Je voudrais savoir si quelqu'un a déjà entendu parler de cette alimentation séparée fabriquée apparemment par un fondu d'électronique. Et si personne ne connait cette alimentation visiblement artisanale, il y a peut-être des spécialistes qui pourraient nous éclairer sur la qualité ou les défauts d'une telle option... Merci
PS : J'ai essayé de faire un lien vers des photos à la fin du message....
Following the success of the original TeddyCap and requests to create such a power supply, here is the DualTeddyCap.
This power supply provides the functionality of two independent HiCaps and one NapSc in a single box.
Like the TeddyCap, this power supply is a significant improvement over the HiCap. It uses a superior design and high quality components to provide sound quality which is far superior.
It can be used to substitute two HiCap/HiCap2 power supplies in Naim systems, and as a bonus it can also replace the NapSc.
The DualTeddyCap is your ideal upgrade if you have:
· A NAP82 or NAP282 preamplifier
· Two Naim components such as a preamplifier (NAC32.5, NAC42, NAC62, NAC72, NAC102, NAC202, etc) and a Naim CD player that has a HiCap input (such as the CD3.5, CD5, CD5X), active crossovers, or an independent Naim phono stage, etc.
Sound:
In general, you’ll experience more clarity, tighter bass, more details, more natural voices, and no downside. Moving from HiCap to this PSU has the same type of effect as moving from no HiCap to adding a HiCap.
This design is based on the experience gained with the original TeddyCap and provides even better performance (note that this design is no longer based on SuperRegulators but uses an improved regulator).
In a nutshell:
When the AC voltage is rectified, a ripple is added to the DC voltage. This ripple translates into noise at all audible frequencies and has a very negative effect on the sound quality. The better the power supply can filter this ripple the better the sound will be. To get an idea of how much the power supply can influence the sound quality, sufficient to mention that almost all NAIM preamplifiers are based on the same amplification circuitry, and differ in their ability to connect more or better power supplies. Noise on the power rail translates into distortion, coloration, and less natural sound.
The amplitude of the ripple mentioned above decreases with the size/quality of the transformer and smoothing capacitors being used. Naim Audio uses a brut force technique for the HiCap; they use a 500VA transformer and rely on large low ESR capacitors. Not only that this technique is less efficient in noise filtering, but over time these capacitor quality decreases (ESR increases), and as a result the ripple increases, this is the reason why the HiCap requires re-capping every 10 years or so.
The most common way to reduce ripple is to use a linear voltage regulator such as the LM317 used for the HiCap. All linear (feedback) regulators however, including the superior SuperRegulator, have a limitation which is inherent to the way they operate; they can only fix a problem after it occurs. Since the speed in which they can fix the problem (regulate) is constant, their ripple rejection capability decreases with frequency. The LM317 has a ripple rejection of around 80db at 50Hz, which drops to merely 20db at very high frequencies (note that a -60db difference means x1000 times less!!!).
The innovation in this power supply is the incorporation of a very effective low-pass filter that in conjunction with the linear regulator provides a theoretical (impossible to measure with ordinary equipment) ripple rejection of more than 120db all over the audible spectrum and up to more than 1MHz. This powerful filter allows using a smaller transformer and smaller smoothing capacitors. Since it does not rely on the smoothing capacitors to eliminate the noise, it does not require re-capping when the quality of these capacitors decreases. The other advantage of using smaller capacitors for the filter is that capacitors other than electrolytic can be used. Electrolytic capacitors are limited in high frequencies, and have leakage noise. This PSU is using a combination of Tantalum, and X7R ceramic capacitors capable of filtering very high frequencies (over 1MHz). Surprisingly, filtering high frequencies above 100 KHz is very audible.
This power supply uses a custom designed EI core transformer with independent secondaries for each output connector, allowing each connector to be used independently. This EI core transformer was specially designed for audio, and is superior to toroidal transformers as it has better rejection mains noise (Toroidal transformer are better suited for power amplifiers due to their high efficiency but they have poor mains noise rejection, while EI core, C core, and R core are more suitable for pre amplifiers). This PSU is designed to remain powered constantly with no degradation over the years.
In addition to its much better sound and maintenance-free longevity, this PSU has the following advantages:
· Unlike the HiCap which uses huge transformers, causing inrush current that often blows home fuses; this design allows using much more reasonably sized transformer that will not blow fuses.
· This PSU is built in a smaller box, saving the space used by two HiCaps and Napsc on your expensive hi-fi rack…
· As a bonus, this PSU comes with a "Napsc" compatible output to power your preamplifier’s control circuitry.
· The DualTeddyCap is supplied with two superior quality 5-pin cables replacing the SNAIC-5. These cables are made using silver plated wires with PFTE insulation and have a very low capacitance of only 15pF/ft, less than a quarter of the black SNAIC!!!
· These cables are connected directly to the PSU, avoiding additional plug/socket.
Size: 25 x 15 x 7 cm
You can read about this PSU and the original TeddyCap here:
http://www.pinkfishmedia.net/forum/show ... hp?t=21574
http://www.pinkfishmedia.net/forum/show ... hp?t=29501
<a href="http://picasaweb.google.fr/e.capitaine/ ... 5442"><img src="http://lh5.google.fr/e.capitaine/RwaWJJ ... f6c6_0.JPG" /></a>
