The Elektor Forum will close. See also this link. From Friday March 15st it is no longer possible to log in to the forum. However, the content of the forum will remain visible until the end of March. As of April 1st the forum will definitely go off the air.

Nixie VU meter

HiFi, LoFi, Tubes, Transistors, ICs, Commercial, DIY

Postby janneman01 » Tue Jan 01, 2013 12:00 am

Hello,

I have just completed the nixie VU meter from the 11/2012 issue.
It's working on my bench, and I had to change some component values and add a few components. Also would like to share some typos in the BOM. Anybody out there who build this yet?

jan didden
janneman01
 
Posts: 24
Joined: Thu Jan 02, 2014 10:37 am

Postby janneman01 » Fri Jan 11, 2013 12:00 am

One change I made is to add 100k resistors from the connection between input capacitors C1 and C4 and the ucontroller to ground. Without those, it took a very long time for those capacitors to discharge and the indication only went down very slowly. Anybody else experienced that?
Also, in the BOM there are two trimmers 'P2' - the last one, 1kohm, should be 'P3'.
Lastly, I had to lower current setting resistors R4 & R7 to 330 ohms to get the indication colums up to about 85 mm and make their sensitivity equal. But I realise that this may be due to different tubes I have.
All in all, a very nice project, thank you Elektor!

jan

PS This was also my very first SMD project and it worked first time
janneman01
 
Posts: 24
Joined: Thu Jan 02, 2014 10:37 am

Postby james hill » Sun Feb 17, 2013 12:00 am

Hi Jan

Thanks for the tip, the 100K to ground on the input fixes the response issue. I soldered two SMD resistors to C1 and C4 and linked to ground.

The R4/R7 mod was also necessary, I piggy-backed an additional 1K resistor on top of the original devices.

My IN-9's would still not reach 100% @10mA ,initially needing about double this. I "exercised" the tubes with a HV power supply a ballast resistor and after a couple of "sweeps" they came down to the specified 01-15mA for full scale. Not sure why this should be.

The project was working fine, however I got careless with the inputs, disconnecting them with the unit powered up. This has blown the Psoc, with the Vdd pin now being 2 ohms to ground. I assume this may have been static. I have ordered another chip from Elektor but as a note to others, take care!

I hope Elektor will issue a PCB revision and an amendment to this project so others will not have to botch in additional resistors. I am not sure how the prototype worked without them?

Best Regards,

James
james hill
 
Posts: 4
Joined: Thu Jan 02, 2014 10:37 am


Return to Audio & Video

Who is online

Users browsing this forum: No registered users and 1 guest