š¤£ I have 60 pcs of 2200uF caps, and another 60 pcs of 4800~5800uF caps.
Yes I intend to have separate PSU enclosure that measures 40 x 40 x 20 (cm)
Thank you very much for taking your valuable time to answer my query, with age by the time I got to the end of the answer I have forgotten what I have read in beginning š¤£
I will print them and keep them on my desk as reference.
Thank you!
Thank you for the kind advice.
I am sure everyone has his own magic formula to the nth degree, but is there a general acceptable rule of thumb for amplifier power output : transformer size : capacitor size (may be even taking max ripple current into consideration).
My story was I was trying to build a Aleph 1.2 clone ā+ā, I.E. with additional 16 output mosfets and perhaps raising VCC by 10V. I then spotted a pair of Apogee Scintilla 1 ohm in my neighbourhood (8 hours return journey šļ¼that got me thinking that since I am confined to 2500VA transformer for each channel due to wall power socket limitation (no, I donāt want do special cable run and/or resort to 3 phase, thank you) instead of raising VCC to 70V, I would keep it at 30~35V, but have ample current reserve to drive the 1 ohm speaker.
All suggestions are welcome. So the Aleph clone that I am thinking of building is one that delivers 60W@8 ohm and 480W@1 ohm.
Even with due consideration ti the low efficiency of single ended class A, am I too conservative with 480W@1 ohm with the 2500VA transformer? Should I raise the VCC so that output power is increase to 600W or 800W at 1 ohm load?
One circuit: see photo. You have to find out - a matter of understanding;-)
Plastic screws: first use metal, listen a while, weeks, months, then use plastics and listen;-)
First figure out what max ripple voltage you can tolerate. At full load 5% should be adequate which would be around 1.5V. (Keep in mind the Scintillas with be a smoking ruin if you feed that full power for more that a few hundred millisceonds). Then calulate back what cap value is needed to support 1.5V ripple.
Typically Computer grade caps have aluminium posts and I remember them being supplied with aluminium screws. You need a metal that will be compatible with Aluminium or corrosion will undo your efforts. You need a minimum torque on the screws to get a reliable connection. Very few plastics (not nylon) could even hold the torque needed. Data here: https://www.westfloridacomponents.com/mm5/graphics/M01/500C174U025BF2B.pdf
Typically Computer grade caps have aluminium posts and I remember them being supplied with aluminium screws. You need a metal that will be compatible with Aluminium or corrosion will undo your efforts. You need a minimum torque on the screws to get a reliable connection. Very few plastics (not nylon) could even hold the torque needed. Data here: https://www.westfloridacomponents.com/mm5/graphics/M01/500C174U025BF2B.pdf
NE WAY, have you built any solid-state audio amps before? It may be that your experience is limited, and imho you may be risking a high energy accident, and for a naive aim of better sound quality. If you have made a few such amps, then have you tried to increase their power supply rail filtering to get a benefit? I'd suggest way too many on-line audio aficionados that wax lyrical about the size of their amp filtering really have no basis for their comments, and appear to lead many newbs astray.
Do you have a power supply of any type to even start a campaign of reforming, and initial testing? Are you saying you don't yet have even a simple voltmeter?
Do you have a power supply of any type to even start a campaign of reforming, and initial testing? Are you saying you don't yet have even a simple voltmeter?
Thank you Trobbins for your kind concerns.
Just to put your mind at ease, my experience is indeed limited, havenāt built anything during the last 40 years, only 2 solid state amps when I was in high school, and converted my 2 pairs of QUAD II amps to run on bridge mode. I have an electronic engineering qualification but I will have to confess that I did not practice at circuit board level, only dealt at system level.
I just moved to a new country, but yes, I do have a multimeter.
The filter capacitors thingy is not quite a myth, ripple voltage et al, but like everything else there is a diminishing return, which is subjective for each person.
My hearing is deteriorating, but nonetheless I enjoy DIYing, even though I may not be able to hear the subtle difference.
Just to put your mind at ease, my experience is indeed limited, havenāt built anything during the last 40 years, only 2 solid state amps when I was in high school, and converted my 2 pairs of QUAD II amps to run on bridge mode. I have an electronic engineering qualification but I will have to confess that I did not practice at circuit board level, only dealt at system level.
I just moved to a new country, but yes, I do have a multimeter.
The filter capacitors thingy is not quite a myth, ripple voltage et al, but like everything else there is a diminishing return, which is subjective for each person.
My hearing is deteriorating, but nonetheless I enjoy DIYing, even though I may not be able to hear the subtle difference.
No I do not have any power supply for reforming, I am in the process of building one.
DIY reforming of large e-caps can take a lot of time, especially if you play it safe and only do one at a time. There are many methods available, so its worthwhile seeking them out and appreciating what best suits your equipment and time. I can only stress that accidents can happen, and using PPE in the form of eye protection for this situation is similar to testing charged batteries and is professional conduct. And when prototyping use passive safety in the form of terminal shrouding and fixed probing.
Given you have a few e-caps, you may want to consider finding a 2nd hand variac and use that with an isolation transformer and simple rectifier to act as variable dc supply. Also have a bleed resistor in place, and never assume a capacitor has previously been discharged - sort of like a sparky starting to fit some new wiring. E-caps can also recover terminal voltage over time, so a safe stored large capacitor is one with a fixed bleed across it..
Just my 2c.
Given you have a few e-caps, you may want to consider finding a 2nd hand variac and use that with an isolation transformer and simple rectifier to act as variable dc supply. Also have a bleed resistor in place, and never assume a capacitor has previously been discharged - sort of like a sparky starting to fit some new wiring. E-caps can also recover terminal voltage over time, so a safe stored large capacitor is one with a fixed bleed across it..
Just my 2c.
I was once told a story about a prank played in an electric motor factory.
Someone went into stores with a high voltage power supply and charged up most of the motor capacitors that were in stock.
Engineers were getting shocks off them for months.
A pair of probes connected to a surge proof resistor is a useful tool. A high value resistor would take too long with big capacitors.
Someone went into stores with a high voltage power supply and charged up most of the motor capacitors that were in stock.
Engineers were getting shocks off them for months.
A pair of probes connected to a surge proof resistor is a useful tool. A high value resistor would take too long with big capacitors.
Thank you very much Trobbins for your suggestions, they are certainly worth a lot more than 2c!
Getting a variac to use with my step up transformer and bridge rectifier and a simple cap is exactly what I have in mind.
I intend to reform 10 at a time, also intend to use an 8 steps PLC to automatically reform the capacitor at 10% voltage step up per hour to 80% of the rated voltage. So I will only need to check on them every hour or two.
Thanks for the reminder about discharging capacitors.