Fuses for the Shameless!

[frankmarsi]

9-25-06

Dear CSP members, those of you who are fortunate to own AR-LSTs', the threat of burnt out fuses is looming and waiting for you.

Imagine you're really groov'in at high volumes one afternoon and suddenly no sound. First we'd run over to our amps and feel if they're hot to the touch, then over to our speakers to hear if they're still functioning, then after much wasted time we might just see if we're still O.K. to look in the fuse department. Back in the mid ‘70s when I was running only two AR-3a’s with a single PL400 in a larger room I automatically ran the back of the speaker as this was a daily ocurrence for me using 1.5 to 3 amp fuses with “Micro-Static” tweeters instead of the long since burnt AR tweeter.

That's what happened to me several weeks ago and I went nuts trying to find the cause of my speakers not working. Of course being a vintage Phase Linear owner my amps were my first suspect, then loose speaker wires and the interconnects and then finally after a very unsettling 20 minutes I realized it was my fuses. After 35 years of use they finally burnt after a rigorous listening session, why, and how could they do this to me?. I looked everywhere on the web and on foot going to several hardware stores, nothing. Then one PM I found an old 'Mom & Pop' hardware store and this guy had only 2 1/2 amp fuses at almost $4.50 with tax. Well as thick as my skull might be I had a similar experience this past Saturday evening, I mean I was really pushing my four poor old LSTs' and two PL amps. The V.U.meters were nearly at ‘O’ position on peaks. I’m talking about 'balls-to-the-wall' volume levels to all of you low volume level mellow-fellow, "it don't have to be loud for me to enjoy this" listeners out there, where-as I myself am more of the live concert freakish type of listener, generally speaking of course. With of all things, the 'red-neck' favorite; Lenard Skyrd's live, re-mastered version of "Free-Bird" and as anyone who has listened to it at high volumes would know it really pumps out the wattage the last few bars. I went to sleep in my usual ‘ear-ringing’ stuper with out knowing anything was wrong and the next day two speakers were dead- fuses I realized a bit quicker this time, although I still didn’t believe it. Long story made longer here's a fair priced out-let on Ebay, I suggest you stock up while you can, it will come to be when these guys are even more difficult to get than a pristine AR speaker.

Your friend and mine, Frank Marsi

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewI...AMEWN%3AIT&rd=1

[roundhome]

>9-25-06

>Dear CSP members, those of you who are fortunate to own

>AR-LSTs', the threat of burnt out fuses is looming and waiting

>for you.

>Imagine you're really groov'in at high volumes one afternoon

>and suddenly no sound. First we'd run over to our amps and

>feel if they're hot to the touch, then over to our speakers to

>hear if they're still functioning, then after much wasted time

>we might just see if we're still O.K. to look in the fuse

>department. Back in the mid ‘70s when I was running only two

>AR-3a’s with a single PL400 in a larger room I automatically

>ran the back of the speaker as this was a daily ocurrence for

>me using 1.5 to 3 amp fuses with “Micro-Static” tweeters

>instead of the long since burnt AR tweeter.

>That's what happened to me several weeks ago and I went nuts

>trying to find the cause of my speakers not working. Of course

>being a vintage Phase Linear owner my amps were my first

>suspect, then loose speaker wires and the interconnects and

>then finally after a very unsettling 20 minutes I realized it

>was my fuses. After 35 years of use they finally burnt after a

>rigorous listening session, why, and how could they do this to

>me?. I looked everywhere on the web and on foot going to

>several hardware stores, nothing. Then one PM I found an old

>'Mom & Pop' hardware store and this guy had only 2 1/2 amp

>fuses at almost $4.50 with tax. Well as thick as my skull

>might be I had a similar experience this past Saturday

>evening, I mean I was really pushing my four poor old LSTs'

>and two PL amps. The V.U.meters were nearly at ‘O’ position on

>peaks. I’m talking about 'balls-to-the-wall' volume levels to

>all of you low volume level mellow-fellow, "it don't have

>to be loud for me to enjoy this" listeners out there,

>where-as I myself am more of the live concert freakish type of

>listener, generally speaking of course. With of all things,

>the 'red-neck' favorite; Lenard Skyrd's live, re-mastered

>version of "Free-Bird" and as anyone who has

>listened to it at high volumes would know it really pumps out

>the wattage the last few bars. I went to sleep in my usual

>‘ear-ringing’ stuper with out knowing anything was wrong and

>the next day two speakers were dead- fuses I realized a bit

>quicker this time, although I still didn’t believe it. Long

>story made longer here's a fair priced out-let on Ebay, I

>suggest you stock up while you can, it will come to be when

>these guys are even more difficult to get than a pristine AR

>speaker.

>Your friend and mine, Frank Marsi

>

>http://cgi.ebay.com/ws/eBayISAPI.dll?ViewI...AMEWN%3AIT&rd=1

>

>

Frank just go to Home depo the have them

[frankmarsi]

Here's another fine mess I got myelf into!

FM

[dynaco_dan]

Hi there;

Out of curiosity, what do they charge for each fuse at the Home Depot in the USA?

What amperage ratings do they carry, please?

I believe that AR only used 6/10, 8/10, 1 1/4, 2 and 3 amp FNM Cooper/Bussmann fuses.

I believe that, The Larger and Smaller Advent, used 1 amp FNM's.

Dynaco speakers used fast blow fuses.

Littlefuse, makes an equivalent FLM fuse of those sizes, I believe, in case a member comes across these in their travels.

Are the fuses all the same price at the Home Depot?

Are they Cooper/Bussmann FNM or Littlefuse FLM fuses?

As a side note, Fuseone.com was recommended here on this site last year by a member.

I went to that site, out of interest, to see what they had to offer.

Their prices were great, at least compared to Canada.

I sent them a inquiry email about quantity purchases, and also if other models were available as well.

I was going to report back here and write-up about what they had to offer our members.

They had an incomplete model list with prices and quantities on-hand.

I will guess that this is a surplus seller and cannot supply other than what is listed, but, they did list other manufacturers names though.

Strange.

They had 3 different email address's.

One was for orders, one for something else and one for employmnt opportunities.

I tried the first one, no response.

Next I tried the first two, same questions, no response.

Finally, I sent to all three, the same questions, no response, again.

All toll, I sent them about 15 different emails, with no response.

Would I ever do business with them?

Not very likely.

I haven't been back there for months now.

.

I exited this write-up and fortunately, I could get back into it and edit it again.

I feel, it is most prudent, to downsize our fuses, from what AR originally recommended, for our classic speakers.

In the case of the AR-LST's alone, perhaps 1 3/4 or even 1 1/2 amp fuses, might offer more protection, as is, to our scarce, and getting scarcer tweeters, in particular.

This is where I really wish, that we could all, easily install, just in the case of AR-LST's alone, individual proper fuses for the tweeters, mids and woofers.

Separate fast blow fuses, for the tweeters and mids, and a reduced slow blow fuse for the woofers.

I don't think, that there is a single classic 3-way speaker, that can be tri-fused, or tri-amped, without major crossover modifications.

[roundhome]

I'm not sure on the price about a year and half ago I walked in and they had about 10 different sizes my LST had FNM-2 so I grabbed a box paid and walked out.

its about 45 miles from me but next time I go in I will check

Jim

[rrcrain]

>> I don't think, that there is a single classic 3-way speaker, that >> can be tri-fused, or tri-amped, without major crossover >> modifications.

>> Have a good one.

>> Vern

Vern,

Unfortunately, I think your right but thankfully, your statement made me aware that since I HAVE done a minor mod to my AR90 crossovers, I can at least bi-fuse mine (new word?) What fuses would be a decent starting point? I'll make a guess the same fuse could be used on the upper side of my 90s as is used on the upper end of an AR9.

[dynaco_dan]

Unfortunately, I think your right but thankfully, your

>statement made me aware that since I HAVE done a minor mod to

>my AR90 crossovers, I can at least bi-fuse mine (new word?)

.

>What fuses would be a decent starting point?

.. Hopefully there will be an answer to my questions below, Richard.

I'll make a guess

>the same fuse could be used on the upper side of my 90s as is

>used on the upper end of an AR9.

.. We will need to see power handling capabilites, number of comparable drivers and impedance, of both the AR-90 and AR-9 speaker system, for a starting point.

Hi Richard;

Do you have a paper with the recommended fuse type and size from AR for your AR-90's and AR-9's?

Does anyone else have an owners manual for the AR-90 and AR-9 speaker system?

What did AR suggest for fusing both these factory speakers?

What fuse types and styles are other members successfully using presently?

[rrcrain]

AR recommended a 50 watt amp minimum and rated the AR90 to run at 300 watts max with the normal exemptions. The speaker is a 4 ohm design and from the graph, they appear to dip to about 2 ohm at certain frequencies.

AR recommended using a Buss Fusetron Dual Element Type FNM-2. I'm assuming this would still apply for the bass section.

[dynaco_dan]

>AR recommended a 50 watt amp minimum and rated the AR90 to

>run at 300 watts max with the normal exemptions. The speaker

>is a 4 ohm design and from the graph, they appear to dip to

>about 2 ohm at certain frequencies.

.

.

.

.

.

>AR recommended using a Buss Fusetron Dual Element Type FNM-2.

>I'm assuming this would still apply for the bass section.

Hi there;

If AR recommended an FNM 2 amp fuse, then that is for the entire speaker system, not just the woofer.

Generally speaking, the woofer draws far more amperage than the mids and the tweeters.

Because of this, I might suggest, Buss FNM 1 1/4 or Littlefuse FLM 1 1/4 or even 1 amp, for the woofer only.

For referance only, the AR-3A uses a 1 1/4 FNM fuse and the ARLST uses a 2 amp FNM fuse, both have a 12" single woofer.

For the tweeters, my suggestion will be, to use a fast blow fuse starting at 1 amp, because these are quite cheap.

You may increase the amperage rating of either at your own discretion and risk.

I am certain that other, more technically orientd members, will be along very shortly, with their valuable suggestions.

Because this is what I feel is a lower safe limit, only by blowing a tweeter, will you find, that you chose to go up too high, a higher limit than the driver was capable of.

Generally you will find, that a woofer will burn out or blow with an oscillating amp, clipping amps, excessive deep and prolongerd tones and just plain abuse.

The tweeters and mids are more from high frequency extremes, such as fast forwarding a tape machine, with the volume up, an oscillating amp and clipping amps, to name but a few possible causes.

The burn characteristics of a slow blow fuse follows more closely a woofer.

FNM and FLM fuses are costly, about 20 - 25 times the price of fast blow fuses.

Whatever their costs, they are a lot less, both in cost and work, than if a scarce original driver is destroyed.

James has done some speaker fusing on his own home speakers this year.

He was kind enough to download a photo of his very neat fuseholder and interconnecting mounting and wiring.

If you need to see what a safe and very neat installation looks like, there is your opportunity.

Good luck and please keep us up to date with your choices, please.

[soundminded]

Well folks, I did it. Exactly what I know not to do, what everyone who reads advice knows not to do but I tempted fate and did it anyway, and this time I lost. Yes, I damaged one of my 6 bolt AR2a woofers because it wasn't fused and I was making some connections with the amplifier on and I got a loud 60 hz hum. One thing I found out for sure, that woofer will not take 85 watts RMS for very long. The voice coil is clearly damaged, undoubtedly deformed because the driver makes a rasping sound when driven even moderately loudly. I guess I'll be buying a lot of fuses and fuse holders this afternoon. Now everything gets fused. Do as I say, not as I do.

[dynaco_dan]

Sorry for your loss.

[dynaco_dan]

Hi again;

I do hope that there is something positive, that can come out of this for all of us to learn from your accident.

I don't know if you had an FNM fuse of the correct amperage on the back of the speaker or amplifier, whether this would have saved the driver or not.

Perhaps, if there were fuseholders in the amps chassis, such as, but not limited to, Dynaco 150, 400, 410, 416 and the AR Amplifier's.

If these had, perhaps, 3 - 5 amp fast blow fuses ahead of the amplifier terminal strip connections.

Now this would be a safety net, sort of, and then we can have our other speaker rated slow or fast blow fuses outside the amps or on the speakers.

This would add very slightly to the overall resistance, but in my opinion not enough to be concerned with.

[soundminded]

It's in a pile of about a dozen drivers which need repair, mostly refoaming. One day I have to drive down to Millersound and get them all fixed. It's just one more of a million things I have around heer which need repair. I'm a little surprised though, I'd have thought it could take the full output of an 85 watt amplifier... and it can without the voice coil melting but it just must have bottomed out too hard.

I'll be using in line fuses. I've got some fuse holders lying around and I'll just pick up some more. I think for this woofer, I'll fuse it at about 40 watts slow blow which is 2.5 amps into 8 ohms. I'll probably fuse the midrange/tweeter section with a 1 or 1.5 amp amp slow blow fuses too. I guess I'll be fusing everything from now on, starting....soon...I hope. This is the first time I ever damaged a good loudspeaker. At least it was not the AR9s.

[frankmarsi]

10-1-06

After a while of owning my AR-3a’s in 1972, I became a helpless tweeter blow out victim.

I became aware of AR’s ‘fuse-kit’ as it were, a standard AGC fuse holder- (the good old fashion strong kind), and an included 11/4 amp fast-blow fuse, which AR offered from their factory. I installed one on the back of each speaker, even though it would have been hard to change fuses as the cabinets were sitting on heavy walnut brackets mounted on a wall in my bedroom, high up at about 5-7 feet as I varied that height during my speaker placement learning years.

After a few days the horrible task of moving each speaker to ‘re-fuse’ during every listening session became a real drag. I was relegated to playing at only moderate volumes. My amplification was a Dynaco ST120 and Dynaco PAS-3X, both kit built. After maybe ?? or more tweeter blow outs. Acoustic Research so kindly started sending raw drivers to me after shipping became a problem for them after 3 or more returns of both cabinets.

I decided to live with out AR’s tweeter and bought the ‘AR-speaker- owners-dream-come-true’, “Micro-Statics”! Wow, finally a chance to have more high end and listen at higher levels. I then started fusing the AR-3a’ midrange and woofer by using a three amp fuse and the Micro-Static’s handled their own weight. I then went out and bought a 400 watt per channel amp and finally I realized what the AR midrange and woofer were all about, never having to worry about those damn little AR tweeters again.

There have been many occasions when these little M/S’s bailed me out;

not only with my AR-3a’s and 2ax’s, but even with my LST’s.

In my long and drawn out process of building and maintaining my AR systems, I plan on replacing every high end driver with the newer AR replacement and driving each speaker with high powered amps as I presently do. Fuses are the only real way to guarantee that I’ll be protecting these speakers.

These speakers are more than merely collectors items.

My feelings go out to “soundminded” as I am well aware of what losing a woofer feels like. I’ve blown four or so in my life, along with a very large number of tweeters.

The point here is; for one reason or another owners of AR speakers must eventually look for an alternative to AR’s high-end driver and still fuse their entire speaker with properly rated devices. When owners choose to let go of that sweet, but weak AR original tweeter, they’ll all be able to install higher-powered amps and really hear what AR speakers sound like. The actual ‘voicing’ of the speaker may change a little bit, but at least you’ll be able to ‘really’ listen at realistic levels. You’ll get used to the new tweeters and everything will be fine. Beyond the wonderful sound and dispersion of AR’s tweeters, I feel their mid-range and bass are truly their strengths.

Your friend and mine,

Frank Marsi

[roundhome]

>I'm not sure on the price about a year and half ago I walked

>in and they had about 10 different sizes my LST had FNM-2 so I

>grabbed a box paid and walked out.

>its about 45 miles from me but next time I go in I will check

>Jim

lost a fuse in one LST today and went to lowe's they had them for 3.57. each.

LST back up and running today.

buy the way Frank when a LST blows a fuse does yours still put out sound just not much out of the mids and tweetets mine do and if they are not sapposed to after popping a fuse I need to work on the crossover.

?

Jim

[frankmarsi]

>>I'm not sure on the price about a year and half ago I

>walked

>>in and they had about 10 different sizes my LST had FNM-2

>so I

>>grabbed a box paid and walked out.

>>its about 45 miles from me but next time I go in I will

>check

>>Jim

>lost a fuse in one LST today and went to lowe's they had them

>for 3.57. each.

>LST back up and running today.

> buy the way Frank when a LST blows a fuse does yours still

>put out sound just not much out of the mids and tweetets mine

>do and if they are not sapposed to after popping a fuse I need

>to work on the crossover.

>?

>Jim

Jim and all, yeah that's true, mine too.

FM

[dynaco_dan]

Hi there;

The AR-LST's still work, at a very much reduced volume level mind you, even with the blown fuses.