Hi,
1.) test the transformer alone on the bulb tester.
2.) Add the rectifier and test again.
3.) Add the smoothing and test again.
Set the bias pots to zero resistance so that the output bias is also zero amps.
4.) Add one channel of F5 and test again.
5.) Add second channel and test again.
Tell us at which stage the bulb stays on.
1.) test the transformer alone on the bulb tester.
2.) Add the rectifier and test again.
3.) Add the smoothing and test again.
Set the bias pots to zero resistance so that the output bias is also zero amps.
4.) Add one channel of F5 and test again.
5.) Add second channel and test again.
Tell us at which stage the bulb stays on.
Oh. Well, there would certainly not hurt to obtain one of the better ones, I've seen a few successful F-5 builds using the Antek 400VA model. But if the money isnt an issue go for more quality. Myself, I'd build with it and up grade later if necessary.
Russellc
Please share your findings CanAm man on these transformers. I would love to know the outcome of this.
Thanks for the inquirey,
russellc
The Antek 300VA is a hefty chunk of core. It should do the
job nicely unless you're planning something special.
Thanks for weighing in. I assume if the 300 VA is OK, so is the 500 VA, or does that not naturally follow? (mine is a standard F-5, but I am contemplating a Cviller board F-5 with dual pairs of mosfets, is that "special" enough to cause problems?)
Thanks for the input,
russellc
bulb glowing , I resume ?
PSU is fed with just 30% of voltage
something is drawing too much current
so - to cut the chase - give us pic of your PSU , exact datasheet of used xformer , for which mains voltage xformer is wired ;
somebody already wrote that you probably mis-wired primaries
Russell, I'm running the 400VA model. The amp sounds great, but my rail voltages are lower than I expected. In addition, during some additional load testing at work, my 400VA (can't speak for others.....) seems to have poor regulation; significant secondardy voltage drop as current increases..... worse than the Antek specs inidicate.
Again, for now, the sound of the amp is very good, with high efficiency speakers. Later on, I'll do some audio load tests, and see how the amp and PSU (and transformer) respond.
Having said that, I still hope to engage Antek in a conversation regarding their specs on the 400 VA, and what I'm seeing in actuality.
Will keep you posted.
Don't know, about the mis-wired primaries. I'm thinking you only have three possible conditions:
1. Primaries wired in series, and not parallel: Probably woulld not blow fuses, but secondary and PSU rail voltages would be about half of what you'd expect.
2. Primaries wired in parallel, but out of phase: Would be a "bucking" configutation, and PSU output would be ~ zero. Depending on start-up transients, may or may not blow fuses.
3. Primares wired properly in parallel: Everything should work properly.
ONE OTHER CONSIDERATION: Make certain you have one in-rush CL-60 on each transformer primary. If you miswire here, you could have one primary winding with two CL-60's, and the second primary winding with NO CL-60s limiting start-up. This very conceiveably blow fast acting fuses! So, make certain how you have your CL-60's wired!
The Antek 300VA is a hefty chunk of core. It should do the
job nicely unless you're planning something special.
i think Nelson was saying "you worry too much about small thing . how is the music "
k , newbie question . in referring to bias , spec is to the voltage . .59v is the original target stated by Nelson . in discussions current , amps is referred to . now i understand ohms law . what i don't understand is how you come to the 1.3 or whatever amps ... the other parts of the equation .
is the voltage part of it the .59 ? if so what is the "r" part and where are you getting that ?
thank you in advance , Woody
is the voltage part of it the .59 ? if so what is the "r" part and where are you getting that ?
thank you in advance , Woody
Woody.....
The "key" is in R11 and R12--the two resistors in the F5 amp that (among other things) allow you to sense the current flow through the MOSFETS.
The resistance of R11 and R12 are 0.47 ohms.
In strick compliance with Mr. Ohm, "I" really does equal "E/R"
As such if you have a "bias voltage" as read across either R11 or R12 of 0.59 volts, then you have a MOSFET current flow of:
E/R = 0.59/0.47 = 1.255 amps ~ 1.3 amps
Voila....
The "key" is in R11 and R12--the two resistors in the F5 amp that (among other things) allow you to sense the current flow through the MOSFETS.
The resistance of R11 and R12 are 0.47 ohms.
In strick compliance with Mr. Ohm, "I" really does equal "E/R"
As such if you have a "bias voltage" as read across either R11 or R12 of 0.59 volts, then you have a MOSFET current flow of:
E/R = 0.59/0.47 = 1.255 amps ~ 1.3 amps
Voila....
I appreciate your efforts. I'll keep an eye out for findings. Thanks for pointing this out here.
Russellc
wow , thank you CanAm bud
so my current bias of .67v is 1.425 amps
Woody.....but keep this in mind (and this is info that Melon Head had provided)...... The real limiting factors are the junction temp of the MOSFET (which is "somewhat related" to heatsink temp, as we realize) AND the maximum Wattage limitation of the MOSFET, which is about 40 watts. I probably would NOT push more than 1.5 amps through the MOSFET, without a supply of spare MOSFETs handy!
At some point in time, I'll probably play with my bias levels, as well. I'm currently sitting at 0.61 volts.....
Ken (also known as Ken Mod)
wow , thank you CanAm bud
so my current bias of .67v is 1.425 amps
Woody....also see my posting #477, which quotes Melon Head on max current per rail, per amp channel...... exceed that, and the Earth may tilt on it's axis..... caveat DIY'er......