foreplay transformer / kit construction help please

[Paul Joppa]

Sounds like the preamp is working correctly all right. I'd keep a close eye on it for a few hours  while the heavy transformer slowly comes up to full temperature, but if that goes without incident it looks like you're in good shape.

The first couple steps of the volume controls are very large - the details are in the manual for them. In the main Foreplay manual there are instructions for reducing the overall gain, so that the volume controls themselves can be set higher for the same level. That will get you to the range where the steps are less abrupt.

Most systems have too much gain, and it looks like yours is one of them. That's why this gain range adjustment is built into the Foreplay. On the Community page at the Bottlehead site there is a white paper on system voltage levels, if you want to study further - though I freely admit, it's a pretty dense paper and has more than anyone should have to know.

Post back after you have stress-teste the preamp and are comfortable with it, and we'll all congratulate you on sorting a hard problem.  :^)

[Grainger49]

  .  .  .   Also in between checking here for updates, I connected the preamp to the amp and cdp, took a deep breath and flipped the switch... and after turning the selector switch there was music (Cannonball Adderley). But only had it powered for a few minutes due to the high volume. I'm confused by the double volume control though - I don't think I have these correct as they are working like a selector switch - the volume increments are hugh in decible levels.  .  .  .   

John,

This sounds like it plays, but loudly.  If it is the wrong volume level then there might be a wiring swap in the Sweetest Whispers (SW).  Take a look at the picture of the completed FP III in the manual, page 35.  If your wiring is right then the resistors in each step are possibly out of whack.  Another possibility is you need a bigger series resistor for your CDP.  Check page 24 of the manual.  It explains how to choose the resistors (supplied by BH) you would want to use as replacements.

Somewhere PJ has posted explaining how many additional steps on the SW each resistor will give you to reach the same volume level you have with the stock resistors.  That will help you select the right ones too.

[johnl]

Hi Paul, Grainger and all

The preamp's working great, sounds great and no smoke. It was on for over an hour and no problem. The volume's much better as well, with 4 of the 33 resistors replaced with 180s. Now it's time to make it look better.

All your help has made my experience with this kit an excellent experience, thanks again,
John

[Paul Joppa]

Excellent news! Finding and fixing problems is pretty frustrating at first, but eventually the satisfaction of a successful effort counts for more. Enjoy the music!