Hi Bill,
Some Carver amplifiers did that. The idea was to load both polarities of the power supply mostly equally. This practice was dropped in later amplifier designs.
I don't know if it makes a difference or not. I do know that driving the "common" speaker terminal can cause real problems when people misinterpret what is going on.
-Chris
Some Carver amplifiers did that. The idea was to load both polarities of the power supply mostly equally. This practice was dropped in later amplifier designs.
I don't know if it makes a difference or not. I do know that driving the "common" speaker terminal can cause real problems when people misinterpret what is going on.
-Chris
They are for sure and it usually makes a big difference.
We used to run a full battery system, DAC, power amp, everything except HT
on valves was supplied by batteries. Heaters for valves were also batteries.
Eventually I just got sick of charging the damn things so then it became a
game of what power supplies came closest.
T
Are we having fun yet? It seems to happen so often.... 'it must be a defective amp design'. Now it is poor PS design. It does not really matter if all audio gear PS could have been improved or not. How is one to know if a unit's PS/PA is sufficiently well designed so that no emi/rfi passes thru PS to amp and audibly affects the amp/sound? The circuit I suggested cost about 20 dollars to build and find out for yourself. But, as usual, most just sit comfortably in thier arm chairs and talk about it. As predicted.
THx-RNMarsh
THx-RNMarsh
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WRT guitar amp cap sizes etc:
There's a great clip on youtube where a guy gradually replaces the PS caps
on a JTM45 / Bluesbreaker (Clapton Beano amp) reissue for smaller original
sized ones and you can really hear the tone open up as the caps get smaller.
On the other hand I've done a lot of work recently on Dumble ODS clones
and the power supplies are quite stiff in comparison - but they can sound
really good too.
Guitar amps are like baking a cake. You gotta have just the right amount of
the right ingredients for things to work.
T
What are the benefits specifically of the double trafo approach?
1: You can use more capacitance with low secondary voltage, but the secondary impedance is lower so you are right back where you started, needing more uF.
2: You get voltage sag. Not a problem with low power stuff like DACs I guess.
3: The CMR (CM to DM conversion) of the transformers adds in db. So if one has 30db CMR, final CMR will be 60db. Also, I suppose if the trafos are both flawed, but in exactly the same way, hooking them up right may cause the flaws to cancel and get you some more CMR. I'm no expert, I could be wrong on any of this.
4: Yes, the leakage inductance and series resistance of the trafos improves filtering. So why couldn't you do that at a fraction of the cost using discrete inductors and resistors? Even do better? Without emitting so much EMI from flux-marginal trafos?
It seems to me the main benefit is the improvement in CMR and balanced output voltage, something it's very hard to get any other way.
1: You can use more capacitance with low secondary voltage, but the secondary impedance is lower so you are right back where you started, needing more uF.
2: You get voltage sag. Not a problem with low power stuff like DACs I guess.
3: The CMR (CM to DM conversion) of the transformers adds in db. So if one has 30db CMR, final CMR will be 60db. Also, I suppose if the trafos are both flawed, but in exactly the same way, hooking them up right may cause the flaws to cancel and get you some more CMR. I'm no expert, I could be wrong on any of this.
4: Yes, the leakage inductance and series resistance of the trafos improves filtering. So why couldn't you do that at a fraction of the cost using discrete inductors and resistors? Even do better? Without emitting so much EMI from flux-marginal trafos?
It seems to me the main benefit is the improvement in CMR and balanced output voltage, something it's very hard to get any other way.
Are we having fun yet? It seems to happen so often.... 'it must be a defective amp design'. Now it is poor PS design. It does not really matter if all audio gear PS could have been improved or not. How is one to know if a unit's PS/PA is sufficiently well designed so that no emi/rfi passes thru PS to amp and audibly affects the amp/sound? The circuit I suggested cost about 20 dollars to build and find out for yourself. But, as usual, most just sit comfortably in thier arm chairs and talk about it. As predicted.
THx-RNMarsh
There already exist relevant standards such as the IEC 61000-4 series, which includes conducted and radiated immunity including mains-targeted tests like EFT / burst. Many real products are tested to these standards, outside of "high-end" audio.
The point is, these are all solved problems for any type of product where you can define testable requirements and pass/fail criteria.
Of course, since high-end audio typically has no verifiable requirements...
Are we having fun yet? It seems to happen so often.... 'it must be a defective amp design'. Now it is poor PS design. It does not really matter if all audio gear PS could have been improved or not. How is one to know if a unit's PS/PA is sufficiently well designed so that no emi/rfi passes thru PS to amp and audibly affects the amp/sound? The circuit I suggested cost about 20 dollars to build and find out for yourself. But, as usual, most just sit comfortably in thier arm chairs and talk about it. As predicted.
THx-RNMarsh
Don't be so dismissive Richard.
You would be amazed at the lengths some of us have gone to with power
supplies... just because we don't paint it all over this forum. The reason is
simple, there are too many so called 'engineers' here that will attack any
idea that is slightly out of the realm of accepted textbook electronic design.
Most of the real creators are busy enough as it is trying to make a buck and
don't have time for this BS.
You asked
T
So I repeat my question...."So just what is a 'respectable' PSU, and where are we likely to find such 'respectable' PSUs."
How would you go about designing line level gear that satisfies your above criteria, and how would you go about designing power amplifier supplies that satisfy your above criteria.
And again, in the real world where are we likely to find (ie examples please) such 'respectable' PSUs in the context of audio reproduction equipment ?.
Dan.
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I gave you a good answer right above. There's plenty of ways to skin a cat. If you need, here's a list of standards that should get you started. List of common EMC test standards - Wikipedia
I'll be willing to help you further, without any voodoo required, when you can rigorously back up any of your audibility claims you've made over the past, say 5 years.
The same as a Monster AVS2000 + HTPS 7000 Sold a lot of those 15 years ago. Flat TV's and the end of the home theater brought that whole market to an end. You can still find them used. Shipping would be painful.
Also, this may be the very best thing to come out of the late back and forth.
Agreed on the PSRR. Hence why I keep asking for effects showing up on the speaker terminals.
I prefer to say complex impedance. These days smaller venues and such are massively polluted by endless amounts electronics with garbage PSU's and LED lighting everywhere. The power factor is abysmal. Nothing is going to change it anytime soon, so anything you can do to help is smart.
There are some classD amps with power factor correction and they DO sound better. Crown had some for awhile, maybe still does. I have popped open any newer generations.
I'm saying the same thing. This whole "right must be right" approach has nothing to do with the real world. It operates on the "wrong is right" principle. (which just means we move forward even with flaws, what do you think error correcting computer memory is for???)
LAUGH, LAUGH LAUGH LAUGH
Good luck... You think Benchmark doesn't exceed those? PUHLEEZZ
What kind of pathetic PSU's do you imagine to find in equipment? It's like you're expecting to find a car distributor with copper wires replacing the resistor cables under the hood of an amplifier.
But John, based on previous statements you have made I would assume you would be somewhat upset if someone found your blowtorch sounded better with a power conditioner? Or is it not as good as it could be?
If you have never tried to get a complex* electrical product through type approval you might not realise it is often not trivial.
*amplifiers are generally in the trivial class though.
Cosmic radiation: ECC memory - Wikipedia
I make no such illusion. You realize some/many of those specifications are for medical and military applications, where the Benchmark would fail miserably, perhaps by intent (I'm forgetting my rules, but some of the medical ones forbid y caps? There goes a ton of good mains filters). On the other hand, I'm sure a power conditioner makes a *huge* difference with the Benchmark DAC as well. (That's sarcasm)
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