Hi,
I am constructing my digital crossover with UCD180 as the amp pushing the tweeter, mid and woofer. Hwever, I have noticed that when I connect the UCD to the tweeter, there is a "blop" when I switch on the amp. I guess this could be due to some discharge when switching on.
However, after a silence of about 5 sec, I started to hear "tat" "tat" at the freuency of about 1 Hz. The strange thing is that this only happens to the tweeter but not with the mid and the woofer. It happens when I disconnect the preamp as well, so I am pretty sure it is the UCD amp causing the problem.
The tweeter I am using is Raven 2.0 with an input impedence of about 2.5ohms.
Any clue as to what has gone wrong?
Thanks in advance
I am constructing my digital crossover with UCD180 as the amp pushing the tweeter, mid and woofer. Hwever, I have noticed that when I connect the UCD to the tweeter, there is a "blop" when I switch on the amp. I guess this could be due to some discharge when switching on.
However, after a silence of about 5 sec, I started to hear "tat" "tat" at the freuency of about 1 Hz. The strange thing is that this only happens to the tweeter but not with the mid and the woofer. It happens when I disconnect the preamp as well, so I am pretty sure it is the UCD amp causing the problem.
The tweeter I am using is Raven 2.0 with an input impedence of about 2.5ohms.
Any clue as to what has gone wrong?
Thanks in advance
That's what we call a beating, your frequency at 1 Hz...Not a probleme with syncronized amplifier!
Fredos
Fredos
Beating at 1Hz..... 😉fredos said:
With a good design of Class-D amplfier you not have problems with heterodyne signals....
Ackcheng;
I did not know that the Raven tweeters use a transformer, basically the protection kicks in, it's or overvoltage protection in combination with a low impedance load (lower impedance makes is worse) and DC coupling. Or the short circuit protection is triggered because of the low impedance. Personally I guess there is an overvoltage protection going on...
Cheers,
Jan-Peter
ackcheng said:
ackcheng said:
I would not add a resistor. If you have for some reason DC at the output (due to DC coupling), then even with a resistor you can get power supply issues (power supply pumping) that triggers the overvoltage protection. Safest would be to add a high quality capacitor in series with the tweeter. This will protect both amp and tweeter, although I guess the ravens are protected basically already by the transformer.
Best regards
Gertjan
If there is a coupling transformer, then try a coupling capacitor of suitable size in series with the primary. If the transformer is only for the tweeter, you can try 10uF or so... (non-polar type)
Thanks! I am planning to use the digital crossover at 2K Hz. I guess, I better place the caps to cut it at 1K Hz to give enough head room. Will try and report back.
Hi ackcheng,
Which digital xover are u going to use?
I'm planning to use active crossover with the UCD too, but at a much lower frequency.
Which digital xover are u going to use?
I'm planning to use active crossover with the UCD too, but at a much lower frequency.
Jan-Peter said:
Hi Jan-Peter !
how safe is a UCD module ? I mean when it come into protection, is there some dangerous signal in the output (big ploc/dirac, CC ?)
I am interrested by UCD design for my compression drivers wich are very fragile and of course I'm looking specialy to pop free modules (both start and stop) and very low noise. Wich kind of UCD has lowest noisefloor ? symetric ? asymetric, UCD180, UCD400 ?
Is there some news about the HG new modules ?
regards
Marc
fredos said:
Mr ackcheng
i dont think this be beating
phps is from then gnd and power loop
the input gnds are connet together in the crossover ,
but the power is multi-channel monoblock,
and the GND of preamp in poweramp borad is separate,
so they will be a loop there,
u must try how to connet the GNDs in ur amp,
if u can post a pic that about the power loop ?
best rg
fumac
Thanks Guys,
I am happy to report back the after I put in a 27uF cap in series, the problem is solved. Good to know that digital crossover can compensate for phase shifts
I am happy to report back the after I put in a 27uF cap in series, the problem is solved. Good to know that digital crossover can compensate for phase shifts
mbon said:
The UcD modules are safe, but only in combination with our power supplies. However if you use very expensive HF compression drivers I would personally mount a high quality capacitor in series.
All UcD modules will have the same noise level. The noise level will be same between asymmetric or symmetric, however for the best performance we recommend to use a symmetrical connection.
All UcD modules works pop free, switch ON or OFF.
Cheers,
Jan-Peter
Crossover at 2kHz is a bit low for Raven 2 (you'll get distortion).
I don't think you need UCD400 with a tweeter having this high efficiency. You don't even need a watt...
I don't think you need UCD400 with a tweeter having this high efficiency. You don't even need a watt...
http://www.orcadesign.com/products/raven/ravenr2.htm#
Manufacturer recommends 2.5k with 24 db/octave filter. I'd tend to use 3.5k. These ribbons tend to distort if crossed too low.
Manufacturer recommends 2.5k with 24 db/octave filter. I'd tend to use 3.5k. These ribbons tend to distort if crossed too low.
Jan-Peter said:
I use ucd 180 and 400 for my multiamped high sensitivity compression drivers system and with hypex power supply you can hear just a very very low bump when turning on and absolute nothing when turning off. Once I tried high quality capacitors betwen ucd and the drivers and my legs are still trembling for what I heard when I switched on the amp. The same happened to a friend of mine so I never would do that again.
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