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Post by chipbuttie on May 26, 2024 9:38:02 GMT -6
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Post by doubledog on May 26, 2024 11:57:48 GMT -6
Ingredients look great. Will be interested to hear how it sounds.
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Post by spacecowboy on May 26, 2024 16:13:34 GMT -6
Wonder why they think a Zener regulator is more faithful to the original psu design?
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Post by chipbuttie on May 26, 2024 18:48:41 GMT -6
In the video he talks about the power supply a bit. I dint know much about electronics but they say they wanted it to make the power from a 500 series chassis sag in a similar way to the original console power supplies
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Post by Vincent R. on May 26, 2024 19:22:05 GMT -6
Very nice looking unit. Video has great details. Wish you could order it assembled.
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Post by spacecowboy on May 26, 2024 19:36:19 GMT -6
Why do they think the original console supply sags? Isn’t it a class A design?
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ericn
Temp
Balance Engineer
Posts: 16,059 
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Post by ericn on May 26, 2024 20:06:24 GMT -6
Why do they think the original console supply sags? Isn’t it a class A design? A pure class A design puts a constant demand on a PSU, the constant draw should be pretty easy to build a PSU around because you know exactly what you need. Between the fact that your going to need to pretty much convert the API chassis +- 15 v to 24 volt so your going to have to have voltage converter in the limited space of. 500 series module and the fact that most 500 series supplies are not current monsters, yeah the constant current demand of Neve design could call for some PSU tricks. Just for reference sake each of my Dan Alexander 2 ch rack mount pres comes with a 1 amp supply. |
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Post by guitfiddler on May 26, 2024 22:05:09 GMT -6
I’m definitely ordering a couple, watch this video and see why this will be a really good preamp out of all the clones
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Post by spacecowboy on May 26, 2024 23:21:43 GMT -6
Why do they think the original console supply sags? Isn’t it a class A design? A pure class A design puts a constant demand on a PSU, the constant draw should be pretty easy to build a PSU around because you know exactly what you need. Between the fact that your going to need to pretty much convert the API chassis +- 15 v to 24 volt so your going to have to have voltage converter in the limited space of. 500 series module and the fact that most 500 series supplies are not current monsters, yeah the constant current demand of Neve design could call for some PSU tricks. Just for reference sake each of my Dan Alexander 2 ch rack mount pres comes with a 1 amp supply. Yeah, every Neve module in 500 series converts +/-16 to 24. But their article says they did it by lowering the positive rail using a Zener to simulate power supply sag like the original consoles. But a class A amp doesn’t experience sag, because the current draw is constant. I don’t get it. Maybe someone can explain it? |
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Post by frans on May 27, 2024 2:03:29 GMT -6
Do you guys know the 51x lunchboxes? They have the form factor and connectors of the API lunchboxes and they supply +/-16 and +/-24 volts, possible because the conncetors on the cards don't use all of the little traces on the card connectors. It can be had over at GroupDIY and there's a whole lot of possible PSUs, you choose what you need. There's also a host of 500 modules just for 51x, for example based on old german broadcast modules. So you can use the typical 500-modules and then some.
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Post by Blackdawg on May 30, 2024 10:04:02 GMT -6
I'll have one of these on the way soon I think.
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Post by svart on May 31, 2024 9:20:12 GMT -6
A pure class A design puts a constant demand on a PSU, the constant draw should be pretty easy to build a PSU around because you know exactly what you need. Between the fact that your going to need to pretty much convert the API chassis +- 15 v to 24 volt so your going to have to have voltage converter in the limited space of. 500 series module and the fact that most 500 series supplies are not current monsters, yeah the constant current demand of Neve design could call for some PSU tricks. Just for reference sake each of my Dan Alexander 2 ch rack mount pres comes with a 1 amp supply. Yeah, every Neve module in 500 series converts +/-16 to 24. But their article says they did it by lowering the positive rail using a Zener to simulate power supply sag like the original consoles. But a class A amp doesn’t experience sag, because the current draw is constant. I don’t get it. Maybe someone can explain it? The current doesn't sag, but the voltage will. V=IR or R=V/I or I=V/R.. So if the current (I) is a constant, then as the source current demands change (R) then V must change. They also state that it's what we call a "linear pass regulator" which is actually quite a good type of linear regulator that uses the zener as only the reference for the power transistor base current. The power transistor works as a variable resistor in this method. It burns heat but is fairly quiet. |
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Post by robschnapf on May 31, 2024 10:25:27 GMT -6
Why do they think the original console supply sags? Isn’t it a class A design? Seemed like a solid explanation in the video. it amounts to slew rate of PS and its ability to deliver. |
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Post by spacecowboy on May 31, 2024 22:53:36 GMT -6
Yeah, every Neve module in 500 series converts +/-16 to 24. But their article says they did it by lowering the positive rail using a Zener to simulate power supply sag like the original consoles. But a class A amp doesn’t experience sag, because the current draw is constant. I don’t get it. Maybe someone can explain it? The current doesn't sag, but the voltage will. V=IR or R=V/I or I=V/R.. So if the current (I) is a constant, then as the source current demands change (R) then V must change. They also state that it's what we call a "linear pass regulator" which is actually quite a good type of linear regulator that uses the zener as only the reference for the power transistor base current. The power transistor works as a variable resistor in this method. It burns heat but is fairly quiet. Can you explain this “So if the current (I) is a constant, then as the source current demands change (R) then V must change.” It reads like the current is constant but changes? Why is (R) changing? |
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Post by robschnapf on Jun 1, 2024 11:14:44 GMT -6
I = current
V = voltage
R = resistance
Maybe space cowboy could further elaborate
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Post by spacecowboy on Jun 1, 2024 13:40:47 GMT -6
Current in the output stage is constant. Current in all the modules output stages are constant. So the PSU output current to the whole desk is constant. The source impedance from the PSU doesn’t change. So… what causes a voltage drop? The load presented to the PSU doesn’t change does it?
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Post by spacecowboy on Jun 1, 2024 17:55:42 GMT -6
To look at this I simulated the 1073 based on the original 1073 channel amp drawings. Letting everything come to steady state then hitting it with a near-clip 30 Hz square wave function equivalent to +18dBu out causes a change of current draw of plus 1.5% and then minus 1.5% before it settles back out. On a 32 channel desk that’s like 60 mA total.
The supply voltage at the output stage changes by 180 mV and then stabilizes back to its original average after a few cycles. But this is not changed by the PSU input impedance. It is isolated due to the RC filter including a 470 uF capacitor that feeds the output stage. It seems like it doesn’t matter what you supply it because this time constant will be much slower at 22 msec.
I am not an expert on power supplies, and have no idea what the original desk PSU is like. So I’m really curious if anyone has used an old desk and felt it “sag”? Because I dont understand exactly how that would work.
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Post by russellcreekps on Jun 1, 2024 19:04:07 GMT -6
Love to hear about how this may stack up against the AML ez1073, if anyone has some thoughts…
Liking that this has a trim knob where the AML only has a screw.
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Post by robschnapf on Jun 2, 2024 7:27:21 GMT -6
It’s not audible like say hitting a low E on a tube rectified tweed amp.
not that kinda audible sag.
You never feel the desk buckle.
It’s just the effect of the slew rate just kinda smoothing or rounding things out.
A big beautiful sound.
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Post by EmRR on Jun 2, 2024 7:35:30 GMT -6
I dunno, every Neve supply I’ve seen was a big honkin’ outboard regulated supply. I tend to think it’s the usual screwy sales language, and they’re talking about dropping voltage from a 500 supply to give the correct reading. It’s actually not an advertising point unless misconstrued.
I have compared PSU types on a bunch of class A tube gear - whole Gates SA-50 console (5 pre and 2 pgm), and no sag from any sort of supply. Constant current draw = constant voltage, including amp clipping. If an ancient unregulated tube PSU doesn’t sag a regulated 500 supply surely won’t.
The AML kit is $108 less, and they’ll also build it for you for very little more. Same transformers.
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Post by eyebytwomuchgeer on Jun 2, 2024 11:20:20 GMT -6
Love to hear about how this may stack up against the AML ez1073, if anyone has some thoughts… Liking that this has a trim knob where the AML only has a screw. Having just built some of the 1084s a few months ago, I would probably go that route again given the cost. For just a bit more, you get the entire EQ section. However, the AML 1084 is an insane build. It’s borderline grueling for anyone that doesn’t build electronic kits on a daily basis. I had initially intended to go with these DIYRE 1073s back in early 2024 when they were announced. But I got impatient and went with the AML. Still thinking about picking up a pair of the DIYRE just to see how they stack up. The AMLs are great. One great thing about the DIYRE builds is that they offer troubleshooting. That’s a nice safety blanket for anyone getting into the DIY game. I built a DIYRE 2-space 500 rack and it was a breeze. The directions and components were straightforward. I’d imagine they’ve done their due diligence to ensure a smooth and “easy” build. The AML stuff is very well designed, but they pack a ton of parts into their builds, but the directions are very well written I have a feeling, sonically, you won’t go wrong with either option. But like you, I prefer an actual knob for the trim instead of the little screwdriver adjustment. |
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Post by russellcreekps on Jun 2, 2024 20:19:16 GMT -6
eyebytwomuchgeer , thanks for that…also, I see AML offers assembly at a reasonable fee.
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Post by bchurch on Jun 3, 2024 7:16:29 GMT -6
Love to hear about how this may stack up against the AML ez1073, if anyone has some thoughts… Liking that this has a trim knob where the AML only has a screw. I'm going to storm the beach on a pair. Granted I have the AML ez1081's - but I'll decide which pair to keep once I get the DIYRE's built and slotted up. The front panel DI and (to a lesser extent) ability to process line-level signals as an insert are both serious 'nice-to-haves'. It's too bad the 500 footprint is so space-prohibitive, being able to add DIYRE's proprietary COLOUR daughtercards would make these impossible to resist. Speaking of, LinkAudioDesign is out there now with very inexpensive API 3/512 and SSL E/G/J preamp clones that *do* provide that option. |
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Post by bchurch on Jun 3, 2024 7:18:22 GMT -6
eyebytwomuchgeer , thanks for that…also, I see AML offers assembly at a reasonable fee. One thing about Colin/AML's kits that has always driven me absolute batcrap, is that they send pre-trimmed/pre-bent resistors. So you have to stuff several dozen of them onto a small pcb using putty/painter tape to keep them in place when you flip the board to solder. That's always been a head scratcher for me. |
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Post by miadaudio on Jun 3, 2024 15:50:54 GMT -6
eyebytwomuchgeer , thanks for that…also, I see AML offers assembly at a reasonable fee. One thing about Colin/AML's kits that has always driven me absolute batcrap, is that they send pre-trimmed/pre-bent resistors. So you have to stuff several dozen of them onto a small pcb using putty/painter tape to keep them in place when you flip the board to solder. That's always been a head scratcher for me. Why don't you use a piece of cardboard to flip the PCB over? Personally I use this but for one offs ,cardboard works fine. Just make sure you don't leave any pin unsoldered because it's more tricky to miss it if they're pre-trimmed. You can count them. For example, make sure you solder 20 PTHs for 10 resistors. Or just solder the resistors from the top. At least one leg and then you can flip the boards. That's 50% more work though...  |
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