzak - observe pictures of original FW amps , same as well made DIY specimens ;
just looking at pictures ........ and thinking about reasons for every wire and position of ... everything ........ will bring you some basic and important knowledge
read all pdfs at FW site ..... , also
(good place for uberpics of FW gadgets is 6moons )
if needed - prior to powering off - pull speaker wires out
in a meantime, while listening da muzak - observe pictures of original FW amps , same as well made DIY specimens ;
just looking at pictures ........ and thinking about reasons for every wire and position of ... everything ........ will bring you some basic and important knowledge
read all pdfs at FW site ..... , also
(good place for uberpics of FW gadgets is 6moons )
I do...
ZM, please understand I appreciate your input , your very valuable help very much!
I read all I could absorb about NP and this entire forum before I jumped in. I know for sure I could not have done this without all the good natured and well thought out advice from yourself, 6L6, Bob Ellis and other watchful and helpful fellows. I understand that neat layout is well thought out layout and leads to fewer problems. I read it and I believe it. I know your are trying to assist me with your comment and also imply that I have asked a question too broad for a proper answer. I can tell I have frustrated you. I taught HS in LA and Detroit for 12 years, I hear that sort of frustration very clearly.
I mean no disrespect.
Most of the wire mess is from a last minute shift to a three tiered approach from a two, moving the TX from over to under and then too, the admonition to have all wires to a star ground be of the same length. Add to that and my own belief that having free flowing air for the full perimeter of the heat sinks both inner and outer would be more important than many other variables in an amp so darn hot (the thing tells you of its presence even in a silent room it gives off that much heat) and you know why the wiring got so "intricate".
I respect the good advice I get; I find sadly, I cannot always accommodate all of it
So to all of you, again, my heart felt thanks!
The amp is now running fine. I know much more about large shifts in operating parameters, understand about triggering voltages, optional vias, PCB symmetries and LEDs...the list goes on.
And after a long night of satisfied listening, tomorrow I will install some switches to avert a noisey shut down.
Cheers All!
ZM, please understand I appreciate your input , your very valuable help very much!
I read all I could absorb about NP and this entire forum before I jumped in. I know for sure I could not have done this without all the good natured and well thought out advice from yourself, 6L6, Bob Ellis and other watchful and helpful fellows. I understand that neat layout is well thought out layout and leads to fewer problems. I read it and I believe it. I know your are trying to assist me with your comment and also imply that I have asked a question too broad for a proper answer. I can tell I have frustrated you. I taught HS in LA and Detroit for 12 years, I hear that sort of frustration very clearly.
I mean no disrespect.
Most of the wire mess is from a last minute shift to a three tiered approach from a two, moving the TX from over to under and then too, the admonition to have all wires to a star ground be of the same length. Add to that and my own belief that having free flowing air for the full perimeter of the heat sinks both inner and outer would be more important than many other variables in an amp so darn hot (the thing tells you of its presence even in a silent room it gives off that much heat) and you know why the wiring got so "intricate".
I respect the good advice I get; I find sadly, I cannot always accommodate all of it
So to all of you, again, my heart felt thanks!
The amp is now running fine. I know much more about large shifts in operating parameters, understand about triggering voltages, optional vias, PCB symmetries and LEDs...the list goes on.
And after a long night of satisfied listening, tomorrow I will install some switches to avert a noisey shut down.
Cheers All!
no , you didn't
I would try to help you more , but I'm really not so well informed in exact pcb layout and several optional positions ......
jdg123, I am working a a Krell clone, KSA-100 from Jim's Audio on Ebay--and that is actually the name of the diyaudio thread-- at
http://www.diyaudio.com/forums/solid-state/183562-ksa-100-jims-audio-ebay-32.html
Our distinguished colleague Kaplaars has added a Zobel Network to his audio out plugs. Please see page 32, number 319. Would this help with the pop? Other than that, I have seen some speaker protection circuits that has a delay method available somewhere. Give Kaplaars are private message and I'll bet he has some ideas.
http://www.diyaudio.com/forums/solid-state/183562-ksa-100-jims-audio-ebay-32.html
Our distinguished colleague Kaplaars has added a Zobel Network to his audio out plugs. Please see page 32, number 319. Would this help with the pop? Other than that, I have seen some speaker protection circuits that has a delay method available somewhere. Give Kaplaars are private message and I'll bet he has some ideas.
Hey guys,
It was a quick squeal/whistle at turn off (turn on is silent).
All I did was add some switches to the red terminals ( rated at 6A/125V w silver contacts). I switch off the terminals before the power thus no issue.
One might do a common ground for the black speaker terminals and switch/break only that to save one switch.
It all seems simpler than a Zobel network.
It was a quick squeal/whistle at turn off (turn on is silent).
All I did was add some switches to the red terminals ( rated at 6A/125V w silver contacts). I switch off the terminals before the power thus no issue.
One might do a common ground for the black speaker terminals and switch/break only that to save one switch.
It all seems simpler than a Zobel network.
Zobel Network will not help for the pop, it only provides impedance stability with reactive speaker loads, which may help prevent oscillation on the outputs.
The pop comes from temporary DC inbalance.
No problem. I am also still learning.
I am always scared of posting stuff, fearing that AndrewT will burst my bubble with some elaborate theoretical post explaining why I am wrong.
Fools forever
Bravo! Well Said, Zen! In addition, I pride myself on being even more foolish in private.
point of posting is learning .... increasing level of knowledge
so , nothing and no one will stop me from being a fool in public
Bravo! Well Said, Zen! In addition, I pride myself on being even more foolish in private.
Never be scared of anyone. I refuse to let anyone "live in my head rent free." I would just save the energy to put together projects and maybe, just maybe, save a bit of feeling sorry for AndrewT--he could be a great guy and a great asset to the community if it wasn't for the "personalities over principals" syndrome. Especially towards beginners and newcomers. I hope he can see the compliment.
As for me, I'm happy to have Andrew with us. He has great experience and expertise and I've learned a lot from him. Just remember that his heart is most definitely in the right place and he is always trying to help with good information. On occasion, his passion boils over, but that is a good thing too. I'm happy to have him active on these forums, even if I don't always agree with him.
This stuff is not easy
The web and in particular this forum is a new thing (compared to the length of my life anyway) and I for one greatly appreciate what new skills can be assembled from its proper use. The toughest new skill for me is "humble".
For all the times I have needed a double dose of humble and not been able to muster it, I apologize. For others in the same or similar boat, I have a lot of room and understanding.
It is tough to communicate in the rarified atmosphere of disembodied voices but I truly believe we are all bound, well and happily, by a desire to understand and an appreciation of the good that comes from DIY.
Cheers to all!
The web and in particular this forum is a new thing (compared to the length of my life anyway) and I for one greatly appreciate what new skills can be assembled from its proper use. The toughest new skill for me is "humble".
For all the times I have needed a double dose of humble and not been able to muster it, I apologize. For others in the same or similar boat, I have a lot of room and understanding.
It is tough to communicate in the rarified atmosphere of disembodied voices but I truly believe we are all bound, well and happily, by a desire to understand and an appreciation of the good that comes from DIY.
Cheers to all!