[mcullinan]

Maybe users of high end audio should take a SPL-alizer test to see if they are ok to drive their new equipment...
Mike

[martyo]

Maybe users of high end audio should take a SPL-alizer test to see if they are ok to drive their new equipment...
Mike

We need more of this kind of wisdom. 

[WEEZ]

gjs_cds,

Thanks for your post.

WEEZ

[MarkM]

I move that we bring some sanity into this discussion.

The manufacture is probably thinking that they can get away with a first order crossover and a low 2KHz Fc because the tweeter's Fs is 500 Hz.  (Assuming that they're using the Vifa XT25TG30-04 ... which appears to be a very safe assumption.)


In short, this speaker design is inadequate for high intensity levels; and it's no surprise that tweeters are being blown if a user sets the volume to concert-level intensity.  I predict that tweeters will continue to be blown if the behavior doesn’t change.  (The gear may have nothing to do with it.)  Further, a 550 amp (rated at 250 watts @ 8 ohms) is entirely inappropriate for a 90 dB efficiency speaker @ 4 ohms.  (Thereby putting the AvaHifi amp functionally in the 400 to 500 watts range @ 4 ohms, I'm estimating.)  That flushing sound is the emptying of a wallet. 

Good research.   If you want to keep pushing your speakers, you should consider the option of inserting a fuse in series with the tweeter of your speakers.     Resolution might be compromised.

[Wayner]

ricmon,

We all care for you here at Audio Circles, but......volume control at 2 o'clock? Man, you are going to have hearing loss in just a few short years. That extreme volume in even a large living room has no where to go except to your eardrum, my friend. I have a rule of midnight with the volume control, and thats when I've had some beers. Normal listening with a happy volume can be done at 10-10:30 on any receiver or amp/preamp combo. The 2 o'clock zone is kill zone for the ear components.

Try and find a happy zone in a lower volume setting and leave it there. My car can go 130 MPH. I don't need to know if it can actually do it. It wasn't designed to operate at 130 MPH. Death probably will result if driven at that speed for extended periods.

W

[mark funk]

First, I have never never never heard of an AVA amp ever failing, not to say it could not happen (take my word for it I know Murphy lives) but I think a lot of people do not really know what real watts are, 250 AVA watts are real watts not paper watts and 250 is a LOT of power and then into 4 ohms, like MarkM said but more likely over 500 watts. I play my Dahlquist DQ10s with a T-5 and 550EXR6, when I like to fire it up I can go to 2:00 ( and DQ10s are hard to drive, but I could never get 117db ) but if my amp was putting out 500 watts that mite, NO that would do a number on the DQ10s too! I would think a 350 would be more then enough for a 90db speaker. What is probable happing is all that 500 watts is turning your voice coils into a pool of molten copper, and with 25 amp fuses, well you mine as well use a penny of a fuse. Not trying to rag but be careful, the 550 is a high, vary high power amp! I hope every thing works out good for you I do not like hearing about people having problems like this. Call Frank he is a good man, he calls it the way it is and that is hard to find these days! And yes I care about you and all of our AVA family. Just trying to help!

[doug s.]

i'd go easy on ric.  first of all, he said the tweeters blew when there was an amp failure, signified w/a tube flash.  and, tweeters usually blow from too little power, not too much.  also, the mfr of his speakers said they should be able to more than handle the power of his amp.  and, most tube amps do not increase power into lower ohm speakers, unlike s/s amps.  i dunno about the ava's in this regard....  also, "2 oclock" on the preamp is completely meaningless w/o knowing the gain/sensitivity of the system.  again, i do not know how much gain or how sensitive ava equipment is...

i suspect there's a problem ric has encountered, & he will get it sorted out, & all will be well w/his gear, & he won't be blowing tweets or his ears....  he's yust blowin' steam cuz he's torqued that he's not able to listen to his rig.  that's happened to a lot of folks every now-n-again, imo...

hang in there, ricmon...   

doug s.

[mfsoa]

I always hated the "oclock" unit - Totally meaningless.

If we talked "%" that would mean a little more, but still without source and sensitivity I guess % doesn't help much either.

 

Goober, I'm curious if you've ever measurd the SPLs you listen at?

[gjs_cds]

Reality check...

First, I have never never never heard of an AVA amp ever failing...

I have had to have two pieces of audio gear repaired in my life.  I have two pieces of AVA HiFi gear.  Both pieces had to be repaired.  I bought both used, one direct from AVA and another off of Audiogon (serial number traced fine).  (I was a PhD student at the time.)  Both failed after about 5 or 6 years after I had possession of them.  The pre-amp switches corroded; a channel went out on the amp.  Frank put in gold plated switches (at my expense), and I paid to upgrade the amp because I wanted the 3 year warranty and because the repair bill was uncertain.  And this isn't to say that I'm dissatisfied with the product or his service; AVA HiFi's (analog) build quality, engineering and sonic results are second to none.  The gear will be in my system indefinitely; buying used gear does have it's risks.

tweeters usually blow from too little power, not too much.  also, the mfr of his speakers said they should be able to more than handle the power of his amp. 

I've been an avid speaker builder for about 11 years now, and I've worked with (and have had long ongoing discussions with) some of the best builders from the DC area and around the US.  With that said, I've never heard of the "tweeters blow because of too little power" theory.  I'd like for someone to explain the physics behind that hypothesis.. because if it's true--I really want to figure that one out.  Secondly, manufacturers lie about (or otherwise mislead the public relative to) their specs all the time.  Even some of the ultra-HiFi amps have been caught with their pants down--and by the ad revenue generating machine Stereophile, no less.

[mfsoa]

I've always heard the "it's too little power that blows speakers" thing.

The thinking is it's the clipped waveforn that does it more than too much oomph.

Not saying it's true, but I have heard it said a bunch of times.

I'd be curious to know if this is an urban myth...

[martyo]

I think a few of us with AVA preamps and amps, both this generation and past generations were simply trying to give a frame of reference as to the "o'clock" references. It does appear from my own experience with a super pas 3i and T5 that the current generation has more gain, although Frank says it's the same. He says what we're experiencing is the increased dynamic range of all the Ultra line and T8, that was even further increased with the 6N1P upgrade. As far as how far you turn the volume knob, the current preamps are usually below 1/2 way, maybe only a 1/3 in BrianM's case, while the older gear was 2/3 to 3/4 when cranking.

[gjs_cds]

I've always heard the "it's too little power that blows speakers" thing.

The thinking is it's the clipped waveforn that does it more than too much oomph.

Yeah--that's what I was guessing too.  Less an underpowered thing, and more a distortion thing.  (Distortion due to pushing an amp beyond it's limits and into clipping?)  If this is indeed the case, underpowered isn't really the problem; it's the misuse of an under powered amp in relation to relatively inefficient speakers.  Regardless, an Ultra 550 does not suffer from this phenomenon.

[martyo]

Hey gjs_cds,

What are the 2+2's? I've been out of the action until recently for a long time. I heard Acoustats the were powered by built in Threshold amps I think, a long time ago.

Sorry for going off topic.

[doug s.]

while tweeters can & do get blown from overpowering them, most of the time your ears will give out before the tweeters.  overpowering a speaker is usually a result of using spl-limited speakers really loudly, in a room too big for the capability of the speakers, or maybe getting carried away at a party or something.      overdriving an amp that has less power than a speaker can handle, however, will result in clipping, & this can easily fry a tweeter.

doug s.

[denjo]

There could be some truth about tweeters blowing with amplifier underpower. Before I stepped up to Thiel CS2.4, I had the baby 1.6s (4 ohm load but a high 90 dB sensitivity). I paired them with my Cary 300 SEI (8w) and it seems this was responsible for blowing the tweeters!!

[gjs_cds]

Hey gjs_cds,

What are the 2+2's? I've been out of the action until recently for a long time. I heard Acoustats the were powered by built in Threshold amps I think, a long time ago.

Sorry for going off topic.

The 2+2s are full-range electrostatic speakers, and mine have the latest Medallion (C) transformer upgrade.  (The boxes behind each speaker is a transformer, not an amp.)  They're not self-powered, are remarkably inefficient, and (I believe) have a nominal impedance of under 4 ohms.  (They require a lot of wattage / current, as do all full-range electrostats.)  So as you can see--AVA HiFi's HC amps are a great choice for the loudspeaker.

The company was sold during the late 80s and then again in the 90s, then again to an Italian company--where it finally went under.  (Although a Chinese co. has recently purchased the name and the designs, so there may be life in the brand nonetheless.) 

Each speaker is approximately 3 feet wide by 8 feet tall and around an inch thick.  Electrostatics are dipolar in nature, and with an approximate 16 square feet of radiating space per speaker--they offer remarkable resolution and quite a soundstage. 

[richidoo]

There could be some truth about tweeters blowing with amplifier underpower. Before I stepped up to Thiel CS2.4, I had the baby 1.6s (4 ohm load but a high 90 dB sensitivity). I paired them with my Cary 300 SEI (8w) and it seems this was responsible for blowing the tweeters!!

Same thing with my Legacy tweeters. My Cary SLI-80 bent them while trying to play a heavy dance CD. Bill Duddleston explained he sees it often. Low power tubes can hurt tweeters when they are pushed to hard with his low impedance designs. He said not so much a problem with piston tweets though.

[avahifi]

Anyway, it is probably obvious by now that with normal source material and normal gain source players (CD, Phono, Tuner, etc) that 2 o'clock on the volume control with a recent AVA preamp and FV550 amp into 90 dB efficient speakers is gonna be blown speakers, or ears, whichever comes first.

But, I still need answers to my questions from my last post herein so I can get to the bottom of the "no  sound now from the preamp" issue.

Thanks

Frank Van Alstine

Just for your info, a new Ultra DAC puts out a plus and minus 3 volt peak signal with a test CD with all the bits turned on.  The OmegaStar, about 2.5 volts. These are in the middle of the "normal" range.

[dB Cooper]

Anyway, it is probably obvious by now that with normal source material and normal gain source players (CD, Phono, Tuner, etc) that 2 o'clock on the volume control with a recent AVA preamp and FV550 amp into 90 dB efficient speakers is gonna be blown speakers, or ears, whichever comes first.

Well, at least the 25 amp speaker fuses won't blow.
Put down that SPLiff ric and let us know wot's oppnin'!

[TjMV3]

If I remember correctly,  you can not use 12AU7 or 12AX7 tubes,  in the line stage,   as a substitute for the 12AT7;  with AVA gear.  Is that correct?   

I could swear that I read somewhere on here (in some post,  quite some time ago) Frank saying,   you could only tube roll 12AT7 tubes from various,  different manufactors.  No other subtitutes.