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View Full Version : Cables the diameter of your finger? What about inside the amplifier?



A.S.
10-11-2010, 08:53 PM
On this post (http://www.harbeth.co.uk/usergroup/showthread.php?1044-Analysis-of-speaker-cables&p=11639#post11639) I mentioned how extremely small the semiconductor junctions are inside your solid state power amplifier. It is those junctions of dissimilar materials where a small control signal (from your CD player) is boosted up into a big current millions of times greater, sufficient to drive your speakers. The semiconductor junctions are nothing more than a gate across a dam: the power supply is the dam or reservoir.

So, keeping our feet firmly on the ground, do we need speaker cables that are a) exotic in their construction or will bog standard (tinned?) copper wire do the job adequately b) do the cables need to be as thick as water hose?

Here's a picture inside a typical 50W-80W transistor amplifier (actually a Quad 306). One picture shows an overview, where I've marked the red and black output terminals: the other is a close-up where I've traced-out the signal track back from those terminals on the typical copper tin foil which is the track itself. For comparison you can see that the blue diode is about 3mm diameter.

Is there really any point in using chunky cable when the signal is running around inside the power amp on thin tracks? You decide.

honmanm
10-11-2010, 09:45 PM
Lovely pictures (and interesting to note the heat marks on the board where the leads to the banana sockets are soldered into the ends of the tracks). As a counterpoint here is an internal photo of an anti-Quad (NVA AP50):

http://i68.servimg.com/u/f68/13/48/07/74/nva_ap13.jpg

Mr Dunn of NVA would probably have one use the same wire from the back of the amp to the speakers as he has used from the boards to the sockets.

Labarum
11-11-2010, 01:24 AM
Is there really any point in using chunky cable when the signal is running around inside the power amp on thin tracks? You decide.

No, no point at all.

Of course the printed board tracks and internal amp wiring is very short compared to the wires from the amp to the speakers, so the external wires need to be a little more chunky, so as not to introduce a significant series resistance. This is well achieved by ordinary 79 strand speaker wire (2 square millimetre cross section). If the leads are many metres long there may be need to go up to 4 square millimetres. More is just nonsense.

All you need is

http://www.qed.co.uk/181/gb/product/speaker_cables/classic_42_79_strand.htm

2 per metre.

If you need to hide the wire under carpets get some ultra flat cable

http://www.qed.co.uk/180/gb/product/speaker_cables/ultra-flat.htm

That's expensive! 2.50 per metre.

Buy the cable that does the job without any sales hype. Save your money for more music.

LarsS
11-11-2010, 09:59 AM
What about the other end, the crossover? Some people find the biwire brass jumpers inadequate, and yet they are really chunky compared to any printed circuit board I have seen when it comes to area and thickness. The crossover get a lot more voltage and current and needs to be constructed thereafter I presume. We discuss cables forever , has anyone tested different materials used on the board tracks. AND how PURE is the copper in question.

HUG-1
11-11-2010, 10:53 AM
Exchanging the Harbeth-fitted thick heavy gold plated brass bi-wire links for another material and expecting a sonic improvement is just nuts. It is totally and utterly impossible.

HUG-1
11-11-2010, 10:55 AM
... interesting to note the heat marks on the board where the leads to the banana sockets are soldered into the ends of the tracks...No that is not heat marks at all. That is the flux lubricant that is inside all electronic solder - a brown tree-resin which is visible around most solder joints on one or other side of the circuit board when examined carefully.

honmanm
11-11-2010, 10:59 AM
Given the ratio between PCB track length and cable length (probably at least 1:20, more likely 1:50), imperfections in PCB tracks are going to be relatively insignificant, especially if they are nice and wide as in the crossover pic that Alan posted on the other thread.

A "serious" issue with PCB layout (at least for amplifiers and power supplies) is the routing of ground paths, and in the subjectivist camp PCB conformal coating is seen as a Bad Thing (note the un-coated boards in the NVA amplifier linked to above).

But the subjectivist camp don't measure, so that doesn't really answer your question, I think... however what has helped me is to identify the biggest problem, solve that, then reassess to find the next one, and so on. In my opinion making a host of small tweaks can mask the big problem that one really needs to solve...

Labarum
11-11-2010, 11:11 AM
AND how PURE is the copper in question.

Is there any evidence that the purity of the conductor or its precise composition makes a difference at audio frequencies?

As long as it's DC resistance is low enough and its capacitance and inductance are not crazy, does it make any difference?

I guess a 16A or 30A mains cable as used in house wiring would work as well as anything, though it might not look so good.

honmanm
11-11-2010, 02:43 PM
I guess a 16A or 30A mains cable as used in house wiring would work as well as anything, though it might not look so good.

Solid-core twin-and-earth works surprisingly well - the 3.5mm sq type is a good entry level cable. Compared to enamelled transformer wire of the same cross section, there seemed to be a loss of resolution - this was with a notoriously cable-sensitive NVA amp, and the P3ESRs. FWIW I'm presently using approx 2mm sq enamelled wire (Maplins YN80B) left over from the new amp project...

DSRANCE
11-11-2010, 03:16 PM
I'm in a quandary here, as I've used bell wire, QED 79 strand, RS 42 and 56 strand, Nordost Flatline, Chord Rumour and Odyssey silver plated PTFE insulated and mains cables of various gauges.

I don't care for standard 79 strand to be honest, but accept it's small in size and easily hidden. The QED Micro was popular in certain dealer chains as wives liked it, but this stuff really did have an audible effect I found in runs of 5m and over. I also found gthe twin and earth cables not to be of the finest quality and I thought that sometimes this was audible, although I'd almost certainly fail a blind test ;)

My favourite speaker cable for general purpose use is the 2.5 and 4mm Van Damme round blue stuff. It's cheap to buy, apparently uses good quality copper in its construction and doesn't look too intrusive. I also found the old Quad speaker cable (the thick beige round stuff with two chunky conductors within) really excellent with a wide range of equipment of varying loading.

I'm sure Harbeth would argue that, as their products have a benign impedance rarely dipping below 8 Ohms, that the gauge of speaker cable doesn't matter so much. I'm sure that's absolutely correct, but as my favoured cables are relatively inexpensive to buy, I'd err on the safe side and use the 4mm if possible. Anyway, the wire links inside a Quad 306 are the least of its trouble - give me a 606/707/early 909 any day - much more headroom when the music has some percussion in it..... :)

Don Leman
11-11-2010, 04:30 PM
I rarely get involved in discussions about speaker wire, but the thought occured to me that there are two possibilities; it either makes a difference or it doesn't.

If it doesn't, then it really doesn't make any any difference what you use.

On the other hand if it does make a difference wouldn't you want to use what the person who designed the speaker used in its development. To use anything else would mean you were introducing a colouration not present when he voiced the crossover.

hifi_dave
11-11-2010, 05:46 PM
Why stop at the speaker cable ? Why not use exactly the same system as the designer, in an identical room, playing the same music ? Only then will you be certain of hearing what the designer hears.

singslingr
11-11-2010, 09:37 PM
Why stop at the speaker cable ? Why not use exactly the same system as the designer, in an identical room, playing the same music ? Only then will you be certain of hearing what the designer hears.

Good point hifi_dave.

In my experience, cables make a difference - but only up to a point. And for me, that point is based on price - I'm prepared to spend US$500 on cables but not more. And I have to be able to hear improvements before paying.

STHLS5
11-11-2010, 11:14 PM
Why stop at the speaker cable ? Why not use exactly the same system as the designer, in an identical room, playing the same music ? Only then will you be certain of hearing what the designer hears.


I would have but Harbeth's designer said the speakers meant to be played in an average or typical home. The designer also said any well designed amplifiers would be sufficient for Harbeth speakers. The same goes for the cables.

I got no problem to those who could hear the difference. I only wanted to know the reason. It is no point suggesting, say a health product which supposedly make you younger, but then with a disclaimer that it may also make you older so try it first.

So far, contrary to earlier assertion that cables improve sound now we have agreed they make a difference. Difference is not improvement. And no cable can improve or increase the final frequencies coming out at the amplifier's terminals.

ST

HUG-1
12-11-2010, 09:13 AM
... It is no point suggesting, say a health product which supposedly make your younger, but then with a disclaimer that it may also make you older so try it first....Congratulations, you are the winner of the HUG 2010 Quote of the Year.

It is an interesting philosophical and engineering point. How can a cable receive rave reviews by some subjectivists whilst others revile it? Perhaps the answer lies not in the cable but solely in the mind of the listener.

hifi_dave
12-11-2010, 10:01 AM
There is more to it than that.

For example, a cable which sounds light, bright and thin (Nordost) might suit one system better than another whilst a cable like Supra, which is fat and warm would suit another. Personal taste also comes into play.

Labarum
12-11-2010, 10:13 AM
There is more to it than that.

For example, a cable which sounds light, bright and thin (Nordost) might suit one system better than another whilst a cable like Supra, which is fat and warm would suit another. Personal taste also comes into play.

Ah. In the olde days we didn't faf about changing cables to "tune" the system, we fiddled with the tone controls. It was far cheaper, more convenient and much more effective.

<evry big grin>

oticus
12-11-2010, 10:20 AM
And a remote handset with tone controls saved grovelling about on the floor fiddling with those cables too. And was reversible at the press of a button (tone bypass).

Labarum
12-11-2010, 10:39 AM
And a remote handset with tone controls saved grovelling about on the floor . . .

Remote control? I know what you mean, but I was thingking of the realy old days!

http://www.clarisonus.com/Archives/Amp_Design/Williamson%201952%20The%20Williamson%20Amplifier.p df

Drdennis
12-11-2010, 10:42 AM
This may be covered elsewhere, but what about the OFC wire in my 30th Anniversary Compact 7 ES3's?

STHLS5
12-11-2010, 11:24 AM
This may be covered elsewhere, but what about the OFC wire in my 30th Anniversary Compact 7 ES3's?

OFC lasts longer because it is less prone to corrosion. Just like the gold plated link over a standard brass link. As far as sound, you wouldn't hear any difference. However, due to the demand of customers who still insist they make a difference ( via their distributors) , Harbeth makes them if there is a market for them. If I am not mistaken, even the Super HL5 is made with the super tweeter because there's a huge demand for speakers with super tweeter, even though Alan's personal belief is that you don't really need frequencies above 16kHz for musical enjoyment. That's business. That's survival.

Dear moderator, did I get it right this time? :)

Labarum
12-11-2010, 11:33 AM
. . . If I am not mistaken, even the Super HL5 is made with the super tweeter because there's a huge demand for speakers with super tweeter, even though Alan's personal belief is that you don't really need frequencies above 16kHz for musical enjoyment . . .

Ah, I wondered what the super tweeter was included for! I didn't seem to fit the com[any philosophy.Mind you, Tannoy seem wedded to them.

hifi_dave
12-11-2010, 01:09 PM
We might not 'need' the super tweeter but it's output is clearly audible and it does wonderful things for the air and prescence in a good recording. Tape over it and hear the difference.

A.S.
12-11-2010, 02:08 PM
Alan here ... looks right to me.

BTW, it is an unavoidable fact in the same unavoidably factual way that my hair is now 30% white, that my upper hearing is not as extended as it was as a boy. When I was a teenager I could clearly hear the 19kHz stereo-FM carrier frequency (on headphones). Later I could just about hear the 15kHz line-scan frequency whistle of old CRT TVs. Now I'd be surprised if I can hear much above about 13kHz, and that's after a lifetime living and working in almost silence and avoiding loud music. It's a fact that as we age the top end of our hearing range diminishes. What can you do to minimise that inevitability? Don't listen to loud music. Does the restricted range mean I can't enjoy music? Not in the least because the % of music that is in those super-high harmonics is utterly negligible.

Labarum
12-11-2010, 02:18 PM
I am confused by your post that follows Dave's, Alan. What are you saying? That a super-tweeter makes a difference, or it doesn't?

PS I have a few years on you and my hair is 70% white!

A.S.
12-11-2010, 03:54 PM
I am confused by your post that follows Dave's, Alan. What are you saying? That a super-tweeter makes a difference, or it doesn't?I think what I'm saying is that the functionality of the super tweeter is directly linked to the hearing acuity of the listener, and that is conceivably linked to the age of the listener. So for old folk (like me?) it may not be critically important but for a listener with exceptionally extended hearing and/or half my age it could be much appreciated.

But I, at my age, wouldn't select a speaker solely because it has a super tweeter but for other reasons. If it so happenes to have a super tweeter that's a plus.

hifi_dave
12-11-2010, 05:06 PM
OK, I'm an old git, far older than Alan and I can still hear that superb, Super Tweet. Either that or it's my fillings picking up RF !!!

Maybe it's my job. Listening to fine nuances of the best Hi-Fi systems for a few hours every day, might sharpen my hearing. It's definitely made me a fussy sod.

Sebastien
12-11-2010, 05:51 PM
I'm 29 years old, have long brown hair ;-) and love the SHL5's super tweeter. I already gave my opinion on it in a previous post.

Sebastien

honmanm
12-11-2010, 10:05 PM
Sebastien, you're a lucky young man... somewhere around that age I formulated the Honman theory of hi-fi which was that by the time you can afford gear that does anything worthwhile beyond 15kHz, you can't hear the benefits.

denjo
12-11-2010, 10:47 PM
Sebastien, you're a lucky young man... somewhere around that age I formulated the Honman theory of hi-fi which was that by the time you can afford gear that does anything worthwhile beyond 15kHz, you can't hear the benefits.

honmanm: that is very true with just about anything else in life! Cars for example! By the time a person can afford a Ferrarri (or Porsche), he/she can hardly get in and out the low chassis of the car! Its called the Human theory! There is a subsidairy theory which states that the minute a person can afford something worhtwhile, buy it! Don't wait until a day when you can no longer enjoy its benefits!

STHLS5
13-11-2010, 12:53 AM
We have previously discussed about effects of frequencies above human hearing range. (I can't locate the thread) .I still believe they have some benefits even though it may not be readily heard and not necessarily must be heard. Alan has written somewhere here that the super tweeter helps to smooth the higher frequencies which can be perceived to be irritating.

For the past 1 week, I have added another super tweeter to SHL5 which extend to 50kHz. I cannot tell if there's any effect for now. I am looking for fatigue factor which is going to be very difficult given that Harbeths are naturally less fatiguing than other speakers.

I also believe that age is not a factor to benefit from hypersonic. But in todays world belief alone is worthless without scientific explanation.

ST

Labarum
13-11-2010, 05:46 AM
Has there been any serious research into the benefits of supertweeters?

STHLS5
13-11-2010, 07:34 AM
I have previously posted Oohashi's research under "Hearing and Perception" thread. I am unable to find the the thread. Anyway, if my memory serves me correct, I think he used special speakers/tweeter which extended to 50kHz or 100kHz. Another interesting toy that I used was Corda Analoguer (http://gilmore2.chem.northwestern.edu/projects/showfile.php?file=meier4_prj.htm) to check for myself if SACD and super tweeter really of any use.. I think I should start to play with it again.

ST

Labarum
13-11-2010, 07:42 AM
Perhaps a Mod would move these super tweeter posts to a separate thread?

If a tweeter is radiating up to or above 50kHz but the source has no data above 20kHz if CD and lower for other sources, what is the tweeter outputting? Noise?

My simple mind is very confused.

STHLS5
13-11-2010, 07:48 AM
Perhaps a Mod would move these super tweeter posts to a separate thread?

If a tweeter is radiating up to or above 50kHz but the source has no data above 20kHz if CD and lower for other sources, what is the tweeter outputting? Noise?

My simple mind is very confused.

No! SHL5 stops at 24kHz. Other tweeters like Murata, Tannoy and a few others goes up to 50 or 100kHz. Do you perceive any difference in SACD format? I believe the true test is long term listening. Fatigue factor.

ST

honmanm
13-11-2010, 11:05 AM
I believe the true test is long term listening. Fatigue factor.

That's an interesting question that probably deserves a thread all of its own... what is listening fatigue and how does one combat it... (of course the "pat" answer would be, buy a certain brand of speaker!).

After discovering the joys of an old Quad 33/303 (approx age 25) I've never been able to tolerate a fatiguing system - many times I was impressed by a system demonstrated by a dealer, but equally relieved to return home to the Quad/Sumo/small Maggie setup! The interesting thing about that rig is that the speakers were 3dB down at 18kHz... perhaps at least in my case a shortage of high treble was preferable to low-quality high treble.

To be honest, prior to the surprise enounter with Harbeths, I didn't know there was such a thing as a non-fatiguing "box" speaker... (I've subsequently discovered it's not the only one).

Sebastien
13-11-2010, 02:03 PM
That's an interesting question that probably deserves a thread all of its own... what is listening fatigue and how does one combat it...

Yes, Harbeth tend less to fatigue his listener but the listener can be tired by himself. Even with a pair of Harbeth, a music to loud can fatigue the listener or an hard day at work with a lot of noise. What I've found with the SHL5 is that you can listen to low level of sound and everything stay balance.

"Cables the diameter of your finger?..." as the thread subjet. It makes me wonder about "Cables the diameter of a toothpick." for exemple an Anti-Cable speaker's cable. Anyone have try these?

Sebastien

P.s.: to moderator: I realized that some thread are close. Any reason for that? Maybe I had miss an information about that. Please refer me to the link if there is any. Thank you.

honmanm
14-11-2010, 02:43 PM
(sorry all, on reviewing the post it is a bit of an essay)

For the past 2 years or so I've been using anti-cables belonging to a friend who discovered that he prefers a high-capacitance cable type.

They probably have about as much copper in them as any other quality cable - I think they're 12 AWG, which oddly enough corresponds to the optimum guage from the AES paper on the cable measurement thread. They are basically enamelled transformer wire (it's debatable whether the copper is any different from standard transformer wire... that's a test for another day) and work out just a little more expensive than buying the same guage wire from the likes of Maplins / Radio Shack.

The enamel insulation is very thin (most of the super-thick cables seem to get that extra thickness from insulation not conductor).

The anti-cables seem to work well - nothing to complain about - but for the moment I'm using a greater length of smaller guage transfromer wire to allow the equipment to be moved around the room (room integration is currently my biggest problem).

We don't have an ISO standard toothpick in the house to compare with, but [correction] the anti-cable does look like it's about thhthpick diameter.

Before changing from anti-cable to the other wire - similar construction but only 60% of the cross-sectional area - they were both measured - the resistance of 2m of anti-cable is about 0.1 ohm, the longer 3.5m run of thinner transformer wire is about 0.3 ohm

With the 25W NVA amp I was a little surprised to hear a difference (note no instant changeover box involved, so very subjective) - less bass (expected) and cleaner top-end (unexpected). However on reflection this is likely to be because the combination of cable and speaker presents an easier load to the amplifier - and less bass means less power-supply distress for a small amplifier.

Now that the DIY amp is up and running, I'm keen to repeat the comparison, and expect the subjective differences to be a lot smaller... which is why Alan's switchover box looks like an interesting "next project".

honmanm
14-11-2010, 06:46 PM
Update... I've dug out the anti-cables and put them back in the system - I did one channel at a time.

I had expected that there would be little change, if any - similar cable construction and layout, different resistance but new amplifier has a very meaty power supply.

Immediately after changing the RH (long wire) channel from generic transformer wire to anti-cable there was a noticeable difference. There seemed to be more HF energy on that side, and the central image became diffuse. So thinking that the generic wire had more resistance, that speaker was moved further from the listening position - no effect.

Changed the LH channel from a shorter length of generic wire to anti-cable: no audible effect.

At this point confusion was reigning - the most likely possibility was that the contortions required to change cables had unbalanced my hearing. So the RH channel was changed back to the original wire, with the expectation that things would remain as they were, with the diffuse image. However the presentation returned to what it had been at the beginning, similar tonal balance from both speakers and a well-defined image (this is with anti-cable on LH channel and generic wire on RH channel).

Given that situation it's quite likely that the connectors on one of the anti-cables need attention. Will investigate further and (if it's not boring everyone to tears) report back.

STHLS5
14-11-2010, 11:07 PM
With the 25W NVA amp I was a little surprised to hear a difference


I have certainly overlooked other important factors when we talk about cables and amplifiers. We need to make sure the room's influence is within acceptable level. And the amplifier's output should be adequate to meet your speakers and the volume you play.

Didin't Alan post a paper by Mr Harwood that amplifier and 100W for momentary requirement? I have to look for it again. I read it half way and thought it was important so I reserved for later reading but now can;t even remember where to look? Any help?


ST

JoeH
22-12-2010, 03:45 AM
Speaker wire: I have my Model 30's connected by audioquest Rocket 88 bi-wired. I orginally used 25 year old Fulton Brown and the focus and detail of the current wire was a real upgrade to my speakers. My dealer let me try about 8 different wires and the Rocket 88 in single wire and bi-wired confirguration. He thought the bi-wiring locked the speaker because it got around the stock jumper.