You are here

Log in or register to post comments
tom collins
tom collins's picture
Offline
Last seen: 2 years 1 month ago
Joined: Apr 3 2007 - 11:54am
help: calling all smart guys.

Gents:
here is a puzzler. my system includes the following setup. Arcam a80 integrated biamped with arcam p80 power-amp. The manual suggests this. Speakers are aerial 6 with biwiring capability. these speakers are power sucking pigs, but sound great at strong volume. the maker says they are 4-6 ohms, but i suspect on big transients, they dip lower. this becomes relevant in a minute. i have been using nordost blue heaven, 4 metre biwired on both ends with no problems whatsoever from day one. i have used the p80 to drive the bass units and the a80 to drive the mid/treble. i can turn the volume to full (only for test purposes) without any problem. here is the problem.

i bought a set of 3 metre red dawn version 2 and received it yesterday. it is terminated identically to my blue heaven. i wired everything up in the usual manner. i started at low volume and things sounded good, eventually, at about 75% power, the protection circuit kicked in on the bass channel. lowering volume and waiting restored power. i tried many combinations including reversing polarity, switching the amp assignments, standard bi-wiring with only the integrated amp. these all caused the same results. the only thing that worked was to use only 1 of the leads in the integrated run to the speaker with the speaker connections bridged as if i was only using one standard wire. this permitted full volume.

so, i was hoping one of you gurus would have some thoughts for me. by the way, the only numbers of any use i have for the amp are output impedence <50 ohms and nominal output level 700mv. no such specs on the speakers, just the 4-6 ohms of which i believe is closer to 2 ohms at some transient peaks.

thanks in advance for any assistance you can render.

RGibran
RGibran's picture
Offline
Last seen: 2 years 4 weeks ago
Joined: Oct 11 2005 - 5:50pm
Re: help: calling all smart guys.

JA

mrlowry
mrlowry's picture
Offline
Last seen: 2 years 2 months ago
Joined: May 30 2006 - 1:37pm
Re: help: calling all smart guys.

Have you tried the new cables one at a time to see if possible one of them is terminated improperly. That's not likely but it is possible. It also sounds like it might be a capacitance problem but Nordost claims to be a low capacitance cable.

Jan Vigne
Jan Vigne's picture
Offline
Last seen: Never ago
Joined: Mar 18 2006 - 12:57pm
Re: help: calling all smart guys.


Quote:
i bought a set of 3 metre red dawn version 2 and received it yesterday. it is terminated identically to my blue heaven. i wired everything up in the usual manner. i started at low volume and things sounded good, eventually, at about 75% power, the protection circuit kicked in on the bass channel. lowering volume and waiting restored power. i tried many combinations including reversing polarity, switching the amp assignments, standard bi-wiring with only the integrated amp. these all caused the same results. the only thing that worked was to use only 1 of the leads in the integrated run to the speaker with the speaker connections bridged as if i was only using one standard wire. this permitted full volume.

As I read this, it is unclear just what you were trying with all of your cable switching. It sounds as if at one point you had the grounds of two amplfiers tied together.

That's not good.

Since you just bought the speaker cable I would contact the retailer and discuss this issue with their service department. If there is a fault in the cable, they are responsible for replacing the cable. Otherwise, they have more experience with the product than anyone other than the manufacturer.

However, as a guess, I would say the real issue is to be found in the last sentence of the above quote, "this permitted full volume." Depending on just what "full volume" means to you, the problem with the new cable might just be coincidental to the new cable.

tom collins
tom collins's picture
Offline
Last seen: 2 years 1 month ago
Joined: Apr 3 2007 - 11:54am
Re: help: calling all smart guys.

thanks so far.

jan: i have been very careful about the routing of the wires and am certain that none have been crossed as you suggest might be the case. up until the time that the protection circuit kicks in, everything sounds great. my goal is improvement, more definition, the usual reasons. it is just strange that a cable that should be an upgrade should create such problems. any other thoughts? in regard to the volume, there are 72 steps and it would previously play comfortably at step 65; no i don't crank it all the way. also, the combined output rating is 130 watts per side at 8 ohms.

thanks guys.

mrlowry
mrlowry's picture
Offline
Last seen: 2 years 2 months ago
Joined: May 30 2006 - 1:37pm
Re: help: calling all smart guys.

Are you using the old and new set of cables (one for the "top" and one for the "bottom")? If so this may sound like a silly question but have you removed the jumpers? If you hadn't it shouldn't have worked before so I bet you have.

Arcam amps aren't muscle amps made to drive super difficult loads. That said Arcams will certainly run 4 ohm speakers. I've used them extensively with Magnapan and Thiel products. However if your speakers have a really wild impedance curve that could contribute to the issue too. I don't have any hands on experience with your speakers.

tom collins
tom collins's picture
Offline
Last seen: 2 years 1 month ago
Joined: Apr 3 2007 - 11:54am
Re: help: calling all smart guys.

mr. lowery: no, i guess i was not overly clear, but i wasn't using them together. each set is terminated as if it were 2 sets of single wires. that is how i hook them up. my suspicion is that the new cables have so little resistence that they exceed the amp's ability to provide power on dynamic transients. i may end up selling the dawns and keeping the heavens if i can't solve this, but would rather avoid that.

Jan Vigne
Jan Vigne's picture
Offline
Last seen: Never ago
Joined: Mar 18 2006 - 12:57pm
Re: help: calling all smart guys.


Quote:
the only thing that worked was to use only 1 of the leads in the integrated run to the speaker with the speaker connections bridged as if i was only using one standard wire. this permitted full volume.


Quote:
jan: i have been very careful about the routing of the wires and am certain that none have been crossed as you suggest might be the case. up until the time that the protection circuit kicks in, everything sounds great. my goal is improvement, more definition, the usual reasons. it is just strange that a cable that should be an upgrade should create such problems. any other thoughts? in regard to the volume, there are 72 steps and it would previously play comfortably at step 65; no i don't crank it all the way. also, the combined output rating is 130 watts per side at 8 ohms.

I wasn't really suggesting you crossed any wires. I was suggesting you're driving the amp too hard into a less than easy load. It's possible the amp now has some problems and the cables are just coincidental to the issue becoming obvious.

You are confusing how far the volume knob will turn with how much power the amplifier can produce. Full power does not occur at full rotation of the knob. At "65" out of "72" you are more than likely clipping the amplifier's outputs.

What do you mean "the combined output rating is 130 watts per side at 8 ohms." Are you taking the rated power output of both amplifiers and adding them together? I just keep getting the impression that loud is important to you.


Quote:
these speakers are power sucking pigs, but sound great at strong volume. the maker says they are 4-6 ohms, but i suspect on big transients, they dip lower.

The transient material does not determine where the impedance falls. And you need to consider both impedance and electrical phase angle before you make any decisions regarding what sort of load the speakers present to the amplifier. But your reference to "big transients" still has me believing the amp is simply being stressed beyond its limits.


Quote:
my suspicion is that the new cables have so little resistence that they exceed the amp's ability to provide power on dynamic transients.

That would be impossible. Capacitance and inductance are the most common cable related issues when an amplifier shuts down.

Does the system play properly when you have the old biwire cables in place?

Why not give the retailer a call?

andy_c
andy_c's picture
Offline
Last seen: 1 month 1 week ago
Joined: Dec 25 2007 - 12:48pm
Re: help: calling all smart guys.

Hi Tom,

This sounds an awful lot like what happened to another user in this thread at Audio Circle. Briefly, he changed cables on the amp used to power the woofers in his biamped setup to ones having a higher capacitance per unit length. For reasons explained in that thread, this combination caused his woofer amps to oscillate and shut down.

Does the problem go away again when you switch back to nordost blue heaven on the woofer amp? If not, then you have introduced some inadvertent wiring error and should re-check your wiring. If so, just for experiment, if you have any zip cord lying around, also try that on the woofer amp. Zip cord has very low capacitance per unit length (though the inductance is high), which helps prevent amplifier oscillation. If the zip cord and blue heaven both work okay on the woofer side, but the red dawn does not, I'd recommend sticking with the blue heaven for the woofer side.

tom collins
tom collins's picture
Offline
Last seen: 2 years 1 month ago
Joined: Apr 3 2007 - 11:54am
Re: help: calling all smart guys.

andy c: i think you get the prize. the thread got very long winded, but Frank Van Alstine made a short, cogent response about half-way down with the argument for capacitance. i am not wise in the ways of these things, but my problem is exactly the same. last night, i took a good long time and rehooked everything up even testing the cables for continuity with my meter to make sure the leads were going where they were supposed to, so i am sure it was hooked up correctly - all with the red dawn wire. starting at a low level and gradually raising the volume, the system sounded fantastic, these wires are clearer and better defined than the blue heavens, however, when i approached my normal listening level, the protection circuit shut down the bass driving amp as before. i also noted that the bass amp was quite warm to the touch when it has always been previously cool. as i listened to an album side, the protection circuit came in at progressively lower levels. Frank mentioned that an amp with this problem would get hot, he was right.
i then reinstalled the previous blue heaven wires and all was restored to normal.
i can only conclude that my amp and speakers are just not compatible with that wire - same as the guy in the link. its just too bad that i got to hear that greater level of clarity from the red dawns, now i will have to go looking for something else.
thanks to all who responded. anyone need a good set of nordost red dawn version 2? take a look on audiogon.

tom collins

andy_c
andy_c's picture
Offline
Last seen: 1 month 1 week ago
Joined: Dec 25 2007 - 12:48pm
Re: help: calling all smart guys.

Hi Tom,

Sorry you ended up having to sell the red dawn cables. Have you tried using them only on the mid/tweet, with the blue heaven on the bass? This may be stable for you while allowing for some improvement in sound. Just a thought.

tom collins
tom collins's picture
Offline
Last seen: 2 years 1 month ago
Joined: Apr 3 2007 - 11:54am
Re: help: calling all smart guys.

first: thanks to all who offered suggestions.
second: i sent them back this morning as the seller is a great guy who offered to buy them back at no penalty.
third: an individual in my audio club who make wires is making me a custom set. he understood the problem i had with the red dawns and has successfully dealt with it on other amp/speaker applications and offers 100% money back guarantee for satisfaction. after hearing the red dawns at lower volume levels and what an improvement that can be had, i just have to try again.
thanks again guys.

mrlowry
mrlowry's picture
Offline
Last seen: 2 years 2 months ago
Joined: May 30 2006 - 1:37pm
Re: help: calling all smart guys.

A speaker cable and amp combination having a capacitance incompatibility that can shut down the amp is a pretty rare occurrence. Which is why only two of us (myself and Andy) thought of it as a possibility. I'm glad that you've decided to continue experimenting with cables. There are many great cables that will NOT cause the amp to oscillate.

tom collins
tom collins's picture
Offline
Last seen: 2 years 1 month ago
Joined: Apr 3 2007 - 11:54am
Re: help: calling all smart guys.

mr l: thanks for the thoughts. at this point, choosing between trying some new cables or buying new amps, the cables win out. i can try these custom made cables risk free for $400 or less. also, the blue heavens are in no way "bad" cables, in fact they are very good and may stay put in the end. maybe when business picks up, i can look at changing amps. to me, trying new things makes this hobby more interesting. i had a new electric line on a dedicated 20 amp fuse installed last weekend - a nice improvement for about $200 parts and labor.

KBK
KBK's picture
Offline
Last seen: Never ago
Joined: Sep 30 2007 - 12:30pm
Re: help: calling all smart guys.


Quote:
first: thanks to all who offered suggestions.
second: i sent them back this morning as the seller is a great guy who offered to buy them back at no penalty.
third: an individual in my audio club who make wires is making me a custom set. he understood the problem i had with the red dawns and has successfully dealt with it on other amp/speaker applications and offers 100% money back guarantee for satisfaction. after hearing the red dawns at lower volume levels and what an improvement that can be had, i just have to try again.
thanks again guys.

Yes. Capacitive problems with cables and amps, etc...show up as dynamic combinations -not as static test bench measurements.

tom collins
tom collins's picture
Offline
Last seen: 2 years 1 month ago
Joined: Apr 3 2007 - 11:54am
Re: help: calling all smart guys.

thanks for reminding me of this KBK. the cables are made by morrow audio. you can find him on a-gon or the web. i have over 100 hours on them now. the system works fine, the sound is not as intense in the top end as with the nordost. in fact, i can play music without the speaker covers on. this seems to have allowed the rest of the range to open up a bit with more detail. i can also listen at higher levels for longer periods of time without fatigue. guess i'll have a nice pair of blue heavens for sale soon.

mrlowry
mrlowry's picture
Offline
Last seen: 2 years 2 months ago
Joined: May 30 2006 - 1:37pm
Re: help: calling all smart guys.


Quote:
the sound is not as intense in the top end as with the nordost. in fact, i can play music without the speaker covers on. this seems to have allowed the rest of the range to open up a bit with more detail. i can also listen at higher levels for longer periods of time without fatigue. guess i'll have a nice pair of blue heavens for sale soon.

Not surprising, I consider the Nordost stuff to be pretty darn bright. They wouldn't have been my first suggestion to pair with Arcam.

commsysman
commsysman's picture
Offline
Last seen: 13 hours 31 min ago
Joined: Apr 4 2006 - 11:33am
Re: help: calling all smart guys.

You need very low resistance and very low capacitance in your speaker cables; the ones you have are neither!

Do what I did to solve the problem.

Buy a 100 foot spool of 10 gauge Alpha hookup wire, cut 8 12-foot lengths of wire, and terminate them with Audioquest Gold-plated spade lugs carefully soldered to the wire ends. This will give you much lower resistance than any commercially made cables that I know of, and lower capacitance than most. The resistance of each wire, properly soldered, will be approximately .015 ohm.

This wire has over 100 30-gauge strands and is fairly flexible. DO NOT use ties or anything else to "bundle" them. Let each wire lay separately on the floor or use some heat-shrink sleeving every 2 feet or so to keep them from tangling too much, but nice neat "bundling" that keeps the wires right next to each other adds lots of capacitance between wires; bad!

For my application, bi-wired Vandersteen 3A's, I used 8 individual 1/4" spade lugs on all 8 wires for the speaker ends, and FOUR 5/16" lugs for compatibility with the Bryston amplifier binding posts. The cost was about 260 dollars total, and I challenge anyone to buy a better set at any price.

To solder the amplifier end, I stripped each wire back 1 1/4 inches and then soldered the first wire of each pair into a large lug (I slipped 3 3-inch pieces of 3/8" red or black shrink tubing onto both wires of the pair first), and then took the second wire, split 50 strands off and twisted them, and then did the same with the other 50. Then I spiraled one bundle around the bare part of the first wire, then the second bundle alongside them, and then thoroughly soldered the two wires together behind the lug (completely flood and saturate with solder), and then used a heat gun to shrink the tubing over the soldered area.

Make sure that you push each wire end into a can of rosin flux before soldering, or you may not get good flow between all of the strands; be sure to solder very thoroughly and use 63/37 rosin core solder only. Get good flow through the wire and around the lug ends.

This will give you lower resistance than any commercial cable I have yet seen; most of them give you a lot of fancy insulation, a lot of total bullshit about their perfect copper or whatever, and resistance that isn't really that low! Anywhere from 70 to 90 percent of what you pay goes for cosmetics and some sort of fancy configuration that supports the bullshit index in the brochure; it doesn't contribute to a better cable.

It will also give you very low capacitance if you let the wires be mostly free of each other and don't bundle them tightly.

You can buy the Alpha 10-gauge hookup wire in several colors from Mouser Electronics for about $200 for a 100-foot spool; I like the blue. I use small pieces of red and black heat-shrink tubing at each end for color-coding. The Mouser part # for blue is 602-3081-100-06; the last number varies the color. Alpha wire is available from most electronics stores.

tom collins
tom collins's picture
Offline
Last seen: 2 years 1 month ago
Joined: Apr 3 2007 - 11:54am
Re: help: calling all smart guys.

commsys:

i just wanted to personally thank you for the effort you put into the post in answer to my question. that sounds like a very good way to make your own and i do not doubt they sound great.

the morrow cables that i have substituted for the nordost have about 200 hours now, which was the recommended break-in. i am very pleased with these. the sound is smooth, soundstage large and stable, previously too bright recordings flow much better.

i am good....for now.

commsysman
commsysman's picture
Offline
Last seen: 13 hours 31 min ago
Joined: Apr 4 2006 - 11:33am
Re: help: calling all smart guys.

The "too bright" part is almost always caused by too much capacitance in combination with poor amplifier stability.

Very glad you solved your problem!

  • X
    Enter your Stereophile.com username.
    Enter the password that accompanies your username.
    Loading