Speakers 30ft from amp - help please!

admin_exported

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Due to a house move and the peculiarities of our new living room my Spendor A9s will be located about 30ft from my Cyrus Mono X200 power amps (and the pre-amp and the sources). Sadly my wife is adamant that I can't move the rest of the equipment closer.

Can anybody please recommend some speaker cable that will not degrade the sound over these distances. If there is such a product....

Thanks. John.
 

Crocodile

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You could try some Van Damme 4mm OFC. Either the Studio Blue or shotgun depending on what's easiest/most aesthetic to run. If your terminals will take it, you could also look at the 6mm but 4mm should be OK at that length.

You'll have to Google as posting links now seems to send posts for moderation & it may never appear.
 
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Anonymous

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I would go for the thickest wire you can find, possibly 4mm diameter. Also, be sure to let your wife know the cost of such cable >)
 
T

the record spot

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tremon said:
I would go for the thickest wire you can find, possibly 4mm diameter. Also, be sure to let your wife know the cost of such cable >)

Couldn't agree more. Less than a tenner tops I'd say...!
 

Timbot

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I've used Audiovisual Online before for longer runs of speaker cable and found them to be good for service. They stock the Van Damme mentioned above and can also fit terminations.
 
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Anonymous

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Thanks very much for the help and suggestions gentlemen. I'll have a good look at the Van Damme cables.

Your thoughts about my wife's involvment in this issue are also carefully noted....
 
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Anonymous

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Go to Maplin's and buy two rolls of 12AWG OFC wire.

Then you'll have excellent speaker wire _and_ you can show her the receipt, it's a win-win.
 

oldric_naubhoff

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check out Dynaudio OCOS, there's a nice white paper on Dynaudio web site (have a read if you're not intimidated by lenghty equations). they are designed in such a way to yield unchanged characteristics over up to 100m runs. they are also quite thin. unfortunately they are not as cheep as other suggestions.
 

dannycanham

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Wow. I am obsessed with putting my speakers around 6ft away from their amps. Absolutely no help I know but you've already been given some good advice so I'll just join in with wow 30ft.
 
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Anonymous

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BTW, as you are running cheap transistor (non-linear + high feedback) amps into these cables you should put ferrite core clamps over the speaker cables just next to the amplifier, so stop the 30' aerials conducting RF back into the amp's feedback circuits. Even consider using 2 at the length you have.
 
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Anonymous

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I'm sure you could find a way to make a deal with your wife. You can get nice wall mounted supports, or the fancy cyrus rack, or hide them under a table, or get a bookshelf and put them in that - there are so many ways. If any components are big or ugly, then this would be your opportunity to upgrade them :grin: You can get infra red signal redirectors so they can be hidden. All of this will mean it will be more convenient than in another room, and I would be concerned about the sound degradation - I guess there is no way to find out for sure until you try it
 

chebby

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noogle said:
Globs said:
BTW, as you are running cheap transistor (non-linear + high feedback) amps into these cables...

Cyrus Mono X200s cheap??? :?

Also, don't they have "Zero feedback circuit design"?

I think 'Globs' is just making his point that it's not a single-ended pentode or single ended triode valve amp. I am guessing almost any modern solid state amp would be described the same way and not just those from Cyrus.

Another chap, similarly, comes here quite regularly to recommend 40 - 50 year old, ultra efficient, wardrobe sized speakers with 15" (or even 30") bass drivers even when the OPs have asked about compact floorstanders.
 
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Anonymous

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noogle said:
Globs said:
BTW, as you are running cheap transistor (non-linear + high feedback) amps into these cables...

Cyrus Mono X200s cheap??? :?

Also, don't they have "Zero feedback circuit design"?

Cheap design - not cheap money, the two are entirely unrelated ;) As for zero feedback - have you a schematic, it would be interesting. In fact I have no idea why designers keep using outdating GNFB, you could quite easily just wrap feedback around a FET based VAS and use the output devices as simple voltage followers (current amplifiers) - a much better solution. (ETA: Perhaps that's what Cyrus have done with these, not sure why it's not standard practice TBH)

You can test how much feedback amps transmit back from the speaker quite easily:

1) Put a cellphone on a speaker when the amp is on, and the volume turned down.

2) Now ring the cellphone (you may want to turn the ringer off)

3) If you can hear the GSM chirruping through the speakers the RF is getting back into the input section of your amp, via the feedback circuit.
 

oldric_naubhoff

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Globs said:
In fact I have no idea why designers keep using outdating GNFB, you could quite easily just wrap feedback around a FET based VAS and use the output devices as simple voltage followers (current amplifiers) - a much better solution.

maybe because using GNFB gives serious marketing advantage. benchmarking characteristics are automatically very much improved. you get ruler flat freq response regardles of load impedence, you get extemely low harmonic distortion on test signals and another added benefit would be lowering of output impedences so you can also say in marketing blurb that your amp has 1000000000000 :) damping factor (like it really matters in a passive system since speaker driver - crossover interaction is what matters most as far as damping of cones movement is concerned in a passive set up).

now, I'm not 100% sure (I'm not an electrical engineer) but IMO the true reason to abuse GNFB in transistor amps is different. tubes work differntly so what you say about making output devices voltage followers makes sense with tubes. they simply reach optimal workng temperature and regardles of current flow that temp stays more or less the same. with transistors it is different. I can't explain it better but their temperature changes with amount of current flowing through them. that's the main source of SS devices distorion. if you don't regulate the temp the amp might go into thermal runaway. so the reason of using DC servo mechanisms is too keep circuit stable and you get the benefit of lowering measured distortion in benchmark tests.

Globs said:
ETA: Perhaps that's what Cyrus have done with these, not sure why it's not standard practice TBH

because of what I just wrote I'd say it's not what they did and therefore it'll not become a standard practise. there are patented fedbackless SS circuits though. Pathos and DartZeel being two of them and they definitely are different. Pathos's Inpol can only be class A and DartZeel also does fedbackless A/B amps. Cyrus MonoX is A/B so it might similar to the DartZeel, or who knows, it might be a completely different approach.
 

noogle

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I just sat my cheap iPhone 4 on top of my cheap speakers and my cheap NAP250 power amp (and my cheap pre-amp) and rang the phone. I didn't get as much as a single chirrup (apart from my ringtone).
 

noogle

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BTW - these Cyrus amps have a great spec - 150W into 8ohms, 240W into 4ohms, 200VA torroidal, burst peak power >1500W, max slew rate 700V/s, max output current 80A, S/N 114dBA, distortion <0.004% (1kHz/8ohms).
 

chebby

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noogle said:
I just sat my cheap iPhone 4 on top of my cheap speakers and my cheap NAP250 power amp (and my cheap pre-amp) and rang the phone. I didn't get as much as a single chirrup (apart from my ringtone).

I spent two years in the forum 'naughty box' when I had an all Naim system (Nait 5i, CD5i, NAT05, nSATs, NAC A5) especially when I got the magnificent little nSATs.

You'll get used to it.
 
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Anonymous

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noogle said:
BTW - these Cyrus amps have a great spec - 150W into 8ohms, 240W into 4ohms, 200VA torroidal, burst peak power >1500W, max slew rate 700V/s, max output current 80A, S/N 114dBA, distortion <0.004% (1kHz/8ohms).

A great spec would involve double the power into 4ohm (300 W in this case) and a TIM measurement. The fact they do not offer that and pimp the tired, old and misleading THD is worrying.

BTW a 200VA toroid would have trouble supplying 240W in a consistent way. Burst peak power is meaningless in the same way that you can buy 1500W computer speakers for £20.

The fact your Naim did not pick up the RF is a good sign, for all the compromises in the Naim amps they are well thought out and engineered.
 

noogle

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Globs said:
noogle said:
BTW - these Cyrus amps have a great spec - 150W into 8ohms, 240W into 4ohms, 200VA torroidal, burst peak power >1500W, max slew rate 700V/s, max output current 80A, S/N 114dBA, distortion <0.004% (1kHz/8ohms).

A great spec would involve double the power into 4ohm (300 W in this case) and a TIM measurement. The fact they do not offer that and pimp the tired, old and misleading THD is worrying.

BTW a 200VA toroid would have trouble supplying 240W in a consistent way. Burst peak power is meaningless in the same way that you can buy 1500W computer speakers for £20.

The fact your Naim did not pick up the RF is a good sign, for all the compromises in the Naim amps they are well thought out and engineered.

1500W burst peak power is great for dynamics. Lots of lovely punchy transistor power to drive low-impedance speakers! No need for socking great output transformers! Sexy low-profile black boxes! No wooly bass! No smooth soft clipping at 15W output! No more kids' burnt fingers! Low noise floor and huge dynamic range for hi-rez music! No more embarrasment having to hang round in small groups with valve-lovers talking about negative feedback! ;)

I'd bet you a substantial amount you could bury the Cyrus amps in a pile of ringing cellphones and not hear any RF interference.

The words "Naim" and "compromise" are regularly used in the same sentence - they are all just a bunch of slackers in Salisbury who don't undersand the true path of righteousness. ;-)
 
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Anonymous

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Lets examine this 1500 Watts then. The rated outout is 150W RMS at 8ohms, which indicates a rail voltage of around 49V. To get this 1500W you would need 1500/49 = 30.6A. Now as we have a rail voltage limit of 49V you are going to have to drive a load of 49/30.6 = 1.6 ohms. Can you explain how an 8ohm speaker can present a 1.6 load to this amp.

BTW My Usher amp can source 65A peak.

As for Naim's compromises I feel this is derailng the thread somewhat, but lets look at the facts:

a) We know Class-A is a better topology for audio than Class B

b) We know that transistors are not as linear as triodes

c) We know that global negative feedback multiplies harmonics in a non-linear amp

On all those three counts Naim amps are compromised. I know they are well regarded and sound very nice, but for that money those compromises are too far for me and belong in the middle range - not in hi-end hi-fi, sorry.

Back to topic: The fact that your amplifiers are RF resistant is good, but is still something to look out for if you are using 30' speaker cables - the physics of antenna are unchanged. I suspect the CE rules are causing designers to add a little more RF suppression which is fine if done correctly.
 

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