[jacc1234]

I've had luck attaching the circuit ground to my outlet's ground (don't try this unless you're confident you know what you're doing). Also changing the physical placement of the amp can make a big difference. An old girlfriend left one of those yoga foam block things at my place and it's useful for propping the amp to a sweet spot where there's very little noise. It looks like crap...but closing your eyes fixes that eyesore...and it makes the music sound better...haha.

I have had some luck with re-positioning and depending on how things end up at my office might consider looking into attaching it to a ground.

Are you just attaching the amp ground to the rounded ground slot in the outlet, or are you actually opening the outlet and connecting it to the internal ground wire?

Thanks!

 

[hav2uo4]

I have had some luck with re-positioning and depending on how things end up at my office might consider looking into attaching it to a ground.

Are you just attaching the amp ground to the rounded ground slot in the outlet, or are you actually opening the outlet and connecting it to the internal ground wire?

Thanks!

I just run an alligator clip from the ground of another amp that uses all three prongs and clip it to the barrel connector of my nutube amp. But that wouldn't fly in an office environment...haha. The round slot would be good enough if you re-purposed a power cord and made sure to insulate hot and neutral well so they'll never contact anything. But depending on source, sometimes it's less noisy to let the amp "float."

 

[JImmye00]

I was hoping to build a nice case for this unit. Does anyone have a schematic drawing of a case they built so i know the dimensions of where all my holes need to be drilled? Thanks!

 

[silverfishla]

I was hoping to build a nice case for this unit. Does anyone have a schematic drawing of a case they built so i know the dimensions of where all my holes need to be drilled? Thanks!

I just bought a case that had dimensions for the fit of the pcb and room heightwise, then eyeballed it. Of course, I also lifted the input, outputs, volume knob, power switch to off the board. I can link you to that case if you like. You can see it in a previous post. If you mean that you want a case for your completed project (as per build), I can't really help there...

 

[technicus]

Hello everyone! I just bought the PCBs and got the order in to Mouser the other day. As I was reading the forums about headphones and resistor selections as well as odd noise I have two questions:

1) I have the Sony MDR-V6 headphones (63 ohms), would a different resistor selection be more suitable?

2) Some people were mentioning noise... I was able to find a desktop style power supplies (like your laptop power supply) which were grounded that meet the 24v @ 1A requirement (1.25A if you want to be precise):
Cui 490-SDI30-24-U-P5
Phihong 552-PSAC30U-240L6

Cost of either is about $17.50 so $5 more. I also tend to favor the desktop style as I have power strips and a wallwart wouldn't work usually. I also have this thing that everything must have a ground...

 

[JImmye00]

I just bought a case that had dimensions for the fit of the pcb and room heightwise, then eyeballed it. Of course, I also lifted the input, outputs, volume knob, power switch to off the board. I can link you to that case if you like. You can see it in a previous post. If you mean that you want a case for your completed project (as per build), I can't really help there...

If you could link me the post that would really help. Thanks

 

[JImmye00]

Hope this works...Pete's multi-pot footprint is excellent for hacking a ground connection. I had to file a small notch into the inside of the case to clear the wire.

I just put together everything for my build but the volume pot. dont wanna mess it up since its so expensive. so im guessing that the pot goes in to the rear two rows of holes in the pcb so that the pot is flush with the front of the PCB? next question is from this pictuyre it looks like you soldered in the second from the front and "bridged to the third row? or am i seeing things? last question is ground the pot where is the best place to do this on the pot?

 

[JImmye00]

Well, I'm not real sure what would be causing this. I didn't notice noise like that on the one I built with the upgraded pot.

The noise that was caused by oscillation using the FET was very loud. I would expect a little noise as the pot hits its limits, but nothing terrible.

Pete

Pete, i purchased the upgraded pot that you recommended which rows on the pcb does this pot get inserted into? dont wanna guess and mess it up being it was 40$
Thanks!

 

[johnnyb]

Hello everyone! I just bought the PCBs and got the order in to Mouser the other day. As I was reading the forums about headphones and resistor selections as well as odd noise I have two questions:

1) I have the Sony MDR-V6 headphones (63 ohms), would a different resistor selection be more suitable?

2) Some people were mentioning noise... I was able to find a desktop style power supplies (like your laptop power supply) which were grounded that meet the 24v @ 1A requirement (1.25A if you want to be precise):
Cui 490-SDI30-24-U-P5
Phihong 552-PSAC30U-240L6

Cost of either is about $17.50 so $5 more. I also tend to favor the desktop style as I have power strips and a wallwart wouldn't work usually. I also have this thing that everything must have a ground...

I would think that these types of switching power supplies would be noisy compared to the wallwart. Perhaps someone can recommend a good linear power supply that puts out 24v that would be a suitable wallwart replacement?

 

[jekjek]

I would think that these types of switching power supplies would be noisy compared to the wallwart. Perhaps someone can recommend a good linear power supply that puts out 24v that would be a suitable wallwart replacement?

I am using International Power 24v Power Supply as below

https://www.ebay.com/itm/INTERNATIO...m=302432244590&_trksid=p2045573.c100705.m4780

I bought a new old stock at 5 dollar excluding shipping

 

[technicus]

I am using International Power 24v Power Supply as below

https://www.ebay.com/itm/INTERNATIONAL-POWER-IHB24-1-2-POWER-SUPPLY-120-240V-AC-24V-DC-D575275/302432244590?_trkparms=ao=1&asc=20170105155410&meid=0861ab70ac6e4d13b94c5393cffbd6bc&pid=100705&rk=1&rkt=1&&itm=302432244590&_trksid=p2045573.c100705.m4780

I bought a new old stock at 5 dollar excluding shipping

Somewhere I have a bunch of these that I got from dumpster diving a long time ago... don't know why I didn't bother to check if they were switching versus linear.

 

[jekjek]

Somewhere I have a bunch of these that I got from dumpster diving a long time ago... don't know why I didn't bother to check if they were switching versus linear.

I boxed this power supply using standard ATX PSU case from a computer.
I hope it help this community

 

[technicus]

Got my PCB with the Nutube in today, now I just need the bits. That being said, does anyone know if the PCB was tinned for lead-free?

 

[pmillett]

Got my PCB with the Nutube in today, now I just need the bits. That being said, does anyone know if the PCB was tinned for lead-free?

It has tin/lead HASL (hot air solder leveled) coating.

Pete

 

[pmillett]

Pete, i purchased the upgraded pot that you recommended which rows on the pcb does this pot get inserted into? dont wanna guess and mess it up being it was 40$
Thanks!

The photo above shows it... it should really only fit one way unless you force it. The edge of the pot should be aligned with the edge of the PCB.

Pete