Hello. Decided to build Aleph Jzm and now keep ordering boards and components. Got the Thatcher PSU Board, Antek AS-4220 transformer and IXYS VBE60-06A rectifiers.
Have few questions regarding power supply and components connections:
-Searched for components to stuff the PSU board according to BOM and found that RES 2.2K OHM 5% 3W AXIAL, manufacturer part # ROX3SJ2K2 is not available from Digikey or Mouser. Is
283-2.2K-RC, Metal Oxide Resistor 2.2KOhms, 5% tolerance a good replacement?
- Same is true for a safety capacitor, CAP CER 3300PF 400VAC Y5U RADIAL. Is the C771U332MSWDBA7317 , Mouser # 80-C771U332MSWDB7317, the correct replacement?
- Both BOM and PS schematics call for the 0.33 Ohm 5% 3 Watt resistors (R1-R3, R4-R6 etc.), part number PNP300JR-73-0R33. However, on the Alep Jzm build guide step 53 it is a picture of PS with these resistors at 0.47 Ohm. Does it matter 0.33 or 0.47?
- The snubber network. I would like to use it; however, there are two issues:
First, I use IXYS rectifiers and they can’t be soldered into the little snubber boards supplied with the PCB. Looks like snubber network is in parallel to rectifier AC input and so in my case connections could be made by two options shown below. Which option is the best or it doesn’t matter?
Second, I didn’t find the exact transformer I use, Antek AS-4220, within ones tested by Quasimodo jug. However, similar Antek transformers are listed in Quasimodo results (ONLY) thread: Antek-3220 Cx=10nF; Cs=150 nF and Rs =18.3 OHM, Antek-4222 Cx and Cs are same and Rs=16.6 OHM and Antek-4224 Cx and Cs are same and Rs=13.7 OHM. Could I just use Cx=10nF; Cs=150 nF and Rs =16 or 17 OHM? And what power rating this Rs resistor should have- is 1/2 W good?
-Is soldering wires to the PS plate better in terms of contact quality or resistance to corrosion than using of connection tabs or screw terminals as shown in Aleph Jzm build thread?
Thank you for your help,
Andrei
Have few questions regarding power supply and components connections:
-Searched for components to stuff the PSU board according to BOM and found that RES 2.2K OHM 5% 3W AXIAL, manufacturer part # ROX3SJ2K2 is not available from Digikey or Mouser. Is
283-2.2K-RC, Metal Oxide Resistor 2.2KOhms, 5% tolerance a good replacement?
- Same is true for a safety capacitor, CAP CER 3300PF 400VAC Y5U RADIAL. Is the C771U332MSWDBA7317 , Mouser # 80-C771U332MSWDB7317, the correct replacement?
- Both BOM and PS schematics call for the 0.33 Ohm 5% 3 Watt resistors (R1-R3, R4-R6 etc.), part number PNP300JR-73-0R33. However, on the Alep Jzm build guide step 53 it is a picture of PS with these resistors at 0.47 Ohm. Does it matter 0.33 or 0.47?
- The snubber network. I would like to use it; however, there are two issues:
First, I use IXYS rectifiers and they can’t be soldered into the little snubber boards supplied with the PCB. Looks like snubber network is in parallel to rectifier AC input and so in my case connections could be made by two options shown below. Which option is the best or it doesn’t matter?
Second, I didn’t find the exact transformer I use, Antek AS-4220, within ones tested by Quasimodo jug. However, similar Antek transformers are listed in Quasimodo results (ONLY) thread: Antek-3220 Cx=10nF; Cs=150 nF and Rs =18.3 OHM, Antek-4222 Cx and Cs are same and Rs=16.6 OHM and Antek-4224 Cx and Cs are same and Rs=13.7 OHM. Could I just use Cx=10nF; Cs=150 nF and Rs =16 or 17 OHM? And what power rating this Rs resistor should have- is 1/2 W good?
-Is soldering wires to the PS plate better in terms of contact quality or resistance to corrosion than using of connection tabs or screw terminals as shown in Aleph Jzm build thread?
Thank you for your help,
Andrei
Your 2k2 3W MOX resistor p/n looks good. That resistor's function is to bleed off voltage in the PSU caps once the amp is turned off. The amp boards do the same, but if you're working on the PSU without amp boards, these resistors do that job. These resistors are important for that reason, but any good 3W 2k2 will do the job. You could go for MOX, metal film, or wirewound. You can even go for higher resistance, say up to 3k, which will result in a slower bleed-off. This resistor is not having a sonic impact, so no need to overthink it.
Similar story for the 3300pF cap. These are "jellybean" type parts and distributor stock fluctuates for different part numbers. The key considerations on the cap are the safety rating and confirming that the voltage is adequate.
Filter Resistors can be 0R47 or 0R33 3W MOX style. Either value can work just fine. You could also consider wirewound style in this position. Any potential inductance from a wirewound may be good in this role as a CRC filter.
3 Parallel 0R47 yield 0R16, and 3 parallel 0R33 yield 0R11 - fairly close. The tradeoffs are a little more filtering with 0R47's at the cost of a little voltage drop. If you want to model it, try Duncan's PSU Designer II software. If you don't, pick one or the other and prepare to enjoy the music when the amp is done.
Transformer/snubber - my rule of thumb for Antek is go with 18-22 Ohm when using parallel secondary configuration. This has been good for the 18V, 20V, and 25V donuts. So use any standard value 1/4 or 1/2W resistor in that range and you'll be good to go.
As for attaching the snubbers - I'd suggest building without the snubbers first. Get the amp up and running. I assume you'll be using some kind of eye or spade connectors for the wired connections to your IXYS bridges. Consider making a snubber setup with the resistor and 2 caps connected between 2 eyes or spades that will connect on top of your bridge. It will be flying in the air above the bridge - solder it all nicely and use a bit of heatshrink and you'll be good to go. Once the amp is proven, pull 2 screws per bridge, add the snubbers, re-assembly, and enjoy the music.
Similar story for the 3300pF cap. These are "jellybean" type parts and distributor stock fluctuates for different part numbers. The key considerations on the cap are the safety rating and confirming that the voltage is adequate.
Filter Resistors can be 0R47 or 0R33 3W MOX style. Either value can work just fine. You could also consider wirewound style in this position. Any potential inductance from a wirewound may be good in this role as a CRC filter.
3 Parallel 0R47 yield 0R16, and 3 parallel 0R33 yield 0R11 - fairly close. The tradeoffs are a little more filtering with 0R47's at the cost of a little voltage drop. If you want to model it, try Duncan's PSU Designer II software. If you don't, pick one or the other and prepare to enjoy the music when the amp is done.
Transformer/snubber - my rule of thumb for Antek is go with 18-22 Ohm when using parallel secondary configuration. This has been good for the 18V, 20V, and 25V donuts. So use any standard value 1/4 or 1/2W resistor in that range and you'll be good to go.
As for attaching the snubbers - I'd suggest building without the snubbers first. Get the amp up and running. I assume you'll be using some kind of eye or spade connectors for the wired connections to your IXYS bridges. Consider making a snubber setup with the resistor and 2 caps connected between 2 eyes or spades that will connect on top of your bridge. It will be flying in the air above the bridge - solder it all nicely and use a bit of heatshrink and you'll be good to go. Once the amp is proven, pull 2 screws per bridge, add the snubbers, re-assembly, and enjoy the music.
Hi,
@rhthatcher: thank you for the suggestion how to attach snubbers. If I understood you correctly, components of the snubber setup should be soldered directly to each other without any PCB, wrapped in heatshrink to prevent shorts and then screwed onto the bridges using resistor or capacitor's legs?
Thank you.
@rhthatcher: thank you for the suggestion how to attach snubbers. If I understood you correctly, components of the snubber setup should be soldered directly to each other without any PCB, wrapped in heatshrink to prevent shorts and then screwed onto the bridges using resistor or capacitor's legs?
Thank you.
Your connections to the SOT-227 package rectifier is not correct.
The AC should be screw terminals 1 and 2, DC- should be screw terminal 3, and DC+ should be screw terminal 4.
The AC should be screw terminals 1 and 2, DC- should be screw terminal 3, and DC+ should be screw terminal 4.
Hello,
Got few more questions how to connect PS components.
On the first picture shown a wire from Antek secondary, 12 AWG, and my IXYS rectifier. The screw on IXYS is M4. The wire is too thick to wrap it around the screw and I am not sure this is the right way. How to connect them the best way?
The wire itself is tinned suggesting this was done to facilitate connection. Read about crimping and found a couple of generic crimp terminals at home, picture 2. One is ring-terminated, the other has a "half-ring" ( don't know what is the right name for this thing). The ring-terminated is too small for 12 AWG; however, I think if such terminals should be used this is the preferred one. Is this true and, if yes, how to find it in Mouser (again, I just don't know a proper name). Should it be copper, or gold plated like in my Nak CA-7 preamp, or it doesn't really matter?
The last question is regarding connecting of the PS board to amp plates. I will be using the screw terminal block 4-position, part 277-1579-ND. The last picture, taken from the Aleph Jzm build guide, shows this connection. Can't understand how it was done and what this black thing at the end of each wire is. Are wires just tinned/untinned, inserted into terminal and secured with the screw or it's some "adapter" ( that black thing) between the wire and the terminal?
Thank a lot for your help. I am at the stage of placing order with Mouser and try to include in it all the required components.
Got few more questions how to connect PS components.
On the first picture shown a wire from Antek secondary, 12 AWG, and my IXYS rectifier. The screw on IXYS is M4. The wire is too thick to wrap it around the screw and I am not sure this is the right way. How to connect them the best way?
The wire itself is tinned suggesting this was done to facilitate connection. Read about crimping and found a couple of generic crimp terminals at home, picture 2. One is ring-terminated, the other has a "half-ring" ( don't know what is the right name for this thing). The ring-terminated is too small for 12 AWG; however, I think if such terminals should be used this is the preferred one. Is this true and, if yes, how to find it in Mouser (again, I just don't know a proper name). Should it be copper, or gold plated like in my Nak CA-7 preamp, or it doesn't really matter?
The last question is regarding connecting of the PS board to amp plates. I will be using the screw terminal block 4-position, part 277-1579-ND. The last picture, taken from the Aleph Jzm build guide, shows this connection. Can't understand how it was done and what this black thing at the end of each wire is. Are wires just tinned/untinned, inserted into terminal and secured with the screw or it's some "adapter" ( that black thing) between the wire and the terminal?
Thank a lot for your help. I am at the stage of placing order with Mouser and try to include in it all the required components.
There's some fine terminal connectors on Bezos bookstore and some cheap ones.
I have these and these and like the solid crimp. There should be veesions that accomodate 12ga wire. I solder after crimping for good measure by tucking the solder iron up under the heat shrink guard and getting some solder into the interface.
The ferrules connectors are what you see going into the screw down terminal block. Kit is very affordable and handy dandy tool. Here's one option.
I have these and these and like the solid crimp. There should be veesions that accomodate 12ga wire. I solder after crimping for good measure by tucking the solder iron up under the heat shrink guard and getting some solder into the interface.
The ferrules connectors are what you see going into the screw down terminal block. Kit is very affordable and handy dandy tool. Here's one option.
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@birdbox, many thanks for the info.
Found this at the "bookstore" which are 10-12AWG, and since it's for M4 screw I need #8. Are they good for stranded wire only or solid wire could be also crumped?
Regarding ferrules- I understand they are required for stranded wires. I'm going to use solid copper wire- can I just insert it into the terminal and secure with the screw?
Thank you.
Found this at the "bookstore" which are 10-12AWG, and since it's for M4 screw I need #8. Are they good for stranded wire only or solid wire could be also crumped?
Regarding ferrules- I understand they are required for stranded wires. I'm going to use solid copper wire- can I just insert it into the terminal and secure with the screw?
Thank you.
Those ring terminals look good to me. Someone else can correct me if I'm wrong. I've used stranded wire exclusively so I can voice they work well. As I already mentioned I still add a little solder by getting a narrow tip soldering iron under the heat shrink cover and sneak some solder up there so the wires can pull out regardless how how good my crimp is. You need a decent crimper designed for that application.
For the ferrules, those are for stranded wire. If you use solid core I see no reason you can't just go direct into the screw down terminal block (aka, no ferrule).
Looking forward to hearing your impression once glorious tunes are being played.
For the ferrules, those are for stranded wire. If you use solid core I see no reason you can't just go direct into the screw down terminal block (aka, no ferrule).
Looking forward to hearing your impression once glorious tunes are being played.
Found one "little" thing needed to get this glorious impression (except assembly of course) - WIRES!
Looked at what's left at hand and found 20 AWG solid copper wire - this should be OK for inputs but almost no 16 AWG, which was recommended in the Jzm built thread (step 56). Found this 16 AWG kit at Amazon. Any good?
Looked at what's left at hand and found 20 AWG solid copper wire - this should be OK for inputs but almost no 16 AWG, which was recommended in the Jzm built thread (step 56). Found this 16 AWG kit at Amazon. Any good?
I really like the BNTechGo silicone stranded wire. It's easy to work with and once it's on hand, you'll likely use it for all sorts of projects. You can choose the amount to buy based on budget.
Happy Thanksgiving all!
I'm using the long weekend to finally start my build and am using this power supply. I think I have a good grasp on most of what's going on here, but I do have a question that might be a bit dumb; when attaching the snubber boards to the rectifiers is it recommended to solder the rectifier lugs to the boards? Looking at photos I can't tell if others are doing that or not.
Thanks rhthatcher for the boards, and thanks in advance for any replies. Cheers!
I'm using the long weekend to finally start my build and am using this power supply. I think I have a good grasp on most of what's going on here, but I do have a question that might be a bit dumb; when attaching the snubber boards to the rectifiers is it recommended to solder the rectifier lugs to the boards? Looking at photos I can't tell if others are doing that or not.
Thanks rhthatcher for the boards, and thanks in advance for any replies. Cheers!
I'm the master of 'overkill'. I'm always including terminal blocks/strips and crimp on connectors in my builds. But, when it comes to inserting your wires into a terminal block you can save a little bit of money by lightly tinning the wire and just inserting it. Just IMHO.
P.S. rhthatcher's stuff is awesome.
Regards,
Dan
Yes, you at least need the AC input spades soldered (even just a tiny amount) to ensure the snubber circuit does its job. Additionally, make sure you space the snubber PCB off the rectifier base (I use a couple thick resistor leads, to get about 3/4 mm spacing) before soldering the rectifier spades to the snubber PCB. The purpose of this "lift" is to ensure no traces on the snubber PCB short to the rectifier body.
Any friends with KiCAD? The below pic isn't a bridge rectifier (It's from my Schade amplifier) but an example of how easy it is to whip up a little board for your IXYS.
Regards,
Dan
I finally got to the point of assembling power supply and understood I have no clear idea how properly mount a transformer to the chassis.
I have an Antek 4220 donut and Antek CA-005 Steel Cover enclosure. Supposedly the transformer should be mounted into cover then the rectangular bottom plate of the cover should be bolted to the chassis. But it's whole bunch of parts which I don't know how to assemble. Specifically, where rubber washers should be used, supposedly around the transformer to protect its body from touching metal parts? Then there are metal parts; how they should be assembled relative to each other?
I also don't know if positioning of transformer wires though the small side slots of the enclosure is correct since I have had hard time stuffing all of them into these slots. I can move the wires to solder them into the PCB; however, they should be bent almost like 180 degrees around and I don't know if this is good.
Thank you.
I have an Antek 4220 donut and Antek CA-005 Steel Cover enclosure. Supposedly the transformer should be mounted into cover then the rectangular bottom plate of the cover should be bolted to the chassis. But it's whole bunch of parts which I don't know how to assemble. Specifically, where rubber washers should be used, supposedly around the transformer to protect its body from touching metal parts? Then there are metal parts; how they should be assembled relative to each other?
I also don't know if positioning of transformer wires though the small side slots of the enclosure is correct since I have had hard time stuffing all of them into these slots. I can move the wires to solder them into the PCB; however, they should be bent almost like 180 degrees around and I don't know if this is good.
Thank you.
I might figure out how to mount the transformer: the donut is mounted on a bottom plate "upside down" and wires go down through openings on the plate:
Length of wires is sufficient to attach primaries to PS board and secondaries to rectifiers. Donut is mounted between two big rubber washers. The UFO-shaped part sits at the top of the donut and is secured with the nut-this keeps the donut firmly attached to the bottom plate. The outer enclosure is secured to the central bolt with a decorative nut and nylon isolator.
Now I need to find four 1/3 -1/2 inch sturdy stands which lift the whole assembly over the chassis, drill holes in the chassis and find a central bolt which is long enough- the one supplied by Antek is a little bit shorter than required.
Do you guys think it's a right way of mounting the transformer?
Length of wires is sufficient to attach primaries to PS board and secondaries to rectifiers. Donut is mounted between two big rubber washers. The UFO-shaped part sits at the top of the donut and is secured with the nut-this keeps the donut firmly attached to the bottom plate. The outer enclosure is secured to the central bolt with a decorative nut and nylon isolator.
Now I need to find four 1/3 -1/2 inch sturdy stands which lift the whole assembly over the chassis, drill holes in the chassis and find a central bolt which is long enough- the one supplied by Antek is a little bit shorter than required.
Do you guys think it's a right way of mounting the transformer?
It looks good. With the nylon washer electrically isolating the bolt from the transformer cover, there should be no problem.
If you cannot find a bolt with the correct length, you can try a piece of threaded rod. In one of my amps, I stacked two transformers so I needed a long bolt. I ended up purchasing a piece of threaded rod and cut it to the correct length. Be sure to take the nut to the hardware store to find the correct threaded rod size. You will need to purchase a nut so that there is a nut at both ends of the threaded bolt.
If you cannot find a bolt with the correct length, you can try a piece of threaded rod. In one of my amps, I stacked two transformers so I needed a long bolt. I ended up purchasing a piece of threaded rod and cut it to the correct length. Be sure to take the nut to the hardware store to find the correct threaded rod size. You will need to purchase a nut so that there is a nut at both ends of the threaded bolt.