better power cable

[Shadders]

The amount of feedback is the open loop gain divided by (subtracted from in dB) the closed loop gain. The figure you calculated from the global feedback resistors is the closed loop gain.
The Naim circuit does have fairly high feedback. The NCC200 has less open loop gain due to the emitter degeneration in the LTP.

Hi,
Yes - and what is in vogue at the moment is low global feedback, in favour of local feedback. This, at this time seems to be the preference, and amplifiers stated to have this approach get the preferential subjective review.

The Naim clone has NO (zero) LTP emitter degeneration - no designed local feedback in this part of the circuit. The VAS has NO (zero) designed local feedback (no emitter resistor).

So we have a Naim clone that sounds wonderful using lots of global feedback and NO designed local feedback to achieve the relevant performance, in complete opposite to the in vogue hifi which uses local feedback and reduced global feedback.

So the folklore that global feedback is bad, or any feedback is bad, is just that - folklore, myth, utter rot.

When you referred to lots of feedback, the remark was intended to be negative against the Audiolab unit, yet the Naim clone unit is worse in its design and could be considered out of vogue.

Since people do not know about the design, they accept the folklore as is for the Naim clone. When people make statements about Audiolab as you have done, they accept it as fact, despite Naim clone being worse.

Regards,
Shadders.

 

[S-Man]

When you referred to lots of feedback, the remark was intended to be negative against the Audiolab unit,

No it was not! It was a straightforward statement.

You really need to stop assuming you know what people think!!!

I actually have a zero global feedback amp and a zero global feedback preamp. They don't feature in my system on a regular basis.

Once again...

You really need to stop assuming you know what people think!!!


And another thing: Post #199 shows that you are not particularly well infomed on technical matters, and yet you keep citing your definitive position when it comes to mains cables.

 

[pocketkitchen]

The Audiolab sold by the bucket full and the shop where I used to work sold loads. Despite that though, none of us staff actually liked the thing that much, preferring the 8000s, or Meridian, Naim or Linn integrateds. Each to their own. Objectively it was a good amp which suited well a number of popular speakers.

 

[Andrew C!]

Even the law of averages will show that there must be a case where an AV amplifier must sound better than a hifi amplifier - yet we never hear that on a hifi forum.

My Onkyo av amp powered a pair of Chartwell speakers for about 6 -8 weeks whilst I was waiting for my D&D’s to arrive. I could have happily lived with that combo.

I compared an 8000a against the Arcam and Cyrus equivalents back in the day, and purchased the 8000a. I kept it until going Naim.

 

[Shadders]

No it was not! It was a straightforward statement.

Hi,
Why even mention feedback ("So loads of feedback then.") and nothing else ?

And another thing: Post #199 shows that you are not particularly well infomed on technical matters, and yet you keep citing your definitive position when it comes to mains cables

You knew what i was referring to - both have high global feedback, where the Naim clone has no designed local feedback, and relies predominantly on designed global feedback.

Again, according to hifi folklore the Naim clone using predominantly designed global feedback is poor, yet it is ok because it is Naim ?

In all the 11 pages so far, not one technical presentation of how mains cables improve equipment sound. I wonder why. Just more folklore.

Regards,
Shadders.

 

[Pete L]

Can't recall anybody having an after-market power cable in the UK at that time,

The only thing I do remember from those days as far as power cables are concerned was when there was suddenly a craze for solid-core speaker cables. Several reviewers advocated making mains leads out of twin-and-earth solid core mains wire in order to 'maximise' the effect of the speaker cables. I think I tried making one but it seemed too dangerous as the plugs are designed to accept stranded conductors, not solid core. I was still living with my parents at the time and when my dad saw what I was doing he 'put his foot down' muttering something about the house burning down. He was probably right!

Actually I think JMH had a hand in all that too....

Pete

 

[suzywong]

In the late 80s, we were looking at rearranging the living room, which meant reconfiguring the hifi (LP12, Meridian 101/103D and Briks).

At the time the speaker cables were 5m of NACA4. The rearrangement we had envisaged needed 10m, so I soldered up some speaker cables using B&Q’s finest twin-and-earth solid - they didn’t sound as good as the NACA4. Then tried bog standard 13A stranded....

Then we decided to not rearrange the living room, and went back to the NACA4.

 

[Tom Bonjour]

The only thing I do remember from those days as far as power cables are concerned was when there was suddenly a craze for solid-core speaker cables. Several reviewers advocated making mains leads out of twin-and-earth solid core mains wire in order to 'maximise' the effect of the speaker cables. I think I tried making one but it seemed too dangerous as the plugs are designed to accept stranded conductors, not solid core. I was still living with my parents at the time and when my dad saw what I was doing he 'put his foot down' muttering something about the house burning down. He was probably right!

Actually I think JMH had a hand in all that too....

Pete

Now I wonder if using that solid core mains wire for a mains cable would sound any different. Here in the USA we call it Romex and I usually use 12/3, 12 gauge with 3 conductors. I am pretty doubtful about mains cable making any difference but I am always experimenting. It would be a little stiff, but not a lot worse than Naim NACA5.

 

[Pete L]

In the late 80s, we were looking at rearranging the living room, which meant reconfiguring the hifi (LP12, Meridian 101/103D and Briks).

At the time the speaker cables were 5m of NACA4. The rearrangement we had envisaged needed 10m, so I soldered up some speaker cables using B&Q’s finest twin-and-earth solid - they didn’t sound as good as the NACA4. Then tried bog standard 13A stranded....

Then we decided to not rearrange the living room, and went back to the NACA4.

In 1989 when I got married, my wife and I bought a flat and I needed longer speaker cables for my LP12/42.5/Hi-Cap/110/Kans. I had been using NACA4 but it was around that time when there was the craze for solid core speaker cables, DNM and Mission (or was it Cyrus?). I believe it was also around the same time as the Pioneer A400 was championed as being superior to a 32/Hi-Cap/250 in some quarters. Anyway my curiosity got the better of me and I bought some solid core speaker cable - against the advice of my dealer! It sounded absolutely awful - thin, hard and completely lacking dynamics. I quickly reverted back to NACA4!

Pete

 

[Pete L]

Now I wonder if using that solid core mains wire for a mains cable would sound any different. Here in the USA we call it Romex and I usually use 12/3, 12 gauge with 3 conductors. I am pretty doubtful about mains cable making any difference but I am always experimenting. It would be a little stiff, but not a lot worse than Naim NACA5.

Tom, I don't know what your cables are like in the US but there are certainly problems over here with using solid core twin-and-earth 'house wiring' for making mains leads. Firstly the 13amp wall plugs and IEC connectors have terminals which are really designed to accept stranded conductors, not solid core. Yes they can be connected, but they don't really 'feel' safe and secure. Even after tightening the screws down if the cables are 'wobbled' slightly then the wires work loose very quickly.

The other issue is that the leads are obviously very stiff and if they are repeatedly bent in order to manipulate them into position then the conductors can easily break.

So the safety issues as far as I am concerned are sufficient to rule them out entirely, even if they sounded superb.

Pete

 

[Pete L]

I believe Mapleshade Audio in the US used to market solid core mains cables. They were unconventional in that the outer insulating sheath, instead of being thick rubber or PVC or whatever, was basically very thin transparent polythene, like a long tubular plastic bag! They looked positively dangerous and I have certainly seen them criticised safety-wise. There is a video on YouTube if you search under Mapleshade Audio.

The company founder/owner is Pierre Sprey, who apparently used to design military jet aircraft in the US.

Pete

 

[Tom Bonjour]

Tom, I don't know what your cables are like in the US but there are certainly problems over here with using solid core twin-and-earth 'house wiring' for making mains leads. Firstly the 13amp wall plugs and IEC connectors have terminals which are really designed to accept stranded conductors, not solid core. Yes they can be connected, but they don't really 'feel' safe and secure. Even after tightening the screws down if the cables are 'wobbled' slightly then the wires work loose very quickly.

The other issue is that the leads are obviously very stiff and if they are repeatedly bent in order to manipulate them into position then the conductors can easily break.

So the safety issues as far as I am concerned are sufficient to rule them out entirely, even if they sounded superb.

Pete

I am not familiar with the wire used for general wiring in Great Britain. 12/3 Romex is rated at 20 amps here and it is what I almost always use for wiring even for 15 amp circuits. I have done a bit of general wiring in my life. If I try this it will only be as an experiment. I have seen many references to mains cables sounding different and this thread has made me wonder a bit. Your concern about loosening connections reminded of something that may be of interest. In this old farmhouse, here in Indiana, all of the wiring connections in the junction boxes etc., were twisted tightly, then soldered and then wrapped in electrical tape. This work was done in the 1970's, during a complete remodel. This was pretty old school at the time. However it certainly holds up over time.

 

[Pete L]

then soldered

Tom, interesting that you mention this. I know that in the past some so-called 'audiophile' mains leads had the conductors, which were very thick (though not solid core) soldered onto the terminals of the 13 amp plug, rather than being screwed in as usual. Don't know if it actually broke any safety regulations but I have certainly seen the practice criticised on safety grounds.

The 'fad' for solid core wires, whether speaker or mains, now seems to have largely disappeared, which perhaps says something about how they sound. Safety first above all else anyway. Not worth risking your life or property to achieve better sound!

Pete

 

[sq225917]

More likely to do with their shit hand feel and impossible to route nicely.

If using for 13 amp plugs always fold the wire into the pin, easier to bite down for the screw. Soldering is a bad idea for mains plugs, a poor connection in terms of stability and lifespan.

 

[martin clark]

Tom

12AWG is about 4sq.mm and generally US code uses radial circuits. So 20A fuse or breaker per line.

UK with its (post WW2, economy on mind) uses the unusual ring config, so domestic mains circuits here are effectively 5sq.mm (2 x 2.5sqmm minimum) cables to every socket, 25% more CSA than 12awg but also, all solid-core as with Romex. The breaker is rated at 32A for this service, and the UK regs limit the floor area served and also risk category (e.g. wet rooms, kitchens) so most newer or (older, re-wired) houses have several rings, separated by floor level and then by any specific zone of use considerations. Lighting cicuits, ditto.

At 240Vac the usual Class B rccd breaker actually takes about 60A+ to break in under 10secs. Lots of power available (also why the uk mains plugtop has its own fuse - that is to protect against the case the local flex to a small appliance gets damaged, while fundamentally not sized to deal with the prospective fault current of 100A+ required to break the Ring fuse to isolate the flex; no-one wants 10ga leads to a desklamp...); but in toto, - no, the wiring really is not so different really.

(but no - no 'wire nuts' - that's one thing we get right, along with mains plugs that hurt more than Lego to stand on, & can't be accidentally pulled out of the socket)

 

[Tom Bonjour]

Tom

12AWG is about 4sq.mm and generally US code uses radial circuits. So 20A fuse or breaker per line.

UK with its (post WW2, economy on mind) uses the unusual ring config, so domestic mains circuits here are effectively 5sq.mm (2 x 2.5sqmm) cables to every socket, 25% more CSA than 12awg but also, all solid-core as with Romex. The breaker is rated at 32A for this service, and the UK regs limit the floor area served and also risk category (e.g. wet rooms, kitchens) so most newer or (older, re-wired) houses have several rings, separated by floor level and then by any specific zone of use considerations. Lighting cicuits, ditto.

At 240Vac the usual Class B rccd breaker actually takes about 60A+ to break in under 10secs. Lots of power available (also why the uk mains plugtop has its own fuse - that is to protect against the case the local flex to a small appliance gets damaged, while fundamentally not sized to deal with the prospective fault current of 100A+ required to break the Ring fuse to isolate the flex; no-one wants 10ga leads to a desklamp...); but in toto, - no, the wiring really is not so different really.

(but no - no 'wire nuts' - that's one thing we get right, along with mains plugs that hurt more than Lego to stand on, & can't be accidentally pulled out of the socket)

Thanks for sharing all that information, Martin. I believe your 4 sq. mm is 11 gauge here, a size which is seldom seen. I am not sure what a ring configuration is, though I have seen many references when people write about running dedicated mains lines for their HIFi. If you could explain that, I would be quite interested to learn about the ring configuration. I often prefer to use 12 gauge even if I want the circuit breaker to be 15 amps. 12 gauge is acceptable here for both 15A and 20A circuits.I am surprised that you have such high current capacities on your circuits in Great Britain with your 240V customary mains, that certainly puts a lot more power (Watts) at the outlet than is customary here. I had not really understood that aspect of how things are done over there. Yes wire nuts are very often used here. Are most wire junctions in Great Britain twisted, soldered and taped?

 

[misterdog]

I am not sure what a ring configuration is

The socket in the centre with only 3 wires is called a spur.

 

[Tom Bonjour]

The socket in the centre with only 3 wires is called a spur.

Thanks for sending this diagram. After writing my reply, I realized that I could search the Internet for an explanation. This diagram is quite helpful. This a very different approach, I will study it a bit.

 

[martin clark]

Tom

(eta: misterdog's diagram tells you everything useful)

The ring concept is quite simple - the cable, lets just call it romex, runs out from the distribution board, around the perimeter of the area it serves (for example, in a small UK house post ww2, the ground floor excluding kitchen) and back to the breaker board. So what you get is 2 x the Romex CSA, but less total wiring overall than running radials to all the sockets that 'ring' might serve (say 8-10 double outlets). Recent (last 20yrs updates of IEEE regs increasing use of RCCDs and consequent segregation to avoid nuisance tripping on local circuits these days, esp post 2015 ish, means there is a now a move to just running everything as radials even domestically- the wire is way cheaper than the breakers. But given the rather modest (pokey!) floor area of UK newbuild homes, the ring persists. It's still a proven reliable & economic way of doing things.

As to how the things are physically put together - given the current rating and prospective power (heat in case of joint resistivity) the wiring traditionally was run 'loop -in' - the cable locally& carefully stripped and the exposed section to make the contact bent to the socket contact and out again, in one piece, no jointing allowed!
These days, joints are allowed on fixed wiring at such junctions (-and so, for which, on say in-wall mains outlets, tend to be sized for 6sq.mm>10ga in your terms, and large gauge clamp screws to allow for this) but all fixed wiring runs only in 1 continuous piece otherwise: twisting/jointing(wirenuts), taping, and esp soldering - all prohibited AFAIK.

 

[booja30]

Isn't it problematic to have, for example, a device powered somewhere on the ring that depends on the ring topology (e.g. more that 2.5mm^2 of conductor) but there is a fault on the ring? That is to say you could assume all is good since all the receptacles are working, but the ring is actually broken at some point.

I agree wire nuts are terrible (I rewired my house and installed a new panel back in Seattle and still have callouses) and solid core is a PITA to work with in many cramped junction boxes. But I am a fan of radial topology!