dINgO Pup kit BUILD THREAD

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Joe Malone
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Re: dINgO Pup kit BUILD THREAD

Post by Joe Malone »

HI Just noticed this post hadn't been answered.
survivorsound wrote:
Tue Jan 14, 2020 6:29 am

Questions:
  • 1. What happens if unbalanced input impedance is set at 47K, a la Neve opamps used in the fader buffer / gain position? Does the LM4562 or 5532 or any chip care if the fader is 5k or 10k or 600Ω or whatever? Is there an advantage to lowering the input impedance here?
Doesn't matter it will work fine with either load resistor value.
2. What do R14 & R15 do?
R14 & R15 discharge the output caps to 0v to stop pops
3. Are .1uF caps necessary at power pins of each op amp?
Yes for good stability
4. Is there any advantage in the audio band to adding bypass Wimas to C1, C4, C10, C11. and if so, what would those values be?
No but if will not matter if you do.
5. Is there any advantage to increasing the size of C13 & C14?[/list]
No 100uF is heaps for the 2 opamps locally.
Joe :-)
JLM Audio
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MrMesh
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Re: dINgO Pup kit BUILD THREAD

Post by MrMesh »

Hi Joe, similar to a prior question. Is it fine to use a standard 18V plug pack? If yes, would the included 24v zener diodes be fine or would I need to go a different value?
Cheers!

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Re: dINgO Pup kit BUILD THREAD

Post by Joe Malone »

MrMesh wrote:
Wed Mar 22, 2023 8:36 pm
Hi Joe, similar to a prior question. Is it fine to use a standard 18V plug pack? If yes, would the included 24v zener diodes be fine or would I need to go a different value?
Cheers!
You really need at least +/-12v = 24vdc with 12v zeners or +/-18v = 36v with 18v Zeners. With 18vdc plug pack you would need 9v zeners to give +/-9v which will work but a bit low headroom.
Joe :-)
JLM Audio
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MrMesh
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Re: dINgO Pup kit BUILD THREAD

Post by MrMesh »

Thanks. Went with the 48V power pack and 24v zener diodes in the end.

I've used 4mm ply board for the front/back panels of an encosure (which houses the dingo pup), could I use a metal DC jack given no continuity to the remainder of the enclosure? Would I need to chassis ground the XLR input grounds via a separate wire or is not needed?

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Joe Malone
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Re: dINgO Pup kit BUILD THREAD

Post by Joe Malone »

MrMesh wrote:
Fri Apr 14, 2023 9:35 am
Thanks. Went with the 48V power pack and 24v zener diodes in the end.

I've used 4mm ply board for the front/back panels of an enclosure (which houses the dingo pup), could I use a metal DC jack given no continuity to the remainder of the enclosure?
Yes that would work as long as your 48v power supply is fully floating. So no mains ground to 0v etc.
Would I need to chassis ground the XLR input grounds via a separate wire or is not needed?
No the 0v made by the 2 x 24v zeners is connected to pin1 of the XLR's already. And since you are using the dc input the 0v is fully floating but so you can wire any metal parts to 0v or not as it shouldn't make any difference unless you have pots and switches on the front panel which is wood so each control metal outside will need to be wired together and to 0v especially if metal knobs used otherwise it will be easy to inject noise when touching controls. A metal case is better as it automatically shields and joins all controls to 0v.
Joe :-)
JLM Audio
Capturing Audio without Injury

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