Well, after being fairly lazy about trying to sort this out I guess I have the time to try and sort through this now, so here it goes.
What I will be doing here is offering up a board very similar to that which was made last time round which will accommodate a set of ultra fast switching diodes (either dual TO-247 devices, or single TO-220) along with a snubbing network and space four heat sinks etc.
There will be some minimum order numbers which I will have to hit before this becomes worthwhile doing though, which would be 100 of the PCB’s and at least 25 full set’s of component kits (although again like last time I will try and supply the spade PCB connectors as I’m not sure how easy these will be for people to et hold of individually)
You can see a picture of the board in an assembled state at the end of this little lot of text, and I will include a description of the components which would be in the kit on the wiki page which I will go and set up now to try and gauge interest in doing this again, but if any people have any questions about things then feel free to post on here and I will try and answer them as quickly as possible (which also goes for the pricing which I will have to go off and work out for the component kits now, but which would probably remain at £4 per PCB as it was last time so long as the board house don’t’ charge me any more this time).
Andrew.
Old Component order page
Old PCB order page
Old Component order page
What I will be doing here is offering up a board very similar to that which was made last time round which will accommodate a set of ultra fast switching diodes (either dual TO-247 devices, or single TO-220) along with a snubbing network and space four heat sinks etc.
There will be some minimum order numbers which I will have to hit before this becomes worthwhile doing though, which would be 100 of the PCB’s and at least 25 full set’s of component kits (although again like last time I will try and supply the spade PCB connectors as I’m not sure how easy these will be for people to et hold of individually)
You can see a picture of the board in an assembled state at the end of this little lot of text, and I will include a description of the components which would be in the kit on the wiki page which I will go and set up now to try and gauge interest in doing this again, but if any people have any questions about things then feel free to post on here and I will try and answer them as quickly as possible (which also goes for the pricing which I will have to go off and work out for the component kits now, but which would probably remain at £4 per PCB as it was last time so long as the board house don’t’ charge me any more this time).
Andrew.
Old Component order page
Old PCB order page
Old Component order page
Attachments
Just one more picture to give a clearer look at teh PCB and show the alternate method for cooling if you want to put a lot of current through the diodes.
EDIT:
Ok, here is the link to the new wiki page, it doesn't have much information on it yet, as most of that can be found in the old threads (or you could ask here) and I have to head out now so it may be added at a later date if this looks like it will take place again.
Andrew.
New Group order wiki page
EDIT:
Ok, here is the link to the new wiki page, it doesn't have much information on it yet, as most of that can be found in the old threads (or you could ask here) and I have to head out now so it may be added at a later date if this looks like it will take place again.
Andrew.
New Group order wiki page
Attachments
I only want to remind you that your insulation distances are too small. I recommend that you increase them to 1 mm or more. Calculate for max voltage 200 volts at least.
You may also place the pads in zick-zack so you get more space. What don't you place the e TO220 devices a bit from the heatsink. It's easier to bend these TO220's compared to the TO247's.
You may also place the pads in zick-zack so you get more space. What don't you place the e TO220 devices a bit from the heatsink. It's easier to bend these TO220's compared to the TO247's.
As long as there are sufficient order numbers to hit the price cuts that I need to place the orders I should have no problems with people taking the components they want for the boards. However, as I doub't this will be as large an order as last time if it does go through, it will probably work out a little more for some of the components, so you could expect I think a price of around £9.00 for a PCB and all of the componets apart from the diodes (although this could be a bit more if I can't get the parts from the same sources as last time)
Hey this is just what the doctor ordered... I've been looking for a high speed diode set for my Aleph 1.2s I'm building. I guess this is it???
Tell me....I'm using a 2000VA 50v dual primary toroid and 6 72,000uF caps to make a CRCpi type PSU with some resistors inbetween the first four 72KuF caps and the last two 72KuF caps. Is this the fastest switching setup I could get for my project?
What is the difference between this and a "hexfred" setup? I am told by a good friend of mine that I should use 8 hexfred high spped diodes in TO247 cases. I see from the picture that there are four per PCB.....if I'm using dual primaries, then could I benefit from using one of these boards (4 diodes) per primary out from my trannie? In other words two PCB setups per chassis?
Sounds good. Someone school me and I'll be in.
Thanks
Chris
Tell me....I'm using a 2000VA 50v dual primary toroid and 6 72,000uF caps to make a CRCpi type PSU with some resistors inbetween the first four 72KuF caps and the last two 72KuF caps. Is this the fastest switching setup I could get for my project?
What is the difference between this and a "hexfred" setup? I am told by a good friend of mine that I should use 8 hexfred high spped diodes in TO247 cases. I see from the picture that there are four per PCB.....if I'm using dual primaries, then could I benefit from using one of these boards (4 diodes) per primary out from my trannie? In other words two PCB setups per chassis?
Sounds good. Someone school me and I'll be in.
Thanks
Chris
Hi, as this is a fairly generic PCB allowing you to use any suitable connected single TO-220 or double TO-247 diode type package you should be able to find a device which will do what you want it to for your amp (the diodes that were in the kits last time were the ones that are used int he PASS labs amplifiers so they should be a good starting point for you to look at).
Also, the way the PCB is configured, it is equaly possible to use one or two of them for a single supply (so long as you have dual secondaries on your transformer which it looks like you have) depending on what you fancy putting into your amp.
Anyway, hope this has answerd your questions, but if it's not specific enough, just let me know and I'll try to clarify things a bit more.
Andrew.
Also, the way the PCB is configured, it is equaly possible to use one or two of them for a single supply (so long as you have dual secondaries on your transformer which it looks like you have) depending on what you fancy putting into your amp.
Anyway, hope this has answerd your questions, but if it's not specific enough, just let me know and I'll try to clarify things a bit more.
Andrew.
Right...I'll have dual secondarys...so while I'm spending the big bucks, I might as well get two of these PCB per trannie right? I'll use TO247 diodes and I should have an ultra fast low drag bridge right???
Aside from physical size characteristics, is there a difference bewteen the TO220 and the TO247? I take it either style will work? What stats am I looking for in a diode? Some say fast, others say ultra fast. One such example is a "Fairchild Ultrafast REcovery" TO-220 with Max v of 600 but after that, the stats on each are a mystery to me. Tell me which ones are important to me. I know I need at lease 60 volts...that's what my rail votage will be.
Tell me if I'm way off here. Sorry about the newbie questions.
Chris
Aside from physical size characteristics, is there a difference bewteen the TO220 and the TO247? I take it either style will work? What stats am I looking for in a diode? Some say fast, others say ultra fast. One such example is a "Fairchild Ultrafast REcovery" TO-220 with Max v of 600 but after that, the stats on each are a mystery to me. Tell me which ones are important to me. I know I need at lease 60 volts...that's what my rail votage will be.
Tell me if I'm way off here. Sorry about the newbie questions.
Chris
wytco0 said:
You can very easily use a centre tapped transformer with one of these boards, it's just that if you want to be extravagent and use two boards in one power suply then you should have proper dual secondaries.
And Clarkcr, the main advantage of the TO-247 devices is that they can generaly handle far higher curents than the TO-220 devices (as well as dissipating more power from the larger package) so in larger supplys like it sounds you have for your aleph both of these things could be considered benifits. Also, Personaly I would always try and over rate the voltge on the parts I am using in an application like this to double the voltage that they will generaly have applied to them (so in your case I would go with a minumum of 100V, but probably a lot more, just to give a bit of protection against any possible short voltage spikes which may get passed through the transformer from the mains). Other than that, from what people seem to have said on here it is quite often a matter of preference as to what sort of diode to go for, although getting a decent part from a technical point of view can have benifits too.
Thank you for your help. I have a couple more questions on diodes though:
Some are faster than others correct? If so, how do I tell when looking up their stats which are faster than others? In the Mouser catalog I have, they have all kinds of stats on these, none of which (except max voltage) do I have a clue what they mean
Also, is there a difference between dual secondarys and dual primarys? I might have made up "dual primariys" in my attempt to understand transformers.
One more thing....don't you feel that with all that juice coming out of the transformer and going into those caps, one would want to keep the connectors large and heavy? Afterall, the buss bar connecting the capacitor terminals are always heavy copper...it seems funny to me the thin foil on the PCB board might be a bit light?
Thanks again
C
Some are faster than others correct? If so, how do I tell when looking up their stats which are faster than others? In the Mouser catalog I have, they have all kinds of stats on these, none of which (except max voltage) do I have a clue what they mean
Also, is there a difference between dual secondarys and dual primarys? I might have made up "dual primariys" in my attempt to understand transformers.
One more thing....don't you feel that with all that juice coming out of the transformer and going into those caps, one would want to keep the connectors large and heavy? Afterall, the buss bar connecting the capacitor terminals are always heavy copper...it seems funny to me the thin foil on the PCB board might be a bit light?
Thanks again
C
Hi, lets see if I can have a go at answering these then:
First, if you want to know which are the faster diodes to use, simply look for their recovery time (should be specified on the data sheet for most parts if it isn't listed in your catalouge) which should give you some idea how quickly the different diodes will switch off.
second, yes there are diferences between dual primarys and dual secondaries (the primarys are what you connect up to the mains side of thigs, but transformers do quite often come with two so they can be used for 120V and 240V) but from what you mentioned about how you wanted to connect up your transformer, it did sound as though you meand dual secondaries (the windings which give you your output voltage) so you should be ok here I think.
And finaly, although the PCB tracks will not be quite so low impedance a pathway as a thick copper bar, they are still quite capable of carrying high current (in the art of electronics, they quote a 2oz PCB trak only 0.2" wide as being able to cary a 20A current, and as these boards have wider tracks and should have thicker copper then they should be fairly robust).
First, if you want to know which are the faster diodes to use, simply look for their recovery time (should be specified on the data sheet for most parts if it isn't listed in your catalouge) which should give you some idea how quickly the different diodes will switch off.
second, yes there are diferences between dual primarys and dual secondaries (the primarys are what you connect up to the mains side of thigs, but transformers do quite often come with two so they can be used for 120V and 240V) but from what you mentioned about how you wanted to connect up your transformer, it did sound as though you meand dual secondaries (the windings which give you your output voltage) so you should be ok here I think.
And finaly, although the PCB tracks will not be quite so low impedance a pathway as a thick copper bar, they are still quite capable of carrying high current (in the art of electronics, they quote a 2oz PCB trak only 0.2" wide as being able to cary a 20A current, and as these boards have wider tracks and should have thicker copper then they should be fairly robust).
Hi, I'm not entierly sure what you mean by is there a circuit for this (but if you click on a link below you can see a rough schematic from the original board) as it's simply a rectifier bridge with snubbers on it. However, there are indeed still some available (infact, I would still like to get in about another 30 or so orders before this becomes worth my while doing again) if you are interested.
edit: scrap that actualy, as I have just checked out the wiki page again, and so long as everyone on there is sure about how many they want, then it does look like I will be putting an order in for some boards soon. I guess I will have to go and rework the board, and get some new qutes at the start of next week. So, hopefuly I should be able to let people know the actual price of the boards by the end of next week, allong with the cost of the component kits too.
Andrew.
edit: scrap that actualy, as I have just checked out the wiki page again, and so long as everyone on there is sure about how many they want, then it does look like I will be putting an order in for some boards soon. I guess I will have to go and rework the board, and get some new qutes at the start of next week. So, hopefuly I should be able to let people know the actual price of the boards by the end of next week, allong with the cost of the component kits too.
Andrew.
I sorry I haven't be about much recently, but my rather poor excuse is that it rained.
This can be eplained somewhat by the microwave link that my net connection comes over not being all that reliable, especialy when it rains (and as Cambridge is now very much in it's rainy season, it can dissapear for days at a time without a lot of thinigs that will fix it).
But, this will sitl be going ahead now, although I haven't had a chance to finalise the prices or anything yet (hopefuly, if I get my work finished this afternoon, and I can still get on the net later tonight, I'll try and look into it then) so people will have to wait a little longer for that.
And, wijx as I don't see you name down on the wiki page, would you like me to add you on there or are you on under a different name at the moment?
Andrew.
This can be eplained somewhat by the microwave link that my net connection comes over not being all that reliable, especialy when it rains (and as Cambridge is now very much in it's rainy season, it can dissapear for days at a time without a lot of thinigs that will fix it).
But, this will sitl be going ahead now, although I haven't had a chance to finalise the prices or anything yet (hopefuly, if I get my work finished this afternoon, and I can still get on the net later tonight, I'll try and look into it then) so people will have to wait a little longer for that.
And, wijx as I don't see you name down on the wiki page, would you like me to add you on there or are you on under a different name at the moment?
Andrew.
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