Audiophiles v sound engineers

[Arkless Electronics]

Can you remind me, what parts of this do you think are wrong?

What part of that, beyond saying you are wrong, I am not going to discuss it as we've been there before, do you not get?

 

[Arkless Electronics]

This is getting on for half my lifetime ago so my memory is a bit fuzzy, but as I recall our studio was pretty much exclusively single-ended. We had a Soundcraft Spirit Studio 16/8/2 desk, the muti-track recorder was an Alesis ADAT (an early digital 8 track that recorded to a SVHS tape!) and a rack of outboard kit (digital reverbs, delays, compressors etc). I am certain all that lot was wired up with bog-standard mono 1/4” jack plugs, a right bloody rats nest to be honest. Its only recently I went through what was left of the cables that had been sitting in my cellar for ages and flung a bin-sack full of filthy junk out, and none were TRS jacks. I can remember the couple of XLRs we had were used one on the JP6 and the others were just mic leads!

Back then and with the "amateur" kit you describe unbalanced was more common... go to remotely pro gear and it's balanced and these days even most of the amateur/home studio gear is balanced.

 

[Julf]

What part of that, beyond saying you are wrong, I am not going to discuss it as we've been there before, do you not get?

So you are saying that you keep being just as wrong as you were then?

 

[Arkless Electronics]

This is one channel of a fully balanced Class A/B amplifier, too many components ?

THD+N -107 dB 0.00045 % 40 W, 8 Ω, 1 kHz

The Neurochrome Modulus composite amplifier topology uses a precision amplifier to perform error correction on a less precise power amplifier. The Modulus-186 is a composite amplifier, which uses an LME49720 to perform error correction on an LM3886 power amplifier IC. This results in an amplifier which has the precision of the LME49720 and the power of the LM3886. This error correction is the central point of the Neurochrome Modulus composite architecture. The composite design will correct for many types of error, including distortion and power supply induced errors.

The error correction circuit in the Modulus-186 has its own regulated power supply. Consequently, the power supply for the error correction circuit is clean and free of ripple, even if there is some ripple voltage on the power supply to the board. In addition, the error correction circuit (LME49720 and associated components) has its own power supply rejection (the PSRR of the LME49720 due to its design and architecture). The end result is that the error correction circuit will correct for any distortion and supply-induced errors by the LM3886. This is done without introducing any errors of its own, while staying within the performance limitations of the LME49720. The end result is a powerful amplifier with vanishingly low distortion.

As mentioned, the error correction circuit also corrects for power supply induced errors in the power amplifier. This makes the Modulus-186 indifferent to the type of power supply used. When operated at levels below clipping, the Modulus-186 performs as well on a well regulated switching supply as it does on an unregulated power supply.

pseudo-differential cable between the single-ended (unbalanced, RCA) source and the differential (balanced, XLR) input on the Modulus-186. These cables can easily be made by the savvy DIYer. They are also available commercially.

That ain't fully balanced if it uses a single LM3886 as it's a single channel amp IC! Beyond that, your point is?

 

[misterdog]

From Tom's description.

The Modulus-186 has a differential (balanced, XLR) input. There are two reasons for this:

1. Differential signalling sounds better.
2. Differential signalling measures better as it rejects hum.

Using differential signalling moves the ground connection between the various pieces of equipment out of the signal path. This results in a reduction in mains hum of about 90 dB (31,600×), which is nearly as good as you would get from an input transformer (but without the distortion of the transformer).

Though Tom is the electrical engineer, I only go by what I read.

 

[Arkless Electronics]

From Tom's description.



Though Tom is the electrical engineer, I only go by what I read.

It may have a balanced input through a balanced receiver IC (ie not natively balanced) but to be "fully balanced" a power amp must be bridge mode. I believe some of the models higher in the range are....

 

[Julf]

Though Tom is the electrical engineer, I only go by what I read.

Seems the Modulus-186 has differential (balanced) inputs, but not a "fully balanced" circuit topology from input to output.

 

[misterdog]

It may have a balanced input through a balanced receiver IC (ie not natively balanced) but to be "fully balanced" a power amp must be bridge mode.

Both Si and myself run in bridged mode so we are sorted then

 

[Sue Pertwee-Tyr]

The important part is the differential input, and any op-amp input already has both inverting and non-inverting circuitry. Even if you have to add an extra transistor to an input stage, it is not an additional component in series with the signal path, but in parallel - yes, you have two transistors instead of one, but each only handles half the signal, so the total path length is no longer / more complicated than with unbalanced. The same applies to outputs.

I totally disagree and for all the reasons I gave the last time we "debated" just this for pages.
Please don't bother replying to this as lifes too short.... I refer you to everything I said last time.

And you are totally wrong, for all the reasons I gave the last time we "debated" just this for pages.
Please don't bother replying to this as lifes too short.... I refer you to everything I said last time.

I find this interesting, coming as it does from this forum’s principal proponents of the ‘the science is settled, don’t argue with the physics’ viewpoint, usually on cable threads and the like.

It seems to me, the science may be settled, but there is no agreement as to where and how it has settled...

 

[camverton]

Both Si and myself run in bridged mode so we are sorted then

That’s nice, perhaps you can find a bridge to connect Jez and julf!

 

[Arkless Electronics]

I find this interesting, coming as it does from this forum’s principal proponents of the ‘the science is settled, don’t argue with the physics’ viewpoint, usually on cable threads and the like.

It seems to me, the science may be settled, but there is no agreement as to where and how it has settled...

Nah it's just that Julf is CEO of "Pedant's R' Us!" and and was awarded a lifetime subscription to "Semantic's Weekly" magazine

 

[richardg]

This is getting on for half my lifetime ago so my memory is a bit fuzzy, but as I recall our studio was pretty much exclusively single-ended. We had a Soundcraft Spirit Studio 16/8/2 desk, the muti-track recorder was an Alesis ADAT (an early digital 8 track that recorded to a SVHS tape!) and a rack of outboard kit (digital reverbs, delays, compressors etc). I am certain all that lot was wired up with bog-standard mono 1/4” jack plugs, a right bloody rats nest to be honest. Its only recently I went through what was left of the cables that had been sitting in my cellar for ages and flung a bin-sack full of filthy junk out, and none were TRS jacks. I can remember the couple of XLRs we had were used one on the JP6 and the others were just mic leads!

Every piece I had in my studio in 2012 came with XLR ins and outs apart from a couple of pieces of vintage stuff. Monitors, compressors, amps, desk, everything.

I avoided hardware that did not have them, as the chain seemed quieter with XLR. Not sure if there is any theory that stands up there, maybe my jack input components were just old and shit.

 

[Sue Pertwee-Tyr]

Nah it's just that Julf is CEO of "Pedant's R' Us!" and and was awarded a lifetime subscription to "Semantic's Weekly" magazine

Well I haven't read the previous exchange you're referring to, but surely if it was just a matter of semantics and pedantry, it wouldn't generate quite so much heat. It certainly appears as though there's a pretty fundamental difference of view between you, about matters technical. That's the interesting thing, because even if we accept the view that the science is 'settled', the engineering might not be.

 

[flowjm]

As far as I can tell, they're arguing over what the word 'balanced' means in the context of electrictronic signals.

 

[Sue Pertwee-Tyr]

As far as I can tell, they're arguing over what the word 'balanced' means in the context of electrictronic signals.

Ah, interesting, thank you. That's plausible, but hardly explains the evident heat in the disagreement (perhaps Jez' participation is all the explanation we require, however ).

It doesn't invalidate my point, that if engineers aren't in agreement about implementation, especially of 'core' concepts like balanced operation, then perhaps they should wind their necks in a bit over other engineers' implementation of other technologies (and yes, there are plenty of real-life, honest-to-goodness engineers designing cables and support systems).

 

[Julf]

It doesn't invalidate my point, that if engineers aren't in agreement about implementation, especially of 'core' concepts like balanced operation, then perhaps they should wind their necks in a bit over other engineers' implementation of other technologies (and yes, there are plenty of real-life, honest-to-goodness engineers designing cables and support systems).

Sorry to take the wind out of your argument, but the disagreement between me and Jez is about terminology, not about core concepts. Debating the terms we use and their definitions is an important part of science and engineering - it helps us clarify the terms we use, and ensure a common understanding.

 

[Arkless Electronics]

/\ Indeed. Julf and I get on well.. it's just "engineers joshing about" and now't more than that

 

[Joe P]

Julf and Jez,

I know it's all in good fun and to gain a better understand, but when you two joust I can't help but hear this music...

Joe

 

[paulfromcamden]

the chain seemed quieter with XLR. Not sure if there is any theory that stands up there

Yep that's exactly the purpose of balanced cables.

 

[Arkless Electronics]

Yep that's exactly the purpose of balanced cables.

Julf like pedantry alert but it's the balanced amps themselves that are the important concept here, not the cables... in fact in some respects any old cable, not even screened, will do BECAUSE it's balanced.

Oh and whilst nothing to do with the posts here, can we bring back capital punishment for referring to balanced as "XLR".... which is of course a type of plug and nothing else.