Crispy
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"Done me wrong," it's the same old song" - forever
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Post by Crispy on Mar 22, 2013 19:51:08 GMT
Hi Chris If the PCB is actually marked 100 , and 470, then that should be their actual values. Kind Regards Alex Hi Alex I have heard from the supplier and the values are what you said - Thanks. Next bit of help needed, can you tell me from the colour code of a resistor what the wattage is. It is an 0R22 resistor - colour code - Black, Red, Red, Silver, Brown. I also need help with the bridge rectifier, the one I ordered is far too big with the pins offset as you can see from the pic below. The space between the holes is 13mm and I think the rectifier sits on top with no heat sink. Not sure where to start looking so any help appreciated. Chris
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XTRProf
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Post by XTRProf on Mar 23, 2013 0:03:58 GMT
Next bit of help needed, can you tell me from the colour code of a resistor what the wattage is. It is an 0R22 resistor - colour code - Black, Red, Red, Silver, Brown. Sorry, there is no colour code for power. Only size and written on resistor for those bigger ones will tell. Usually it goes like this 1/8W, 1/4W, 1/2W, 1W, etc. As a reference, the usual ones used on the PCBA is the 1/4W. So you can judge what the wattage is from that size for correlation. I also need help with the bridge rectifier, the one I ordered is far too big with the pins offset as you can see from the pic below. The space between the holes is 13mm and I think the rectifier sits on top with no heat sink. Don't order the smaller bridge rectifier. As someone who believes in the American free wheeling ways of doing things much in excess in AV, that will do. Just bend leads into holes of PCB and improvise. Leads too short, solder extension leads and form them to go nicely into PCB holes. Hopes this helps.
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pingu
Been here a while!
Reallising what has been taken on with the GB
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Post by pingu on Mar 23, 2013 0:37:49 GMT
Hi Chris If the PCB is actually marked 100 , and 470, then that should be their actual values. Kind Regards Alex Hi Alex I have heard from the supplier and the values are what you said - Thanks. Next bit of help needed, can you tell me from the colour code of a resistor what the wattage is. It is an 0R22 resistor - colour code - Black, Red, Red, Silver, Brown. I also need help with the bridge rectifier, the one I ordered is far too big with the pins offset as you can see from the pic below. The space between the holes is 13mm and I think the rectifier sits on top with no heat sink. Not sure where to start looking so any help appreciated. Chris Hi Chris, If you just use 4 ultra fast or Schottky diodes in the ususal 4 pointed mode on a bit of vero board or just use the circuit board and adapt the connections that will do the trick. I am told it is better to use diodes than the bridge rectifers anyway so try this; www.world-designs.co.uk/forum/showthread.php?t=4131&highlight=schottkies&page=5Post 48 by Richard Also if you read that thread I think you can get rid of those caps by using the ultra fast diodes. Martin
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Deleted
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Post by Deleted on Mar 23, 2013 17:33:57 GMT
Hi Chris, I agree with Chong and Martin. My personal preference would be the UF diodes set up in normal bridge rectifier configuration. To my bodging mentality, I'd make sure that the diodes that run from AC in to + DC out and AC in to - DC out are the ones that take the through-hole positions, then tag on the other two diodes to the exposed legs of the first pair. When bodging like this I like to make sure there is a mechanical connection before the soldered one. Therefore I'd hook the legs of the second pair around those of the first so that they hold even before any solder is applied. probably just paranoid-android stuff though
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Crispy
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"Done me wrong," it's the same old song" - forever
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Post by Crispy on Mar 25, 2013 17:04:18 GMT
Hi Chris, I agree with Chong and Martin. My personal preference would be the UF diodes set up in normal bridge rectifier configuration. To my bodging mentality, I'd make sure that the diodes that run from AC in to + DC out and AC in to - DC out are the ones that take the through-hole positions, then tag on the other two diodes to the exposed legs of the first pair. When bodging like this I like to make sure there is a mechanical connection before the soldered one. Therefore I'd hook the legs of the second pair around those of the first so that they hold even before any solder is applied. probably just paranoid-android stuff though Thanks Martin, Chong and Chris. Using ultrafast diodes directly onto the board seems the easiest way of doing things I have a slack hand full of UF4007 ultrafst diodes leftover from my V2 - can I use these? the only problem is they are rated at 1amp do you think I would have any problems with these or should I use some different types? Thanks again for the advice. Chris
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Deleted
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Post by Deleted on Mar 25, 2013 19:39:33 GMT
Hi Chris,
My integrated amp, as standard, ran on four 50v 4700uf reservoir caps (yours seems to be using 2 of the same for each channel) and used 3A rectifier diodes. I later upped the caps to 4x 10000uf with the diodes going up to 6A.
So I'd guessthat 3 to 6 area should be OK for yours too?
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pingu
Been here a while!
Reallising what has been taken on with the GB
Posts: 332
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Post by pingu on Mar 25, 2013 22:18:59 GMT
Hi Chris, I agree with Chong and Martin. My personal preference would be the UF diodes set up in normal bridge rectifier configuration. To my bodging mentality, I'd make sure that the diodes that run from AC in to + DC out and AC in to - DC out are the ones that take the through-hole positions, then tag on the other two diodes to the exposed legs of the first pair. When bodging like this I like to make sure there is a mechanical connection before the soldered one. Therefore I'd hook the legs of the second pair around those of the first so that they hold even before any solder is applied. probably just paranoid-android stuff though Thanks Martin, Chong and Chris. Using ultrafast diodes directly onto the board seems the easiest way of doing things I have a slack hand full of UF4007 ultrafst diodes leftover from my V2 - can I use these? the only problem is they are rated at 1amp do you think I would have any problems with these or should I use some different types? Thanks again for the advice. Chris Hi Chris, CJ is about right I think Seems that it is a 24v input so diode of at least double plus a bit more (not sure how to work that bit out I just add about 150% to the voltage and the same to the amps). So at least 60v better 75v or 100v. Amps I always double the amps so 6 amps sounds about right. These are a bit higher voltage but the amps are OK 8amp 600v so Ok for mains if you buy a few. http://docs-europe.electrocomponents...6b80f8c96e.pdf from RS and not too expensive. I think any ultra fast soft recovery diode around 100v 6a will be OK tho. So maybe Farnell, Mouser, or Rapid will have cheaper ones. May be I am not correct but over spec for diodes in rectifiers seems to be what people use. Martin
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XTRProf
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Pssst ! Got any spare capacitors ?
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Post by XTRProf on Mar 26, 2013 11:38:19 GMT
Time to signal (email) Prof Frans to the rescue?
Btw, what's the recommended bridge rectifier amperage for this pcb?
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Deleted
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Post by Deleted on Mar 26, 2013 11:47:47 GMT
Time to signal (email) Prof Frans to the rescue? Why ? Aren't you capable of reading pages from Rod Elliot's sound.westhost.com/ There is a great deal of in depth information there.
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XTRProf
Fully Modded
Pssst ! Got any spare capacitors ?
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Post by XTRProf on Mar 26, 2013 12:11:17 GMT
Time to signal (email) Prof Frans to the rescue? Why ? Aren't you capable of reading pages from Rod Elliot's sound.westhost.com/ There is a great deal of in depth information there. Oh, no need to read to save time and also have personalised service too and not like those answering machine.
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Crispy
500+
"Done me wrong," it's the same old song" - forever
Posts: 631
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Post by Crispy on Mar 27, 2013 16:57:12 GMT
Chong, I do not have a clue - there is nothing marked on the board and nothing marked on the schematic, but judging by the actual size it has to fit I am guessing it is not very high (6A?) I E-mailed the supplier but no response. I was thinking of using the following ultra fast diodes like Martin & Chris suggested, unless anybody can see a problem with that uk.farnell.com/multicomp/sf63g/diode-rectif-s-fast-6a-150v-do201ad/dp/1872601?Ntt=1872601
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Deleted
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Post by Deleted on Mar 27, 2013 20:54:18 GMT
Chong, I do not have a clue - there is nothing marked on the board and nothing marked on the schematic, but judging by the actual size it has to fit I am guessing it is not very high (6A?) I E-mailed the supplier but no response. I was thinking of using the following ultra fast diodes like Martin & Chris suggested, unless anybody can see a problem with that uk.farnell.com/multicomp/sf63g/diode-rectif-s-fast-6a-150v-do201ad/dp/1872601?Ntt=1872601Chris They should be O.K. However , in a Class AB power amplifier like this, as distinct from a Class A P.A. with it's steady current draw, I would have probably gone with 8A or 10A individual diodes. Kind Regards Alex
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Crispy
500+
"Done me wrong," it's the same old song" - forever
Posts: 631
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Post by Crispy on Mar 28, 2013 20:28:39 GMT
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Post by Deleted on Mar 28, 2013 23:59:19 GMT
Hi Chris Good move For my part I think it’s better to start out with something that works reliably over time and then latter you can try other diodes if you feel the need. I’m still using nothing special bridge rectifiers in my build of Alex’s class A PA and TBH not felt any great need to change things rectifier wise. With those bridges If they don’t quite fit in the space provided on the board then you could bolt them to the chassis and run short insulated high current wires from bridge to board. Then just heat shrink over the Rectifier terminals to get the whole thing insulated and safe. Having them bolted to the chassis will help the bridges to run even cooler which is always nice. Coming along nicely Take care
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Crispy
500+
"Done me wrong," it's the same old song" - forever
Posts: 631
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Post by Crispy on Mar 29, 2013 9:47:27 GMT
With those bridges If they don’t quite fit in the space provided on the board then you could bolt them to the chassis and run short insulated high current wires from bridge to board. Then just heat shrink over the Rectifier terminals to get the whole thing insulated and safe. Having them bolted to the chassis will help the bridges to run even cooler which is always nice. Coming along nicely Take care Shaun, I looked at the info sheet on these bridges and they should be a perfect fit If they are not then I may well do as you suggested bolting the 35amp ones down instead if there is enough room in my cases At least now I have a couple of alternatives. Thanks for the advice and encouragement. Chris
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Deleted
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Post by Deleted on Mar 29, 2013 10:13:39 GMT
Hi Chris
Yup you are right those bridges look like a perfect fit and a good place to start.
I’m going to be using the 3A 200V versions for my next build (phonoclone). Nothing fancy but reliable sounds good to me.
Keep us posted
Take care
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Crispy
500+
"Done me wrong," it's the same old song" - forever
Posts: 631
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Post by Crispy on Apr 3, 2013 18:04:07 GMT
The bridges finally came from E-bay today so I wasted no time in getting them soldered in place. I presume they do not need a heat sink, but I am not sure so I deliberately soldered them high off the board to dissipate more heat? £2.32 well spent
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Deleted
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Post by Deleted on Apr 3, 2013 20:01:14 GMT
Hi Chris
looking good
Spot on leaving plenty of room around the bridge for adequate cooling.
the hole in the top is for chassis mounting so no heat sink required and with 8A bridges they should not run to hot.
Good work
Take care
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Deleted
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Post by Deleted on Apr 18, 2013 23:56:20 GMT
Hi Chris How’s she coming along? Good I hope Take care
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Crispy
500+
"Done me wrong," it's the same old song" - forever
Posts: 631
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Post by Crispy on Apr 19, 2013 8:55:50 GMT
Hi Chris How’s she coming along? Good I hope Take care Hi Shaun, I am afraid to say the project is at a temporary standstill, work is extremely quiet at the moment and funds for the project have dried up. I have a graphical calculator for sale on E-Bay at the moment and it has a bid for £35, so when the auction ends I will be able to buy a few more components for the boards I will post some pics once I get a bit further on. Thanks for the interest and I will definitely need some help choosing some of the transistors later on. Regards Chris
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Deleted
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Post by Deleted on Apr 19, 2013 9:33:00 GMT
Hi Chris How’s she coming along? Good I hope Take care Hi Shaun, I am afraid to say the project is at a temporary standstill, work is extremely quiet at the moment and funds for the project have dried up. I have a graphical calculator for sale on E-Bay at the moment and it has a bid for £35, so when the auction ends I will be able to buy a few more components for the boards I will post some pics once I get a bit further on. Thanks for the interest and I will definitely need some help choosing some of the transistors later on. Regards Chris Hi Chris Good news as I’ve enjoyed watching your superb looking build come together. So when you are ready for a chat re components just ask away. Take care
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Crispy
500+
"Done me wrong," it's the same old song" - forever
Posts: 631
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Post by Crispy on Apr 23, 2013 9:25:34 GMT
Hi Shaun, I have a graphical calculator for sale on E-Bay at the moment and it has a bid for £35, so when the auction ends I will be able to buy a few more components for the boards Hi Chris Good news as I’ve enjoyed watching your superb looking build come together. So when you are ready for a chat re components just ask away. Take care Hi Shaun, My calculator sold for £45 so I now have some funds to get a few more components for my boards. I may get some parts ordered before the weekend? I have got a lot of work to do - my daughter is hoping to move into a flat this weekend with her boyfriend, so I have been busy plumbing, painting decorating etc. I should have plenty of time next week though - along with a mega listen to Mike's modded T50RP's
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Deleted
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Post by Deleted on Apr 23, 2013 11:33:51 GMT
Hi Chris ''my daughter is hoping to move into a flat this weekend with her boyfriend, so I have been busy plumbing, painting decorating etc.'' I know the story looking forward to the rest of your build. take care
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Crispy
500+
"Done me wrong," it's the same old song" - forever
Posts: 631
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Post by Crispy on May 7, 2013 16:58:25 GMT
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Deleted
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Post by Deleted on May 7, 2013 21:47:17 GMT
Hi Chris Nice to see things moving along but this looks like a job for superAlex.
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