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I have a 5 channel amp - not mentioning the brand at this stage. It has blown twice the 2.5 years I have owned it, and needed to be sent back to the factory twice - and it has taken quite a long time, each time. Service at the manufacturer wanted to know my specific set up - I am using the speaker cable that my dealer recommended, and installed, but the manufacturer "strongly suspects" that my cable choice, and possibly length of cable, is causing the amp to oscillate and then blow. The cable length isn't dramatic, by the way.
Thoughts appreciated.
Follow Ups:
If your speaker cable is the Transparent Reference XL there are two "networks" in it.
The positive leg of each cable has a 2.5 micro Henries inductor.
The output end of each cable has a 1000 pF capacitor and a 31.7 ohm resistor connected end to end, parallel across the two legs of the cable.
Absolutely. You can, however, install a simple circuit (called a Zobel Network) to mitigate the more common issues certain topologies of loudspeaker cable could present.
Mention the brand.
Probably, but I'd be more worried about cables that might make an amp suck.
Sure can....
I still don't want to mention the specific manufacturers (except to say that neither have been mentioned by others below) but the amp manufacturer "strongly suspects" there is a cable problem and the cable manufacturer is saying that this is highly unlikely. FWIW, the cable is a 10-guage twisted pair from a reputable mainstream cable manufacturer, nothing esoteric, and the cable runs are not long.
Just talked to the dealer, and they will do a bunch of due diligence when the amp returns from repair. There is a good chance I'll be asking the amp manufacturer for a warranty extension.
This has been an enlightening and educational experience, and also a major PITA.
" the cable is a 10-guage twisted pair from a reputable mainstream cable manufacturer".
If the speaker cable is as listed in your profile then it has a network box. Components inside are unknown, but could it be that it is this that your amplifier doesn't like?
NB: If I am right then it would only be fair to identify the cable as otherwise you are asking for advice without letting the people who are trying to help you know about what is a significant departure from a simple twisted pair.
NT
Your secret is safe with me. I won't tell that you have the cables and amp posted on your sytem profile!
But yes, it is the Classe CA-5300 and the Transparent TWP.
Classe has not said anything beyond that Transparent makes a quality product, but they think there is a problem. I did ask them for recommendations, and thus far they have not given specific recommendations.
Like others have stated,when you get the amp repaired use cheap zip cord and see if the cable was causing the problem!
I just setup my HT yesterday after I moved. And you got it - zip cord for everyone. For goodness sakes it's a HT. And just for the record my stereo gets basically the same but in 12 larger gauge.
Another take on speaker wire!
I have read this before. It is interesting, but there are many more designs that have come out since he wrote this. I'd be interested in what he had to say about more current designs.
Dave
I agree!
It was rough going at first but I did get 4 out of the 5 speakers to work.
Funny thing HT is being mentioned. I Am having trouble with setting it up in my new home. I'm having trouble mixing older and newer gear together.
Oh BTW - I DO use lamp cord.
...If you use Naim amplification (seemingly not in your case).
Naim use the inductance of the speaker cable rather than adding components to the output stage in order to provide stability. Hence if the cable used does not provide the requisite inductance then the amp may become unstable and "blow". This is also a reason why Naim recommend a minimum length of their cable.
The above is particuarly relevant for older Naim amps. I understand that modern ones are less vulnerable.
...do not buy poorly designed Naim amplification.
Not my kind of sound regardless of the cables...tight and dry, dry, dry.
For the amplifier to be stable, you need a load on the output stage at RF in order to damp any oscillation stimulated by induced RF. The load is usually a Zobel or R-L or both. What Naim did was to factor the cable impedance into the design of the network. The advantage of doing that is eliminating some passive components between the output stage and the loudspeaker. But in order to take advantage of it, they need control over the cable impedance.
With Spectral + MIT, the Zobel network is in the cable rather than in the amp.
This isn't bad design, it's just a different way of approaching the problem, by looking at things as a system.
I get the design. But the problem is the reality that many audiophiles love to experiment with cables and think they know better than the designer of the amp. Perhaps the cables should have been permanently attached to the amp.
n
I get the design too, and IMHO the manufacturer made a poor design choice.
It's not that the user necessarily thinks he knows better than the amp designer but it is expected that one shouldn't have to worry about blowing up the amp if you choose not to use cables supplied by the amp maker.
If I buy a flashlight made by Duracell should I be forced to use Duracell batteries for fear of wrecking the flashlight?
You are "forced" to use a specific Transmission Fluid with virtually every model car or truck you can buy. Fail to use ATF+4 in your Chrysler Automatic and you can expect to be replacing it in 60,000 miles.Sometimes it matters, sometimes it doesn't, but even with your flashlight analogy, you are "forced" to use a compatible battery.
There are a number of topologies an amplifier designer can choose to explore and implement. Some are more stable than others, even though they may all work into an easy 8-ohm load loudspeaker.
If you want to use unusual cables and loudspeaker loads, then the QUAD 303 is stable unconditionally into any load, including a direct short circuit. Others seem to explode if you look at them funny. It's not like there isn't a choice, but it does help if you meet the amplifier designer half way.
Edits: 11/11/16 11/11/16 11/11/16
n
n
NO, it sounds like for the sake of saving a few bucks in parts they burdened the end user with having to buy wickedly expensive cables as well as taking on an extremely high risk of amp failure.
Hey now that IS a better amp!!!
All else being equal, the fewer the number of passive components between the amplifier output stage and the loudspeaker driver, the better. You need a functioning crossover obviously, but if you can eliminate passive components after the output stage in the amp, why not take advantage of the theoretical performance improvement?Naim's approach eliminates a series resistor and inductor that most other amplifiers require as part of the RF damping circuit, and their approach also provides tighter tolerances on the impedances that make up the circuit.
Naim speaker cables are also on the cheap side compared to what most audiophiles use.
Here's another way to think about it. Some people spend gobs of money on complex speaker cable geometries like Nordost and Cardas to try to minimize the combination of series resistance, series inductance, and parallel capacitance. But inside their amp is usually a Zobel (R-C in parallel with the output), followed by an R-L in series with the output. Instead of spending tons of money to reduce the cable impedance, why not put it to work for you?
Edits: 10/14/16
They came up with expensive version for those who want to spend more on wires!
These Lumina speaker cables are 3300USD/ 3 m pair. Old NACA 5 used to be 10/per foot now it's 25/foot ( plus 88 bucks for Naim banana plugs ) so they are not as cheap as they used to be.
They are becoming more accommodating other manufactures' ware to gain broader customer base.
...that the end user shouldn't be burdened with having to choose special cables for his amp. The amp SHOULD BE engineered to accommodate a very wide range of cables of the customer's choosing. The amp SHOULD BE engineered to that principle. Most are, but there are a few 'tweaky' audiophool amps that are not. ;-)Engineering is always a matter of trade-offs and choices. They made the wrong trade-offs, IHMO.
Edits: 10/14/16
No Abe, that's just YOUR philosophy.
One person's philosophy is to engineer components for maximum compatibility with other components from other makers, and accept you might give up a little performance as a result.
Another person's philosophy is to engineer systems to maximize the performance of their design approach, and accept that their gear may not appeal to audiophiles who want to mix & match and play on the cable merry-go-round.
Both are valid engineering approaches based on different goals.
...they think they know exactly what their customer needs rather than asking the customer.
No Abe, that's just YOUR philosophy.
No Dave, my philosophy is in agreement with most amp manufacturers. Only a couple outliers design 'tweaky' amps that require proprietary cables.
These are essentially general market products and should have been designed as general purpose products.
Otherwise they should be sold as tweakers and DIYers products and NOT for the unknowing general public.
THAT is either poor engineering, poor marketing or the company just didn't give a shit and just wanted it out on the market.
The Naim approach to audio is the OPPOSITE of tweaker. They tend to use custom connectors and connection methods so you can't go cable tweaking. Their separates are specifically designed to be used with each other and NOT be mixed and matched with other company's products. And their unique connection methods make it a hurdle to do so. So no, they are not general market products.
You either buy into their systems approach or not. If you're the kind of audiophile who buys a power amp because it has bass slam, and matches it to a tubed pre to warm up the tone, and uses silver cables to add some top end sparkle and air, and isolation footers because they take away some grain, etc. - then you are not a candidate for a Naim system.
...do not buy tweaky components from manufacturers that require the use of their proprietary speaker cables and interconnects for best performance. Avoid manufacturers that try to lock you into their proprietary line of accessories.
Polk Audio used to make a litz wire speaker cable about 30 years ago or so. It was highly capacitive. Some amps didn't like that, went into oscillation and blew up. Transistor get hot really fast if the amp oscillates. It is an engineering problem and one that should not happen!
n
It is my understanding that my Threshold CAS-1 would also not like that cable. I haven't tried for obvious reasons.
Dave
Never tried that model.
Jeremy
Cobra Cable
Cobra Cable was sold by Polk Audio many years ago but has long since been discontinued. The idea was to reduce the cable inductance but in doing so, increased cable capacitance. Cobra wire had many separate strands that were individually insulated with a thin material. These all ran in parallel and comprised one conductor. The insulation was colored black for one group. The other conductor was a similar group of strands but the insulation was colored red. The strands of each color were interwoven with each other and formed a braided but cross-coupled two-conductor cable. Of course, the strands being very close to each other and with thin insulation, resulted in an unusually high cable capacitance. The high capacitance of Cobra Cable was the same as connecting an unusually high value capacitor directly across the amplifier terminals. Reports indicated that a resistor-inductor termination could be added to prevent oscillation when this wire was used with unstable amplifier designs that cause transient overshoot and even amplifier oscillation.
n
I remember auditioning a Naim Nait about 20 years ago. The dealer also sent Naim speaker cable along with a Naim compatible IC. He told me to ONLY use the Naim speaker cable. It wasn't simply a matter of retaining the Naim synergy either. I was told bad things would happen to the amp if the Naim speaker wasn't used. The odd part is I ended up keeping the Naim speaker wire and returning the Naim and compatible IC. The Exposure integrated I preferred (vs the Nait) also recommended Naim speaker wire for similar reasons. Perhaps none of this applies to the modern Naim and Exposure components.
Like anyone would really need an amp like that. Did they name that line of amplifiers the "Give me a hard time and more problems" line.
That sounds like they were trying putting lipstick on a pig with that story. That's some BAD engineering dude!
n
The point wasn't the cables. The point was who the heck would design such an unstable amp were cables would blow it out.
So actually this thread DOES agree that cables can have a huge effect.
I always felt cables in any manner should be as transparent as possible. Not adding or subtracting to the situation - just do the job they were intended for. As I'm redoing one of my IC on a setup TODAY!!!
to invent a load that will stress an amp -- Apogee Scintillas were such a load for most amps, and who knows what could be designed in future that would cause a bad reaction from some. Inability to drive Apogee Scintillas says nothing about an amp's design for most applications.
I remember the times, and I (at least now, in my dotage) can recall no precedents in home audio for the ultra-high capacitance presented by Cobra cables no matter which speakers they were used to connect. I think you might better ask "who the heck would design such an . . . amp w[h]ere [nothing remotely conceivably ever connected to it] . . . would [stress or damage] it [in any way whatsoever]". I suppose such a design were possible, but it would be very expensive.
Of course "cables can have a huge effect" -- just imagine the effect of a 100' run of 64-gauge in most set-ups.
Jeremy
Jeremy
SO I have been around for a long time...
Anyway, over the year every now and then ithits the news about some am or other which has so little stability it goes into a death spin if the 'wrong' cable us used.
Maybe a dozen or so designs..
Usually the oscillation stuff.
I guess designing amps is not child's play. However that does not stop some folks.
It's 5 amp boards. How can you f#@k that up. It's not like they're inventing the amplifier. If you have an amp that is that unstable then it IS an engineer problem. And cables are NOT the right answer. What ya got there is part stereo and part time bomb.
However it does seem that HT amps have an inherent weakness and do seem to toast quickly. Usually due to power issues.
Actually I do remember my advice to a friend, and myself included, was to not sink a lot of money into a HT amp. Because it wasn't going to be around very long. And the friend I told that too did buy an expensive amp. And low and behold two years later - it was a very expensive door stop. But he did acknowledge that I told him that and did replace it with a much cheaper HT amp. Odd - it's been 10 years and he still has it?????
Edits: 10/13/16
n
If the amp NEEDS Special Cables, it should COME WITH THEM in the BOX.
Too much is never enough
If the amp NEEDS Special Cables, it should COME WITH THEM in the BOX.
I think we're all on the same page here. But I'll add that if an amp NEEDS Special Cables, it's not an amp that I would buy.
Agree 100%.
Too much is never enough
It seems like the good engineers over at Naim and those other companies painted themselves in an audio corner they can't get out of. And corporate told them to push push push and get it out there!But really that is a poorly designed amp if it does that.
Addendum: Abe you really should check out a VTA ST-70 with those Gold Lion KT66. It's still the best amp I've had or heard.
Edits: 10/14/16
...you have some weird ass audiophool cables, a weird ass hyper sensitive on the brink of instability audiophool amp, or something is already out of whack. Just my 2-cents worth of course.
What happens when you try cheap ass lamp cord? Does that freak out the amp? :-)
Naaa, I just use a $2500 light bulb.I'm thinking this guy needs new cables. Perhaps the one WITHOUT the short. Or a tech with an honest answer other than that story.
Actually, and I'm being honest saying this, this guy should go back to zip cord and ebay his $$ cables.
Edits: 10/13/16
Exactly!
New cables will be the EASY BUTTON of troubleshooting and with cheap lamp cord at least you know that some audiophool cable 'designer' didn't design some audiophool 'magic crap' into it. Lamp cord is pretty benign and dirt cheap. If the amp still blows up, the problem is likely the amp or the speakers.
Laughing...
Two cases I know of.
One of the first speaker cables in the USA were the Cobra cables imported by Polk Audio I believe. They presented a load to some amps that was reactive enough to blow up some amps(and probably cause some instability in more amps). Eventually a corrective network was added to the cables.
For many years(I don't know if it's still true) Naim would not guarantee warranting their amps unless they were used with their speaker cable. Again some cables could cause instability in Naim amps due to their reactive load. Obviously Naim cables were safe.
When I worked ages ago at an ARC/Mark Levinson/GAS dealer's, we had to tell customers who walked in with Cobra they'd like to test on our systems that we were sorry, but no-go. We'd seen a couple of amps that had been "Cobra'd" and heard about a few more that had cooked off. Not pretty.
Jim
http://jimtranr.com
Maybe, due to wider bandwidth of certain aftermarket products. Not taken into account by the original engineers of the amp or pre-amp.
It's MIT or forget it, from what I've read and heard
"Hope is a good thing. Maybe, the best of things. And no good thing ever dies."
Years ago I had a customer that traded in a top-of-the-line Audio Research amplifier (solid state) in a sealed box.It had blown up several times while driving some wicked cables.
Audio Research finally replaced it with a brand-new-in-the-box unit, and he promptly traded it in to me (and I gave him some safe wire).
Edits: 10/12/16
That was my guess + maybe the wrong type and/or rated fuse(s).
Ah, I never thought of fuses. That might be a possibility.
Some designs like Alpha Core Goertz trade their low inductance for very high capacitance which can make some amps unhappy.
What kind of cable do you use? Ideally, do you know the LCR metrics?
Zackly! But in the age of "magic" wire, just try to find out those simple values -- does Monster, e.g., disclose any such information? Much like trying to discover wow, rumble and flutter on a turntable (the greater the cost, the less information likely disclosed) or phono-cartridge stereo separation ABOVE 1 kHz, where it matters more (Ortofon is a conspicuous and commendable exception in that regard).
Jeremy
Inductance, Capacitance, and Resistance? OP might not be familiar with the abbreviations.
How right you are! Thanks!
They tested OK electrically but always caused ground hum and other noises, just not with every piece of gear. That made identifying the problem frustrating.
Edits: 10/13/16
The three metrics related to cables.
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