Balanced Processor and Balanced Interconnects

[Stockinv]

I currently have B&W 802D speakers with McIntosh 501 amps and an Aragon Stage I processor. My local hi-end stereo guy is telling me that I will get a much better sound if I upgrade my system to one with a processor that has balanced outputs and balanced (xlr) interconnects. He suggests the Classe SSP-600 Processor and balanced interconnects. Total cost would be about $8,500. Will I get the bang for my buck?

[gd]

My BS detector just went off.

Make him prove it by setting up an elaborate A/B comparison.

Your Aragon is excellent... a Classe might better it, but it won't be because of balanced ICs.

[whoaru99]

I currently have B&W 802D speakers with McIntosh 501 amps and an Aragon Stage I processor. My local hi-end stereo guy is telling me that I will get a much better sound if I upgrade my system to one with a processor that has balanced outputs and balanced (xlr) interconnects. He suggests the Classe SSP-600 Processor and balanced interconnects. Total cost would be about $8,500. Will I get the bang for my buck?

"Much better" and "worth it" are so subjective no one can really answer this question for you. Only you can decide this via a side-by-side audition.

IMHO, while I don't have either piece of equipment, I have a really hard time thinking this change would be worth $8,500. But, as I said before, "worth it" is subjective and, IMO, heavily dependent on personal finance. I have my only little theory that the more disposable income one has, the less difference there needs to be for an expensive change to be "worth it".

[Victor]

My local hi-end stereo guy is telling me that I will get a much better sound if I upgrade my system to one with a processor that has balanced outputs and balanced (xlr) interconnects.

This is complete nonsense. Balanced interface alone will never give you better sound. In fact the THD might even get worst.

However if you want balanced interface, it can be done for next to nothing. Classe processor uses simple single-ended to balanced converter. You can add this circuit in a form of a single IC to the output of your processor. The entire exercise will cost you about $50 in parts considering the cost of the new box and a power supply.

All components, schematics and step by step instructions are readily available. You do not need to design anything, - it all has been done for you. If you have rudimentary soldering skills and reasonably DIY aptitude you can save yourself the $8500 and achieve the identical results.

The question I would ask here is this, - why do it?

Victor

[whoaru99]

This is complete nonsense. Balanced interface alone will never give you better sound. In fact the THD might even get worst.

Victor

Generally, I agree.

However, if one had poorly shielded or very long unbalanced cables in a "noisy" environment, balanced interface might sound better. This would be an exceptional case in the typical HT setup; not the norm by any means.

[Stockinv]

Balanced Interconnects

Currently, my unbalanced interconnects are about 16 feet long. I'm wondering how much a difference it would make with balanced interconnects and/or shorter runs.

[Victor]

Currently, my unbalanced interconnects are about 16 feet long. I'm wondering how much a difference it would make with balanced interconnects and/or shorter runs.

Shorter runs are always preferable, but they are not always practical. Will there be measurable effects if you were to use shorter single-ended cable runs? Yes, most likely there will be, but you will never hear them. We are talking about the difference in THD of 0.01% at worst, and it is very likely that the difference will be in 0.001% range.

As far as the use of balanced interconnects, well, - here the things are not as simple. In the context of a typical home set-up, my take on it is this; - make sure that you have a good reason to use them.

The good reason might be that your system is completely balanced from the source to the power amps, as it is in my case. Let me be more specific. My crossover box, the DCX2496 has been modified to take advantage of a balanced D/A output without resorting to single ended conversion as it is done in a stock unit. I process the signal in the balanced fashion starting at the D/A outputs. My power amps at the moment utilize a balanced to single-ended converter with a reasonable degree of noise suppression, although I am not concerned about noise in my system, - still the balanced interface makes since in my case only because my D/A is balanced to begin with, besides I am thinking about adding a fully balanced power amp, similar to Ampzilla2000.

Another reason to use the balanced interconnects perhaps might be if you are really concerned with noise. This is rare in a home environment, although it may happen. Usually this concern arises if you are dealing with a very long wire runs, - around of 200 feet or more, which is the case with professional installations.

If you use balanced interface in order to suppress noise, you must make sure that at the very least your input balanced receiver is not just a simple differential amp, but a more sophisticated circuit. For the most part the manufacturers give you a bare minimum diff-amp and you end up with a mediocre noise suppression at best. End result of this is actually very little noise suppression, with a minor rise of the THD due to the use of this diff-amp.

So, personally I would not use balanced interface unless I know for sure what circuitry is being used, because clearly here the cure might be worst then the disease.

regards,
Victor

[Kobus]

Classe processor uses simple single-ended to balanced converter.

So, is Classe equipment not fully balanced. I am surprised.

Kobus

[Victor]

Kobus,

Here is a direct quote from the Classe website:

“…Both models utilize the same digital audio and video processing circuits as well as single-ended analog audio paths…”

it further states, and I quote:

“…The SSP-600 builds upon the versatile foundation of the SSP-300 by adding a second, linear power supply, and an additional analog circuit board, which includes a balanced two-channel preamplifier and 7.1 channels of balanced audio outputs…”

What does it mean? The second linear power supply has got nothing to do with balanced processing unless the other model uses a single power supply approach. This is unlikely, because this is not a Hi-Fi approach.

The additional analog board with a 2-channle pre-amp might be a fully balanced design and it also might be a simple single-ended to balanced converter. In any case this statement only addresses 2-channels, most likely Left and Right. What about the rest of the channels? The comment is unclear and if the SSP-600 was truly fully balanced for all channels the Classe would let us know in no uncertain terms.

However, none of that is really important because the processor is the source here. Balanced interface also requires a receiver in order to operate correctly. The balanced receiver is really responsible for all the noise rejection. The source is by far less important as it is trivial to make sure that the source’s balanced circuit works well.

If SSP-600 is fully balanced inside then there is a reason in my opinion to consider balanced interface. If SSP-600 is not fully balanced, but uses a single-ended to balance converter then I would stay with single-ended cables.

Victor

[Kobus]

Thanks Victor,

Sorry, I thought you meant their products per se is not fully balanced. As I understand it, their 2ch pre-amp, cdp etc is fully balanced.

Kobus

[RebelMan]

The additional analog board with a 2-channle pre-amp might be a fully balanced design and it also might be a simple single-ended to balanced converter. In any case this statement only addresses 2-channels, most likely Left and Right. What about the rest of the channels? The comment is unclear and if the SSP-600 was truly fully balanced for all channels the Classe would let us know in no uncertain terms.

They do and it does. Stated from the Classe' website... "The SSP-600 adds to the performance and capability of the SSP-300 by including a fully-balanced output stage for all eight channels and a balanced input pair which allows the SSP-600 to act as a simple, yet high-quality balanced stereo preamplifier. A separate linear power supply is dedicated to the additional balanced audio circuitry."

The second linear power supply has got nothing to do with balanced processing unless the other model uses a single power supply approach. This is unlikely, because this is not a Hi-Fi approach.

Victor, it is not clear how this statement is applicable in the case of the SSP-600. Can you explain what you mean by "processing"? Are you referring to the digital domain or something else?

[Victor]

They do and it does. Stated from the Classe' website... "The SSP-600 adds to the performance and capability of the SSP-300 by including a fully-balanced output stage for all eight channels and a balanced input pair which allows the SSP-600 to act as a simple, yet high-quality balanced stereo preamplifier. A separate linear power supply is dedicated to the additional balanced audio circuitry."

Victor, it is not clear how this statement is applicable in the case of the SSP-600. Can you explain what you mean by "processing"? Are you referring to the digital domain or something else?

I clearly missed that statement. Naturally it would be great to see the schematics but Classe does not publish it.

It seems that the description talks about the extra power supply as separate from the power supply used for the DACs. Well, we are guessing here. I understood the description as saying that the power supply for the single-ended circuit is clearly separate from the power supply used for the balanced circuit. If that is the case, I am not sure I understand the rational here. Anyway, it does not matter really.

Again, if the SSP-600 has balanced DACs, that followed by a fully balanced filters, that is impressive and certainly makes this units a candidate for a balanced interface. However, in the context of a typical home Hi-Fi environment the benefits of fully balanced interface are questionable at best.

Victor

[whoaru99]

They do and it does. Stated from the Classe' website... "The SSP-600 adds to the performance and capability of the SSP-300 by including a fully-balanced output stage for all eight channels and a balanced input pair which allows the SSP-600 to act as a simple, yet high-quality balanced stereo preamplifier. A separate linear power supply is dedicated to the additional balanced audio circuitry."

Victor, it is not clear how this statement is applicable in the case of the SSP-600. Can you explain what you mean by "processing"? Are you referring to the digital domain or something else?

Fully balanced inputs and outputs usually do not equate to a design that is fully balanced from input to output and all points between.

Two channels MAY be fully balanced in to out, but I really doubt all of them are - I'd bet money on it.

If the gear is fully balanced all the way though, the mfg will be very clear to point that out.

[Victor]

Fully balanced processor needs to use a balanced D/A section, followed by a balanced anti-imaging filter and possibly a balanced amplifer. It would need to done for all 7.1 channels! This in itself is not all that problematic to design, but it might be somewhat costly, particularly with a descrete circuit design approach.

The problem as I see it can be with features like the mute function, volume control, etc. Those functions, while still very doable, present design problems that might just be too expensive to solve. Reason being that implementing them in digital domain, which is cheap, does not offer the results that a Hi-Fi approach would mandate, - so to do it 'right' the manufacturer must implement an 'analog' volume control and perhaps a relay-driven 'mute'.

In any event if Classe has done the fully balanced design I think that their marketing department vould be more outspoken about this, as this would sertainly set the Classe products apart from its competition.

Victor

[RebelMan]

Fully balanced inputs and outputs usually do not equate to a design that is fully balanced from input to output and all points between.

In many cases this is true but such is not the case with the SSP-600.

Two channels MAY be fully balanced in to out, but I really doubt all of them are - I'd bet money on it.

If the gear is fully balanced all the way though, the mfg will be very clear to point that out.

The SSP-600 utilizes fully balanced two-channel analog circuitry from stem to stern. All eight XLR outputs are fully balanced and use ultra-high performance components to boot. As for the remaining single-ended inputs, they are converted to balanced mode at the output stage and are thus not fully balanced, this much is true. However, this needn’t matter. The SSP-600 is a digital processor first and foremost.

The digital AES/EBU input on the SSP is fully balanced and the incoming signal remains this way throughout the digital domain. After running through the 32-bit Freescale Motorola DSP, each channel is converted to a balanced analog signal using its own differential 24-bit multi-bit delta-sigma DAC. The manufacturer is very clear about this.

[RebelMan]

In any event if Classe has done the fully balanced design I think that their marketing department vould be more outspoken about this, as this would sertainly set the Classe products apart from its competition.

Classé has a less than reliable track record of voluntarily publishing all the information they could and probably should. Apparently you haven't seen or heard of the SSP-900 either, but it's very real and is literally in a class all its own.

[Victor]

Classé has a less than reliable track record of voluntarily publishing all the information they could and probably should. Apparently you haven't seen or heard of the SSP-900 either, but it's very real and is literally in a class all its own.

True enough I never heard of SSP-900. I looked it up and, well, - for the price of $25K it better serve beer too. I am not convinced that the addition of fully differential circuits, 1080P switching and scaling, multi-zone capability is worth the cost that it commands, but it sure looks impressive.

The SSP-600 is a digital processor first and foremost.

The digital AES/EBU input on the SSP is fully balanced and the incoming signal remains this way throughout the digital domain. After running through the 32-bit Freescale Motorola DSP, each channel is converted to a balanced analog signal using its own differential 24-bit multi-bit delta-sigma DAC.

The AES/BU is balanced by default. In fact it is inferior to the commonly used single-ended SPDI/F when it comes to noise rejection. The digital signal processing is not balanced by definition and it does not matter how the signal gets to the DSP processor, as the interface plays no role in subsequent processing.

The notion of balanced interface really only applies to analog signals, where the common-mode noise might be an issue. Clearly the Right and Left channels of SSP-600 and all the outputs of SSP-900 are good candidates for the balanced interface in my opinion.

However, the use of balanced interface offers more of an intellectual benefit then the practical one. It is the knowledge that you are using the interface that actually makes some engineering sense is of note here. I do that in my rig. In practical terms and in the context of a typical home environment this would be of very little if any importance at all.

Victor

[whoaru99]

The SSP-600 utilizes fully balanced two-channel analog circuitry from stem to stern. All eight XLR outputs are fully balanced and use ultra-high performance components to boot. As for the remaining single-ended inputs, they are converted to balanced mode at the output stage and are thus not fully balanced, this much is true. However, this needn’t matter. The SSP-600 is a digital processor first and foremost.

Well, no doubt it should be a very fine piece of gear.

But, talking about and referencing balanced inputs/outputs is very misleading to those who don't know to look deeper or ask more pointed questions - that's my only point. Don't get me wrong, it's not just Classe that is (IMHO intentionally) vague about this.

[RebelMan]

The AES/BU is balanced by default. In fact it is inferior to the commonly used single-ended SPDI/F when it comes to noise rejection. The digital signal processing is not balanced by definition and it does not matter how the signal gets to the DSP processor, as the interface plays no role in subsequent processing.

This is an inaccurate statement. Rather it should have been stated that a balanced 110 ohm twisted-pair cable is more susceptible to interference than an unbalanced 75 ohm coaxial cable is. The IEC specs clearly define both interfaces, AES (in all of its incarnations) and SPDIF, as having the same formatted digital audio data but differ on subcodes. The protocols between each interface have similarities but they are not the same.

Given that there are few if any consumer appliances that use BNC connections and that virtually no one (except maybe a few like yourself) would ever consider implementing interface conversions, which can work but still doesn't make them the same, makes the AES/EBU connection the only and a better alternative to S/PDIF, provided of course that proper impendance matching cables are used in the process. AES (aka AES3) improves upon and has the potential to do more good than S/PDIF.

All the advantages that come with balanced interfaces apply to digital and analog signals alike. Both use voltage signaling and both are susceptible to interference so it does matter how this information is received by the DSP. The inherit limits placed on the S/PDIF interface are there by design mostly having to do with costs and compatibility. AES/EBU implemented components have their design purposes too mostly having to do with noise rejection.

It isn't necessary to have long runs in order to reap the benefits of AES/EBU connections either. I suspect most people do not have the means or the conveniences to suspend or completely isolate the cables that connect and power their equipment. Nor would I suspect that they have isolation chambers to shield their equipment from other wayward noises found in most homes.

Whether the efforts put forth in the design of the balanced AES/EBU XLR interface are noticed by the consumer or not is empirically subjective but the measured differences are no less real. You cannot see or hear bacteria either but you can still observe it effects.