B_Limo, in a lot of cases, the answer is... "It depends"... But here are some specifics as they have applied to class D amp I have used... ROwland M312, Merrill Veritas monos, Belcanto REF100M and REF500M, Rowland M925.
Q: Leave on 24/7?
A: Yes, in all cases... Takes at least 24 hours of playing time for all class D amps in my test set to reach peak performance after being off for a spell.
Q: Plug in its own AC circuit?
A: It depends.... Amps with high degree of power supply isolation like Rowland M925 do not inject much noise back into the AC line, others do. In all cases, you may get slightly better dynamics by plugging power amps in a dedicated outlet.
Q: Stacking or not.... RF leaks?
A: It depends again on degree of isolation... Newer amps like Rowland M925 and Merrill Veritas do not leak RF... Try moving an FM radio on top of them... You will not hear any additional hash on the radio... IMO stacking is OK with these... Both amps are based on Hypex NCore NC1200 modules.
Q: What power cords?
A. Use high current capable power cords... with class D amps, instant current swings/transients can be huge. Do not use analog cords for low power applications, nor old style "digital" cords like the old Shunyata VX.... They will "caramelize" the sound. Note that some cable manufacturers might have today new styles of digital-ready PCs that handle high current class D amps... E.g. Check with the Shunyata factory for their recommendations.
Let me know if you have further questions. G. |
Hi Mapman, what is fascinating is that the NCore NC1200 modules do not seem to leak RF into the air regardless of power supply design.... Merrill Veritas use the basic non regulated Hypex SMPS that matches the power conversion module... While Rowland M925 uses a custom massive multi-regulated SMPS.... Neither amps generate any extra noise in an FM tuner operating near them.
Perhaps Tim can do the test on his D-Sonic powered by the AbleTech module and tell us results.
All, please note that if some RF leak occurs, that does not mean at all that the particular class D amp does not generate good music... the ICEpower ASP1000-based Bel Canto Ref1000 Mk.2 and Rowland M312 remain absolutely marvelous amps... Just do not stack an FM tuner just on top of them.
G. |
Hi Mapman, no I have never had an amp manufactured by Class D Audio in my system. |
Yep... Worth pointing out that my old Rowland M7 monos, which were almost class A amps, reached best performance after one week (yes, that is 7 days) of operation... Tried that one fine Christmas break... The creatures sucked up 720W per side for some three weeks... By the end of the first week they did sound really golden... When wifie received the AC bill she almost threw me out of the house.
May Gaia bless class D... Rowland M925 monos are on 24/7, and I never heard one peep of complaint from Mrs. Better Half.
G. |
Hi Richard... Congrats for M525!!!!
Is the unit new or used? If used, how many hours on it? Overtight bass is likely to relax with more playing time.
G. |
Hi Richard, I suspect that the perceived lack of bass impact with Rowland M125 in your system might have been a meer lack of overall power rather than an architecture issue in the device... Assuming that the overall size of images and stage was not too far from desired when using a single unit, If you used a pair of M125s in bridged configuration you would likely to achieve correct base response, and overall excellent imaging and staging proportions. G. |
Hi Richard, if a single M125 created a great stage and images in your large room, M525 is sure to be amazing for those parameters.... In addition, M525 is known for inducing a great bass experience.
G. |
Thank you Tim, keep me posted... But do not worry too much if you hear a bit of increased hash on the tuner... IMO the impact of a little bit of RF leakage from a class D amp does not necessarily translate into a perceivable degradation of overall system performance. E.g. ICEpower modules seem to leak a bit... Yet, Bel Canto REF1000M and Rowland M312 remain marvelous sounding amps in their own rights. G. |
Could you also give us initial comments on other Rowland M525 parameters compared to Parasound A21....
Overall stage and image sizes;
Authority;
Transients distortion and speed;
Macro and microdynamics;
Harmonic complexity;
treble sweetness in complex passages;
Sense of the recording venue surrounding instruments.
Saluti, G.
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B_limo, if you live around the Springs, there is a Rowland dealer with vast experience in JRDG gear -- My friend Ron of Black Forest Audio keeps a super selection of new and pre-owned gear in his stash, ranging from late 1980s classics to Jeff's latest amps and preamps for you to listen to... 719.475.7501.
G. |
That's exciting Richard.... You basically got an essentially brand new M525 for the priced of a used one! Let us know how things develop. G. |
Thank you Al, I conducted the test with an ancient tuner a few years ago.... Device is a rather low end NAD from approx. 1979. The tuner has a button that causes it to reject interference in FM... If the switch is in the off position, the device picks up very significant statics whenever tuned to weaker stations, and in some days, FM is plainly unlistenable, regardless of station or switch setting... or amp connected to the system. Call it a hyperdistractable/ADD FM tuner... Or just a plainly crappy tuner.
But I might have conducted the test in AM... I just can't remember.
G |
Hi Tim, I recommend that you repeat test walking around with the radio as follows....
Amp 1 on, 2 and 3 off;
Amp 1 off, 2 on, 3 off;
Amp 1 and 2 off, 3 on;
Amp 1 and 2 on, 3 off;
Amp 1 on, 2 off, 3 on;
All three amps on.
G. |
Tim, if you use a battery powered radio, and you find that one of the amps seems to leak, try sliding the radio along/around the amp case, and then along the power cord, the speaker wires, and the input ICs.... There is no telling from where the leak might originate... It might even come from a totally different device... Make no assumptions, as reasonable as they might seem.
G. |
