Apologies as this is a little bit off topic, but as I know respected DIYers are watching this topic then I feel I will get a suitable and safe answer.
I may have to place my transformer in a seperate enclosure than either of the amplifiers and thus make some power umbilical chords. It would appear that XLR connectors would be suitable - 250V AC rated and good for 16A current, but are they safe for power chords from the transformer?
They should be safe for two two non rectified 24V feeds, plus also ok for the zero volt line, however what about carrying the safety earth? My concern is that XLR connectors have soldered connections and not mechanical, something that I would prefer as solder has the potential to melt during fault situations.
Using a 4 pin XLR I could have the two 24V non rectified feeds, the zero vault line, plus the earth saftey wire in one cable. Am I being overly cautious with regards the soldered connection, or would it be better to have a seperate umbilical for the safety earth?
I may have to place my transformer in a seperate enclosure than either of the amplifiers and thus make some power umbilical chords. It would appear that XLR connectors would be suitable - 250V AC rated and good for 16A current, but are they safe for power chords from the transformer?
They should be safe for two two non rectified 24V feeds, plus also ok for the zero volt line, however what about carrying the safety earth? My concern is that XLR connectors have soldered connections and not mechanical, something that I would prefer as solder has the potential to melt during fault situations.
Using a 4 pin XLR I could have the two 24V non rectified feeds, the zero vault line, plus the earth saftey wire in one cable. Am I being overly cautious with regards the soldered connection, or would it be better to have a seperate umbilical for the safety earth?
If you use a shielded cable and tie the shield to the XLR shells on both sides it will provide adequate chassis grounding.
However IF I'm not using the Neutrik power conn connectors I am a fan of mic connectors rather than XLR connectors for power. They screw on and have less chance of signal cables being plugged in by others.
Use the 4 conductor connector and tie the chassis ground to the shells and the 1'st pin on the conductors.
However IF I'm not using the Neutrik power conn connectors I am a fan of mic connectors rather than XLR connectors for power. They screw on and have less chance of signal cables being plugged in by others.
Use the 4 conductor connector and tie the chassis ground to the shells and the 1'st pin on the conductors.
Hi everyone. Things are slowing in some regards around here and picking up in others. The summer is upon us and the weather is 95 -97F and near 100% humidity. Fun stuff. The AC is on all day, off at night so far.
I am in a much more positive mood now that this thing is shipped. I hope to be chiming in more often and be more a part of anyones build if I can help.
There are only a few kits not shipped now. We are matching LDRs, well they are done as of yesterday and now I am putting them through the spreadsheet. So a few of you that ordered LDRs must wait a few more days for kits to ship. I have I think 3 orders left to ship that involve kits.
That means most of you are out there wondering when yours will get to you. Well I shipped on the 22nd of May and then again on the 2nd of June, there was another smaller batch shipped between those dates. I have had orders get to New Zealand as fast as 3 days and unfortunately that is not the norm. Right now orders shipping of just LDRs have taken almost exactly a month by First Class mail going to the following locations : Italy, Greece, Germany, Australia and Taiwan. Nothing I can do about that. Shipping by any other method is either longer or much more expensive.
I have had two requests for replacement parts. One guy was missing a BC546 and 2 shoulder washers. Another was missing some resistors. The guy with the missing BC546 I would have requested that he accept my apology and please see if he could locate one but I know that the shoulder washers would be really hard to find the right one at the right size so I am shipping him replacements. IF YOU ARE MISSING COMPONENTS please consider if you can replace them yourself and if not please contact me directly. If you post here it wont twist my arm any further as I am more than willing to help but it will probably stir the pot and I have already had enough stress for this year
.
Anyway, my apologies if anything was amiss and lets get it sorted if there is. I would prefer that you notify me ASAP if you are missing anything so that I can place fewer orders to suppliers and cut down on shipping costs.
Hope you are all having fun building if you already have your kit. Its an enjoyable build. Please take care with routing of signal wires to avoid interaction with the power supply's onboard and offboard components. They will all inject noise. Again you must must must use the insulation strip or mica pad included in your kit and you must use the shoulder washer. Any deviation from that will result in smoke sooner or later and probably instantly. This comment is in regards to the LM3886. There is no need to isolate the Caddock from its heatsink as the resistive surface of the Caddock is isolated from anything outside of the case. Obviously you will want to make sure the legs of the Caddock are LOOOONG so the heatsink fits and you will want to make sure that the legs do not touch anything but air.
Uriah
I am in a much more positive mood now that this thing is shipped. I hope to be chiming in more often and be more a part of anyones build if I can help.
There are only a few kits not shipped now. We are matching LDRs, well they are done as of yesterday and now I am putting them through the spreadsheet. So a few of you that ordered LDRs must wait a few more days for kits to ship. I have I think 3 orders left to ship that involve kits.
That means most of you are out there wondering when yours will get to you. Well I shipped on the 22nd of May and then again on the 2nd of June, there was another smaller batch shipped between those dates. I have had orders get to New Zealand as fast as 3 days and unfortunately that is not the norm. Right now orders shipping of just LDRs have taken almost exactly a month by First Class mail going to the following locations : Italy, Greece, Germany, Australia and Taiwan. Nothing I can do about that. Shipping by any other method is either longer or much more expensive.
I have had two requests for replacement parts. One guy was missing a BC546 and 2 shoulder washers. Another was missing some resistors. The guy with the missing BC546 I would have requested that he accept my apology and please see if he could locate one but I know that the shoulder washers would be really hard to find the right one at the right size so I am shipping him replacements. IF YOU ARE MISSING COMPONENTS please consider if you can replace them yourself and if not please contact me directly. If you post here it wont twist my arm any further as I am more than willing to help but it will probably stir the pot and I have already had enough stress for this year
.Anyway, my apologies if anything was amiss and lets get it sorted if there is. I would prefer that you notify me ASAP if you are missing anything so that I can place fewer orders to suppliers and cut down on shipping costs.
Hope you are all having fun building if you already have your kit. Its an enjoyable build. Please take care with routing of signal wires to avoid interaction with the power supply's onboard and offboard components. They will all inject noise. Again you must must must use the insulation strip or mica pad included in your kit and you must use the shoulder washer. Any deviation from that will result in smoke sooner or later and probably instantly. This comment is in regards to the LM3886. There is no need to isolate the Caddock from its heatsink as the resistive surface of the Caddock is isolated from anything outside of the case. Obviously you will want to make sure the legs of the Caddock are LOOOONG so the heatsink fits and you will want to make sure that the legs do not touch anything but air.
Uriah
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separate PSU
and have a look at
http://www.diyaudio.com/forums/chip-amps/115698-understanding-star-grounding.html#post1403775
http://www.diyaudio.com/forums/soli...-concern-pre-amp-traffo-help.html#post2026680
http://www.diyaudio.com/forums/chip...r-grounding-suggested-layout.html#post1781690
There are probably many others giving umbilical cable safety.
and have a look at
http://www.diyaudio.com/forums/chip-amps/115698-understanding-star-grounding.html#post1403775
http://www.diyaudio.com/forums/soli...-concern-pre-amp-traffo-help.html#post2026680
http://www.diyaudio.com/forums/chip...r-grounding-suggested-layout.html#post1781690
There are probably many others giving umbilical cable safety.
Standard XLR carries 3 pins and shield, thus already giving you the 4 wires you need.
Hey guys, what about doing rectification BEFORE going out of the transformer enclosure. That way this umbilical cord will not radiate a heavy 50hz radiation. I have thought about that before, why it is not a common practice when placing the trafo in a separate enclosure?
I thought that was what was being discussed.
In my opinion it's the only way to do it properly.
Transformer + rectifier + smoothing all very close together.
But then you risk a signal level cable being plugged in by someone else unaware of the intended use.
It can be an AC or DC umbilical.
I lean towards DC also so I can have DC, a small resistance of the cable and more capacitance in the load enclosure to form a CRC filter.. But that is a matter of preference not requirement..
In the case of the My Ref it is just easier to have an AC umbilical since the rectification and smoothing is on the main PCB.
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I have always liked the idea of XLR for carrying power but there is that risk of someone who doesnt know what you did plugging in some other XLR source or what have you to your power supply. Probably would be fine since your diodes would not allow any power to come back toward the source but why risk it.
The nice thing is that they are round and therefore easy to drill out. Great for a DIYer. I have seen people using other round connectors that are usually on the back of computers. They are 7 pin sockets with 2 holes that force correct orientation. I forget the name. Anyway, there are lots of options other than XLR to get this job done and still have an easy hole to drill.
I think this link will work MOUSER INTERCONNECTS
If not here is one example of a connector that could be considered
Just make sure to check if they need to be assembled when you get them. Some connectors like this need special pin insertion tools.
Uriah
The nice thing is that they are round and therefore easy to drill out. Great for a DIYer. I have seen people using other round connectors that are usually on the back of computers. They are 7 pin sockets with 2 holes that force correct orientation. I forget the name. Anyway, there are lots of options other than XLR to get this job done and still have an easy hole to drill.
I think this link will work MOUSER INTERCONNECTS
If not here is one example of a connector that could be considered
Just make sure to check if they need to be assembled when you get them. Some connectors like this need special pin insertion tools.
Uriah
It will depend on which side you place the trafo. It is not the same being 2 inches away from the LM3886 that 2 inches away from the rectifier diodes side. Considering you will have a heatsink there, you will have to place the trafo anywhere, so 2 inches is more than enought.
Regards,
Regi
I always recommend that you follow the National guidelines for determining the heatsink size.
Then double the result.
If you have 2 chipamps on that sink then use should use 4times the national guideline.
If National say Rth s-a = 3.8C/W for Ta=25degC, then use 1.9C/W for mono and 0.9 to 1.0C/W for stereo.
If the heatsink is inside the chassis then Ta > 25degC
Then double the result.
If you have 2 chipamps on that sink then use should use 4times the national guideline.
If National say Rth s-a = 3.8C/W for Ta=25degC, then use 1.9C/W for mono and 0.9 to 1.0C/W for stereo.
If the heatsink is inside the chassis then Ta > 25degC
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