At the preamp RCA inputs we find audio signal from source DAC, CD player or audio card etc.
Input RCA center is "hot" (+) wire and another connection in the same RCA is " cold" (-) aka "audio path ground".
This audio GND wire are connected directly to the stepped attenuator ground connection point ,
nothing else , not psu ground yellow green wire.
With a lot of free space inside the enclosure you have many possibilites,
MKP polypropylene 10uF ( in horizontal position under the pcb for example) from Mouser etc.
can be nicer upgrade for ultimate sound quality.
🙂 Have fun
Edit : Cooper colour inside the enclosure are metal foil or just painting ?
Get some metal shielding can quiet noise level
Thanks for all of the reply's.
The copper colour is actually thin copper sheet, that is all grounded to the star ground near the AC power entry.
I generally try and use a single star ground to keep things simple but I'll have to saty I spend my life confused about grounding no matter how much read!
I'm terrible with instruction so I'll do a drawing of how all of the grounds are connected to show the actual setup.
The copper colour is actually thin copper sheet, that is all grounded to the star ground near the AC power entry.
I generally try and use a single star ground to keep things simple but I'll have to saty I spend my life confused about grounding no matter how much read!
I'm terrible with instruction so I'll do a drawing of how all of the grounds are connected to show the actual setup.
Ok this is how it's wired, simple right 🙂
All thoughts welcome
All thoughts welcome
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point named PCB GROUND - make that point your star ground
after that, all problems are due to longish wires to Nutube and actual specimen of same
after that, all problems are due to longish wires to Nutube and actual specimen of same
Use different colours stranded wire pairs for internal wiring.
Just do it step by step from B1 Korg build guide,
so many little interesting details about mechanical chassis connections, RCA's together
with audio signal routing and power supply.
You can figure out the principe logic from this process 🙂
Look at B1K build video diyAudio Passworks Korg NuTube Preamp Kit Build Tips & Hints - YouTube
Thank you for all the suggestions I will have a play on the weekend.
How would you describe the noise (there must be some) that comes from your builds while not playing music?
How would you describe the noise (there must be some) that comes from your builds while not playing music?
I've built two units, both according to the build guide. Neither has noise except a little ringing when switching inputs. At listening levels, I can't hear anything when music isn't playing.
My B1K replaced a regular B1. At idle the K has a tiny bit of white noise that the solid-state B1 did not, but that's it.
Air Gap
I used the included foam between the NuTube and circuit board and my preamp is absolutely dead quiet. I think there is a huge variation between tubes and it just boils down to the luck of the draw.
I used the included foam between the NuTube and circuit board and my preamp is absolutely dead quiet. I think there is a huge variation between tubes and it just boils down to the luck of the draw.
^^ This.
There is huge variance in the microphony of the Nutube. Some are quiet, some are very noisy and need multiple noise mitigation strategies.
Most fall somewhere in between.
There is huge variance in the microphony of the Nutube. Some are quiet, some are very noisy and need multiple noise mitigation strategies.
Most fall somewhere in between.
Power supply inside the chassis can bring transformer mechanical micro vibrations,
pollution with his magnetic field and some heat too.
The kit version external SMPS power supply is a better solution to avoid unwanted noise.
Maybe try how your psu perform outside of the enclosure.
Less noisy ?
Close all air ventilation holes with more copper sheet around.
🙂 Kind regards
I bought the Nutube a couple months ago, but still cant figure out why I hear an increased high pitch noise coming from the right speaker. Seems like a capacitor charging and then discharging, actually I need to disconnect the speaker because the sound gets annoying. Does someone experience something similar before?
@ Jtmsrl
In the Mr Pass photo we see the chassis is closed if play music
and don't have any air ventilation holes B1 with Korg Triode
In the Mr Pass photo we see the chassis is closed if play music
and don't have any air ventilation holes B1 with Korg Triode
What's weird is that this is just on the right channel and yes, doing all that. I even have a rubber on top of the Nutube
I think the new design is smarter. Mine followed the old double side foam tape suggestion. The Nutube is fused to the pcb. It’s like cement. Every vibration is transmitted to the Nutube and the pcb acts like a sail. That air gap looks ideal. I would like to remove my foam tape, not sure how. All is not lost, my Nutube has gotten less sensitive over time.
The more I think about moving the power supply the more I like it, because I'm about to build my son a new amp I might put the PSU in that amp. Any thoughts on the best power plugs to bring the 24v across?
What is achieved by closing the vent holes?
Non plastic but all metal psu plug from First Watt article
and B1K build guide step 8
and vent holes close is made against microphony step 56
B1 with Korg Nutube - diyAudio Guides
Edit: Mark Johnson two links with pdf articles about wiring of safety earth( ground) , audio grounds ,
ground loops and much more is very useful for Diyers.
Highly recommended The diyAudio First Watt M2x
Thanks Gentelmens 🙂
and B1K build guide step 8
and vent holes close is made against microphony step 56
B1 with Korg Nutube - diyAudio Guides
Edit: Mark Johnson two links with pdf articles about wiring of safety earth( ground) , audio grounds ,
ground loops and much more is very useful for Diyers.
Highly recommended The diyAudio First Watt M2x
Thanks Gentelmens 🙂