[budyog]

I had my budies over on Saturday and  we watch/listened to Todd Rundgren "Liars" DVD concert. A super show, sounded great, to get that concert feeling  I cranked it up and pushed my system to a new level. I blew both channel 5 amp fuses at the same time! Wow! Things were cooking. I could have grilled a steak on the heat fins of my 350EXR. Good old AVA, At least it did not blow until the show was over and we put some other music on.
We were now done that evening, I shut things down and the next day, replaced the fuses and I am rocking again.
Boy, did it sound GOOD!. If you like Todd, get the "Liars" concert DVD, It is blow-away.
 Hey Frank, did I blow them because of the power I was outputting or the heat build up of the amp?

[skrivis]

I had my budies over on Saturday and  we watch/listened to Todd Rundgren "Liars" DVD concert. A super show, sounded great, to get that concert feeling  I cranked it up and pushed my system to a new level. I blew both channel 5 amp fuses at the same time! Wow! Things were cooking. I could have grilled a steak on the heat fins of my 350EXR. Good old AVA, At least it did not blow until the show was over and we put some other music on.
We were now done that evening, I shut things down and the next day, replace ...

The heat doesn't help, but I don't think that the amp would survive being hot enough to melt the fusible element inside the glass fuse. You'd probably see scorch marks on the wall next to the amp too.

[budyog]

I will have to take a look at the wall! The paint is probably peeling.

[skrivis]

I will have to take a look at the wall! The paint is probably peeling.

That's from all the burritos the night before.

I was a big Todd fan when I was younger, but his practice of cramming more playing time on his albums meant they were really compressed. (Narrower grooves for more playing times means less dynamic range.) I have a couple of the CD versions and they're still compressed. Maybe they've been re-released with that fixed...

I also didn't like a lot of his newer material. I prefer his older stuff, going back to the Nazz.

Is the DVD mostly newer stuff?

[budyog]

Skrivis, I put my review of the latest Todd in the "Latest music " thread.

[avahifi]

Lets see, 5 amps into 8 ohms is 200 watts.  So, you were dumping 200 watts into the voice coils of your speakers.  It would have been interesting if you could have put your hands on the speaker voice coils instead of the amp heat sinks!     Ouch!!!

Lucky you did not fuse more than 5 amps or likely you would have been buying all new speaker drivers.

By the way, we have never had a thermal output device failure of Fet Valve or OmegaStar amp in our own chassis design.  Those heat fins are very efficient in getting the heat out of the transistors themselves and out to the extreme ends of the sinks.

Frank Van Alstine

[budyog]

How about from grilling a T-bone?

I won't and don't need to put any bigger than a 5-amp fuse. It was interesting to have both channels fry their fuses at the same time. This is the max I want to go. Thanks for buiding a tank Frank! Back in the days I remember frying all sorts af amps and speakers. I want stuff that is bullet proof and you make it.

[skrivis]

How about from grilling a T-bone?

I won't and don't need to put any bigger than a 5-amp fuse. It was interesting to have both channels fry their fuses at the same time. This is the max I want to go. Thanks for buiding a tank Frank! Back in the days I remember frying all sorts af amps and speakers. I want stuff that is bullet proof and you make it.

Low bass frequencies are often mono or nearly so. That's probably what took out your fuses.

You're lucky that this wasn't one of those amps where the designer thinks that fuses make things sound bad and doesn't include any protection. You could be replacing a lot more than a 10 cent fuse.

[budyog]

Skrivis wrote

Low bass frequencies are often mono or nearly so. That's probably what took out your fuses.

More than likley!
I have no problem with fuses. I guess in my case as much as I have always pushed my systems to their limit, the AVA stuff with fuses is the reason I am not blowing other things like years ago. It just sounds sooooooo good!
A very cheap fix.

[skrivis]

Skrivis wrote

Low bass frequencies are often mono or nearly so. That's probably what took out your fuses.

More than likley!
I have no problem with fuses. I guess in my case as much as I have always pushed my systems to their limit, the AVA stuff with fuses is the reason I am not blowing other things like years ago. It just sounds sooooooo good!
A very cheap fix.

Oh, one of those. hehe

One of my friends who is still in the music biz has a PA system with 70KW of Crown amps powering the mains. It's neat to look at and eveything, but I'm not sure that I want to be near it when it's working.

He has some JBL 15" drivers hanging on the wall in his garage that were a victim of Pink Floyd. It got so loud that several drivers actually had flames coming from them. (I think this was from the "Animals" tour.)

I sure am glad I wore earplugs back in the day...

So should I tell him to pay you a visit? He can probably surround your house with stacks and you just open the windows.

[budyog]

Skrivis wrote

So should I tell him to pay you a visit? He can probably surround your house with stacks and you just open the windows.

Ha Ha, Skrivis. Now, I do like my music sometimes loud, but quality is another issue and the AVA gear does it right! Quality sound with quality power and quality build. Thankfully, I live on a busy street in a busy area and the sound doesn't phase anyone.

[orb]

I recently inherited a Van Alstine Transcendence 500 Hafler mod.  I'm trying to use it to power the mids and highs of my Infinity Reference Standard Gamma speakers.  And it keeps blowing 5 amp fuses.  I would have thought that this amp was more than capable of this task; after all it's not burdened with the high power demand of low frequencies which it was represented as being equally capable of doing.

Yeah, I like to listen at something approaching control room levels, but always in the past I have been able to hear distortion before it blew fuses or endangered speakers.

I know this is not a current Van Alstine product, but I would like to think they weren't misrepresenting it when they sold it to my father.

Any thoughts?

[avahifi]

The thought is that if you are blowing the 5 amp speaker fuses you are putting more than 200 watts per side into your speakers.

You certainly can make the speaker fuses bigger (up to 8 amp quick blow) but then likely next time you will set your speakers on fire.

The amplifier puts out almost 300 watts per channel clean.  I suspect you are trying to emulate a rock concert in your room.  In general that cannnot and should not be attempted.

Blowing the speaker fuses is not a sign of a fault with the amplifier, it is just a sign it is trying to protect your ears and your speakers from damage.

Frank Van Alstine

[orb]

Mr. Van Alstine,

Thank you.  I am honored by your interest in my posting regarding the T-500.  I have a great deal of respect for your work.  After re-reading my original posting I can see how you might have taken umbrage.  That was not my intent, and I apologise.

That said, I do feel that you were, in turn, perhaps a bit dismissive in your reply.  You suggest that I am in danger of setting my speakers on fire and that I am trying to reproduce a rock concert in my listening room.

My posting stated, perhaps not clearly enough, that the standard I aspire to is sound approaching that which I have heard in recording studio control rooms.  I also have a modest degree of experience in live sound reinforcement.  I actually do know quite a lot about the difference.

High among the qualities which appeal to me about the IRS Gammas is their capability of reproducing control room equivalent sound pressure levels.  This has been mentioned in published reviews by people who have the opportunity to compare them with many more systems than I can.  They are clean and dynamic -- qualities which I also ascribe to those of your products with which I am familiar.

As the topic of this thread indicates, I am fully aware that I am "pushing the limit."  I chose to enter a post here partly out of frustration and partly in hopes of eliciting information which would help me understand where that limit is in my current system.  The 5 amp fuses are blowing at a lower SPL than I have observed with other amplifiers in the same system.

And so far, even when I am at my most exuberant, the amplifiers (and in one case the house wiring) have crapped out before the speakers exhibited any signs of distress (flames, etc.)

I have thus far not seen or heard anything to indicate that the IRS Gammas present a particularly difficult load to an amplifier.  But I also cannot find any definitive information about the load they do present.  The system is nominally 4 ohms, but bi-amped, as I am running it, I have found nothing to indicate what the dynamic load characteristics are for each amp individually.

It follows that I have no way of knowing how your amplifier relates to this speaker system.  I would like to hope that blown fuses are a diagnostic tool rather than merely protection from bleeding ears.

I would appreciate any information you or anyone else might offer.  In the meantime, the system is pleasing to listen to.  I do not always have to "push the limit."  And when I get the itch to do so -- fuses are cheap!

Ray Baisden

[avahifi]

Again, all the blown fuses are telling you is that you are putting more than 200 watts sustained into your speakers and that is too much for safe operation of the speakers or your ears in a normal home enviornment.

But, if more is necessary, fuse bigger up to 8 amps.

And if that is not enough, find a decent used Hafler P500 version of the DH-500 amplifier.  It has a significantly larger power transfomer and with our OmegaStar 500EX circuits installed will make 400 watts per channel stereo, or 1200 to 1600 watts bridged mono with one of our OmegaStar phase inverter.

Frank Van Alstine

[skrivis]

High among the qualities which appeal to me about the IRS Gammas is their capability of reproducing control room equivalent sound pressure levels. This has been mentioned in published reviews by people who have the opportunity to compare them with many more systems than I can.

Which is why I carried a pair of ear plugs around with me all the time when I worked in the music biz... some engineers and producers just got carried away. (As did some musicians.)

One of the most useful things I did for people was to get them to turn it down so they could actually hear.

[orb]

I am puzzled by the responses to my post which seem eager to assume that I am talking about unreasonable and potentially damaging sound pressure levels.

I agree with the previous poster that uncomfortable, and perhaps dangerous, sound levels do occur, although it has been my experience that this happens far more often in live performance than in the studio.  

I've used earplugs too, but never in a studio (they're not exactly conducive to mixing; it would wind up being too loud with signifcant frequency imbalance).  And I've even walked out of a few concerts which were just insane.  I must be doing something right because at the age of 59 I can still hear the full frequency range from 20 to 20khz.

Competent engineers in reputable studios hardly ever get carried away with their levels, but a good control room reference system is capable of reproducing highly dynamic sound which can require remarkably high momentary peak power capability.  The power demand of a given signal is also affected significantly by the resistive load the speaker presents to the amp, and this changes at different frequencies.

I would really appreciate hearing from anybody who has any information or experience with the load characteristics of the Infinity Reference Standard Gamma speaker system, particularly of the mid and high bi-amp set up.

Thanks for the interest and concern, but please accept my assurance that I am not a reckless fool bent on sonic mayhem.

[skrivis]

I am puzzled by the responses to my post which seem eager to assume that I am talking about unreasonable and potentially damaging sound pressure levels.

I agree with the previous poster that uncomfortable, and perhaps dangerous, sound levels do occur, although it has been my experience that this happens far more often in live performance than in the studio.  

I've used earplugs too, but never in a studio (they're not exactly conducive to mixing; it would wind up being too loud with signifcant frequenc ...

Well, you're driving just your mids and highs, and blowing 5A fuses. It's possible that the amp is seeing almost a dead short from the speakers, and this would blow fuses pretty quickly. However, assuming that these speakers present a rational load and are moderately efficient, that's an awful lot of power to be dumping into each channel. Thus the comments that you're pushing it too loud.

I kept earplugs with me because I couldn't always control the volume level. Some people confuse loud and dynamic.

Dynamic music can certainly produce peaks of 200W at the speaker without the average level being unreasonable. Those peaks aren't likely to blow fuses though, since they're of very short duration.

200W is also a lot of power to be dumping into mids and tweets. I'd think you'd be seeing some drivers expiring prematurely.

I use 4A fuses to protect my speakers. The only time I've ever blown one was when I did something stupid like plugging or unplugging a patch cable with the equipment on. My speakers are full-range.

I don't even want to think how loud it would be for me to blow 5A fuses, much less 5A just into the mids and highs.

You might want to check and see what kind of load the speakers are presenting to your amp. Is it unusually low or high? Is there possibly a pad in there that's decreasing the level present at the output? You could be just heating up resistors. Could there be very high frequency trash in your system? That could take out the fuses too. (But again I'd think your tweeters would die pretty quickly too.) Are you using really long, thin speakers cables? That would lessen the amount of power actually arriving at the speakers.