Battery operation does seem to complicate things - swings and roundabouts perhaps? I noted this recently when using a laptop to drive a keyboard with MIDI content - keyboard obviously mains powered, but double insulated connection; and I normally ran the laptop from its power block, because the battery had limited life running solo. I experimented with battery only, the adapter completely out of the picture - and noted a similar loss of life, sparkle in the keyboard sound.
The connection between how the laptop was powered, and then link via MIDI to keyboard internals seems very tenuous - yet an effect was noted. The condition of the battery, impedance of battery only operation may or may not be part of it ... there are times when one gets sick of everything "being important", it gets to be a right pain!
The connection between how the laptop was powered, and then link via MIDI to keyboard internals seems very tenuous - yet an effect was noted. The condition of the battery, impedance of battery only operation may or may not be part of it ... there are times when one gets sick of everything "being important", it gets to be a right pain!
Well of course, carbon resistors sound dark and metal film ones sound metallic, so lead-acid batteries must sound leaden.
The amp I was using was balanced I/P to output so low voltage power supply OP rails of +/-24V. That is two SLA batteries per OP phase so four SLAs in all and another one on top either side for +/- 36V for the front end of the amplifier.
Well I have heard it said that different battery types can sound different. Never tried anything other than SLA type. If they sound like lead, that lead is surely more clolourful and life like than the mains supply ever was.
Funny thing was a DAC was built up for another audiophile and the SLA batteries were put in a wooden box temporarily until a nice metal box was sourced. We did the SLA install in the new metal box and the audiophile was complaining that it sounded less organic or some words similar. Thought he was nuts until we did the A/B in the development system. Crazy how a box can make a difference.
Anyway, enough of the ramblings. I'd like to know if anyone has a chance to try it with this amplifier. Mind you it's not going to be as revealing as a really good tube or discrete design, but my money is on that it would be noticeable.
For me it was worth the maintenance as the other alternative wasn't going to satisfy. Once you've tasted it it's hard to go back.
Well I have heard it said that different battery types can sound different. Never tried anything other than SLA type. If they sound like lead, that lead is surely more clolourful and life like than the mains supply ever was.
Funny thing was a DAC was built up for another audiophile and the SLA batteries were put in a wooden box temporarily until a nice metal box was sourced. We did the SLA install in the new metal box and the audiophile was complaining that it sounded less organic or some words similar. Thought he was nuts until we did the A/B in the development system. Crazy how a box can make a difference.
Anyway, enough of the ramblings. I'd like to know if anyone has a chance to try it with this amplifier. Mind you it's not going to be as revealing as a really good tube or discrete design, but my money is on that it would be noticeable.
For me it was worth the maintenance as the other alternative wasn't going to satisfy. Once you've tasted it it's hard to go back.
I am sure you heard a difference. But with no data to back up your assertions and the inference you never even hooked up test equipment Occam's Razor is not in your favor.
Why not? Bar Imax all parameters measure up with the best you can build. So it can't drive apogee full ranges, which is fine cos I can't afford them.
If one is concerned with mains noise getting into the amplifier, using giant supply caps and unplugging the amp from the mains is certainly a good test. At reasonable listening levels, the reservoir caps will have plenty of energy storage to keep the amp going for a while. This will offer the lowest supply output impedance - lower than that of a battery.
For a well-designed amplifier with good PSRR, there is no significant benefit of increasing the supply cap to extreme levels. The only benefit I see is that the peak undistorted output power will be slightly higher with bigger supply caps. This is because the bigger supply caps will result in lower ripple voltage, hence, the supply voltages will droop less with the bigger cap. No surprises there.
Batteries tend to have a relatively high output impedance compared to capacitors, so batteries are actually more likely to degrade the circuit performance rather than improve it. I really see no need for the use of batteries in home hifi amplifier, provided that the amplifier design is of a quality similar to that of the Modulus-86.
In the old days, batteries were used in noise-sensitive circuits. Even there, I don't see a need for them today. Modern components (both passives and ICs), along with our better understanding of electromagnetic field theory, allow for the design of circuits with stellar performance without resorting to battery power.
But hey... Each to their own.
~Tom
Not crazy at all - this is the "nightmare" of the "everything matters" quandary. In one sense people who don't listen too closely to what their systems produce are better off, because they never become aware of the subtleties of changes in sound caused by "everything". The bigger picture explanation is that all systems inject some audible, low level distortion and the spectrum, nature of that distortion is under the influence of every aspect of the makeup of the parts of the system.
Metals are always a "problem", because they impact electrical fields - wood is good because it's invisible electrically - that's the hand waving explanation; the "real" cause/effect relationship might be a major exercise of detective work - is it worth doing?
That's the usual mantra, , but there are ways of getting around that. You don't test a car by driving down a smooth highway, but by how it behaves on a nasty test track, with potholes and severe corrugations - that's how I test audio systems, by how they handle highly complex audio tracks, "poorly" recorded. This exposes variations in a very obvious manner - things that the the typical "objective" measurements would struggle to shine a light on ...
, but there are ways of getting around that. You don't test a car by driving down a smooth highway, but by how it behaves on a nasty test track, with potholes and severe corrugations - that's how I test audio systems, by how they handle highly complex audio tracks, "poorly" recorded. This exposes variations in a very obvious manner - things that the the typical "objective" measurements would struggle to shine a light on ...
Doesn't matter and I don't care. If I told you that I had a fantastic sexual relationship with one of the world's most beautiful woman (not that I would if I had), and you told me that I had no objective data to back up my assertions, would I care? No. It only matters to me, and I am not interested in convincing anyone.
I did actually hook up an earlier AP2 to the front end of the amplifier. It had distortion figures that would rival the best closed loop designs. However it was open loop. Does it matter? No, why, because you could achieve the same results with an IC op-amp, but it wouldn't sound anywhere as good.
To use test equipment to arrive at conclusions about amplifier performance is amateurs work. They should only be used as a guide.
The only thing I would consider is a spectrum analyser. But I would never trust what I see on it over what my ears tell me. It is a commonly held belief that even order distortion is more preferable than odd order distortion. The test bed differential amplifier I used was configurable to do both and measured on the AP2. To me low order odd harmonic distortion was much more preferable over low order even harmonic distortion.
As I said before, to me it doesn't matter how it measures. There are plenty of good measuring amps that don't sound any good.
It may be really good for an IC based design. But that may always be its limitation, as a similarly designed discrete or tube design will be superior.
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Guys. Relax. Let's get back on topic. Let's get the SNR up a little, shall we?
My value proposition is simple: I provide well engineered, well designed, well characterized, and well documented circuits. When you buy my products and assemble them according to the BOM and instructions, you can have full confidence that you will achieve the same performance as I get.
If you would rather buy a product that is supported by paid "reviews" and savvy marketing using emotional verbiage, then I will likely not deliver what you want.
I do agree that in the end it's the perceived sound quality that matters, however, there is a pretty clear correlation between measurements and sound quality. This has been documented in actual controlled studies, such as the work of Harmon Kardon linked to by twest820 many posts ago.
The APx525 that I use for my measurements is a state-of-the-art piece of gear. I have full confidence in my measurements.
Let's return this thread to discussions involving the Modulus-86 and Power-86 companion power supply board to be available next week.
Those who wish to discuss batteries or other power supplies, please start a thread in the Power Supply forum. I'll gladly participate there as time allows.
Discussions about measurements vs perceived sound quality would be better served in the rather lengthy thread on the topic going on in the Lounge forum.
There's no need for flame wars, so please extinguish those.
Happy Festivus, merry Christmas, and happy holidays everyone.
~Tom
My value proposition is simple: I provide well engineered, well designed, well characterized, and well documented circuits. When you buy my products and assemble them according to the BOM and instructions, you can have full confidence that you will achieve the same performance as I get.
If you would rather buy a product that is supported by paid "reviews" and savvy marketing using emotional verbiage, then I will likely not deliver what you want.
I do agree that in the end it's the perceived sound quality that matters, however, there is a pretty clear correlation between measurements and sound quality. This has been documented in actual controlled studies, such as the work of Harmon Kardon linked to by twest820 many posts ago.
The APx525 that I use for my measurements is a state-of-the-art piece of gear. I have full confidence in my measurements.
Let's return this thread to discussions involving the Modulus-86 and Power-86 companion power supply board to be available next week.
Those who wish to discuss batteries or other power supplies, please start a thread in the Power Supply forum. I'll gladly participate there as time allows.
Discussions about measurements vs perceived sound quality would be better served in the rather lengthy thread on the topic going on in the Lounge forum.
There's no need for flame wars, so please extinguish those.
Happy Festivus, merry Christmas, and happy holidays everyone.
~Tom
Trying to improve the S/N of this thread. Earlier on someone recommend the neutrik EMC series for ultimate performance EMC Series - Neutrik. These work out around £5 more (or 3.5x cost) compared to the standard Neutrik XLRs. Was there any conclusion on if these would hinder performance, or just be belt and braces?
I wasn't proposing that the Modulus-86 was a poor design that needed correcting with batteries. Never did I propose that.
I believed this was a discussion forum and that there was discussion about the merits of PSRR and whether power supply noise was audible or not.
If to not threadjack in the Vendor's Bazaar sub-forum is considered not to have a contrary view or opinion to the original posting person and that all replies must agree with that original posters views then I apologise for that. However I did read the rules before making comments in this thread to be sure I wasn't over stepping them since it was a Vendor's product.
Moving on with the regular scheduled program...
I think there would be value in having an EMC filter built into the female input connector on the chassis. This filter would either be a ferrite bead on pins 2, 3 or caps from pins 2, 3 to pin 1. However, as I recall the Neutrik EMC connectors were cable-mount only. No chassis connectors available.
If you're concerned about EMC, I suggest either putting a ferrite bead over the connections to pins 2, 3 at the input connector or soldering a 100 pF capacitor (mica or C0G/NP0 dielectric) from each pin 2, 3 to pin 1.. Use shielded cable between the input XLR connector and the input terminal block on the Modulus-86 board.
For residential applications, all this is mostly belts & suspenders. No harm done in implementing the additional filtering, but it's not an absolute necessity. Using shielded cable (mic cable) from the XLR connector to the input of the Modulus-86 board is enough, as the Modulus-86 has built-in EMC/EMI filter. The Modulus-86 also has on-board ESD protection against the zaps that occur during hot-swapping and other connector mating activity.
~Tom
I think there would be value in having an EMC filter built into the female input connector on the chassis. This filter would either be a ferrite bead on pins 2, 3 or caps from pins 2, 3 to pin 1. However, as I recall the Neutrik EMC connectors were cable-mount only. No chassis connectors available.
If you're concerned about EMC, I suggest either putting a ferrite bead over the connections to pins 2, 3 at the input connector or soldering a 100 pF capacitor (mica or C0G/NP0 dielectric) from each pin 2, 3 to pin 1.. Use shielded cable between the input XLR connector and the input terminal block on the Modulus-86 board.
For residential applications, all this is mostly belts & suspenders. No harm done in implementing the additional filtering, but it's not an absolute necessity. Using shielded cable (mic cable) from the XLR connector to the input of the Modulus-86 board is enough, as the Modulus-86 has built-in EMC/EMI filter. The Modulus-86 also has on-board ESD protection against the zaps that occur during hot-swapping and other connector mating activity.
~Tom
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On a different note, but still relating to power supplies: I was reviewing my various Audio Amateur/Audio Express/Audio Electronic issues, and I came across a design for a choke power supply for a transconductance power amplifier (2 inductors for plus and minus PS). The specified inductor was a Triad 40mH inductor rated for 2 amps, but I went to the Triad site and they do have an inductor rated for 32 mH at 5 amps.
Recognizing that everything is a tradeoff, and a pair of inductors would be large, heavy and expensive, would there be tangible benefits for using a CLC power supply with 10K as the first C, and more like 20-30 for the second C with respect to: (i) inrush current control; and (ii) regulation, so that the full power is met without significant sag? I'm assuming the Modulus PSRR leads to insignificant or no increase in audio quality in terms of distortion, noise, hum, and so forth.
TomChr, thank you for supporting this thread. I am very interested in the Modulus, and feel that $60 a board is not unreasonable and having choices is a good thing (at least in this case).
Recognizing that everything is a tradeoff, and a pair of inductors would be large, heavy and expensive, would there be tangible benefits for using a CLC power supply with 10K as the first C, and more like 20-30 for the second C with respect to: (i) inrush current control; and (ii) regulation, so that the full power is met without significant sag? I'm assuming the Modulus PSRR leads to insignificant or no increase in audio quality in terms of distortion, noise, hum, and so forth.
TomChr, thank you for supporting this thread. I am very interested in the Modulus, and feel that $60 a board is not unreasonable and having choices is a good thing (at least in this case).
I think Frank is a fan of the Modulus. He is just telling you how he separates the great amps from the good. A method with which I concur with, by the way. The logic behind this method is; any amp that 'highlights' certain attributes in a recording is likely to make bad recordings even worse. How many of us have purchased 'audiophile' recordings and found them muted and lifeless? Well, they record them this way on purpose to limit the 'character' sound some hi-end amps have. Have I surmised you well Frank?