Built Crack with Speedball, Now contemplating Foreplay 3

[pmit2188]

I am truely impressed with the performance of my new crack amp. I love to show people the difference between plugging in to the reciever and then the crack amp. It makes my HD600s sing.
I am thinking about starting a preamp project since the crack amp was so simple and enjoyable. I have Paradigm studio 60 speakers (92db "room" and 89db "anchoic"). Before purchasing my next project I figured I better get my ducks in a row and know what preamp and amp I am going to buy so they work together properly. I also have an Oppo bdp95 for my source with both RCA stereo out and balanced out.  A bench test I read said the RCA out sends just below 2V and the balanced sends around 2.5V I am currently using the RCA out directly to the crack amp and it sounds great (is that OK?). Can I use the balanced out to the Foreplay 3 somehow and will the Foreplay 3 work with another kit amp that delivers more wattage than the kits that bottlehead offer?. Paradigm recommends that you use a 15 to 220 watt amp. I do like to listen to music loud but after building the crack amp I found that the only reason I do that is to here all of the sound. With the crack amp I don't have to listen to it loud to everything planely.  I also like the new subwoofer I am using so it would be nice to be able to send a signal to the subwoofer.
Iv'e been reading some of the posts and I'm sure that some of this is old hat but any input would be much appreciated.  Thanks , Tim

 

[Paul Joppa]

None of our gear uses balanced-line inputs or outputs in stock form, at this point. There are ways to connect balanced to unbalanced gear, though they generally reduce or eliminate the potential benefit of balanced lines. The Jensen Transformers web site has several technical white papers on the subject, which are actually quite good.

The Foreplay is optimized for nominal unity gain operation. It has 10-12dB total gain, so with the control a bit above halfway the gain is unity and the output voltage equals the input voltage - this leaves plenty of extra gain for the rare occasions when you need it, with plenty of lower volume settings for late-night listening.

Consequently, you want an amp whose input sensitivity, combined with your speakers' sensitivity, gives normal listening levels with 2-v peak inputs. Very many amplifiers are much too sensitive, especially if you have sensitive speakers or purchase an amp with much more power than you will actually use.

I have a white paper on the Bottlehead Community page, discussing signals and noise in some detail. It might be of some help. I'm afraid the subject is a bit technical, but I'm glad to help when needed.

 

[pmit2188]

Thanks Paul I'll reread your white page.