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Posted: 12/15/2003 6:42:36 PM EDT
Link Posted: 12/15/2003 6:50:19 PM EDT
That's a knob, right? Am I missing something here? It's a $485 KNOB?! Holy hell I'm in the wrong line of work. Cpt. Redleg
Link Posted: 12/15/2003 6:50:38 PM EDT
I wonder if they make charging handles...
Link Posted: 12/15/2003 6:52:51 PM EDT
Which is the real knob, the Silver Rock or the one who buys it???
Link Posted: 12/15/2003 6:53:54 PM EDT
Obviously for people with large bank accounts and correspondingly small IQ’s and penises to match. Good grief! I know all about “It’s my money I’ll spend it any damn way I please” but anyone that buys that is just psychotically delusional and needs to seek help immediately.
Link Posted: 12/15/2003 6:54:30 PM EDT
The beech wood is coated several times with C37 lacquer for best sound as pointed out by Dieter Ennemoser. How can this make a difference??? Well, hearing is believing as we always say. The sound becomes much more open and free flowing with a nice improvement in resolution. Dynamics are better and overall naturalness is improved.
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ROTFLMFAO...
Link Posted: 12/15/2003 6:54:51 PM EDT
When I retire I'm going to make synthetic ruby scope mounting rings that will be as hard as diamonds as science will allow. They've come with a calibrated torque wrench and titanium screws in a hand carved oak box made of timbers salvaged from the first church ever built in Boston. Each set will be serial numbered in a matched pair and be honed to tollerances that they should have done to the Hubble Telescope. I figure I'll charge $100,000 a pair. And will sell a few to people here [lol] - bet me!
Link Posted: 12/15/2003 6:55:06 PM EDT
Hey, more power to them if they can get that price for a little piece of brass and wood. There are lots of toys for people who have too much money...
Link Posted: 12/15/2003 7:15:52 PM EDT
[Last Edit: 12/15/2003 7:17:20 PM EDT by Merrell]
This is such BS. Just like high-buck speaker wires. About 10 or 15 years ago, Bob Pease (who is one of the electrical gurus at National Semiconductor) challenged ANY of the "esoteric" speaker wire manufacturers to an objective electrical & blind audio test of their products. Not a one accepted, stating that their advantages were too "subtle" to be detected by electrical testing, and could only be appreciated by the human ear. Snake-oil salesman, every one, and the only people who will argue the point are those that have just dropped a bundle on their "rhodium Litz-wire hybrid sonic waveguides" or whatever horse-hockey name they've dreamed up this year. The only justice in this whole mess is that anyone who is a big enough jackass to spend $500 on a knob deserves to get the shaft.
Link Posted: 12/15/2003 7:23:39 PM EDT
[Last Edit: 12/15/2003 7:24:02 PM EDT by gus]
Jeez! Did you look around that web site??? PT Barnum was absolutely right! They have a pair of rheostats mounted in a cheesy wooden box (as opposed to a pre-amp) and the price is more than my complete home theater - and I have a very nice system! What a fucking joke!!!
Link Posted: 12/15/2003 7:25:18 PM EDT
Seems like the perfect accessory for the $6800 Potentiometer to me. Of course, for that kind of do-re-mi, it'd better go to 11.
Link Posted: 12/15/2003 7:28:35 PM EDT
Originally Posted By Paul: When I retire I'm going to make synthetic ruby scope mounting rings that will be as hard as diamonds as science will allow. They've come with a calibrated torque wrench and titanium screws in a hand carved oak box made of timbers salvaged from the first church ever built in Boston. Each set will be serial numbered in a matched pair and [red]be honed to tollerances that they should have done to the Hubble Telescope.[/red] I figure I'll charge $100,000 a pair. And will sell a few to people here [lol] - bet me!
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Hey, the mirror was ground to the proper tolerance, just to the wrong curvature. I wish people would get that right... CW
Link Posted: 12/15/2003 7:32:39 PM EDT
A fool and his money are soon parted.
Link Posted: 12/15/2003 7:34:33 PM EDT
Originally Posted By Cold_Warrior: Hey, the mirror was ground to the proper tolerance, just to the wrong curvature. I wish people would get that right... CW
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So you'll want a pair at a discount price right? [;)] The curvature was within tollerance but the wrong curvature? Wouldn't the curvature be within a tollerance? I am looking for a QC for my ruby ring plant [:D]
Link Posted: 12/15/2003 7:41:42 PM EDT
Originally Posted By Paul:
Originally Posted By Cold_Warrior: Hey, the mirror was ground to the proper tolerance, just to the wrong curvature. I wish people would get that right... CW
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So you'll want a pair at a discount price right? [;)] The curvature was within tollerance but the wrong curvature? Wouldn't the curvature be within a tollerance? I am looking for a QC for my ruby ring plant [:D]
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Essentially: They made it more than within tolerance - but the "prescription" they were given was wrong.
Link Posted: 12/15/2003 7:45:07 PM EDT
Originally Posted By Adam_White:
Originally Posted By Paul:
Originally Posted By Cold_Warrior: Hey, the mirror was ground to the proper tolerance, just to the wrong curvature. I wish people would get that right... CW
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So you'll want a pair at a discount price right? [;)] The curvature was within tollerance but the wrong curvature? Wouldn't the curvature be within a tollerance? I am looking for a QC for my ruby ring plant [:D]
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Essentially: They made it more than within tolerance - but the "prescription" they were given was wrong.
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Thanks for the verbage clarification. It is exactly the point except they were given the correct prescription and ground it to a different one. CW
Link Posted: 12/15/2003 7:46:15 PM EDT
... Use this code when ordering: [center]702DLZ3B2[/center] ... I ordered twelve and saved 10%!
Link Posted: 12/15/2003 8:12:22 PM EDT
It'd take a lot of [booze] before that shows up on my credit card....
Link Posted: 12/15/2003 8:20:56 PM EDT
How about 12' of speaker cable for $1060? [url]www.referenceaudiomods.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=ACT_S&Category_Code=CABLES&Product_Count=4[/url]
Link Posted: 12/15/2003 11:06:33 PM EDT
Silver Rocks cannot be returned or exchanged for any reason...
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and that's how they make their money - I guess when your goal is to see how bad you can make people take it up the a$$, they have to add that clause. Jeez, I wonder what crack these guys are smoking. That knob costs more than my JoLida....
Link Posted: 12/15/2003 11:49:15 PM EDT
I've bought a lot of cotton tubing, several dozen op amps, and a few hundred soft-recovery diodes from them and have always received great service. The last time I ordered, the company credit card was turned down since we were over the limit, and they shipped anyway with a note asking us to call. You don't find service like that at most places. On the other hand, some of the stuff is obvious rip-offs. I got to open-up one of their battery packs for the amp they sell. It sells for $2,100, and all it consists of is two small UPS batteries (7.2Ah, about $30 each) plus a small charging ciruit. That's about a 20-fold mark-up!z
Link Posted: 12/15/2003 11:55:42 PM EDT
I read an inflight magazine once about high end home stereo systems. Absolutely mind-boggling sound systems for $200,000 or something absurd like that. For a freaking stereo.
Link Posted: 12/16/2003 1:39:18 AM EDT
Well, it goes like this: If you spend $20,000 on a system, believing it sounds better than anything else....it will. Mind over wallet. My $500 Yamaha system sounds fucking awesome, thanks. Wallet thanks me.
Link Posted: 12/16/2003 3:09:12 AM EDT
It's a joke, I hope and pray. Having been around high-end audio, there are certainly fools out there, but I think they a poking fun with this one...god, I hope they are!
Link Posted: 12/16/2003 3:20:16 AM EDT
[Last Edit: 12/16/2003 3:21:23 AM EDT by gus]
It's one thing to put together a good system - and that can easily cost some money of you buy good speakers and amps and such. But these guys (and a lot of the "high end" crowd) are just nuts! However, no way a $500 system can sound as good as a good component system. That's not to say you can't get decent sound at that price (depends on your standards).
Link Posted: 12/16/2003 4:39:21 AM EDT
i have had $500 systems and several thousand $ systems...not even close in quality. I am sure your $500 system is loud (like mine was) but you dont know how much sound you are missing until you spen a few bucks.
Link Posted: 12/16/2003 7:04:08 AM EDT
Originally Posted By gus: It's one thing to put together a good system - and that can easily cost some money of you buy good speakers and amps and such. But these guys (and a lot of the "high end" crowd) are just nuts! However, no way a $500 system can sound as good as a good component system. That's not to say you can't get decent sound at that price (depends on your standards).
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... That is just about the epitome of my financial stature. Every hobby has its high end nutjobs that sit on top of the hill with their outrageous systems. But for me, if it performs to my expectations, and I can get it at a bargain, I come out ahead because (in theory) I have more cash to spend on other projects.
Link Posted: 12/16/2003 7:29:20 AM EDT
Originally Posted By zoom: I've bought a lot of cotton tubing, several dozen op amps, and a few hundred soft-recovery diodes from them and have always received great service. The last time I ordered, the company credit card was turned down since we were over the limit, and they shipped anyway with a note asking us to call. You don't find service like that at most places. On the other hand, some of the stuff is obvious rip-offs. I got to open-up one of their battery packs for the amp they sell. It sells for $2,100, and all it consists of is two small UPS batteries (7.2Ah, about $30 each) plus a small charging ciruit. That's about a 20-fold mark-up!z
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er, no offense, but they are selling op amp modules with garden variety opamps and TWO! (count em TWO!) electrolytic bypass caps for $116... [url]http://www.referenceaudiomods.com/Merchant2/merchant.mvc?Screen=CTGY&Store_Code=RAM&Category_Code=OPAMPS[/url] And just how much are those op amps by themselves??? (TI / Burr-Brown OPA627's) [url]http://focus.ti.com/docs/prod/folders/print/opa627.html[/url] (hint: they are in the SOIC pkgs.) Adding bypass locally (at each chip) is the oldest trick in the book (and it can compensate for otherwise poorly designed systems). If they knew what the hell they were doing, there is something else they could very easily do, they don't and I'm surely not going to tell them. The other amps (AD825's) are $1.65 @ from Analog Devices (the manufacturer) The two caps are maybe a buck (if bought in low quantity) The PCB should be done as a panel, making the unit cost under a buck per The connectors (DIP or SIP) are roughly a buck (depending on style & finish I could solder one of these up in 2 minutes (with my glasses on, naturally) JFET input amplifiers typically have excellent current noise specs (pA or fA per root hertz) but less attractive voltage noise (nV per root hertz), both of which rise at lower frequencies. There are certain circuits which may be improved by the substitution of a JFET amp, and others which may be degraded. At least they're not taking you to the cleaners on the price of the diodes, although replacing a bridge rectifier with anything beyond garden-variety rectifiers is ridiculous.
Your preamp, power amp, CD player, etc. must convert AC wall voltage to DC voltage to power the internal circuitry. Diodes do that job, some better than others. These are the better ones. Extremely fast switching, 'soft-recovery' diodes simply sound better for audio purposes. We also have very low-noise Schottky diodes that work great in the heater circuits of tubed equipment (due to their switching characteristics) and in almost any low voltage power supply. Not all fast diodes are created equal. We have done the extensive listening to find the best.
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Everybody knows how important the power supply of any piece of hi-fi equipment is. But how do you upgrade it? One way is to replace the bridge rectifier diodes with these hyperfast, soft recovery diodes. They can easily cope with the changes on the current draw from the transformer plus don't have the distortion and harshness that usually accompanies normal diodes. This results in an improvement in overall sound quality, a lower noise floor and better dynamics. Hyperfast soft recovery diodes; 4A 600V; 6A 1200V; 8A 600V; 12A 1000V FRED, or Fast Recovery Epitaxial Diode have a extremely fast response time, high current capacity and very little overshoot (ringing). It is important to match up the current / voltage requirements. Usually for non-amplified devices, the 4A / 600V versions will suffice and for power amplifiers, the 12A / 1000V is usually required. It is also important to take heat dissipation into account, particularly for the high-power versions and heat sinking is likely to be required.
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Balderdash! Snake oil salesmen all! "We did extensive listening, and this rectifier sounds the nest" BS BS BS! I DEFY anyone to pick out a modified rectifier in an audio system. You are rectifying a 60Hz sine wave and ns of recovery are going to be noticeable? BS. Fast recovery diodes are required in switching much higher frequencies than line power. *sheesh* One of the more "I am so full of myself" "Audio Guru" pages I found while looking around: [url]http://www.modwright.com/products/?product_id=8[/url] Changing resistors to Vishays and caddocks. There are differences in resistors (carbon composition, carbon film, metal film, etc) and NOBODY is using carbon comps in audio gear and changing from one brand to another will do ZIPPO to audio performance (unmeasurable) When these boneheads start using phrases like "treble hardness, grit, image blur, poor resolution" and start calling their products "Signature Truth" and "Absolute Truth" it's time to watch your wallet and run the other way. Electronic design is something that does not lend itself to dilettantes, who claim their mods are from some higher astral plane, too esoteric to be measured. Are there differences in components? Certainly. Polypropylene capacitors DO sound better than cheap mylars, but I know WHY and it's not some mystical foo-foo incantation, like these guys insinuate. Consider also the source material which (amazingly) was recorded without the benefits of these "self-proclaimed wizards". Weakest link in the chain determines overall audio quality. In short, there is a point of diminishing returns in audio equipment, and at some point (usually in the 5 to 10K range) you really start throwing good money after bad. The high-end guys have always claimed that "only their golden ears could hear the improvement" when, in fact, it was usually psychological (I just spent all this dough on these mods, I'm [i]sure[/i] I can hear an improvement... (not hammering you zoom, just a bit of reality from an older analog designer)
Link Posted: 12/16/2003 8:10:01 AM EDT
Wallly World has an awesome surround system for sale right now- think its 39.99 for the whole system...think yhey use the hollow tubes to send the sound through to the speakers l(like back in grade skool) F-ing garbage.
Link Posted: 12/16/2003 9:19:24 AM EDT
Check out what they say about their amp. Sonic benefits Better micro and macro dynamics Less aggressive more relaxed sound More resolution [b]Reveals more emotional content[/b] [ROFL]
Link Posted: 12/16/2003 10:58:44 AM EDT
In no way is a $500 system going to comapare to a $5000-10,000 system. I learned this while interning in studios that had full on ultra THX systems. Believe me-the sound quality between the two is like night and day! However, once you hit that point, anything else is just for show. $500 nobs? The only parts like that I have seen in that price range in studios are things like fader assemblies on big pro mixing boards. $1000 cables? I think not!!!!! The studio grade cables used are not even half as expensive! We used Monster cables, as did the studio that had the ultra THX system..and it sounded plenty awesome. Snake oil..pure and simple.
Link Posted: 12/16/2003 4:16:56 PM EDT
I should append my earlier post that there is nothing wrong with tinkering with equipment in an effort to improve it, in fact, it's one of the most educational endeavours that one can undertake. Playing around with stereo equipment can be an excellent introduction into the intricacies of electronic design. What I do take exception to is unsubstantiated claims for performance (by those out to make a fast buck). carry on...
Link Posted: 12/16/2003 4:58:03 PM EDT
Hubble: See http://cems.alfred.edu/students98/spinelim/body.html for what was wrong with the Hubble. Stereo: I love to see special "gold coated" digital fiber optic cables. The light travels through the cheap plastic cable and it doesn't care if it is wrapped in paper. What good is the gold doing?
Link Posted: 12/17/2003 1:22:43 PM EDT
Originally Posted By Merrell: er, no offense, but they are selling op amp modules with garden variety opamps and TWO! (count em TWO!) electrolytic bypass caps for $116...
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We paid less than $20 each in qty 50. I have several guys that listen over headphones 4+ hours per day, and unanimously they preferred the replacement opamps on our headphone distribution amps to the stock ones. I also get less complaints about headaches from those guys. It was well worth the money and time. Aside: I replaced the headphone amps with single-ended class A MOSFET battery-powered amps I built, and the guys love them. After telling you that, you're probably ready to put me in the camp with the tweakers.
The PCB should be done as a panel, making the unit cost under a buck per
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But for qty around 50, could you do that? No. That's why I bought.
I could solder one of these up in 2 minutes (with my glasses on, naturally)
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I'm 75, and except on a rare good day when my hands aren't shaking and my close-up vision is better than normal (yes, it changes daily), I can't depending on being able to solder so I don't usually have that luxury. I'm a security guard working in a security company so it's not like I can go down the hall and find someone else to help.
At least they're not taking you to the cleaners on the price of the diodes,
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Considering I haven't found anywhere else that has them as reliably, I don't care about paying $1 more per part. Digikey and other places seem to sell-out of them for weeks at a time. I haven't bought enough for the price to make a difference.
although replacing a bridge rectifier with anything beyond garden-variety rectifiers is ridiculous.
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I disagree with that. Maybe it isn't true any longer (since most of my experience is with much older opamps), but I've heard plenty of power supply noise negatively affect audio preamps that use opamps. Less reverse-recovery noise on the + and - voltage rails has to help. Also, the few power supplies I've built that use fast, soft recovery diodes (since that's what I happened to have laying around at the time) interfere with my AM radio less than the others. That tells me there is a difference for the better. Now whether or not you can hear it is up for discussion.z
Link Posted: 12/17/2003 1:31:30 PM EDT
When i was in school, studying to be an EE, we learned that the filter caps in a power supply got rid of any noise from the rectifier. If you're getting rectifier noise, you lack filter capacity. The little switching spike is nothing compared to the big humps the caps are filtering out to begin with. I can't imagine that tiny little bit of switching noise ever being a factor. If it were, you still wouldn't be able to hear it over all that hum. Snake oil indeed!
Link Posted: 12/17/2003 5:51:45 PM EDT
Noise generated from a power supply can often be traced to excessive ESR (equivalent series resistance) & dielectric absorption in the filtering capacitors (to say nothing of lead inductance, stray capacitance and a host of other effects). I'm all for tinkering with equipment to try to improve it (or just to have fun), but the idea that low levels of distortion caused in the power stage travelling through the signal chain to the point where they cause audible effects indicates other problems with the equipment (poor PSRR in the amplifiers and not knowing where to reference grounds come to mind) Anyway, it is fun to fiddle with the stuff and there are many simple things which can be done to improve sound quality, it does strike me as a little but of fishing when an esoteric manufacturer will grab ahold of an obscure technical nuance of a component, then claim they have the "answer" to all their sonic ills (the "sonic wooden knob job" being perhaps an exceptional example ;)
Link Posted: 12/18/2003 3:11:28 AM EDT
Originally Posted By Merrell: Noise generated from a power supply can often be traced to excessive ESR (equivalent series resistance) & dielectric absorption in the filtering capacitors (to say nothing of lead inductance, stray capacitance and a host of other effects).
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Series resistance in the filter stage of a power supply circuit is a BAD thing(tm). It would have to come from poor design, poor construction quality, or just crappy components. Given the outrageous claims of some of these manufacturers, none of the above would surprise me. Those "magic" caps so often used (name brands that are unheard of outside the esoteric audio crowd) raise suspicions as well.
Link Posted: 12/18/2003 12:14:35 PM EDT
Those knobs are funny. The brass connector inletted into the knob is probably the same connector used everywhere, the wood itself is turned on a lathe, that probably takes no more than a couple minutes per unit MAYBE. They are then sanded on the lathe, and the lacquer may even be applied on the lathe and high speed buffed in. There is NOTHING about that lacquer that is particularly special. This is total and utter B.S. Even if everything were hand done by a very expensive craftsman (which they are not) they wouldn't cots more than 30 bucks a whack since there is no way there is anything more than 30 minutes of work per unit. These guys are total rip-off artists.
Link Posted: 12/18/2003 12:30:41 PM EDT
I love the people that say you get better sound from CDs if you put them in the freezer prior to playing and draw black lines on the top of the disc. Pure crap, but tons of people swear by it.
Link Posted: 12/18/2003 12:32:10 PM EDT
I've done too much shooting without protection (as a youth, now I plug and muff). I can't detect much (if any)difference between my $300 system and my friends $1500 system. Subtle nuances are wasted on me. Kent
Link Posted: 12/18/2003 12:55:21 PM EDT
[Last Edit: 12/18/2003 12:56:08 PM EDT by gamesniper]
I've listened to some REALLY high end stereo systems that had high end price tags to match, but my current sound system absolutely kicks ass for this price: Sony 110w/ch surround sound amp w/remote $100 (from a buddy that was in the Air Force) Sony 5 disc CD changer JVC dual cassette deck, feather touch controls 4@ Bose 201 speakers Above three items from a pawnshop, $210 4@ monster cable, total $35 I'm satisfied.
Link Posted: 12/18/2003 12:57:58 PM EDT
[Last Edit: 12/18/2003 1:04:26 PM EDT by fight4yourrights]
$2500 [url=https://marketplace.curtco.com/product_detail.php?id=35][b]The Long Arm Flashlight[/b][/url] [img]http://photos.ar15.com/WS_Content/ImageGallery/Attachments/DownloadAttach.asp?sAccountUnq=141&iGalleryUnq=995&iImageUnq=20641[/img] The Long Arm Searchlight, created by Reva International, is a five-pound, waterproof flashlight that produces a one-mile beam of light. It is made with a shock absorbing internal system that can withstand a six-foot drop without being damaged, and provides two hours of uninterrupted light. A redundant sealing system waterproofs the searchlight up to 330 feet in depth, making it the brightest searchlight above or beneath the ocean. Incredible beam penetrates smoke and fog like no other light source available.
Link Posted: 12/18/2003 1:00:50 PM EDT
Series resistance in the filter stage of a power supply circuit is a BAD thing(tm). It would have to come from poor design, poor construction quality, or just crappy components.
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Merrell was talking about series resistance of the filter caps. That isn't (to use your words) due to poor design, poor construction or crappy components. That's an inherent part of any capacitor, especially an electrolytic one like you use in a power supply. Some of the Panasonic caps I've used in power supplies have ESR's of over 1 Ohm. Reducing that by paralleling smaller, better caps works well.
Those "magic" caps so often used (name brands that are unheard of outside the esoteric audio crowd) raise suspicions as well.
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If you believe the datasheets, some of the caps are worth the money. Their usual use is to replace or parallel electrolytic caps. The specs on electrolytic caps is terrible compared to most other caps, but they're used since they're cheap and you can get larger values of capacitance. You never use them when you can use something else.z
Link Posted: 12/18/2003 1:24:57 PM EDT
[Last Edit: 12/18/2003 1:29:21 PM EDT by gus]
Originally Posted By zoom:
Series resistance in the filter stage of a power supply circuit is a BAD thing(tm). It would have to come from poor design, poor construction quality, or just crappy components.
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Merrell was talking about series resistance of the filter caps. That isn't (to use your words) due to poor design, poor construction or crappy components. That's an inherent part of any capacitor, especially an electrolytic one like you use in a power supply. Some of the Panasonic caps I've used in power supplies have ESR's of over 1 Ohm. Reducing that by paralleling smaller, better caps works well.
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What is the output impedance of a typical power transformer as used in a circuit such as this? If 1 ohm of resistance can be a factor in series with a HUGE cap, it must be pretty low. Still, this theoretical, tiny, minute amount of noise is on the power rail, not directly in the signal chain. I still have serious doubts about the ability of one rectifier diode in a power supply to be "cleaner" than another normally functioning brand (but properly spec'ed) as measured or heard anywhere in the signal chain. Still snake oil![;)], IMHBPO.
Those "magic" caps so often used (name brands that are unheard of outside the esoteric audio crowd) raise suspicions as well.
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If you believe the datasheets, some of the caps are worth the money. Their usual use is to replace or parallel electrolytic caps. The specs on electrolytic caps is terrible compared to most other caps, but they're used since they're cheap and you can get larger values of capacitance. You never use them when you can use something else.z
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Still, in the power supply, as long as a high quality cap of sufficient capacity is used, and the power supply is properly designed for the amp or other equipment it is powering, I must doubt the ability of one cap to sound better or worse than another. Now if you're talking coupling caps, that's a different story, but most modern amp designs are direct coupled and have no coupling caps so that is a moot point.
Link Posted: 12/18/2003 1:34:46 PM EDT
Man I wish I had enough money to be a crazy "audiophile" (more so than I already am, I probably have more in my car stereo than many have in their home). I be an even crazier gun-o-phile then too. Guys don't forget the felt dampening dots, amber treatment on top of components and carbon fiber speaker wire stands (to raise the noise floor LOL).
Link Posted: 12/18/2003 1:38:49 PM EDT
[Last Edit: 12/18/2003 1:41:46 PM EDT by gus]
I've even seen AC plugs and recepticles, at a hundred or more dollars a pop, that are alleged to somehow give a system more clarity, or presence, or what ever buzz word popped into the head of the [s]crook[/s] marketer or sales copy writer's head. Or ultra massive, ultra stable platforms to sit a MOSFET power amp on to minimize "acoustic coupling". [ROFL2] Nice microphonic amp design there eh?
Link Posted: 12/18/2003 2:03:32 PM EDT
What is the output impedance of a typical power transformer as used in a circuit such as this?
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That's not important. The cap is a low pass filter, and any resistance in series with it will decrease its effectiveness. If you think of it that way, it makes more sense. The ESR of the caps in the power supply is important. Bypassing electrolytic caps is something you see in textbooks. It's not a practice limited to tweakers.
most modern amp designs are direct coupled and have no coupling caps so that is a moot point.
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Amps usually yes, but preamps and sources very often no. Both of the CD players I've fixed in the past year had electrolytic caps in series with the signal path to block DC. Replacing or bypassing those is the type of use I was talking about.z
Link Posted: 12/18/2003 2:08:39 PM EDT
Am I the only one who finds it humorous that folks who brag about their cheaper systems - and who like their Bose speakers (which is where most of their money went) - spend money on MONSTER cables *cough* gamesniper *cough*. I mean, copper is copper - I can't imagine speaker cables making a difference at that price point. Admittedly, he seems not to have paid too much for those cables, but they are pure marketing gimmicks for most people's equipment expectations.
Link Posted: 12/18/2003 2:22:20 PM EDT
[Last Edit: 12/18/2003 2:28:55 PM EDT by DJbump]
Originally Posted By Merrell: er, no offense, but they are selling op amp modules with garden variety opamps and TWO! (count em TWO!) electrolytic bypass caps for $116... [url]http://www.referenceaudiomods.com/Merchant2/merchant.mvc?Screen=CTGY&Store_Code=RAM&Category_Code=OPAMPS[/url] And just how much are those op amps by themselves??? (TI / Burr-Brown OPA627's)
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Merrell- The Burr Brown/TI OPA627 is not exactly your "garden-variety" opamp. Depending on the grade this part runs (source: Digikey in single quantities) $30-45/pair (AP versus BP) just for the opamps. Garden variety opamps would be as you noted in the case of the Analog Devices 825--a few bucks a pop. I am in no way justifying a nearly $500 knob, or any of Reference Audio's other parts/prices, just pointing this out. And, yes, there is a difference in sound between the 627 and other less expensive opamps, a difference I've heard with my own ears. Is that difference in musical enjoyment worth the price to you or anyone else? Who knows. For me, in the audio application in which I use it (actually I use the 637) it is.
Link Posted: 12/18/2003 3:02:53 PM EDT
[Last Edit: 12/18/2003 7:24:18 PM EDT by gus]
Originally Posted By zoom:
What is the output impedance of a typical power transformer as used in a circuit such as this?
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That's not important. The cap is a low pass filter, and any resistance in series with it will decrease its effectiveness. If you think of it that way, it makes more sense. The ESR of the caps in the power supply is important. Bypassing electrolytic caps is something you see in textbooks. It's not a practice limited to tweakers.
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Ahh but it IS important - if the output impedance is way higher, then the effective series resistance (really it's impedance, being frequency dependant and all) of the cap loses significance. Also, yes it's a low pass filter - it's a high frequency shunt. If the cap is capable of completely shunting the 60hz (120 Hz for a bridge rectifier), then the switching spikes, which are by virtue of their fast rise and fall times much higher in frequency as far as the cap is concerned, will never get out. At DC or anything close to it, the filter cap had better be an effective open, or the cap is shorted. Keep in mind, the internal "ESR" of a filter cap is not in series with the load - it's parallel.
most modern amp designs are direct coupled and have no coupling caps so that is a moot point.
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Amps usually yes, but preamps and sources very often no. Both of the CD players I've fixed in the past year had electrolytic caps in series with the signal path to block DC. Replacing or bypassing those is the type of use I was talking about.z
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Ahh - now there I can see how a cap could influence sound. Not so much as a result of price, but as a result of being properly chosen with regard to the application. Also, I can definitely agree that op amps are not created equal! That would be one of the places I wouldn't mind spending more to get the best. I've forgotten much of what I learned in school, and haven't really ever been much of an audio tweaker in terms of changing things around internally in equipment. I always just bought what sounded best, and came with a schematic in case I ever had to fix it. As a kid, electronics was this big hobby of mine, but once I started doing it for a living it gradually lost its appeal. Then at the end of the cold war, I pretty much bailed to telecommunications and haven't done much in "real" electronics since. Still, I do love great sound!! But I hate rip off artists and the audio industry is chock full of them.
Link Posted: 12/18/2003 3:17:52 PM EDT
Originally Posted By fight4yourrights: The Long Arm Searchlight, created by Reva International, is a five-pound, waterproof flashlight that produces a one-mile beam of light. It is made with a shock absorbing internal system that can withstand a six-foot drop without being damaged, and provides [red]two hours of uninterrupted light[/red]. A redundant sealing system waterproofs the searchlight up to 330 feet in depth, making it the brightest searchlight above or beneath the ocean. Incredible beam penetrates smoke and fog like no other light source available.
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If by "two hours of uninterrupted light" you mean 40 seconds of really, really, super-bright Power-of-God-like light followed by 1 hour, 59 minutes and 20 seconds of darkness. Do they have a mount available for my HP45C?
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