I read on the dutch version of the website that the extra 2x30V 200mA is for pre amps, VU indicators and it's also there for something I can not translate... a 'difference amplifier'? or perhaps 'Differential amplifier on the output'? Do check with them to be sure wether this applies to your power amp.
The PSU needs 40Vac to achieve he maximum rating of 56Vdc. Two toroids would indicate that the amp is built as two seperate mono power amps, including dual mono psu. A 2x18V Toroid will provide 36Vac for the psu of a single amp.
The PSU needs 40Vac to achieve he maximum rating of 56Vdc. Two toroids would indicate that the amp is built as two seperate mono power amps, including dual mono psu. A 2x18V Toroid will provide 36Vac for the psu of a single amp.
Hans L said:
Well, hmmmph.
The answer is, it depends.
The ring radiator, by function of it's design, will be similiar to other ring radiators.
On the other hand, there is no way to know without testing it.
I've seen drivers where the more expensive sibling tests better and examples where it tests worse.
I do agree that, without a head to head comparison between say, and xt25 and the corresponding Scan ring radiator, no clear conclusion can be made.
R2904 Distortion
Hi, I'm using R2904/7000 and found this forum when searching distortion data.
I read this thread and I decided to measure distortion myself.
I used distortion meter for amplifire and result may include some errors.
Absolute value should be unreliable but I can find good XO frequency any way.
I measured at 30cm position and input signal was 1Vrms.
THD data is as follows
2KHz:1.9%
2.5KHz :1.6%
2.8KHz:1%
3KHz:0.7%
3.2KHz:0.4%
3.5KHz:0.24%
4KHz:0.25%
5KHz:0.24%
6KHz:0.24%
Hi, I'm using R2904/7000 and found this forum when searching distortion data.
I read this thread and I decided to measure distortion myself.
I used distortion meter for amplifire and result may include some errors.
Absolute value should be unreliable but I can find good XO frequency any way.
I measured at 30cm position and input signal was 1Vrms.
THD data is as follows
2KHz:1.9%
2.5KHz :1.6%
2.8KHz:1%
3KHz:0.7%
3.2KHz:0.4%
3.5KHz:0.24%
4KHz:0.25%
5KHz:0.24%
6KHz:0.24%
ShinOBIWAN said:
With the Fs as low as it is on this tweeter it allows you to crossover fairly low. When I said the other systems were crossed at 2.2kHz it was with other tweeter from SS that had slightly higher Fs, so 2.2 should be a very good place. IIRC the general rule is 2 octaves above Fs. With a 4th order filter, this should be as close to perfect as you will get.
This general rule of thumb isn't needed when you have access to freq, waterfall and distortion plotsArthur-itis said:
It is a guide, not a rule(!). The other SS tweeters are quite different from the ringrad. Some do well below 2K and are less optimal that low.
It should do well with a 4th order filter (resulting in a 6th order or so) if you are able to get higher order filters right.
Hans.
quote:
Originally posted by Arthur-itis
With the Fs as low as it is on this tweeter it allows you to crossover fairly low.
This general rule of thumb isn't needed when you have access to freq, waterfall and distortion plotsquote:
When I said the other systems were crossed at 2.2kHz it was with other tweeter from SS that had slightly higher Fs, so 2.2 should be a very good place. IIRC the general rule is 2 octaves above Fs.
It is a guide, not a rule(!).
That's what a general rule is. A guide.
The other SS tweeters are quite different from the ringrad. Some do well below 2K and are less optimal that low.quote:
With a 4th order filter, this should be as close to perfect as you will get.
It should do well with a 4th order filter (resulting in a 6th order or so) if you are able to get higher order filters right.
Hans.
Agreed. I was simply referencing things I had seen about their other tweeters. I do note that there was mention of the Vifa Ring Radiator but no mention of the fact that Vifa and SS are part of the same company. How much difference is there between the two drivers? I would have thought there would be some similarity in them with the Vifa version being the obvious second to the SS.
Originally posted by Arthur-itis
With the Fs as low as it is on this tweeter it allows you to crossover fairly low.
This general rule of thumb isn't needed when you have access to freq, waterfall and distortion plotsquote:
When I said the other systems were crossed at 2.2kHz it was with other tweeter from SS that had slightly higher Fs, so 2.2 should be a very good place. IIRC the general rule is 2 octaves above Fs.
It is a guide, not a rule(!).
That's what a general rule is. A guide.
The other SS tweeters are quite different from the ringrad. Some do well below 2K and are less optimal that low.quote:
With a 4th order filter, this should be as close to perfect as you will get.
It should do well with a 4th order filter (resulting in a 6th order or so) if you are able to get higher order filters right.
Hans.
Agreed. I was simply referencing things I had seen about their other tweeters. I do note that there was mention of the Vifa Ring Radiator but no mention of the fact that Vifa and SS are part of the same company. How much difference is there between the two drivers? I would have thought there would be some similarity in them with the Vifa version being the obvious second to the SS.
Hi,
In HobbyHifi there was an article on tweeters, a load of measurements, including distortion measurements at 2.000 Hz to decide whether youi could cross them low or not.
The measurements on the R2904-/12x9 (sorry, not the round one) are until 14V (then it's at 107dB).
2nd, 3rd and 5th order harmonics are measured.
I also have the measurements of the R2904/700000 (round), including waterfall, distortion (@ 90dB) etc.
I don't think I'm allowed to post things like that over here?
The big article (with the measurements up to 14V) is in HobbyHifi 1/2004 and the other in HobbyHifi 6/2002
Grtz, Joris
In HobbyHifi there was an article on tweeters, a load of measurements, including distortion measurements at 2.000 Hz to decide whether youi could cross them low or not.
The measurements on the R2904-/12x9 (sorry, not the round one) are until 14V (then it's at 107dB).
2nd, 3rd and 5th order harmonics are measured.
I also have the measurements of the R2904/700000 (round), including waterfall, distortion (@ 90dB) etc.
I don't think I'm allowed to post things like that over here?
The big article (with the measurements up to 14V) is in HobbyHifi 1/2004 and the other in HobbyHifi 6/2002
Grtz, Joris
Differences between R2904/700000 and the Vifa XT300K/4:
The SPL response of the Vifa is better than the SS up to 20k (read: more flat), and it reaches its flat line at a lower frequency
Above 20k, the SS has less deviation from the "zero-line".
Waterfall: under 3kHz the SS is much better, flat after 0.5msec. (flat means more than 25db under zero).
Between 2 and 5 kHz both units have some small peaks at 15 to 20dB under zerom and both dead after about 1.2 msec
About 5kHz the SS is JUST a little better, flat after about 0.3 msec.
Impulse repsonse: The SS is absolutely better here. The distance of the swing back (if it passes zero after the pulse) is about 60% higher for the Vifa.
Distiortion at 90dB average:
2n order: Up to 3kHz it's almost equal, from 3k to 7k the Vifa is a little better, and above 7 k, the SS is a lot better (the SS is at 0.1% while the Vifa is at 0.7%)
3rd order: in the lower frequencies the SS is WAY bettter: SS is at 0.3% at 500 Hz, while the Vifa is at almost 3%. At 1K they're around 0.1%.
The SS drops below 0.1% above 2.5kHz, while the Vifa stays around 0.03% up to 6kHz.
5th order: the SS has a little peak at 800Hz (there it's at 0.03%, and besides that it's under 0.01% from 500Hz to 20 kHz. The Vifa is between 0.01% and 0.03% from 500 Hz to 2k. Above that it's under 0.01%
Hmm...descibing graphics ghehehe
Grtz, Joris
The SPL response of the Vifa is better than the SS up to 20k (read: more flat), and it reaches its flat line at a lower frequency
Above 20k, the SS has less deviation from the "zero-line".
Waterfall: under 3kHz the SS is much better, flat after 0.5msec. (flat means more than 25db under zero).
Between 2 and 5 kHz both units have some small peaks at 15 to 20dB under zerom and both dead after about 1.2 msec
About 5kHz the SS is JUST a little better, flat after about 0.3 msec.
Impulse repsonse: The SS is absolutely better here. The distance of the swing back (if it passes zero after the pulse) is about 60% higher for the Vifa.
Distiortion at 90dB average:
2n order: Up to 3kHz it's almost equal, from 3k to 7k the Vifa is a little better, and above 7 k, the SS is a lot better (the SS is at 0.1% while the Vifa is at 0.7%)
3rd order: in the lower frequencies the SS is WAY bettter: SS is at 0.3% at 500 Hz, while the Vifa is at almost 3%. At 1K they're around 0.1%.
The SS drops below 0.1% above 2.5kHz, while the Vifa stays around 0.03% up to 6kHz.
5th order: the SS has a little peak at 800Hz (there it's at 0.03%, and besides that it's under 0.01% from 500Hz to 20 kHz. The Vifa is between 0.01% and 0.03% from 500 Hz to 2k. Above that it's under 0.01%
Hmm...descibing graphics ghehehe
Grtz, Joris
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