GoodSoundClub - Romy the Cat's Audio Site - Capacitors versus batteries in regenerators

01-11-2016

Post does not mapped to Knowledge Tree

Romy the Cat

Boston, MA
Posts 10,131
Joined on 05-28-2004

Post #:	1501
Post ID:	22394
Reply to:	22393

It is good read… and not.

For sure it is a good all together observation. I did not read it to the end but scanned it to the end. I do not feel that it “great read” however because it is written still from electrician prospective. The observation complied all that we know about electricity and sound but failed to answer the main question: why electricity might be great from all known to use quantifiable perspectives but sound still bad or why sometime even with objectively and measurably bad electricity we have great sound. If everything would be just about current vs voltage load and harmonic distortions then a playback that run power factor =1 and under a fraction of distortion present shall sound wonderful. Unfortunately practice indicates that it is not always the case. In fact the best electricity day that I ever experienced the sinusoid of power was quite coopted and I would estimate at least 10% of distortions, while sound was spectacular… So, go figure…

"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche

01-24-2016

Post does not mapped to Knowledge Tree

Romy the Cat

Boston, MA
Posts 10,131
Joined on 05-28-2004

Post #:	1502
Post ID:	22422
Reply to:	2931

German StromTank - a posoble alternative to PurePower

I was notified today that there is German company that dose the same thing that PurePower does - on-line converter for audio:

http://www.stromtank.com

For sure the product looks interesting. The 100A vs 10-15A of Purepower is for sure a lot of capacity. I do not know if I buy the idea of running the playback for 8Hr from StomrTank, if you use A/B amplification perhaps, but in my case I could do 2 hours for sure. Behind all claims that Germans make the key is how good their converter sounds, would it be in connected or disconnected mode. In properly operating unit it shall be no difference if you are connected, and if so then why you need 100A to drive the playback disconnected?

"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche

01-25-2016

Post does not mapped to Knowledge Tree

Romy the Cat

Boston, MA
Posts 10,131
Joined on 05-28-2004

Post #:	1503
Post ID:	22423
Reply to:	22422

Some further thoughts about the StormTank

Well, the StormTank is currently is being sold for $30K. I am pretty sure that the regenerating and charging circuitry of StormTank and PurePower is identical. I do not mean they are the same but topology they are very identical and cost no more than any on-line UPS regenerator or let say roughly a couple hundred dollars. So, the main difference under the hood between StormTank and PurePower is the butteries. The PurePower uses the cheap sealed lead butteries, not the cheapest on own class but still not non expensive topological. The StormTank use good and more expensive Lithium Iron Phosphate butteries. The main advantage for LiFePO4 is that they live much longer then lead but basically it is the same. Now, StormTank claims that they have 1000A/H of batteries in there and this is a lot. More batteries means lower impedance of the whole battery back and means deeper filtration of in real time regeneration mode. The PurePower, in my own version, has a bunk of caps that shunt the battery. Intellectually it is very good in practice it has no effect. So, for all intended purpose StormTank sell us a 300 pounds of Lithium Iron Phosphate batteries for $30K + a $200 regenerator.

Now, of cause whatever I wrote above is not very accurate. The true difference between StormTank and PurePower is all above + sound of their $200-worth regenerators. PurePower very much as well as StormTank might ask us to pay as much as they want as long their regenerator has right sound. If PurePower operates properly (a big if) then in my experience it produces VERY interesting sonic result. In fact, if the PurePower not broken then in most cases (not in all) there is not a whole a lot of difference between running it from wall vs running it from batteries. So, the most interesting question is what sonic attribute the StormTank’s regenerator has. Do you pay attention where I am leading you?

What I am trying to say is that in both StormTank and PurePower the regenerator cost let presume $200 and this $200 is responsible for 99.99% of what you might like and or not like in the units sound. The rest as Alex Ross says is the noise. So, what I am thinking. If the StormTank’s regenerator is sonically as good as the PurePower regenerators, or even if it is much better than PurePower, then StormTank need to lose the 250 pounds of the LiFePO4 batters, convert it to the desktop-sixe regenerator and to see it as it is Audio target UPS devise – very similar to what PurePower does. If the quality of the unit is determined by regenerator then there is no need to extort from a user $25K for the batteries that they user arguably do not need. I would not mind to listen the StormTank but I have absolutely no interest to bring 250 pounds of unnecessary batteries in my home.

"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche

01-25-2016

Post does not mapped to Knowledge Tree

drdna
San Francisco, California
Posts 526
Joined on 10-29-2005

Post #:	1504
Post ID:	22424
Reply to:	22423

Capacitors versus batteries in regenerators

Romy the Cat wrote:
Well, the StormTank is currently is being sold for $30K.

Oh well, I can forget about buying one to try it out...

Romy the Cat wrote:
The PurePower has a bank of caps that shunt the battery. Intellectually, it is very good; in practice it has no effect.

I beg to differ. It may contribute to the unique sound of the PurePower. I still have my old SA-3 amplifiers made by Nelson Pass. The massive capacitors take up 90% of the inside of the amplifier, and it does have an impact on the sound when taken to the extreme.

Romy the Cat wrote:
The StormTank use good and more expensive Lithium Iron Phosphate butteries. The main advantage for LiFePO4 is that they live much longer then lead but basically it is the same. Now, StormTank claims that they have 1000A/H of batteries in there and this is a lot. More batteries means lower impedance of the whole battery back and means deeper filtration of in real time regeneration mode.

This is the main selling point of the StormTank: a gigantic battery. Who knows if it makes a difference to the sound, but intellectually it is appealing and is the main marketing point. If it did not weigh hundreds of pounds, standard audiophiles would be less willing to part with $30,000.

It is interesting to me to think about the use of Lithium batteries in the circuit. I have done many experiments with different metals for audio use, as they all have slightly different mechanical, electrical, and physical properties. Lead has a deep, placid but musical quality to its sound which can be quite seductive. I am not familiar at all with the sound that lithium may impart to the circuit, so it would be quite interesting to listen to this unit purely on that basis.

Adrian

01-25-2016

Post does not mapped to Knowledge Tree

xandcg

Rio de Janeiro, BR.
Posts 218
Joined on 09-07-2014

Post #:	1505
Post ID:	22425
Reply to:	22423

Where acquire just good regenerators.

For 30K I believe one can buy a big top of the range Eaton/APC online UPS, which output (teorically) <1% THD for linear load, maybe for the entire house, and still have money to deal with the low impedance and install another regenerator (audio grade). The house load is not linear but I am just making a point.

The question is, I do not know, where acquire just good regenerators?

Think for yourself, do not be sheep.

01-25-2016

Post does not mapped to Knowledge Tree

Romy the Cat

Boston, MA
Posts 10,131
Joined on 05-28-2004

Post #:	1506
Post ID:	22426
Reply to:	22425

Batteries vs batteries

drdna wrote:
I beg to differ. It may contribute to the unique sound of the PurePower. I still have my old SA-3 amplifiers made by Nelson Pass. The massive capacitors take up 90% of the inside of the amplifier, and it does have an impact on the sound when taken to the extreme.

I am not sure that it is so. In the Pass the caps do different things then in PP. The default PP has 460uF, I added I think 48K of ultra-low impedance caps. It shall improve filtration, theoretically. I did not detect sonic difference but it does not mean that the difference is not there when the electricity quality change. BTW, I did not do it with PP+ version and it still sound better then the older PP3000. Anyhow, I do feel that adding the caps “helps” but I personally do not attribute any sonic result to the fact of adding caps in parallel to batteries.

drdna wrote:
It is interesting to me to think about the use of Lithium batteries in the circuit. I have done many experiments with different metals for audio use, as they all have slightly different mechanical, electrical, and physical properties. Lead has a deep, placid but musical quality to its sound which can be quite seductive. I am not familiar at all with the sound that lithium may impart to the circuit, so it would be quite interesting to listen to this unit purely on that basis.

I would very strongly discourage you to experiment with PP and different then the default batteries. The lithium batteries might have different charging demand that might screw up somehow the PP charging circuitry. I do not know how you but I very much NOT willing to have my PP broken. So, I stay as is. Regarding the sound and type of batteries. I do not think that it will have impact. In PP batteries is just a sores of juice and filtering devise. The regenerator and the post- regenerator filtration is the items that “do sound” to much greater degree. I think your feelings about type of the batteries and Sound comes from the community of the folks who use batteries to bias tubes. Yes, in the battery on the grid case the type of the battery create a huge difference.

xandcg wrote:
For 30K I believe one can buy a big top of the range Eaton/APC online UPS, which output (teorically) <1% THD for linear load, maybe for the entire house, and still have money to deal with the low impedance and install another regenerator (audio grade). The house load is not linear but I am just making a point.

The amount of THD is irrelevant. You have no idea how that Eaton/APC will sound.

"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche

01-25-2016

Post does not mapped to Knowledge Tree

Paul S
San Diego, California, USA
Posts 2,644
Joined on 10-12-2006

Post #:	1507
Post ID:	22427
Reply to:	22426

Charged Up on Batteries

It is true that a given battery will have "special" requirements for optimal charging. Also, where the battery is in a circuit and the specific demands of use can influence how and/or how quickly it "wants to be charged", not to mention different batteries sound different, one from another, if only for similar reasons. Of course, there are many contributors that shape a battery's characteristics, not just SLA vs., Li, etc., including how the thing is constructed, or construction vs. application. Another thing to consider is that electrical components only "come to realization" when they are charged and functioning within their designated limits, and I don't know of any batteries that included listening in their development, although some capacitors claim this, whether or not I like they way they sound as I have used them. I have thought for some time that I would one day build my own sound-based UPS, with a big battery as a buffer. Naturally, I find other things to do instead. Meanwhile, I wish someone would assemble the "proper" UPS parts around a big battery, then I wish they would sell them without the battery, and I could buy and install the battery myself. I still reflect on how funny is it that we go from AC to a battery, back to AC, then back to DC. And I still think it's stupid to do this, but who knows of "acceptable" components that can be driven directly from DC. AFAIK, everything would require fairly major DIY mods to "bypass the native power supplies", which are pre-set to depend on AC, or they were designed by people with low sonic demands.

Paul S

01-25-2016

Post does not mapped to Knowledge Tree

rowuk

Germany
Posts 454
Joined on 07-05-2012

Post #:	1508
Post ID:	22428
Reply to:	22427

Is it not mad that we convert AC to DC then back to AC to finally get DC

I have often thought that the necessity of a UPS comes from inadequate power supply design. Sure it is easy to buy a product to insert between the audio system and power line but at the end of the day, are we simply giving our power supplies an easier line frequency to convert to DC or a different impedance to work into or better filtration? Is there any research on what comes out of a sensitive devices power supply that helps create "not as bad" sound. I have seen scope views of the regenerated AC, but never anything from the audio device power supply.

Whenever I feel blue, I start breathing again.

01-25-2016

Post does not mapped to Knowledge Tree

steverino
Posts 367
Joined on 05-23-2009

Post #:	1509
Post ID:	22429
Reply to:	22428

Could well be the power supply

Rowuk,

I think that is a good thought. I think power supplies are an afterthought to most audio designers or they think about it in simplistic terms such as bigger is better. I hate to confess this in a public forum but I have found better sonics result from use of the so called audiophile fuses also. Further, in budget gear I have found components using separate wall warts sound better than those with same box power supplies despite the wall warts being rather underpowered by conventional reasoning. But yes I think power supply design (or the lack thereof) may be the little elephant (or mouse) hiding inside the case.

01-26-2016

Post does not mapped to Knowledge Tree

Romy the Cat

Boston, MA
Posts 10,131
Joined on 05-28-2004

Post #:	1511
Post ID:	22431
Reply to:	22428

A unified theory of power for Audio?

rowuk , you are not wrong feeling that what we do with PS and Mains regenerator is kind of ridicules. Indeed we convert AC to DC, then to AC against and then to DC again. If you use SS then it very much makes sense to run DC directly to B+. I know of guys from Eastern Europe who run tube electronics, ironically high voltage direct heated triodes and they power +850 directly from batteries. Yes, I feel it is “elegant: solution but I feel that there is no future behind this approach. It might work for some kind of boutique installation but universally it would not work. Now, would it be fun if ALL let say digital devises have a mandatory +12V power entry and PS switch internal/external?

Saying all of it I am not sure that running batteries direct would be problem-free solution. The guys who do run batteries report own unique problems. I personally would not explore this direction. What I would love to see instead of going for batteries would be a unified theory of power for Audio or some kind of knowledge that would explain what is relationship between Sound and Power. So far we just tweaking power and not truly know what we do. We accidently catch better result and we think that it was it. I hope our structural engineers and doctors do not use the same skill set…

"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche

01-26-2016

Post does not mapped to Knowledge Tree

steverino
Posts 367
Joined on 05-23-2009

Post #:	1512
Post ID:	22432
Reply to:	22431

A laboratory in the kitchen

It would be nice if we had a unified theory concerning power and audio systems performance but that would not be enough. For example a physicist can provide elegant equations describing heat transfer in a vacuum. But ask them to provide an exact equation describing how a full coffee cup radiates on a kitchen table would elicit all kinds of objections that it was too complicated except for approximation. Of course the same is true of sounds in anechoic chambers vs home listening rooms.

I can't speak for Rowuk or Clark but my thought was simply that the same experimentation used to create audio signal paths should be applied to power supply design. Further, it appears that we are at somewhat of an impasse in signal path design inasmuch as the best sounding components typically employ circuit designs that have been known for decades. Any improvement comes from better implementation rather than a new signal path design. I share your reservations about the use of batteries except perhaps for digital source devices, I think that any notable improvements in sonics will have to come via the AC power supply (and perhaps volume controls) for the foreseeable future.

01-26-2016

Post does not mapped to Knowledge Tree

rowuk

Germany
Posts 454
Joined on 07-05-2012

Post #:	1513
Post ID:	22433
Reply to:	22431

Now that I think about it, maybe there are easy possibilities!

Romy the Cat wrote:
rowuk , you are not wrong feeling that what we do with PS and Mains regenerator is kind of ridicules. Indeed we convert AC to DC, then to AC against and then to DC again. If you use SS then it very much makes sense to run DC directly to B+. I know of guys from Eastern Europe who run tube electronics, ironically high voltage direct heated triodes and they power +850 directly from batteries. Yes, I feel it is “elegant: solution but I feel that there is no future behind this approach. It might work for some kind of boutique installation but universally it would not work. Now, would it be fun if ALL let say digital devises have a mandatory +12V power entry and PS switch internal/external?

Saying all of it I am not sure that running batteries direct would be problem-free solution. The guys who do run batteries report own unique problems. I personally would not explore this direction. What I would love to see instead of going for batteries would be a unified theory of power for Audio or some kind of knowledge that would explain what is relationship between Sound and Power. So far we just tweaking power and not truly know what we do. We accidently catch better result and we think that it was it. I hope our structural engineers and doctors do not use the same skill set…

Class D amps are cheap enough these days, maybe I need to build a power supply with built in regeneration? Maybe I need to think about impedance on the primary side of the PS transformer.
I am not particularly interested in batteries. I tend to leave things on for a while when I am in a listening mood.

Whenever I feel blue, I start breathing again.

01-26-2016

Post does not mapped to Knowledge Tree

Paul S
San Diego, California, USA
Posts 2,644
Joined on 10-12-2006

Post #:	1514
Post ID:	22434
Reply to:	22433

What We Already Know

The information is almost certainly "out there" already, so it's really "just" a matter of rounding it up. And I disagree that power supplies remain a mystery; it's more like our idea of critical listening seldom factors in during "development". With the Tesla battery, or something like it. we finally have a theoretically viable source for DC, and from there we really could simply heat the B+/B-, whatever. With a really big battery it should be possible to run the charger only when not listening. Of course, if I ever cure my frustrations with the AC, all this speculation will be forgotten like a dream... at least for a while...

Paul S

01-26-2016

Post does not mapped to Knowledge Tree

Paul S
San Diego, California, USA
Posts 2,644
Joined on 10-12-2006

Post #:	1515
Post ID:	22435
Reply to:	22433

On Target

Robin, there is On and there is "on", like a standby mode, so I don't really see idling as a serious problem where batteries are concerned; SS gear that is left on all the time might even be switched back to a trickle from the wall. This is usually how I warm up my DAC, and I would certainly do it if I left the thing on all the time.. I think switch mode anything comes with its own problems, so in reality this "solution" is like most others, the old 2 steps forward, 1 step back scenario, best case. Hard to know ahead of time how any solution would actually sound in use, , let alone why, and this is exactly why even the best available "commercial" gear is a mix of good and bad, if only because of R&D, manufacturing, advertising and distribution costs (not to mention customer service...) vs. "the market" and a viable business plan. Ironically, as we all know only too well, costs and timelines increase exponentially when we try for a "short run". C'est la Guerre.

Best regards,
Paul S

01-26-2016

Post does not mapped to Knowledge Tree

rowuk

Germany
Posts 454
Joined on 07-05-2012

Post #:	1516
Post ID:	22436
Reply to:	22435

My type of On

On in my case is staying at operating temperature. All of my amps are tube......... My point is that if we can insert a UPS into the chain and improve sound, there is hope for the power supply! I don't really know of anyone using the batteries from a UPS to listen to audio, so the complexity of an "in box" amplifier solution should not be that tough.

Paul S wrote:
Robin, there is On and there is "on", like a standby mode, so I don't really see idling as a serious problem where batteries are concerned; SS gear that is left on all the time might even be switched back to a trickle from the wall. This is usually how I warm up my DAC, and I would certainly do it if I left the thing on all the time.. I think switch mode anything comes with its own problems, so in reality this "solution" is like most others, the old 2 steps forward, 1 step back scenario, best case. Hard to know ahead of time how any solution would actually sound in use, , let alone why, and this is exactly why even the best available "commercial" gear is a mix of good and bad, if only because of R&D, manufacturing, advertising and distribution costs (not to mention customer service...) vs. "the market" and a viable business plan. Ironically, as we all know only too well, costs and timelines increase exponentially when we try for a "short run". C'est la Guerre.

Best regards,
Paul S

Whenever I feel blue, I start breathing again.

01-26-2016

Post does not mapped to Knowledge Tree

clarkjohnsen
Boston, MA, US
Posts 298
Joined on 06-02-2004

Post #:	1517
Post ID:	22437
Reply to:	22432

"I can't speak for Rowuk or Clark."

Oh go ahead, be my guest! You seem to have a proper handle on the situation. As for "designs that have been known for decades", I know someone who says that there's been nothing new since the RCA Handbook of the mid-Forties (IIRC). Yeah.

So now what?

My best guess is that the AC thing, from outside the house through the DC rectifier, is where to look. In this I would gather that everyone here more or less agrees.

01-26-2016

Post does not mapped to Knowledge Tree

Paul S
San Diego, California, USA
Posts 2,644
Joined on 10-12-2006

Post #:	1518
Post ID:	22438
Reply to:	22436

Who "Listens" With/Tto Batteries

Robin, I think there are quite a few audiophiles in SE Asia who use fairly large and/or complex battery "back-up" systems, and I'll bet some just go ahead and use battery power for listening, or this is effectively what they do. As far as research on this, too bad about the "language issues"...

Plenty of engineers have tried to address AC line problems via PS design in hi-fi equipment, since the math to do it is "well known". And remember the size of and the dirt thrown by the UPS-type devices...

Again, just switch back to [modified] wall power for "standby", even if you want full power idle for some reason.

Best regards,
Paul S

01-27-2016

Post does not mapped to Knowledge Tree

JOHNR
Posts 24
Joined on 10-12-2015

Post #:	1519
Post ID:	22439
Reply to:	22438

Funny electricity

I continue to be amazed at the varied views relating to BAD power at certain times of the day.
I broke with that 10 or more years ago in moving to amplifiers, line amps and DACs configured with switched mode supplies.

I not only keep my DAC permanently powered, I have people who permanently power their entire switched mode supported system.
In one case 4 years non stop.

Indeed Malaysian and Singaporean audiophiles have gone through the stages of battery powering and those to whom I asked the question of sonic quality said no, it does not work well. Many have also experimented with computer smsp modules but these are a waste of time due to noise and inadequate stability.

The simple solution for an iron transformer based SET B+ supply is to use a voltage doubler configuration. It suffers from a source impedance being higher than a bridge supply however, it is not affected by small frequency variations. Also It does not pass audio signals through the power transformer because it has no path. With SET being constant current in nature, the source impedance is not relevant.

For push pull it does not work precisely because of its higher source impedance. The output voltage will droop with increasing current.

I have done a lot of work on filament supplies and concluded that all supplies dump noise energy into the tube which will amplify it by a factor of at least 1. The solution has been to use SMPS techniques derived from either a 48 volt dc supply or 85 to 275 volt ac supply. I did make some 50 of the ac modules for local audiophiles and they did make a lot of difference.

The core problem of all supplies lies with their source impedance.
As an example batteries suffer from a changing impedance related to their state of charge.
AC supplies are dependent upon the impedance of the supply side transformer windings and of course, the cheap and cheerful aluminium connecting cables to the property itself.
Also, I would not expect any of the UPS type systems to be able to handle supply side harmonics, common mode noise (maybe) because all of these noise artifacts will pass right through.

John

01-27-2016

Post does not mapped to Knowledge Tree

Paul S
San Diego, California, USA
Posts 2,644
Joined on 10-12-2006

Post #:	1520
Post ID:	22440
Reply to:	22439

Fe

John, it is interesting that you qualified application by the base metal used in the transformer. Here at GSC, many use "exotic" and/or "amorphous" cores, or perhaps high nickel content (or Si) for chokes. As it happens my own phono stage uses exotic transformers. How would this - in and of itself - factor in with respect to SMPS use?

You have not said directly, but from your circuit I have supposed you have worked extensively with "serious" S/N ratios with - say - LNAs, such as satellite and related relay equipment eg., "telecommunications"? Is this pretty much "all digital" today? Would the modern iteration of this considered to be "full range", as hoped for by audiophiles? I remain hopeful, but I have not yet heard good-sounding streamed audio.

Best regards,
Paul S

	Target	Threads for related reading	Most recent post in related threads	Forum	Replies	Views	Started
»	New	What lives in Symmetric Sound?..	The beginning of our journey is ALWAYS symmetrical...	Audio Discussions Forum	19	174397	05-28-2004
»	New	Always check power-line polarity...	The Cost of Knowing...	Audio For Dummies ™ Forum	11	111780	07-10-2005
»	New	RAAL “Water Drop” tweeter for Macondo...	Your comment takes me by surprise...	Horn-Loaded Speakers Forum	77	922133	02-16-2007
»	New	My feelings about new exciting audio products..	Vacuumstate...	Audio Discussions Forum	25	263959	04-30-2007
»	New	Musique Concrete horns..	These are now sold as Kornhent products...	Horn-Loaded Speakers Forum	6	107915	06-12-2007
»	New	Compression drivers and the “clean signal”...	The NEW “Compression drivers and the clean signal”....	Horn-Loaded Speakers Forum	14	162910	07-12-2007
»	New	Digi Redux; Drive 1 transport and iDAT-44+ DAC..	Confirmation and Relief...	Didital Things Forum	26	229190	09-28-2007
»	New	Metal domes..	Try the one Lansche is using...	Audio Discussions Forum	6	78656	11-08-2007
»	New	The power AC Outlets?..	Where to Pick Up the Gong?...	Audio Discussions Forum	2	43051	10-31-2008
»	New	The Avicenna's failure is the great Avicenna success!..	New life for Avicenna...	Audio Discussions Forum	8	83632	02-03-2009
»	New	Internet and electricity..	Suboptimal. . ....	Didital Things Forum	1	29236	01-07-2010
»	New	Electricity... power strips and ac improvements..	Electricity... power strips and ac improvements...	Audio Discussions Forum	0	16628	03-30-2010
»	New	Another example of energy..	System Warm up...	Audio Discussions Forum	1910	9896166	01-29-2011
»	New	I good spot-light for a turntable?..	Reply...	Analog Playback Forum	15	154215	10-24-2010

	Target	Threads for related reading	Most recent post in related threads	Forum	Replies	Views	Started
»	New	What lives in Symmetric Sound?..	The beginning of our journey is ALWAYS symmetrical...	Audio Discussions Forum	19	174397	05-28-2004
»	New	Always check power-line polarity...	The Cost of Knowing...	Audio For Dummies ™ Forum	11	111780	07-10-2005
»	New	RAAL “Water Drop” tweeter for Macondo...	Your comment takes me by surprise...	Horn-Loaded Speakers Forum	77	922133	02-16-2007
»	New	My feelings about new exciting audio products..	Vacuumstate...	Audio Discussions Forum	25	263959	04-30-2007
»	New	Musique Concrete horns..	These are now sold as Kornhent products...	Horn-Loaded Speakers Forum	6	107915	06-12-2007
»	New	Compression drivers and the “clean signal”...	The NEW “Compression drivers and the clean signal”....	Horn-Loaded Speakers Forum	14	162910	07-12-2007
»	New	Digi Redux; Drive 1 transport and iDAT-44+ DAC..	Confirmation and Relief...	Didital Things Forum	26	229190	09-28-2007
»	New	Metal domes..	Try the one Lansche is using...	Audio Discussions Forum	6	78656	11-08-2007
»	New	The power AC Outlets?..	Where to Pick Up the Gong?...	Audio Discussions Forum	2	43051	10-31-2008
»	New	The Avicenna's failure is the great Avicenna success!..	New life for Avicenna...	Audio Discussions Forum	8	83632	02-03-2009
»	New	Internet and electricity..	Suboptimal. . ....	Didital Things Forum	1	29236	01-07-2010
»	New	Electricity... power strips and ac improvements..	Electricity... power strips and ac improvements...	Audio Discussions Forum	0	16628	03-30-2010
»	New	Another example of energy..	System Warm up...	Audio Discussions Forum	1910	9896166	01-29-2011
»	New	I good spot-light for a turntable?..	Reply...	Analog Playback Forum	15	154215	10-24-2010