What makes 6v better than 2v

dCS Products
61

My point was that comparing one product to another which costs multiples of the comparative product is not of assistance.

The MFA baby is 1500 gbp. Of course the price for any specific Bespoke Audio product is unique - they are bespoke! The cheapest I can now find from reviews is 9000 gbp ( the one I found earlier was 15000 gbp). OK only 6 times more expensive. A bit like someone buying a Network Bridge and advising that they should have bought a Rossini.

As a further example, why buy a Rossini when a Vivaldi stack is better? Without establishing the buyerā€™s budget first that too is unhelpful advice.

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62

Hi Pete, the MFA Baby Ref V2 is actually Ā£6200 new in the UK, but still a lot cheaper than the Bespoke Audio. MFA have just released a new full chassis preamp simply called Reference V2 at Ā£7200, which Jonathan Billington is quite excited about - it will be interesting to hear initial reports on it in the near future.

It also sounds like there may be a new version of the Baby Ref soon which will have remote control as standard, and would solve my problemsā€¦

Cheers, Mike.

63

Thanks Mike. Interesting that there is a new version of the Ref ( the basic Baby is much less expensive if course). Will that new version with remote make it directly competitive with the Townshend Allegri Ref? But at Ā£7200 without the remote I already suspect that it might turn out to be more costly.

Anyway , whatever, I am afraid that I wonā€™t be in the market in 2020 :frowning_face:.

64

Hi Pete, both the new Reference V2 (Ā£7200, already launched) and the Baby Ref V3 (to be launched, Iā€™m assuming similar price to current v2, around Ā£6000) will have full remote control as standard, and I believe heā€™s implemented the remote control differently to the previous (optional) remote, to make it much more reliable.

But from what Iā€™ve read your Townshend is superb so no need to get itchy!

Cheers, Mike.

65

Thanks Mike. Just for the record it isnā€™t me that has the Townshend Allegri+. it is PaleRider and all2ofme . I am interested in it but do not see my being in a position to investigate one further during 2021 so meanwhile will stick with my EAR Yoshino 868 PL ( running NOS Tungsram tubes).

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66

Apologies Pete!

While Iā€™m on, just want to re-emphasise the improvement in my system, having turned the Bartok up to 0db and controlling volume on the preamp. I had assumed that I wouldnā€™t lose anything the way I had it before (controlling volume between -10 to -15db on Bartok and higher volume on preamp) but unless Iā€™m imagining things, the improvement is significant. No way Iā€™m selling the preamp now, planning to get it upgraded with remote in the the New Year, funds permittingā€¦

Once again, thanks to everyone for their input and help.

Cheers, Mike.

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67

Thanks Mike for the precision of the price. I tested the mfa classic v2 at home. It was a good preamp but the Bespoke is far better. Yes the price is higher, but whe I compare thĆ© construction, quality build and finition, I can understand Bespoke is more expensive. But compared to my previous preamp, ar ref5se , it far less expensiveā€¦

68

Vivaldi is a great preamp by itself. Shortest signal path to your power amp. Why bother other solutions?

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69

Attenuating digitally loses resolution

70

Iā€™ve owned my Rossini DAC + Rossini Clock for about 3 weeks now as setup by my dealer at 2 volts into my Ayre KX-R Twenty preamp, but have dabbled with the 6 volt setting occasionally. I donā€™t hear any major differences between the 2 settings except that the 6 volt is louder and I have to turn down the volume of my preamp accordingly. Also both the 2 and 6 volt settings are compatible with my preampā€™s range of volume settings.

Iā€™m upping the voltage to 6 volts tonight for a week or two to see if I can hear any differences.between it and the 2 volt setting which I have been using.

71

Another question (potentially silly, as with most of mine) ā€” if a manufacturer states different input sensitivities for a power amplifier (as T+A do here for their A3000HV) depending on whether the connection is RCA (0.6V) or XLR (1.2V) does that same doubling hold true if the connection the amplifier is fed is single-ended, but with XLR connectors?

Pass Labs donā€™t specify on the spec sheet that @Anupc found whether the 1.1V is full gain from RCA or XLR, let alone whether the entire topology needs to be single ended or balanced.

Concrete example:
My single-ended Townshend Allegri reference ā€” cable with XLR connectors at each end ā€” T+A A3000HV

Would I get full output from the A3000HV at 0.6V or 1.2V?

Looking forward to hearing how the 6V experiment turns out for you, @NordicBob!

72

A balanced audio signal works with three wires. The hot wire carries the actual audio signal, while the cold wire carries the same signal, but phase reversed. So if the hot wire at any moment is at 5 volts, the cold wire would be at -5 volts. A balanced input will take the cold signal, flip it, and add it to the hot signal to create a doubled original signal. The theory behind it is that both the hot and cold signals will pick up the same noise and distortion as it travels the wire. By flipping the cold signal and adding it to the hot, the original signal will be doubled while any noise will be canceled out.

So, an unbalanced cable terminated with a XLR plug works just like a unbalanced cable. There will be no flipping and doubling of the voltage, and therefore the sensitivity of the unbalanced input applies.

In your case, you will get full output from 0.6V.

However, the manual of your A3000HV says this:

IN UNBALANCED
(asymmetrical signal inputs)
Asymmetrical amplifier input (Cinch) with an input sensitivity of 1.5 Veff.
The Cinch sockets, Left and Right Channel, are connected to the pre-amplifierā€™s output sockets of the same name (see Appendix A).
IN BALANCED
(symmetrical signal inputs)
Symmetrical amplifier input (XLR) with an input sensitivity of 3.0 Veff.
Input for pre-amplifiers with symmetrical outputs. The XLR sockets, Left and Right Channel, should be connected to the pre-amplifierā€™s sockets of the same name (see Appendix A).
The appropriate type of connection (UNBALANCED or BALANCED) must be selected using the ā€˜INPUT SELECTā€™ switch.

For the Pass Labs: if you connect single ended to the XLR input socket, I think you need to connect Pin 1 and 3 in the XLR plug.

Is there a reason why you do not use single ended cinch out cables (without XLR plug) from the Townshend into the unbalanced in of the T+A?

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73

Erno, are you sure? The balanced input sensitivity remains as quoted, 1.2v ( or 3V, we have two sets of figures) so a single ended connection of 0.6V or 1.5V would not fully drive the power amp. No worries for Ben though. He just turns up the preamp. However, why doesnā€™t he just use the RCA output from the pre? Electrically thereā€™s no advantage from using the XLR connection as being single ended it will not provide any common mode noise rejection.

74

Just one note of caution. XLR cables made all the difference for CMNR in connecting my Allegri Reference to my Wavelet. Should they? Maybe not. But thereā€™s no mistaking the difference. Precisely because it shouldnā€™t have mattered, and many Iconoclast users report preferring the RCA to the XLRā€”albeit slightlyā€”I tried the RCA. They went back via return mail the next day, not because of SW but because of noise.

75

No, I am not sure. It is getting confusing, with 2 different power amps that I am not familiar with. And using a XLR cable out from a single ended Allegri does not make it more clear.

I will have to study, and see how the XLR out of the single ended Allegri is working, and how these XLR cables are made (pin and shield architecture).

Iā€™ll get back here when I understand.

76

There are a number of issues to settle when comparing XLR to RCA cables even in a single ended setting. Firstly are you comparing like with like ?

The cable itself RCA v. XLR of the same brand and line may be of different constructions or may be the same cable internally just connected differently. In the latter instance the impedance is likely to be nominally incorrect for one or the other (assuming e.g. if following AES standards) . The connector hardware can also make an audible difference. Neither RCA or XLR can properly maintain the correct 75 or 110 ohm standard due to their design but some more recent RCA designs ( e.g. WBT second generation) are better than their predecessors . Further by use of plastics where metal would have previously been used they are less prone to parasitic eddy currents ( e.g. WBT and Eichmann). The only XLR connector that I am aware of that follows this path is the Vampire Wire one.

Of course any comparison is also open to subjective preference anyway.

Finally there is a question of how well the equipment manufacturer has implemented each type of input. An equivalent competence for both should not be assumed :wink:

Given these variables I guess that the final choice needs to be made on a suck it and see basis, balanced or single ended even if theory says that a properly balanced cable with balanced transmitting/receiving circuit should always reject more noise than a single ended one.

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77

Agreed. Sometimes there is no other way. If trying a new cable, make sure you can return it.

Agreed here as well, though as Iconoclast explains, they have gone to substantial lengths to make sure their respective RCA and XLR cables are as identical and AES compliant as possible.

78

Please read the article at the following link, to firstly understand in detail what is single ended, balanced, psuedo balanced, floating balanced and hard balanced.

Understanding is needed to cope with these 6 cases:

  1. Connecting mains floating unbalanced outputs to mains grounded balanced inputs.
  2. Connecting mains grounded unbalanced outputs to mains grounded balanced inputs.
  3. Connecting floating balanced outputs to floating unbalanced inputs.
  4. Connecting hard balanced outputs to floating unbalanced inputs.
  5. Connecting floating balanced outputs to mains grounded unbalanced inputs.
  6. Connecting hard balanced outputs to mains grounded unbalanced inputs.

If there is still no blood running out of your ears :slight_smile: then we can go to look into what exact kind of outputs and inputs we are talking about here, and what cabling should be used, with what kind of internal architecture.

We need to determine the entire chain, from source, through preamp, into power amp. So we need to determine the blanks below:

1. Source:

dCS DAC: Analogue Outputs:

Output levels: 0.2, 0.6, 2 or 6V rms for full-scale preamp or power amp input, set in the menu.

a. Balanced outputs: 1 stereo pair on 2x 3-pin XLR male connectors. These outputs are electronically balanced and floating.
Output impedance is 3Ī©, maximum load is 600Ī© (10k-100kĪ© is recommended).

b. Unbalanced outputs: 1 stereo pair on 2x RCA phono connectors.
Output impedance is 52Ī©, maximum load is 600Ī© (10k-100kĪ© is recommended).

2. Preamp: Analogue Inputs:

a. Balanced:
b. Unbalanced:

3. Preamp: Analogue Outputs:

a. Balanced:
b. Unbalanced:

4. Power amp: Analogue Inputs:

a. Balanced:
b. Unbalanced:

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79

After some studying, this is what I found:

For the Allegri Reference passive, autotransformer volume control preamp:

Input: pseudo-balanced input, with on pin 2 of the XLR signal, and on pin 3 ground. [Pin 1 (ground) on the balanced XLR out from the dCS source is not connected, so ignored] Maximum signal level: 4V RMS 8Hz; 10V RMS 20Hz and up. At -10dB (normal listening) input impedance is 200kohm, for a power amplifier load with 20kohm input impedance.

Usual balanced pin assignment: Pin 1 ground - Pin 2 positive signal - Pin 3 negative signal, so the Allegri drains the negative signal from the dCS to ground. A simple method of driving a balanced line is to inject the signal into the ā€œhotā€ wire through a known source impedance, and connect the ā€œcoldā€ wire to the signalā€™s local ground reference through an identical impedance. Due to common misconceptions about differential signalling, this is often referred to as a quasi-balanced, pseudo-balanced or impedance-balanced output, though it is, in fact, fully balanced and will reject common-mode interference. Internally, the Allegriā€™s design remains single-ended throughout, since there is no negative signal coming in, as opposed to a differential amplifier.

Output: transformer based floating balanced XLR pair, and unbalanced RCAs. This practice also assumes that the balanced input of a following power amplifier has proper differential summing.

To maintain the integrity of the Fractalā„¢ wired transformers, Townshend strongly advises to use their Fractalā„¢ Interconnects for both the input and output cabling. The balanced version of Fractal-Wireā„¢ incorporates two strands of the ultra-fine enamelled copper conductor spiralled together with a parallel drain wire but no shielding, it is terminated with Neutrik XLR plugs. In the unbalanced version, the signal travels through a very thin polyester coated enamelled copper wire, which is spiralled around a much thicker bare copper ground. But technically, all standard XLR cables (balanced pin assignment: Pin 1 ground - Pin 2 positive signal - Pin 3 negative signal) will work.

The Allegri has no active or amplifying audio electronics in the signal path. However, the sources used must have sufficient output to drive the following power amplifier via the controller to the required maximum output power, with some headroom for those quieter recordings.

So, if I understand correctly, setting up the Allegri between a dCS source and a power amp, you will get best SQ when using XLR cables for both its balanced input and output. 6V out from the dCS source will work best. Depending on the balanced input sensitivity of your power amp, you can set the Allegriā€™s minimum attenuation according to the table posted above, using the formula also posted above to determine its line out voltage.

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80

Excellent research there Erno :+1:

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