Hey Guys,
I have a question about the psu, is use this board to power my Aleph J. One thing i noticed was that when i power on the amp, only the + voltage led is lid, after about 5 minutes the - voltage is also burning, is this normal behavior?
for you're information, i use a 500va transformer, nichicon caps, standard BOM parts, and for a softstarter I use a couple of ntc thermisters from rinkerntrafo.nl (Inschakelstroom begrenzing 625VA)
I have a question about the psu, is use this board to power my Aleph J. One thing i noticed was that when i power on the amp, only the + voltage led is lid, after about 5 minutes the - voltage is also burning, is this normal behavior?
for you're information, i use a 500va transformer, nichicon caps, standard BOM parts, and for a softstarter I use a couple of ntc thermisters from rinkerntrafo.nl (Inschakelstroom begrenzing 625VA)
It takes 5 min for the -rail to come up? Or just for the LED to turn on?
Please post well-lit, in-focus photos of your PSU and connections.
Please post well-lit, in-focus photos of your PSU and connections.
its only the led that takes 5 minutes, the rail itself is up, hence the - rail led on the Aleph J is up, i have some pictures on my OneDrive account:
http://1drv.ms/1LK79gs
there are 2 things you dont see on the pics and that is the thermistor section and the on/off switch.
http://1drv.ms/1LK79gs
there are 2 things you dont see on the pics and that is the thermistor section and the on/off switch.
If the voltages are good, replace the suspect LED. 🙂
Or don't worry about it, because the LEDs on the amp PCB are working properly. Every LED in that amp is nothing more than a lamp to turn on and be blue... because we all know Pass amps need blue LEDs... 😀
Or don't worry about it, because the LEDs on the amp PCB are working properly. Every LED in that amp is nothing more than a lamp to turn on and be blue... because we all know Pass amps need blue LEDs... 😀
thanks 6l6, i will check the voltages just to be sure and replace/check the led on the psu pcb.
br,
Leo
br,
Leo
checked the voltages, they are the same on both sides when amp is going up 21,4v measured at psu out, but i discovered something else, when i disconnect the speakers and turn the amp on (btw its a aleph J in combination with Mez B1) both leds immediately turn on. does anyone have a clue, cause i dont
I am making an order list of parts for the F& and power supply.
Mayber someone can help me?
I used to buy the Panasonic TSUP or TSHA caps. These are not available anymore.
Is Nichicon a good replacement?
Which series do you think is the best?
In the First watt F6 the caps are rated at 25V. Isn´t this too small for a rail voltage of 23V?
Mayber someone can help me?
I used to buy the Panasonic TSUP or TSHA caps. These are not available anymore.
Is Nichicon a good replacement?
Which series do you think is the best?
In the First watt F6 the caps are rated at 25V. Isn´t this too small for a rail voltage of 23V?
I went thruh the data sheets from Nichicon and I like the GU Series which is 3000hr at 105°C.
This is like the TSHA Series from Panasonic.
The LS Series is the general purpose series. Which one have you ued in the PSU?
This is like the TSHA Series from Panasonic.
The LS Series is the general purpose series. Which one have you ued in the PSU?
For caps on the PSU3, I went with Nichicon LS series. I just soldered them on last night. 18,000uF each.
LLS1H183MELC Nichicon | 493-7271-ND | DigiKey
LLS1H183MELC Nichicon | 493-7271-ND | DigiKey
Being that 23V is less than 25V, there really isn't a problem at all.
If you choose a cap with a higher voltage rating, it will give longer life when operated at 23V.
Nelson uses 25V caps in the factory-built Firstwatt amps.
Perfect. Good choice!
That looks great!
My parts are almost here. They were cleared from customs and I should have the boards in a few days.
Quick question: what's the point of running a CL-60 thermistor between ground and the chassis?
I was gonna run the CL-60's on the transformer primaries, but decided to buy all the stuff needed to make the soft start today. The CL-60's were only $2, so I bought a couple anyway.
I was gonna run the CL-60's on the transformer primaries, but decided to buy all the stuff needed to make the soft start today. The CL-60's were only $2, so I bought a couple anyway.
It elevates PSU ground about 10ohms above the chassis, so the signal ground won't mix with the chassis ground.
BUT, since it's a thermistor, if there is an electrical fault, it will reduce to about 1/4 ohm and stay intact with real current flowing through it.
Safety and signal isolation. All in one nifty little package. 🙂
BUT, since it's a thermistor, if there is an electrical fault, it will reduce to about 1/4 ohm and stay intact with real current flowing through it.
Safety and signal isolation. All in one nifty little package. 🙂
Is it safe to fire up the PSU board with no load on the outputs? I would like to get my IEC mains, soft start, and PSU hooked up to test before connecting my gain stage (or anything else for that matter). Is this okay to do?
Totally fine!
It may read higher than you expect as it will have no load, but it's very important to do this first to verify that everything is connected in the right place, voltages are proper and the right polarity, etc...
It may read higher than you expect as it will have no load, but it's very important to do this first to verify that everything is connected in the right place, voltages are proper and the right polarity, etc...
The voltages may be around 10% higher than under full load. A variac would be good for this test.
You have 50V caps, rated at higher than the expected 25V, so no problem. I'd burn in the caps
with no load for an hour or so, before using with the amp circuit and a load.
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