<html aria-label="message body"><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body style="overflow-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;">With respect, but is that really *the* standard? A bit of duckduckgo-ing shows me this:<div><br></div><div><a href="https://pinoutguide.com/Audio-Video-Hardware/xlr6_pinout.shtml">https://pinoutguide.com/Audio-Video-Hardware/xlr6_pinout.shtml</a></div><div><br></div><div>and then there is this…</div><div><br></div><div><a href="https://pinoutguide.com/Audio-Video-Hardware/xlr4_pinout.shtml">https://pinoutguide.com/Audio-Video-Hardware/xlr4_pinout.shtml</a></div><div><br></div><div>and of course:</div><div><br></div><div><a href="https://xkcd.com/927/">https://xkcd.com/927/</a></div><div><br></div><div>Ben</div><div><br id="lineBreakAtBeginningOfMessage"><div><br><blockquote type="cite"><div>On 9 Jul 2026, at 15:02, Mike Bryant <mbryant@futurehorizons.com> wrote:</div><br class="Apple-interchange-newline"><div><meta charset="UTF-8"><div class="elementToProof" style="font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-line: none; text-decoration-thickness: auto; text-decoration-style: solid; font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt;">The 6 pin XLR is the standard for +/- power transmission. See last entry on :</div><div class="elementToProof" style="font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-line: none; text-decoration-thickness: auto; text-decoration-style: solid; font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt;"><br></div><div class="elementToProof" style="font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-line: none; text-decoration-thickness: auto; text-decoration-style: solid; font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt;"><a href="https://www.clarkwire.com/pinouts/xlr-audio-pinouts">https://www.clarkwire.com/pinouts/xlr-audio-pinouts</a></div><div id="appendonsend" style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 14px; font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-line: none; text-decoration-thickness: auto; text-decoration-style: solid;"></div><div style="font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-line: none; text-decoration-thickness: auto; text-decoration-style: solid; font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt;"><br></div><hr style="font-family: Helvetica; font-size: 14px; font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-line: none; text-decoration-thickness: auto; text-decoration-style: solid; display: inline-block; width: 997.625px;"><span style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 14px; font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; float: none; display: inline !important;"></span><div id="divRplyFwdMsg" style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 14px; font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-line: none; text-decoration-thickness: auto; text-decoration-style: solid;"><div style="direction: ltr; font-family: Calibri, sans-serif; font-size: 11pt;"><b>From:</b> Synth-diy <synth-diy-bounces@synth-diy.org> on behalf of Ben Stuyts via Synth-diy <synth-diy@synth-diy.org><br><b>Sent:</b> 09 July 2026 12:40<br><b>To:</b> cheater cheater <cheater00social@gmail.com><br><b>Cc:</b> synth-diy <synth-diy@synth-diy.org><br><b>Subject:</b> Re: [sdiy] Converting rack mount to DC input?</div><div style="direction: ltr;"> </div></div><div style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-line: none; text-decoration-thickness: auto; text-decoration-style: solid; font-size: 11pt;">Perhaps a 4 or 5 pin XLR connector is an option? They are not that expensive, and lots of ready-made cables are available.<br><br>Ben<br><br>> On 9 Jul 2026, at 10:18, cheater cheater via Synth-diy <synth-diy@synth-diy.org> wrote:<br>><br>> One way to have DC input, but retain the capability of using the<br>> internal power supply, is to have a 4P2T switch for configuration.<br>><br>> It seems that 4P2T switches are super expensive, especially if they're<br>> supposed to withstand, say, 1A.<br>><br>> So I started looking around. TLDR: classic pcie 8-pin power connectors<br>> are probably the best, and also the cheapest.<br>><br>> My first thought was to look at PCIE x1 slots. The cheapest advanced<br>> connector on earth, for 0.4 Euro at unit price, you get a connector<br>> that handles 1.1A per pin as per eg this document, page 6, 4.4<br>><br>><span class="Apple-converted-space"> </span><a href="https://cdn.amphenol-cs.com/media/wysiwyg/files/documentation/gs-12-233.pdf" id="OWA93021881-237e-0540-b40f-9bf05a8a29f4" class="OWAAutoLink" data-auth="NotApplicable">https://cdn.amphenol-cs.com/media/wysiwyg/files/documentation/gs-12-233.pdf</a><br>><br>>> 4.4 CONTACT CURRENT RATING<br>>> 1.1 amp per contact minimum per EIA-364—70, method 2 and PCI Express Connector High Speed Electrical Test Procedure. The temperature rise shall not exceed 30 degree C. Ambient condition is still air at 25°C.<br>><br>> The connector has 36 pins, so while I don't think it would handle 36A,<br>> I'm sure it would handle something like 2A, especially if you share<br>> pins. You can even leave pins empty to prevent shorts during<br>> insertion.<br>><br>> You could put the connector out the back, and either insert a plug-in<br>> "card" (really just a small edge connector with wires soldered on)<br>> that provides DC, or a pass-through "card" that shorts some pins<br>> together to carry power from the internal power supply. And now<br>> instead of $20-30 per unit, this costs $1 per unit. My main question<br>> is how I would fix the connector, but maybe a simple screw hole in the<br>> connector that mates with a threaded hole in the case could do the<br>> trick.<br>><br>> A pcie x1 port is 25mm long, so it can fit upright in the back of a 1U<br>> rack unit, which is 45mm, so it doesn't take up much space either.<br>><br>> The cheapest one that can be found at Mouser currently and can be<br>> bought in low volumes is roughly 0.4 Euro.<br>><br>><span class="Apple-converted-space"> </span><a href="https://www.mouser.at/ProductDetail/Amphenol-FCI/10018783-10200TLF?qs=V%252BXmToedwojeZUI4fPwmPA%3D%3D" id="OWA885bdfdd-23aa-02c6-1e92-5f656d1b7e80" class="OWAAutoLink" data-auth="NotApplicable">https://www.mouser.at/ProductDetail/Amphenol-FCI/10018783-10200TLF?qs=V%252BXmToedwojeZUI4fPwmPA%3D%3D</a><br>><br>> Qty. Unit Price Ext. Price<br>> 1 € 0,439 € 0,44<br>> 10 € 0,372 € 3,72<br>> 25 € 0,332 € 8,30<br>> 100 € 0,316 € 31,60<br>><br>> By making the connector require a dummy plug to connect the internal<br>> power supply into the circuit, it makes it impossible to connect both<br>> DC power and mains AC, so that makes the design intrinsically safe<br>> without using switches.<br>><br>> Alternatively to a PCIE connector I could use some panel mount plug<br>> with 8 pins, have 4 pins for DC input, and have the other 4 pins carry<br>> power from the internal power supply, and similarly use a shorting<br>> plug to use the internal power supply.<br>><br>> Circular DIN connectors start at about 8 Euro per pair of socket and plug.<br>> Circular metric aren't better.<br>> MIL Spec connectors seem to be cheaper. But the mouser search sucks,<br>> so I can't find them by number of pins.<br>><br>> PCIE 8-pin power connectors are real, real cheap - 10 cents a piece.<br>> They're latching (no need for screws and stuff). There doesn't seem to<br>> be a panel mount version, but one could mount a through-hole connector<br>> to a pcb, and have the pcb have screw holes for mounting to the rear<br>> panel. They handle high power - 150W meaning 3A per pin (half the pins<br>> are return pins). Seems like a winner to me. They're also tiny so they<br>> will easily fit in the back of a 1U unit even vertically. The biggest<br>> pain here might be making the rectangular hole and having it look any<br>> good. might be a case for custom die, maybe a small steel job that<br>> uses two bolts to screw together the two cutting parts through the<br>> sheet metal.<br>><br>> "Pin and socket" connectors are the same kind of thing, just not<br>> specifically PCIE 8-pin. Still cheap at roughly 20 cents a piece...<br>> useful alternative if more than 4 rails are necessary.<br>><br>> D-sub connectors carry up to 3A... and are very cheap and can do panel<br>> mount of some sort. But I'll be damned if I use one of those cursed<br>> things for power.<br>><br>> Automotive connectors seem inexpensive too, but I haven't really<br>> looked into them much other than a quick parametric search.<br>><br>> I wonder what everyone thinks of this.<br>><br>> On Tue, Jul 7, 2026 at 6:39 AM cheater cheater<br>> <cheater00social@gmail.com> wrote:<br>>><br>>> Don't you think this may have had something to do with you<br>>> distributing AC power, rather than DC with 0V potential?<br>>><br>>> On Sat, Jul 4, 2026 at 11:33 PM Mattias Rickardsson <mr@analogue.org> wrote:<br>>>><br>>>> Den lör 4 juli 2026 14:23Florian Anwander via Synth-diy <synth-diy@synth-diy.org> skrev:<br>>>>><br>>>>> Maybe, it's a stupid thought, but...: could it be that a device relies on beeing galvanical separated from other devices. I this case the common supply might clash with the devices concept.<br>>>><br>>>><br>>>> This reminds me of a somewhat similar issue I had many years ago:<br>>>><br>>>> I wanted a Korg MS-20 and a Korg KR-55 to share one external power puck. (Swedish-sold old Korgs had a big external power transformer to step down from 220 V AC to 16 V AC, which is then what the instrument then accepts via a plug with 2 flat prongs that doesn't seem roadworthy with European electrical standards.)<br>>>><br>>>> So I made a short splitter Y cable on the 16 V AC side and attached both instruments and turned them on. But then I connected an audio cable between them (or audio cables from both units to the same mixer) and I had a blown fuse! It was apparently not okay to connect those two grounds together when running off the same AC supply.<br>>>><br>>>> /mr<br>>>><br>>>> ________________________________________________________<br>>>> This is the Synth-diy mailing list<br>>>> Submit email to: Synth-diy@synth-diy.org<br>>>> View archive at:<span class="Apple-converted-space"> </span><a href="https://synth-diy.org/pipermail/synth-diy/" id="OWAbebab796-5bb9-6341-5cb4-845d9198d436" class="OWAAutoLink" data-auth="NotApplicable">https://synth-diy.org/pipermail/synth-diy/</a><br>>>> Check your settings at:<span class="Apple-converted-space"> </span><a href="https://synth-diy.org/mailman/listinfo/synth-diy" id="OWA1a9c3b8a-e86c-0a01-1a7a-dfbb5e356ea7" class="OWAAutoLink" data-auth="NotApplicable">https://synth-diy.org/mailman/listinfo/synth-diy</a><br>>>> Selling or trading? Use marketplace@synth-diy.org<br>><br>> ________________________________________________________<br>> This is the Synth-diy mailing list<br>> Submit email to: Synth-diy@synth-diy.org<br>> View archive at:<span class="Apple-converted-space"> </span><a href="https://synth-diy.org/pipermail/synth-diy/" id="OWA7ddbec2a-fb2e-c653-ab7e-47e3682edd6c" class="OWAAutoLink" data-auth="NotApplicable">https://synth-diy.org/pipermail/synth-diy/</a><br>> Check your settings at:<span class="Apple-converted-space"> </span><a href="https://synth-diy.org/mailman/listinfo/synth-diy" id="OWA9bf3b023-c6e6-20b7-0ad9-544713f34e8e" class="OWAAutoLink" data-auth="NotApplicable">https://synth-diy.org/mailman/listinfo/synth-diy</a><br>> Selling or trading? 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