Adding a VU meter to champ clone (5F1)

Hello there,

I recently build an tweed champ clone style amp (5F1)
from an STF electronics kit.

Sounds amazing and im wery pleased with it.
However im close to finishing the cabinets now for the amp and speaker.
But before i complete it, i was wondering if its a big deal to add an analog VU meter to the amp?

Basicly i have been looking at this:

http://www.ebay.com/itm/VU-meter-for-recording-audio-level-warm-back-light-/330509042731?pt=US_Audio_Cables_Adapters&hash=item4cf3dfc42b

Is it rocket science to add this to the 5f1 circut?
if not.. then how ? :)

and what part's do i need to complete it.

Thanks

Regards:

Danny

I did that to one of my amps (a simplified, one channel brown Deluxe, with 6L6s):



http://i136.photobucket.com/albums/q162/AshCaster/My%20Amps/Brown%20Deluxe/6L6-6G3-build-green.jpg



From the eBay link, I'm not sure if that's 6-12v DC or AC. If it's AC you can simply borrow some of your tube heater supply voltage. If it's DC, borrow some heater supply and rectifiy it with some SS diodes.

For parts:
Basically, you'll need a 3-10 watt resistor (there is a way to calculate the value, but I forget). You take the signal from the output jack, feed it to the meter terminals, and use a resistor to set the meter swing.

http://sound.westhost.com/project55.htm

Although in your application I doubt you need a bridge, one diode will do. The 6V is for the light bulb, they do not care if it is AC or DC.

okey, so basicly i just need the light 6.3v from the heater line.
Then take 2 wires from the output jack and into the meter, and use a high watt resistor to "tune" the meter ? and just put a diode after the resistor so it cant back fire?

Sounds simple enouf, just need to find the correct value resistor

So like this:

http://i48.tinypic.com/6ib0uq.png

I did that to one of my amps (a simplified, one channel brown Deluxe, with 6L6s):
http://i136.photobucket.com/albums/q162/AshCaster/My%20Amps/Brown%20Deluxe/6L6-6G3-build-green.jpg

Uhmmm... Johnny,

D'ya think you could find a little bit bigger meter? lol!

okey, so basicly i just need the light 6.3v from the heater line.
Then take 2 wires from the output jack and into the meter, and use a high watt resistor to "tune" the meter ? and just put a diode after the resistor so it cant back fire?

Sounds simple enouf, just need to find the correct value resistor

So like this:

http://i48.tinypic.com/6ib0uq.png

Im still wondering if this will be the correct way to wire it up?
and what to choose for the resistor.. and pot instead mby? so i can fine tune the calibration? but rly no idea on the value

The meter is 500μA full scale, so a quickie approximation is to assume the meter has no resistance. The amp is about 5W, let us say an 8 ohm speaker with about 8V peak. So with Ohms Law (you do know your Ohm's Law, right?) take the voltage and divide by the current which gives you the resistance needed. So 8V / 0.0005A = 16k. There are other considerations but this will get you in the ballpark. So try a 15k 1/2 watt resistor. Adjust up or down to taste.

The meter is 500μA full scale, so a quickie approximation is to assume the meter has no resistance. The amp is about 5W, let us say an 8 ohm speaker with about 8V peak. So with Ohms Law (you do know your Ohm's Law, right?) take the voltage and divide by the current which gives you the resistance needed. So 8V / 0.0005A = 16k. There are other considerations but this will get you in the ballpark. So try a 15k 1/2 watt resistor. Adjust up or down to taste.

Thanks!

Just ordered the meter and a 15k 2w pot, shud get me in the ballpark :)