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!
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!
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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.
You can find simple wiring schematic of analog sweet spot meter in Mr. Rothacher article
http://blog.audiomaker.tech/pdf/lamp part one.pdf 🙂 Have fun
http://blog.audiomaker.tech/pdf/lamp part one.pdf 🙂 Have fun
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.
I have vu meters in the face of my F5T, which is preferred for the input to the driver, low input or high input (speaker)?
Different meters have a different sensitivity. What I'm wondering, is what circuit requirements might be needed to accomodate a 100uA, 750 Ohm meter in place of a previous 500uA, 650 Ohm meter?