Extended Foreplay 3 volume switches

[John EH]

Hello all,

Was real active here once and I've been out of the hobby for a few years but still occasionally lurk here.

The volume switches in my extended Foreplay 3 are and have always been kind of noisy and it's high time I change them.  Will probably pop in DACT's however I can't find my old Foreplay 3 manual to figure out which ohm value DACT I need.

Anybody?  Also any other recommendation for a cheaper but equal pot would be appreciated.

John

 

[Grainger49]

Hey John!

The FP III volume control is 15k with a series 33k resistor.  The volume is wired oddly, well to me.  The input goes to the wiper.  The "top" of the attenuator goes to the grid of the VA stage, the bottom goes to signal common.

 

[Paul Joppa]

You can use a 10K or 20K Goldpoint, DACT, etc. Some require enlarging the hole and/or the anti-rotation hole. Some are too large to fit against the wood base - best to check the dimensions beforehand! The "odd" wiring reduces the switching noise when the contacts get worn, when used in a shunt-mode control as is standard with Foreplay. The shunt mode is preferred sonically by many, and it gives you the option to optimize the gain on each input.

You can use an ordinary volume control potentiometer if you wish, but it will increase the gain by 10dB and may give you hair-trigger volume control - depending on your system components. If you do this, I'd use a 50K or 100K pot.

The PEC pots are well regarded and inexpensive, if you prefer continuous adjustment.

 

[STURMJ]

I have used DACT pots and selector. They fit in the base fine.  I Am however, tring to figure out the hair trigger problem with my system.

 

[Paul Joppa]

I have used DACT pots and selector. They fit in the base fine.  I Am however, tring to figure out the hair trigger problem with my system.

See my white paper on signals and noise, on the Community page, if you haven't already.

 

[Grainger49]

I have used DACT pots and selector. They fit in the base fine.  I Am however, trying to figure out the hair trigger problem with my system.

See page 24 of the FP III manual for instructions on curing that.