Aleph J illustrated build guide

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#8,581
Dennis Hui said:
The bleeder puts a small load on the power supply that helps slowly drain it after the amp is powered off. This is viewed as a safety feature.

A lower resistor will drain it faster, though at 4.7K, the load is still less than 6mA ( 25V/4700R). With 22K resistor,
the load is proportionally less.

One could argue that the bleeder may not really needed. Your LED and resistor combo is also a drain on the PS, though
it might be a very light one with a large LED resistor. Note also that once the amp channels are attached, a good chunk
of energy in the power supply will be quite quickly drained by the amp boards on power down.

Since the loads from the bleeders are wasting power, you try to balance how quickly the power supply gets drain to a safe voltage level vs how much power you want the bleeders to burn during regular operation.

For an Aleph J (less than 25V rails), the dissipation of a 4.7K bleeder is ~ 25*25/4700 < 0.14W. At 22K, it's < 0.03W. So 3W is definitely not needed.
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Ok thank you for your very detailed response.

I was more of worried with the Yageo bleeder's value of 1W and 100PPM/C, if it wouldn't burn out after a while (since the offically used one was 3W and 300PPM/C). Maybe it was over-spec'd for safety allowance.

Thanks!
 
#8,583
Ben Mah said:
By the way the typical FW PS bleeder is 2.2k, not 22K. It can be seen in the PS schematic on page 1.

The 2.2k at 25V dissipates about 0.3W. 3W was specified probably to keep it running cool.
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Yeah I was also thinking about that, but this link here was the one included in the BOM of the DIY AlephJ Build Guide for noobs, from the net. Maybe an error?

https://www.mouser.com/ProductDetail/667-ERG-3SJ223

Can anyone confirm this?
 
#8,593
One of the most valuable skills in Mouser / Digikey etc. is finding alternate parts.

What you've linked to are very commonly available at even a local store (depending on where you live). Nothing special about them. Simply pick "blue" (indicates acceptable wire gauge) fully insulated parts if you want something as close as possible to those. If you have trouble, please post back. I hope these are easy for you.
 
#8,594
Hi,

Yes there are many parts like that available anywhere.

The only reason why I am asking for recommendations is because the Youtube link provided here:
(at 18:00 mark) warns against using generic poor quality cheap connectors (I think he fried one of his F5 boards because of this)

So I am asking for branded/trusted quality ones just to be sure. I don't know the exact name of this connector, so I don't know what I will be searching for.
 
#8,597
Hi RXV -

You'll get varying opinions re: the types of connectors to use.

My simple opinion is that if you use a proper crimping tool for a connector that is actually intended to be crimped, you will have a trouble-free situation. If you'll notice on the connectors in the video, they are quite different from the ones you linked re: how they are intended to attach to the wire. Thus, the gentleman also recommends soldering in addition to crimping. I don't know what cheap ones he bought, but it's likely his crimping method was sub-par if he got an airgap that caused an arc and/or there was a mismatch between how the component was intended to be used, and how he used it. All speculation.

Either way, if you are worried at all about poor quality connectors, and if you'd like to get some from Mouser - these will do just fine. Get a proper crimping tool, watch a video or two on how to crimp them properly, and you'll likely have years and years of trouble-free operation.

Since I live in MN, I'll support a local company.

https://www.mouser.com/ProductDetail/3M-Electronic-Specialty/MNU14187DMIK?qs=fltJrqpyVmUL2I7qV3PH3Q==
 
#8,598
Dennis Hui said:
Have a look here. You can find their generic names as well.
https://en.wikipedia.org/wiki/FASTON_terminal

Now browse around at the big distributors and see what you like. Make sure you get the right size for the wire gauge you intend to use.
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Hi,

The reason why I also am considering these faston connectors, is because some components already are "faston-ready" such as the IEC inlet, and especially the bridge rectifiers (I haven't seen anyone soldering their wires to the metal tabs of those bridge rectifiers).

Maybe also for practical reasons? In case yu need to easily replace/remove a part, as well as for future projects (ex: change to another First Watt amp)?

I intend to get the thickest gauge wire possible, which I think is for 14awg (is 12awg possible with this project? Maybe hard to insert already)?
 
#8,599
andynor said:
I highly regard direct soldering and or shrinked needle pins instead of fastons. Not as flexible, but ensures tight sleep every night :devily:
Click to expand...
Yes I also intend to do some direct soldering in some areas, but easily removable fastons can also be very practical in case a problem arises or you need to remove some part/pcb for repair/replacement.

Soldering everything up might be a PITA once that happens, so a some faston connectors in some key areas might be more flexible.

Also, I what do you mean by shrinked needle pins? I haven't seen them in any build here.
 
#8,600
ItsAllInMyHead said:
Hi RXV -

You'll get varying opinions re: the types of connectors to use.

My simple opinion is that if you use a proper crimping tool for a connector that is actually intended to be crimped, you will have a trouble-free situation. If you'll notice on the connectors in the video, they are quite different from the ones you linked re: how they are intended to attach to the wire. Thus, the gentleman also recommends soldering in addition to crimping. I don't know what cheap ones he bought, but it's likely his crimping method was sub-par if he got an airgap that caused an arc and/or there was a mismatch between how the component was intended to be used, and how he used it. All speculation.

Either way, if you are worried at all about poor quality connectors, and if you'd like to get some from Mouser - these will do just fine. Get a proper crimping tool, watch a video or two on how to crimp them properly, and you'll likely have years and years of trouble-free operation.

Since I live in MN, I'll support a local company.

https://www.mouser.com/ProductDetail/3M-Electronic-Specialty/MNU14187DMIK?qs=fltJrqpyVmUL2I7qV3PH3Q==
Click to expand...
Yes, that was what I was also thinking, maybe he possibly didn't crimp it properly.

But from what I also understood in his video, he explained that the cheap generic ones (fastons) tend to have thinner metal material, unlike his trusted/branded ones which are a lot thicker (and therefor less prone to arcing/bending).
I believe in this because I have seen those cheap types which are really soft and can be bent just by your fingers (this is what I am avoiding)

One issue that I am also having about those faston types is the size, as I think there are 4.75mm and 6.35mm variants, which I am not sure of what to use (I think the bridge rectifiers' tabs are 6.35mm, the rest I am not sure)

Another type of connector I intend to use are those molex screw-in type (only on one side of the Power Supply PCB). The only downside I see in this type, is that it usually can only accommodate smaller gauges (due to the small hole insert)
 
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