VU Meter Driver

JSA1971

Member
Paid Member
2016-01-10 12:38 am
North Toronto
Hello All,

I have always loved the look of analogue VU meters on an amp, so I’ve purchased a kit from eBay that includes this board. Admittedly it is more for the visual entertainment as opposed to function and I may just have it hooked up to my preamp output.

TA7318P VU Meter Driver Circuit Board Stereo Module Tube Amplifier DB Level IC 889970793033 | eBay

The unit has low level inputs to be driven from a pre amp as well as high level inputs for speaker output level measurement. There is not a lot of info or instructions for the board and the sellers information is translated to English, so it is not very clear and my interpretation of the info is a guess at best. Some research from google has indicated though that the high level inputs should only be used on an amplifier that has a negative speaker connection with a ground reference type which I believe the Aleph J and other first watt projects are. A poster on another site drew out the schematic below. My question is if anyone thinks this connection would damage the output of my aleph J or M2x? My curiosity about hooking it up to the speaker outputs is out of curiosity to see what my amp may actually be outputting when cranked up.

Thanks!
 

Attachments

  • FEADEF13-67DE-4D1D-A3E8-8C7E6B536A0E.jpeg
    FEADEF13-67DE-4D1D-A3E8-8C7E6B536A0E.jpeg
    377.6 KB · Views: 705
Last edited:
Note that in this manner, the vu meter will not respond to actual volume of the speakers, but from the signal entering the amp. If would want to see the a needle movement proportional to volume control, you will need to wire it after that pote, and if you want constant measurement of the incoming signal, then wire it before such a pote.
 

JSA1971

Member
Paid Member
2016-01-10 12:38 am
North Toronto
Hope to see pics when it’s complete!

I will definitely post some pics when I’m done. The meters won’t be built into the faceplate of my Aleph J or M2x. I’m building a stand alone unit that can be attached to any amp I build, which will sit on top of the amp. The over all depth of it won’t be too big so as to not block any ventilation holes. I’ve ordered a piece of aluminum for the face plate and will start working on it hopefully over the Christmas holidays. If this goes well (and I learn from any mistakes), I may order another faceplate for my amp and build it into the case.