Most Mosfet output amps do not have a hard edge on the leading end or trailing end - at least not the laterals (iirc) like the Hitachi ones...
But Nico, still don't have a quantitative number regarding the benefit of the higher rails on the driver... that would be interesting.
_-_-bear
But Nico, still don't have a quantitative number regarding the benefit of the higher rails on the driver... that would be interesting.
_-_-bear
Bear,
there is no definitive answer, calculate the second and third order intercept, simple as that. Harmonically related distortion relates to second order and inter-modulation distortion relates to third order intercept, you should be familiar with theory. If you are not, then just run simulations with two different supply voltages, and draw your own conclusions. It is not interesting it is just fact.
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MiiB,
if I understand correctly you have a need to connect the amplifier to something other than you have defined. Well one really starts a design with a specification and there you should define how you will handle exceptions.
In other words if there is some pre-amp out there that someone might use that puts out more than what you expect then you either insert an attenuator, or the amp gets driven into clipping and it exceeds its design specification, else you add some form of automatic gain control or gain compression that prevents the amp from being driven into clipping.
there is no definitive answer, calculate the second and third order intercept, simple as that. Harmonically related distortion relates to second order and inter-modulation distortion relates to third order intercept, you should be familiar with theory. If you are not, then just run simulations with two different supply voltages, and draw your own conclusions. It is not interesting it is just fact.
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MiiB,
if I understand correctly you have a need to connect the amplifier to something other than you have defined. Well one really starts a design with a specification and there you should define how you will handle exceptions.
In other words if there is some pre-amp out there that someone might use that puts out more than what you expect then you either insert an attenuator, or the amp gets driven into clipping and it exceeds its design specification, else you add some form of automatic gain control or gain compression that prevents the amp from being driven into clipping.
I dont like to use mosfets for the output-- matter of personal taste I presume....but I do feel that pure mosfet designs lack the expansion and dymnamics of the best bjt designs.
When simulating bjt outputs i see vertical flanks at the trailing edge....This will effectivly destroy tweeters....So it's not very disireable...
http://www.diyaudio.com/forums/attachments/solid-state/158743d1266543249-recovery-clipping-soft-clipping-saturation-recovery.jpg
When simulating bjt outputs i see vertical flanks at the trailing edge....This will effectivly destroy tweeters....So it's not very disireable...
http://www.diyaudio.com/forums/attachments/solid-state/158743d1266543249-recovery-clipping-soft-clipping-saturation-recovery.jpg
Nico....
i dont need the amplifier to do anything else than expected..but as you now...nothing in this world is limited to sensible and prescribed use....steroids are used in sports and preamp's with big voltage headroom and party teens exist in every in every country...
question is how do we best prevent accidents....and what is the sonic cost if any of doing that...
i dont need the amplifier to do anything else than expected..but as you now...nothing in this world is limited to sensible and prescribed use....steroids are used in sports and preamp's with big voltage headroom and party teens exist in every in every country...
question is how do we best prevent accidents....and what is the sonic cost if any of doing that...
The same way manufacturers of super sports cars do. Don't drive and drink, you will be sorry.😱
I don't see you point, if an amp clips whether it is transistors , mosfets, whatever, then it will eventually destroy your tweeters. Now how do you prevent a clipped media. In otherwords the recording is clipped. I have seen many MP3 and CDs that actually clips. The nice name for it is gain compressed.🙄
The main concern is high frequency artifacts at a high level...It will regardless of filtering run straight through....and with ribbons that has no impedance rise at high frequencies....Bam burn destroy....
And your'e right....mis use of any substance no matter how funny it may seem, is at play with master-disaster and destruction....decadence, for some, can be a driving force...
And your'e right....mis use of any substance no matter how funny it may seem, is at play with master-disaster and destruction....decadence, for some, can be a driving force...
MiiB,
what you are saying is that ribbon tweeters are very delicate, can one not transformer couple a ribbon tweeter?
what you are saying is that ribbon tweeters are very delicate, can one not transformer couple a ribbon tweeter?
MiiB is it possible that you are hearing the clipping distortion of bipolar designs and hearing that as "dynamics"??
As far as protecting the tweeter - ribbon or not - from the effects of that high slope you show, I would think a simple inductor will cause that high slope to slew no matter what...?
And, if ur talking high power SR/PA applications, best to have a soft knee limiter before those amps to prevent ever clipping no matter what is thrown at them??
_-_-bear
As far as protecting the tweeter - ribbon or not - from the effects of that high slope you show, I would think a simple inductor will cause that high slope to slew no matter what...?
And, if ur talking high power SR/PA applications, best to have a soft knee limiter before those amps to prevent ever clipping no matter what is thrown at them??
_-_-bear
this as nothing to do with this thread. why have you not mentioned some of scotlands finest. eg,John Martyn,The Bathers,The Silencers,Alex Harvey,Annie Lennox,The Blue Nile,Simple Minds early stuff. (like adog chasing is tail you will never get it all thats the fun of hi end hi-fi )
Nico....
I dont know i ribbons are more delicate than other tweeter-types.. as the they the have good cooling with plenty surface..fair impedance (app 8 ohm)...but they hardly have any inductance...so they don't have the impedance rise with increasing frequency like normal dome type do... so at 100 KHz they will draw 4-6 times the power....so when an amplifier goes basurka....they will most likely be the ones to take the beating...
We have at Raidho full warranty on the tweeter and if they brake we replace...we see a few burnt every year, but the burn ratio is really low compared to other types of accidents...more common is peoples or children's fingers poking..cats climbing the speakers or the cleaning lady trying to dust the tweeter of..physical violence destroys far more than 80% of the tweeters we replace
This forum tends to focus most on its efforts on creating circuits with superb specifications when it comes to deliver a sinewave into a given load...but to me the most interesting and most important is the implementation and correlation to the real world..where conditions is not so ideal and misuse and abuse is rather common...🙂
I dont know i ribbons are more delicate than other tweeter-types.. as the they the have good cooling with plenty surface..fair impedance (app 8 ohm)...but they hardly have any inductance...so they don't have the impedance rise with increasing frequency like normal dome type do... so at 100 KHz they will draw 4-6 times the power....so when an amplifier goes basurka....they will most likely be the ones to take the beating...
We have at Raidho full warranty on the tweeter and if they brake we replace...we see a few burnt every year, but the burn ratio is really low compared to other types of accidents...more common is peoples or children's fingers poking..cats climbing the speakers or the cleaning lady trying to dust the tweeter of..physical violence destroys far more than 80% of the tweeters we replace
This forum tends to focus most on its efforts on creating circuits with superb specifications when it comes to deliver a sinewave into a given load...but to me the most interesting and most important is the implementation and correlation to the real world..where conditions is not so ideal and misuse and abuse is rather common...🙂
MiiB, do you have a tracking number perhaps - I am becoming very anxious to receive the package, I know that I am going to be very impressed with your creation. Every time you say something you confirm that you know have a much deeper knowledge than meets the eye.
Kind regards
Nico
Kind regards
Nico
They have good performance from app 3 Khz...they have natural 1 order rolloff due the a semi-ventilated rear side... so a simple 1. order filter will make a smoth second order 12 dB cutoff...
One upside with the tweeter is that it has no low frequency resonance..so it can be operated in serial crossovers...i have no measuring equipment that can measurer upper frequency...but judged by the impulse response it may well extend to more than 100 Khz
http://raidho.dk/uploads/Raidho-Acoustics-Ribbon-Tweeter-FTT75.pdf
One upside with the tweeter is that it has no low frequency resonance..so it can be operated in serial crossovers...i have no measuring equipment that can measurer upper frequency...but judged by the impulse response it may well extend to more than 100 Khz
http://raidho.dk/uploads/Raidho-Acoustics-Ribbon-Tweeter-FTT75.pdf
MiiB, perhaps we should start another thread on ur tweeter?
The Polar curves are different than the freq response curves - the former appears to show an
upward ~6dB/oct lift to the HF... but again, a very small inductor that acts above 20kHz might serve to keep the impedance up??
_-_-bear
The Polar curves are different than the freq response curves - the former appears to show an
upward ~6dB/oct lift to the HF... but again, a very small inductor that acts above 20kHz might serve to keep the impedance up??
_-_-bear
Bear,
I would like to agree with your request, I am at this moment very keen to learning more about ribbons and their behavior and I think MiiB has a lot of knowledge in their design of course without giving away industry secrets.
Up until now I have only had soft dome SCANSPEAKs but MiiB has wet my appetite with his approach and I have been fiddling with some prototypes over in the past two months.
Nico
I would like to agree with your request, I am at this moment very keen to learning more about ribbons and their behavior and I think MiiB has a lot of knowledge in their design of course without giving away industry secrets.
Up until now I have only had soft dome SCANSPEAKs but MiiB has wet my appetite with his approach and I have been fiddling with some prototypes over in the past two months.
Nico
Bear/MiiB,
you don't think that the inductor normally placed at the output of an amp would suffice? Okay all amps do not have an inductor I guess so this is not a given.
you don't think that the inductor normally placed at the output of an amp would suffice? Okay all amps do not have an inductor I guess so this is not a given.
I have on purpose stayed away from threads concerning loudspeakers..as i don't intend to mix the joy of fiddling with hobby amplifiers with my professional job in designing loudspeakers and drive units....however if u start a thread...I'll be happy to give it a go...I'll revert from the commercial way.. and instead try to explain at little about the fundamental thinking and maybe tell a little about my early prototyping...which the turn has roots and methods spun around the late eighties clone of the old apogees..
bear.. the differences in the two plots is due to differences in the baffel...
bear.. the differences in the two plots is due to differences in the baffel...
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Hi MiiB,
thanks for the info. Very nice features indeed, and nearly ohmic impedance, right? Are the other loudspeaker drivers in your system cone-type?
thanks for the info. Very nice features indeed, and nearly ohmic impedance, right? Are the other loudspeaker drivers in your system cone-type?
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