At last! I tamed the beast! After a lot of effort, troubleshooting and back and forth got it to work. It turns out that the main issue, I believe, was that I had not installed R23 and C4 in the circuit, which apparently that option is for the big output transistors. Maybe cleaning all the flux, going over a few suspect connections and rewiring everything, had an effect also. With my FW F4, it was working perfectly right nevertheless without any anomalies whatsoever. There is a big 220uf cap in its input circuit, so I guess it has to do with it working.
With my Pass XA25 it turns out that it was responding in its protection mode. This is apparent because it responds with very low gain and does not get hot. It turns out that after installing R23 and C4 the offset output had gone up to almost 1v. Dialed these down to “0” v and everything was ok.
The LS even without break-in sounds very refined, smooth, transparent as hell, soundstage is huge and all the instruments are very palpable. Gain is a little less than with the ba-3, where my attenuator position was usually at the 9-10 o’clock now it is at 11-12. Even with the F4 its position for equivalent output volume is at the 2-3 o'clock position.
But the big surprise was its synergy with the F4. If you want to know how this linestage really sings you have to listen to it thru the First Watt F4. It is really that good, both are that good, a revelation. There is an effortlessness quality that is very special and musical. It does not have the punch and dynamics of the XA but its presentation is kind of delicate or I could say ethereal. I hope that the tribulations addressed above help future builders. Thanks to Wayne for this outstanding design, and I wonder how it would compare with a PL XP-12.
With my Pass XA25 it turns out that it was responding in its protection mode. This is apparent because it responds with very low gain and does not get hot. It turns out that after installing R23 and C4 the offset output had gone up to almost 1v. Dialed these down to “0” v and everything was ok.
The LS even without break-in sounds very refined, smooth, transparent as hell, soundstage is huge and all the instruments are very palpable. Gain is a little less than with the ba-3, where my attenuator position was usually at the 9-10 o’clock now it is at 11-12. Even with the F4 its position for equivalent output volume is at the 2-3 o'clock position.
But the big surprise was its synergy with the F4. If you want to know how this linestage really sings you have to listen to it thru the First Watt F4. It is really that good, both are that good, a revelation. There is an effortlessness quality that is very special and musical. It does not have the punch and dynamics of the XA but its presentation is kind of delicate or I could say ethereal. I hope that the tribulations addressed above help future builders. Thanks to Wayne for this outstanding design, and I wonder how it would compare with a PL XP-12.