SimpleSE + Preamp

[skipper]

Hi All,

I have just added a preamp to my SimpleSE for the phono section. The preamp seems to have alot of gain. I do have a 50K volume pot on the amp.

1. Is it best to turn it up all the way and use the volume on the preamp (which then has a lot of gain)?
2. Turn the volume on amp half-way and use more of the preamp volume?
3. Disconnect the volume pot on the amp and use it directly.

If I diconnect the volume pot, will the output then be as if it is turned all the way up? Currently I play it with the amp volume all the way up.

Thanks!

 

[boywonder]

Hi All,

If I disconnect the volume pot, will the output then be as if it is turned all the way up? Currently I play it with the amp volume all the way up.

Thanks!

Yes. Replace the pot with an equal value resistor (50K in this case) to ground, and with top of the resistor connected to the input, it'll be the same as the volume "all the way up"

 

[skipper]

The schematics also are shown not to have the volume pot. Thats originally how I had it but at the time my only music input was an ipod. I controlled the volume through it.
Without the pot or resistor wouldn't that be maxed?

 

[boywonder]

The resistor (or pot) does a couple of things. It provides a load for the source (Ipod, CD player, etc) to drive so you want the resistance fairly high so that the voltage signal from the source stays high. Theoretically, no resistor or pot would be a very high impedance (the source would then be driving the input tube grid in parallel with the grid leak R (R11 &R21)) but if the impedance is too high it can be prone to noise and interference.

 

[skipper]

Ok, that is more clear now. I will leave the volume pot connect up on the amp.

Thank a bunch!