Also, by measuring inside edge, middle and outside edge of all 4 tires, on can adjust chassis to desired spec.
That works best on circle track cars. I don't know if it would translate to road course. (My method being referred to.)
Sorry for off thread,
Russellc
So I replaced the MOSFETs with those from Greg (@ggetzoff), I replaced the Keratherm for the new MOSFETs, I re-soldered J12 as @Pechelman suggested, and I replaced the R17 as suggested by Patrick (@ItsAllInMyHead) (I measured the old one and it was fine). I plugged the dim bulb tester in and powered up. The bulb never goes off, so something is still wrong.
I'm completely stumped. Any other suggestions? Do I buy a new set of boards and start again? Do I pull all the parts on the bad board and start with all new parts? I've been working on this for three months and I can't get this one $%^&! board to work. I could really use some help.
Thanks,
/d
I'm completely stumped. Any other suggestions? Do I buy a new set of boards and start again? Do I pull all the parts on the bad board and start with all new parts? I've been working on this for three months and I can't get this one $%^&! board to work. I could really use some help.
Thanks,
/d
Does the bulb dim? My Aleph J dim bulb test never went off and my amp is fine. It did dim somewhat as I recall
I don’t remember mine going out completely. If memory serves the bulb got a little brighter when doing the initial bias adjustment before removing the bulb tester and powering up with my cord.
The bulb will stay lit with the aleph attached to the psu. Those mosfets are hungry. The bulb should light and slightly dim. Mine also started to brighten slowly but all was well. What you don't want is a bulb that goes full nuclear bright from the beginning.
Sorry, I didnt mean you were off topic, you're right it does put 60 degrees Celsius in perspective. My comment wandered off topic as it really didnt help the current thread, I like cars too is all.
Russellc
@Pechelman
Doesn't really dim at all when I flip the power on. Bulb comes on and stays on.
Thanks,
/d
Doesn't really dim at all when I flip the power on. Bulb comes on and stays on.
Thanks,
/d
Have you powered up the psu not attached to the aleph boards?
Does the dim bulb react similarly with the psu attached to the one good board you've built?
It could be that everything is fine. I know I was unsure about how bright the bulb was the first time I powered on with everything attached. Have you checked voltage drop on the resistor you would check when setting bias? It won't be right but it should give you an idea of things are ok.
Does the dim bulb react similarly with the psu attached to the one good board you've built?
It could be that everything is fine. I know I was unsure about how bright the bulb was the first time I powered on with everything attached. Have you checked voltage drop on the resistor you would check when setting bias? It won't be right but it should give you an idea of things are ok.
AJ perfection with "dim" bulb. 100W bulb. Gets a tad brighter in fact after power on. Was using it today A/B with M2X. Both fantastic Ferraris.
All DIY PSUs I've made so far will dim the bulb with no amp boards attached. With one board attached there might be a slight dimming depending on amp.
(It's a great amp—stick it out—it's worth it.)
All DIY PSUs I've made so far will dim the bulb with no amp boards attached. With one board attached there might be a slight dimming depending on amp.
(It's a great amp—stick it out—it's worth it.)
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Yes, I tried the PSU alone and the good board alone. Only the right channel board has problems. Thanks
With the bulb attached;
how much offset to you have?
Also what is the PSU voltage from ground to V+
how much offset to you have?
Also what is the PSU voltage from ground to V+
Jim,
With the bulb in:
The offset is 5v left. It is fixed and turning the variable resistor doesn't change it. The offset is -5v on the right and varies as you adjust the variable the resistor. The left side is getting 5.48v v+ to ground and the right is getting 5.46v v+ to ground.
Thanks,
/d
With the bulb in:
The offset is 5v left. It is fixed and turning the variable resistor doesn't change it. The offset is -5v on the right and varies as you adjust the variable the resistor. The left side is getting 5.48v v+ to ground and the right is getting 5.46v v+ to ground.
Thanks,
/d
Hi everyone!
Yesterday my father came to me and had a listen to my Aleph J. He likes its sound a lot, but he does not want to make such a big "beast" for himself.
He asked me, if it is possible to make aleph j with only one pair of output transistors?
Please, give me advice, what kind of Pass FW amplifier sounds like Aleph J with less power. I think 5Watts would be enough. May be ACA?
Yesterday my father came to me and had a listen to my Aleph J. He likes its sound a lot, but he does not want to make such a big "beast" for himself.
He asked me, if it is possible to make aleph j with only one pair of output transistors?
Please, give me advice, what kind of Pass FW amplifier sounds like Aleph J with less power. I think 5Watts would be enough. May be ACA?
Just getting started and first amp build. Hope this is my only truly dumb question but here goes:
Ordered boards and transistors. Pulled the transistors out of the static bag (J74 andIRFP240), still in the plastic bag, to check that they were correct. Didn't handle them directly, but did not realize how sensitive transistors can be to static.
Should I be worried or is it worth trying to test them? I hate the idea of starting the build with components that may be damaged. From what I've been reading they can still work with slight damage. Edit: can add in Minnesota with wood floors, maybe less static in general if that helps.
Ordered boards and transistors. Pulled the transistors out of the static bag (J74 andIRFP240), still in the plastic bag, to check that they were correct. Didn't handle them directly, but did not realize how sensitive transistors can be to static.
Should I be worried or is it worth trying to test them? I hate the idea of starting the build with components that may be damaged. From what I've been reading they can still work with slight damage. Edit: can add in Minnesota with wood floors, maybe less static in general if that helps.
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hard to give you any definitive advice here, but if you left them inside the bag, and didnt handle them at all with your fingers, then likely impossible you could have done anything to harm to components. I want to say the J74's may have shipped to me in a regular non-esd clear plastic baggie.
Best practice to handle components is with an ESD wrist strap. In reality, I've never done this, always touched metal before handling components, and havent yet fried anything. While the Aleph was my first DIY project I have built a bunch of computers in my past and always just touched the metal computer case before touching anything else.
Best practice to handle components is with an ESD wrist strap. In reality, I've never done this, always touched metal before handling components, and havent yet fried anything. While the Aleph was my first DIY project I have built a bunch of computers in my past and always just touched the metal computer case before touching anything else.
Good tip is to switch off you soldering iron right before soldering, i prefer to disconnect it from the supply line.
Soldering iron has some voltage (and some charge, ofcourse) on it. When you touch the transistor lead, soldering iron may discharge and damage transistor.
Soldering iron has some voltage (and some charge, ofcourse) on it. When you touch the transistor lead, soldering iron may discharge and damage transistor.
IaRIVR, your question is a good one. Most likely everything is OK.
The MOSFET need to be matched as per build guide (great article by Nelson Pass on MOSFET matching http://www.firstwatt.com/pdf/art_matching.pdf).
Good practice to verifying transistor pinout using diode function on DVM or transistor tester which will do a quick test. Lots of info on how to on web.
The JFETs should be matched if bought from DIY Audio Store, but good to verify pinout.
The MOSFET need to be matched as per build guide (great article by Nelson Pass on MOSFET matching http://www.firstwatt.com/pdf/art_matching.pdf).
Good practice to verifying transistor pinout using diode function on DVM or transistor tester which will do a quick test. Lots of info on how to on web.
The JFETs should be matched if bought from DIY Audio Store, but good to verify pinout.