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okay designers and layout artists ... this is my plea for more split rails

Started by midwayfair, April 03, 2014, 08:30:36 PM

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RobA

Quote from: culturejam on April 04, 2014, 02:56:44 PM
Quote from: RobA on April 04, 2014, 05:29:24 AM
I love the TLE2426. There's more to them than just saving space for the generation of a reference voltage. They provide a more stable and better buffered than you get out of even using an op-amp to buffer the output of a resister based voltage reference.

I totally get that. But I can't think of a single time that VREF stability/stiffness was been an issue for a circuit I've worked on. Maybe I'm just lucky, or maybe I'm ignorant to the benefits. ??
I think it often doesn't matter, especially in circuits where you only have one or two Vref connection points. The places where I've been using them lately have several and I need them to be stable and not interact, like multiple differential inputs to transistor based differential amplifiers. Using the TLE2426 does seem to help with dialing in the circuit in these cases.
Affiliations: Music Unfolding (musicunfolding.com), software based effects and Rock•it Frog (rock.it-frog.com), DIY effects (coming soon).

GrindCustoms

Quote from: RobA on April 04, 2014, 02:10:45 PM
Quote from: raulduke on April 04, 2014, 09:44:50 AM
I agree it makes sense to have split rails with Opamp designs. No doubt 'bout that. Makes reading a schematic nice and clear too (like Alan P says, the synth stuff all use bi-polar).

Those VRef Ic's also look pretty neato. Seem to remember them being used in some Subdecay designs.

Like CJ says though, compated to the cost of a few R's and C's it just doesn't add up, and there is usually a spare op-amp stage with most circuit designs to buffer the Vref line.

I hope in the future the guitar pedal world will just ditch the 9V 'standard' and move onto something more appropriate (18V or +9/-9V). The only reason I know it is used is because of the PP3.

Batteries suck, so hopefully they will become less and less common with pedals (I still have to include a battery snap for most of my customer builds on request though).

I really agree about wishing for a move past the silly 9V thing. I'd move to a +/-12 external power supply for my pedals if I could figure out a connector to carry the three voltages that would work with pedals. There are some out there, but they all seem to be huge. I've also been leaning towards moving to a rack mount system and then using a MIDI pedal to control everything.

You ever thought of using Mini-XLR, we use those plugs and jacks on many microphones or body packs, you'd have ground and your + and - ;)

And they're quite affordable too.
Killing Unicorns, day after day...

Building a better world brick by brick:https://rebrickable.com/users/GrindingBricks/mocs/

RobA

Quote from: GrindCustoms on April 04, 2014, 04:50:51 PM
[...]
You ever thought of using Mini-XLR, we use those plugs and jacks on many microphones or body packs, you'd have ground and your + and - ;)

And they're quite affordable too.

No I hadn't, because I didn't even know mini-XLR jacks existed, but now I do :). It does look like a possibility too. Mouser's prices are a bit steep on the connectors. Where do you get yours?

I had thought about using a 3.5mm TRS jack and cable, but I'm a bit concerned about going that path because none of the connectors I've seen are rated for the voltage or current. I take it that the mini-XLR's are rated to take a phantom power supply. Is that right?
Affiliations: Music Unfolding (musicunfolding.com), software based effects and Rock•it Frog (rock.it-frog.com), DIY effects (coming soon).

GrindCustoms

Quote from: RobA on April 04, 2014, 05:27:42 PM
Quote from: GrindCustoms on April 04, 2014, 04:50:51 PM
[...]
You ever thought of using Mini-XLR, we use those plugs and jacks on many microphones or body packs, you'd have ground and your + and - ;)

And they're quite affordable too.

No I hadn't, because I didn't even know mini-XLR jacks existed, but now I do :). It does look like a possibility too. Mouser's prices are a bit steep on the connectors. Where do you get yours?

I had thought about using a 3.5mm TRS jack and cable, but I'm a bit concerned about going that path because none of the connectors I've seen are rated for the voltage or current. I take it that the mini-XLR's are rated to take a phantom power supply. Is that right?

Connectors are a bit over priced on Mouser, check for B&H, that's where i buy all my Pro-Audio supplies.

And yes! It's made to receive 48V phantom power, the plugs are also available right angled. The Jack is the same size than your standard barrel type DC jack with internal nut.
Killing Unicorns, day after day...

Building a better world brick by brick:https://rebrickable.com/users/GrindingBricks/mocs/

stecykmi

Quote from: RobA on April 04, 2014, 05:29:24 AM
One thing to note is that if you use them to actually split the rails and use the center as an actual ground, then you probably are going to need an isolated power supply or use it with a battery. That's not an issue that comes up when using the charge pumps.

this is kind of a big downside, actually.  :-\

RobA

Quote from: GrindCustoms on April 04, 2014, 05:47:35 PM
[....]
Connectors are a bit over priced on Mouser, check for B&H, that's where i buy all my Pro-Audio supplies.

And yes! It's made to receive 48V phantom power, the plugs are also available right angled. The Jack is the same size than your standard barrel type DC jack with internal nut.
Thanks for the pointer for B&H as a source. I will check them out. The mini-XLR do look like they may work well for this purpose. If I stick with individual pedals, these could be a great solution for power distribution.

Quote from: stecykmi on April 05, 2014, 05:18:28 AM
Quote from: RobA on April 04, 2014, 05:29:24 AM
One thing to note is that if you use them to actually split the rails and use the center as an actual ground, then you probably are going to need an isolated power supply or use it with a battery. That's not an issue that comes up when using the charge pumps.

this is kind of a big downside, actually.  :-\

Yeah, it is. I had been working on a compressor design where I used one of the TLE2426 and had it built on breadboard and was really pleased with it. I decided to test it with another pedal to see how it sounded and was just about to plug them together -- I had the power connected to both of them already and was about to connect the audio jacks -- and it suddenly hit me when I looked at the plug in my hand that I was about to plug together "grounds" at two different potentials. Damn.
Affiliations: Music Unfolding (musicunfolding.com), software based effects and Rock•it Frog (rock.it-frog.com), DIY effects (coming soon).