I've been considering adding another RB1070 to my hi-fi as opposed to upgrading to a RB1080...
I have Boston Acoustic VR2 floorstanders at present rated at 200Watts running off a RB1070 @ 4ohm (bi-wired).
This what I can conclude...
Keep in mind that my subjective evaluation is based on Boston providing
a speaker with an ideal 8W (W=ohm) or 4W load (all things being equal
inside the cabinet)...
Reason:
"...The damping factor indicates the ability of an amplifier to resist a
change in it's output signal..."
That said, the higher the damping factor (DF) the better the amp tells
the speaker what to do...i.e. who's boss...!!!
From the starting blocks, this will mean the RB1080 (DF = 1000) is far
ahead of the RB1070 (DF = 500) (1-0). Also, 200Watts for the 1080 and
130Watts for the 1070 (2-0).
8W load: Using a normal 16 gauge speaker wire for both set-ups and an
average "speaker wire" length of 3 meters, the DF at the speaker
terminals results in 250 (75% loss) for the 1080 and 200 (60% loss) for
the 1070 . However, its still 250 compared to 200 (3-0). In terms of
wattage, the 1080 delivers a huge 198.8Watts to the speaker whereas the
1070 only manages 129.2Watts (4-0). That said, this results in 0.60%
loss of power for the 1080, but the 1070 only losses 0.62% of its
power...hmmm...close.......still, we can't forget the 198.8Watts at the
VR2's doorstep!!!....so...I guess it's 4-0 in favour of the 1080...!!
4W: Here the 1070 delivers 160Watts and 98.8% of this power reaches the
speaker, i.e. 158.13Watts. Furthermore, the DF lowers to 125 which is
not a good sign..?!! The 1080 delivers approx. 240Watts in a 4W
load...237.16Watts reach the speaker...almost 80Watts more than the
1070, but here too the DF reduces to 142.86. This means that the 1070
losses 37.5% (from 200 to 125) of its DF as compared to a 43.2% drop for
the 1080 in DF...(5-1), but who cares...237Watts is still alot (6-1).
KNOCK-OUT!!! And now the 10 count starts....can the 1070 pick itself
up..??
1: The 1080 is only stable into 4W and 8W, and so too the 1070...
2: The 1070 is bridged....330Watts...; the 1080 cannot be bridged..(6-2)
3: Its DF rises back to 200, but its only stable into a 8W load...(7-3)
4: The 1070 delivers a monstrous 328.06Watts to the VR2...(7-4)...
5: If we shorten the speaker wire to 2meters so that the speaker is on
average 3m away from the pre-amp, then the DF climbs to 250 (7-5)...
6: The wattage increases to 328.7Watts (7-6).
7: 2x1070 is R100 (17US$) less than the 1080...(7-7)...ok...maybe this one is on
the fringes of prejudice (and so is count 6)....HOWEVER......the 1070 is
UP!!!! :T
Ok...who wins...well which one will cost you less to run....In idle mode
the 1070 consumes 50Watts of power which means 100Watts of power is
consumed when idle for the two amps..The 1080 also consumes 100Watts of
power so its still (7-7)...
Sooooo....in the highly unlikely event of a blown fuse or a
reconditioning of the amp, then, the 1080 system is completely down,
whereas the one 1070 can be reconfigured to run in stereo mode and still
deliver either 130Watts into 8W or 160Watts into 4W and there is
effectively no down time, while the other 1070 is being repaired!!
7-8 in favour of the 1070...!!!! And that's that!!!
Conclusion:
Having done this analysis, one question remains...will there be an
AUDIBLE difference?????? Won't know, can't tell, will have to find
out...
Gut feeling: No audible difference!!! Audible differences only
results when the DF drops to below 10..!!!! So does the DF really
matter?
Also, what good is it to have so much power with little control...?? But
still, just knowing of how much power is available can lead to a
prejudiced and subjective opinion of resultant audio quality....!!
Some interesting links on my "research"...
Quick short calculatory facts, with examples...
Damping factor calculator depending on speaker wire...
Audible differences....in damping factors....
I have Boston Acoustic VR2 floorstanders at present rated at 200Watts running off a RB1070 @ 4ohm (bi-wired).
This what I can conclude...
Keep in mind that my subjective evaluation is based on Boston providing
a speaker with an ideal 8W (W=ohm) or 4W load (all things being equal
inside the cabinet)...
Reason:
"...The damping factor indicates the ability of an amplifier to resist a
change in it's output signal..."
That said, the higher the damping factor (DF) the better the amp tells
the speaker what to do...i.e. who's boss...!!!
From the starting blocks, this will mean the RB1080 (DF = 1000) is far
ahead of the RB1070 (DF = 500) (1-0). Also, 200Watts for the 1080 and
130Watts for the 1070 (2-0).
8W load: Using a normal 16 gauge speaker wire for both set-ups and an
average "speaker wire" length of 3 meters, the DF at the speaker
terminals results in 250 (75% loss) for the 1080 and 200 (60% loss) for
the 1070 . However, its still 250 compared to 200 (3-0). In terms of
wattage, the 1080 delivers a huge 198.8Watts to the speaker whereas the
1070 only manages 129.2Watts (4-0). That said, this results in 0.60%
loss of power for the 1080, but the 1070 only losses 0.62% of its
power...hmmm...close.......still, we can't forget the 198.8Watts at the
VR2's doorstep!!!....so...I guess it's 4-0 in favour of the 1080...!!
4W: Here the 1070 delivers 160Watts and 98.8% of this power reaches the
speaker, i.e. 158.13Watts. Furthermore, the DF lowers to 125 which is
not a good sign..?!! The 1080 delivers approx. 240Watts in a 4W
load...237.16Watts reach the speaker...almost 80Watts more than the
1070, but here too the DF reduces to 142.86. This means that the 1070
losses 37.5% (from 200 to 125) of its DF as compared to a 43.2% drop for
the 1080 in DF...(5-1), but who cares...237Watts is still alot (6-1).
KNOCK-OUT!!! And now the 10 count starts....can the 1070 pick itself
up..??
1: The 1080 is only stable into 4W and 8W, and so too the 1070...
2: The 1070 is bridged....330Watts...; the 1080 cannot be bridged..(6-2)
3: Its DF rises back to 200, but its only stable into a 8W load...(7-3)
4: The 1070 delivers a monstrous 328.06Watts to the VR2...(7-4)...
5: If we shorten the speaker wire to 2meters so that the speaker is on
average 3m away from the pre-amp, then the DF climbs to 250 (7-5)...
6: The wattage increases to 328.7Watts (7-6).
7: 2x1070 is R100 (17US$) less than the 1080...(7-7)...ok...maybe this one is on
the fringes of prejudice (and so is count 6)....HOWEVER......the 1070 is
UP!!!! :T
Ok...who wins...well which one will cost you less to run....In idle mode
the 1070 consumes 50Watts of power which means 100Watts of power is
consumed when idle for the two amps..The 1080 also consumes 100Watts of
power so its still (7-7)...
Sooooo....in the highly unlikely event of a blown fuse or a
reconditioning of the amp, then, the 1080 system is completely down,
whereas the one 1070 can be reconfigured to run in stereo mode and still
deliver either 130Watts into 8W or 160Watts into 4W and there is
effectively no down time, while the other 1070 is being repaired!!
7-8 in favour of the 1070...!!!! And that's that!!!
Conclusion:
Having done this analysis, one question remains...will there be an
AUDIBLE difference?????? Won't know, can't tell, will have to find
out...
Gut feeling: No audible difference!!! Audible differences only
results when the DF drops to below 10..!!!! So does the DF really
matter?
Also, what good is it to have so much power with little control...?? But
still, just knowing of how much power is available can lead to a
prejudiced and subjective opinion of resultant audio quality....!!
Some interesting links on my "research"...
Quick short calculatory facts, with examples...
Damping factor calculator depending on speaker wire...
Audible differences....in damping factors....
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