Belles 350a reference fireworks
I had a similar event last year, likewise with a Modwright Pre paired with a Belles 350A ref (WITH the soft-start circuitry). After LOTS of discussion, we suspect the problem originated with the Modwright Pre, as after checking with Dan Wright, I found my unit did NOT have the latest muting/protection circuitry to block DC surges. Turns out, David Belles uses VERY LITTLE protection circuitry in the 350A Ref, which is why it sounds so great! Dan upgraded my Pre to include the latest circuitry (as well as upgrading to the tube rectifier), and David Belles replaced my amp. Both have been singing sweetly ever since. David Belles (and Bruce Jacobs, marketing) are great to deal with and will certainly take care of you. I would also speak with Dan Wright, and have him cross-check your serial number to make sure it has the necessary protection. The power and finesse of the Belles makes it hard to give up, especially when the problem may have lied elsewhere. |
From the Soundstage review; The 350A Reference is also AC coupled, while the 350A was DC coupled. The difference is essentially safety for your system. An AC-coupled amp will not pass DC to the loudspeakers, while a DC-coupled amp will if any is presented at the input. Under normal conditions, this should not be an issue, but, as we know, sometimes stuff happens. There are also sonic considerations here. AC coupling compromises the sound and may limit bass extension in the bottom octave because a capacitor has to be inserted in the signal path to block DC from passing through the amp to the outputs. Dave Belles managed to insert a capacitor that doesnt limit the deep bass (detected by ear or by SPL meter using the DC-coupled 350A as a reference point). Thus, theres no audible harm to the audio signal from the extra capacitor that I can detect. |
Hi guys, this is Dan Wright from ModWright Intruments Inc. It has come to my attention that some people have had trouble with some of our earlier 9.0SE preamps and the Belles AC coupled amp. Our earliest units did allow for elevated DC levels right at power up due to a brief delay between when the mute circuit actuated the mute relay and when the B+ was energized. This has been addressed in more current units and of course addressed with the tube-rectified supplies. If you have any questions, please don't hesitate to contact me via email at [email protected]. The proper and ideal way to power up and down any system is as follows: 1) Power up preamp. 2) Power up amp. Powering Down: 1) Power down amp. 2) Power down preamp. Thanks, Dan W. |
