Mikorist

"Svi Beograđani otišli kući"

Mogu da se kladim da svi koji prave kućišta imaju čekić.

Boli ih da ne kažem šta...Bitno je da su pukli za sajt vlade 20 milona... i ko zna koliko milona za osvtlenje... Briga za repetitore i radio.

Ja mislim da the best pretpojačivač ima na forumu... Samo koristite pretragu. I meni je bio promakao. Ali nije jeftin a ni simple. Koliko releja i žica ima izgleda ko centrala telefonska Pored toga staviti bilo koji preamp da se poredi, nema veze cena ..... 20K , 30K , 50K $

I onda nije sve gotovo. Obično se šalju prednjice na doradu. Graviranje, dodatna eloksaža, dugmad, rupe za diode, udubljenja za dugmad - dodatne ploče.... I naravno stope krštene , jer su plastične original.

ja ti kažem

kolki treba za Sissy ?

What is Gain Structure? Gain structure (AKA Gain Staging) is a concept that gets talked about a lot in pro audio, but most home audio folks have never heard of it. Understanding gain structure can help you get the cleanest signal possible out of your system and avoid some nasty things. Things like noise and clipping, which might sound cool from a guitar amp, but not from a Hi-Fi system! What's gain? Basically it's amplification of the signal. When we increase the voltage level of the signal, that's gain. Current gain can also be important, but we'll mostly be talking about voltage gain here. The "structure" part of gain structure is the various voltage levels throughout your audio system and the gain it takes to get them to those levels. How is gain expressed? Typically either in amplification factor (times or X) or in decibels (dB). So if one volt goes into an amp and two volts come out, that's a gain of 2X, or 6dB. The dB is a logarithmic function as opposed to a linear one and is often seen on VU meters and other audio scales. Take a look at this month's column by Jan Didden for more about decibels. What is the overall gain of a typical home audio system? Let's start with an extreme example and assume that you're a vinyl lover using a moving magnet cartridge. Your speakers are inefficient and need a lot of power so you have a 300 watt power amp. How much overall voltage gain do you need to get that tiny signal coming out of the phono cartridge up to the 300 watts (50 volts) coming out of your Ear Buster amp? A lot! A gain somewhere in the neighborhood of 13000X or 82dB, sometimes more. Imagine a microscope with that kind of magnification, and all the little specks and dirtballs you might see clouding the image. Similarly, imagine all the noise your system might pick up along the way with so much gain. If you have a moving coil cartridge, its even worse! SET amplifier fans can gloat, as they might have an overall gain of only 2000X. If they are running a CD player into a flea power amp, that might mean a gain of only 4X. But since flea power owners probably use more sensitive speakers, they can still run into noise and clipping problems. Typical gain structure of a home audio system. Where does the structure part come in? It's about how much gain (or loss) each section of the system has. The phono preamp will have a lot just to recover that tiny signal from the cartridge. The preamp or line stage will add a bit more, and then the power amp will have gain also. Keeping the levels reasonable throughout the whole chain gives us good gain structure. Adding up how much gain each section has gives us the overall gain of the system. Now look over at your preamp or integrated amp with that big knob in front that "goes to eleven". What you are looking at is gain's twin brother from an opposite universe, attenuation. All that volume knob does is attenuate the signal that comes before it by dividing the signal and reducing the voltage. Typically in the 12 O'clock position the volume control attenuates by 20dB, cutting the signal to 1/10th of what it was. But it has not changed the gain of each section, only divided the signal, (attenuated it) at a certain spot. Now we know the two sides of the structure, gain and attenuation. Both are important. Most simple home audio systems have only one point along the signal path to control gain, the main volume control, which controls only by attenuation. The gain of each section does not change, you've just divided the signal at one point. So that extreme system with an overall gain of 13000X will still have an overall gain of 13000X, it's just that somewhere along the path you've used a voltage divider (your volume control) to attenuate the signal. And the sections downstream from the volume control will amplify everything just as they always did. But now they are amplifying a smaller signal, the signal you attenuated with the volume control. So how about a practical example? Suppose some evening you're with that Special Lady. You've poured the wine, lit the candles, and now it's time for that famous Barry White CD. Mmmmm, mmm. Bring on the love, baby. Being the smart and smooth audio dude that you are, you know that Mr. W sounds his sexy best played at 2 watts average power on the speakers in your "Love Den." So what voltage levels, gains and attenuations will you need to bring out the best in Barry? Right now you don't care, But Hey! Snap back to reality and look at the sexy graph below. Typical voltage levels and gains Barry's voice is going to be recorded at about 16dB (average) below the maximum level possible on the CD. That is a standard mastering level. If your CD player or DAC is standard, then that's going to mean an average level of about 0.32 volts coming out of the RCA connectors on the back. That 0.32 volts will then be amplified 3X by your preamp and 30X by your power amp. But that's 29 volts out of the power amp – over 100 watts! Not going to set the mood, is it? No, Special Lady has run for the door! That's why we have a volume control in there - to reduce the signal to a reasonable level. You can see that the system has too much gain for the evening's festivities, but that's OK, just turn it down. Now Barry is crooning, not shouting. Throw away some signal in the middle of the chain so that it doesn't get too loud at the end. In this case the volume control has divided the voltage level by 7, (0.14X) or -17dB. So tomorrow when you want to rock out with AC/DC for your victory lap, you can just turn it up and unleash the power. So far, so good. But if we look back at the system, we see that for most situations, we have more gain than we need. Maybe 15 to 20dB (10X) more gain than we really need. And that can lead to noise. Why? Because any noise that occurs after the volume control does not get attenuated. In fact it gets amplified. You've cut down the signal from the CD player by 17dB, so now it's 17dB closer to the noise in every circuit that follows. Any noise from the preamp, the cables, bad connections, etc. will be also be amplified 30X by the power amp. You took a medium level signal of 320mV (0.32 volts) and divided it down to 44mV so its now much closer in level to all the noise living in the bottom of the system. Too much gain or bad gain structure not only gets us into trouble with noise and clipping, it can be a pain for practical reasons, too. I remember a big old Pioneer integrated amp from the 80's, a massive, heavy thing. Big transformer, VU meters, clip lights, serious knobs and switches. Did maybe 75 honest watts into 8 Ohms. You could connect any standard source like CD, radio, tape, phono, and you barely had to crack the volume knob to get a big blast of music. "Wow, this thing's got power, you hardly have to turn it up at all!" But did it really have tons of power? No, it just had too much gain. The volume knob would not get past 9:00 before the amp was clipping, so the useful range of the volume control was from “Nothing” at 7:00 to “Clipping” at 9:00. That sure made adjusting the volume very touchy. Stupid design, far too much gain. Despite all the other good aspects of the amp, the primary user interface, the volume knob, was a pain in the backside. Let's return to the signal path to see where things might be done better, or where they are often done wrong. Generally speaking we want to run amps and preamps at a fairly high level. That means that the signal (the music) will be at a much higher voltage than the noise so we have a higher signal to noise ratio, S/N. That's a good thing. But just how high a signal voltage do we need to run? Usually we want the peaks of the loudest signals to be about 3dB-6dB below the maximum that device can do without distorting for the best s/n ratio. That can be hard to determine unless you've designed, built or measured the amp. Power amplifiers might give you a clue in their specs, but preamps and phono stages usually don't. How much signal does it take at the input to drive the device into clipping? Knowing that will tell you where your gain should be all through the chain. There aren't any set standards as to what the input signal should be for a preamp or power amp to reach its maximum level, but there are some conventions. Input levels that will drive a device to full output can range from 0.77 volts to 2 or 3 volts in the consumer market, and even higher in pro audio. So you may have a preamp that will hit maximum output when it gets a 0.7V input signal. That would be a problem with standard CD players, as they output a maximum of 2V, but the preamp has a volume control, the voltage divider we talked about before, that attenuates the incoming signal. This attenuator is often the very first thing in line after the input selector. Sometimes there will be a buffer circuit before the volume pot, but that is more common in pro gear than consumer equipment. Our 2 volt signal coming from the CD player may need to be attenuated before it ever hits the preamp circuits or it will overdrive them. A typical preamp will amplify the signal by 2 or 3X after it has passed the volume control. This is then passed on to the power amp. The power amp is going to behave much like the preamp, it has a certain amount of gain (30X is typical) and it will take a certain voltage at the input to drive the amp to its maximum power. How much voltage? Again, we may not know. You might find it in the amp's specs, or you might know because you designed or measured it. Either way, at some input voltage level, the amp will reach full power. Here is where we often find a difference in consumer power amps and pro audio power amps. Pro amps have a level adjust on the inputs, high end consumer power amps often do not. They may not need it in simple systems, but if they don't have an input level control they will apply full gain to everything coming in. The result? You have to turn down the preamp volume to keep the power amp from getting too loud. Turning down the preamp will attenuate the signal near the beginning point of the preamp circuits, leaving any and all noise from the following circuits to be fully amplified by the power amp. Because we have attenuated the music signal at the input of the preamp, it's now closer in voltage to the noise in the whole system downstream. We’ve destroyed our good S/N ratio. A good digital source like a CD player, DAC or high quality sound card will have a signal to noise ratio of 90dB or better. But that ratio is the maximum signal over noise. Music isn't recorded at the maximum level, its average level may be down 16, 18 or 22dB below peak, at least on well mastered CD's. But the noise floor of the device doesn't change, so effectively there is a "Music to Noise" ratio of only 74dB or less. In other words, the noise coming out of your speakers will be 74dB below the average music level. That's still very good and most of us can live with that and never hear it, but there is trouble brewing... Looking at the flow chart above, we see two systems. On top is our system with an overall gain of 90X. Below it is a system with a lower gain of 20X. Both start out with a musical signal of the same voltage -0.32 volts and both end with 2 watts at the speaker (4 volts). But along the signal path we see big differences in the signal voltage at corresponding points. The 90X gain system has to reduce the CD output by a large amount or it will be overdriving the power amp and speaker. The 20X system uses only moderate attenuation of the signal because the subsequent gain is much less. Now imagine that we pick up 1mV of noise right after the volume control. In the 90X system, that will reduce the music to noise ratio to 33dB. Not great. In the 20X system 1mV of noise at the same spot would reduce the ratio to 46dB, a 13dB noise advantage for the low gain system. Picking up 1mV of noise at a less sensitive spot like at the inputs of the power amp would result in a 42dB ratio for the 90X and 52dB for the 20X system, a 10dB difference. The above example is simplified for clarity. In reality noise would be picked up all along the signal path and be amplified to various degrees, but starting out with a higher signal voltage still helps at all points along the path. Things can get worse. What if you use a piece of pro gear like the DCX2496 crossover? It's meant for the higher signal levels of the pro world. To drive it to maximum we need 7 volts RMS! It will take lower levels, of course, but remember that those lower input levels are much closer to the DCX noise floor. Our CD player won't drive it high enough with its 2V RMS maximum output. Our preamp might just get us close. It has a gain of 3, so with the volume wide open we'll get 6V into the DCX. That's enough to keep it happy and keep the signal up out of the noise, but then what happens? The pro crossover now outputs 6 volts as well. That level is so hot it's going to drive our precious power amps into severe clipping. Six volts into our power amp with a gain of 30 means 180 volts out of the speaker terminals. Not going to happen unless it's a 4 kilowatt amp! Again, too much gain. If the power amp reaches its maximum output with a 1V input, we have no choice but to turn down the preamp. So we turn down the preamp until its output is 132mV as seen in the 90X system. If the crossover has an optimistically good S/N ratio of 95 dB, that still means 0.2mVof noise added to the signal, so we are at an S/N ratio of only 56dB coming out of the crossover. What to do? To fix this gain structure problem we put an attenuator on the inputs of the power amps to reduce that 6 volt signal to a usable level, or we build amps with low gain. Preferably both. Or we find a crossover that works in a range closer to the signals provided by the CD player and preamp. Obviously the more complex the system gets, the more we need to worry about gain structure. Using a simple system with only a CD player and integrated amp, we can usually just spin the Barry White disc, set the volume, and get down to business. But with a more complex system Barry may get lost in a fog of noise before you do. That's going to spoil the evening. https://www.diyaudio.com/forums/diyaudio-com-articles/186018-gain-structure.html

Mikin će da bude pederski. SILVER. Evo i mene u ovom klubu.

evo teksta When transistorized audio amplifiers appeared in the late 1950s, most of them mimicked traditional tube amplifier circuits. Transistor radios of the time invariably used push-pull transistors between transformers in their output stages. Very soon, however, new transistor amplifier circuits without the transformers were developed and transistor circuitry took on a new route. This was only natural, since the much lower voltages and higher currents offered new opportunities. Now, several decades later, Nelson Pass presents his PASS-SIT-1. I find this transistor very intriguing, since its electrical characteristics are very similar to those of power triodes. What if it also is able to deliver sonic characteristics similar to those of the power triode? Mr. Pass tried his PASS-SIT-1 in the classic, very simple, Nemesis circuit and presented some really encouraging results. He also suggested further exploration. Introduction SITs (static induction transistors) have been around for quite some time. The SIT technology appears to have been developed in the 1950s at Tohoku University, Japan, and SIT FETs have been used in some commercial amplifiers. The SIT is a depletion mode FET with drain characteristics similar to those of the triode. High input impedance, very low drain resistance, yet high transconductance and power capacity, invite to the construction of very simple power amplifiers not depending on negative feedback. Single-stage power amplifiers based on solid-state devices are rare, if not very rare. A few circuits have been published though, Mr. Pass' Zen circuit and subsequent variations possibly being among the most widespread and appreciated. None of these circuits uses an output transformer, and for obvious reasons. Output transformers are bulky, heavy, and expensive. Secondly, solid state devices operate at significantly lower voltages and higher currents than most vacuum tubes. Consequently, the low frequency range is likely to be compromised by low transformer primary winding inductance. Besides, transformers appear not to be overly well recognized by the wider audiophile community. In two previous Linear Audio articles, Mr. Pass briefly presents Jean Hiraga's one-transistor power amplifier design "Nemesis" [1], [2]. In the former article he explores the use of various MOSFET and JFET devices in this indeed very simple circuit. In the latter he introduces the use of the PASS-SIT-1 and presents some interesting findings. He also suggests further exploration using a larger output transformer with better frequency response than those he had available at the time. This article will further explore the use of the extraordinary PASS-SIT-1 device in the Nemesis circuit. The output transformers used are most kindly provided by Jan Didden. A few design considerations and an evaluation circuit will be presented, along with some measurements to verify its performance. To conclude the evaluation, and to hopefully contribute to the experience with simple amplifier circuits, the results of a few listening tests might be helpful. Why the SIT Nemesis? The traditional single-ended triode (SET) amplifier circuit, developed in the early 20th century and still in service, is well recognized by many for its ability to reproduce music with very pleasing subjective qualities. Generally, the SET amplifier merits have been subject to debate for many years, and it appears that subjective experience and objective performance are not always easy to match. It should be safe to assume that the last word on the matter has yet to be spoken. Jean Hiraga presents, in his two Nemesis articles [3], [4], the merits of simple single-ended triode circuits and, in particular, refers to the classic Western Electric WE 25B amplifier. Based on the very same philosophy, he develops the Nemesis circuit to feature a common-source mode power FET in place of the vacuum tube. The Nemesis amplifier is reported to present a subjectively very high sound quality with highly 'natural' properties. Even in mono, on a single speaker, the sound is reported to give the impression of depth both in front of and behind the speaker. In stereo, especially the piano is presented with uncommon acuity, and very life-like impressions of the felt hammers and the pedals. The stereo presentation also reveals the presence of the room. Let me remind: this was back in 1985. Figure 1: The Pass Labs PASS-SIT-1 The electrical characteristics of the PASS-SIT-1 (Figure 1) offer new opportunities. The current versus voltage properties are similar to those of the triode and include low drain resistance and high transconductance. I have designed SET amplifiers for many years and thus considers this development with extraordinary interest and curiosity. What if the PASS-SIT-1 can deliver listening experiences similar to those of the SET? The high voltages and low currents of the SET circuits are not very useful for driving loudspeaker voice coils. This is why an output transformer is almost universally used. Transistor circuits, on the other hand, are fully capable of driving loudspeakers without the output transformer. To keep this evaluation in line with the intentions of Messrs. Pass and Hiraga, however, and to hopefully contribute some experience in relation to other PASS-SIT-1 circuits (published elsewhere), the output transformer is retained. Design considerations This section describes in brief the attempted operational design and performance of the evaluation amplifier. The treatment is similar to most textbooks on SET design, although the more detailed design procedure is outside the scope of this article. The PASS-SIT-1 static operating point should be located in the most linear portion of its operating area. Ideally, the operating point should be chosen to give the highest output power possible, at the lowest distortion possible, with the highest efficiency possible, and all this without exceeding any of the maximum rate specifications. These are of course conflicting requirements, and, as always in this business, compromise is required. Single-ended triode amplifiers are capable of producing a very good perceived sound quality. One of the most important, if not the most important, components is the output transformer. Interfacing the output power device to the loudspeaker without degrading amplifier performance or sound quality is a tall order. Thus, the demands on the output transformer are high and the transformer should be selected carefully. For this evaluation, however, the transformer choice is already made; the Nemesis transformers most kindly provided by Mr. Didden. One sometimes overlooked fact with single-ended amplifiers, is that the power supply is an integrated part of the signal path. The current loop in the output power device and the transformer primary winding inevitably has its return path via the power supply. Thus, power supply properties are as important as those of the output power device and the transformer. Transistor data This is where we need the data sheets. Since the PASS-SIT-1 is not yet in production, and data sheets are not available, we have to find our own data. Figure 2 depicts the operating area, the ID vs. VDS diagram, for one of the individual sample transistors. Figure 2: ID vs. VDS for VGS between -7 and -10 V as measured in one of the individual samples It should be noted that these measurements are not taken under controlled conditions, such as constant temperature, rather at the bench top at reasonable thermal equilibrium on the heat sink. Thus, this diagram should not be considered representative for the PASS-SIT-1 transistor in general. As already pointed out in [2] this diagram appears very similar to the plate diagram of power triodes such as the 300B. If these properties, in a circuit similar to the SET circuit, can also produce a similar sound quality remains to be determined. Output transformer data The output transformers are shown in Figure 3. Their weight exceeds 6.6 kg each. The exact origin of the transformers is unknown to me, although it has been suggested they were wound by Tango. They are intended for use in single-ended power amplifier circuits, has a center-tapped primary winding and two secondary windings. Figure 3: The output transformer Many parameters affect transformer performance, the most obvious being losses (core losses and winding resistance) and frequency range determining factors (inductance, leakage inductance and winding capacitance). The low frequency range of an output transformer is primarily governed by primary winding inductance and the internal resistance of the output power device. The high frequency performance is governed mainly by the leakage inductance, but also (to a lesser degree) winding capacitance. Since the primary winding in a single-ended output circuit will carry direct current, the core will be pre-magnetized. To avoid core saturation by signal currents, a gap is introduced in the core. Unfortunately, this gap also reduces winding inductance. Some measured transformer data are listed in Table 1. Table 1: Some output transformer design data. Inductance was measured at 50 Hz. Circuit diagram Since the PASS-SIT-1 is a depletion mode device, its idle current should be controlled by a gate voltage which is negative with respect to the source. This voltage can be provided by source resistor voltage drop (self bias) or by a separate voltage supply (fixed bias). Both schemes will be evaluated and are shown in Figures 4a and 4b, respectively. Figure 4b: Amplifier circuit using self bias Figure 4b: Amplifier circuit using fixed bias The simplicity of the original Nemesis circuit is striking, and this circuit is even simpler. Besides the transistor and the transformer very few components are required. Alas, since this is a single-ended circuit, power supply quality is of major importance. Operating point The selection of a suitable operating point requires careful consideration. As mentioned above, we are facing conflicting requirements. The most important compromise would be the tradeoff between output power and distortion. Since the transformer is already provided, its primary load 64 ohms will be used in this evaluation. Although FETs in the TO243 case normally are good for higher power levels Mr. Pass recommends we keep PASS-SIT-1 dissipation below 40 watts (just like the 300B, as it happens). FETs are normally more linear in the higher drain current range, but since I didn't want to run one or more Amperes through the transformer primary winding I turned in the higher voltage, lower current direction. Measurements also confirm that the device under test appears more linear in the higher voltage region. Figure 5 shows a sample operating point and a static load line in the ID vs. VDS diagram. Figure 5: Sample operating point in the ID vs. VDS diagram and a static load line. Quiescent current is 600 mA at 60 V drain to source (circle). The static load impedance is 64 ohms. To investigate amplifier performance at a few different operating points, three operating points were selected and tried. Important transistor characteristics at these operating points are detailed in Table 2. Table 2: Operating point data and transistor characteristics. The very low internal drain resistance is of great interest, since it helps create an acceptable low frequency range in a transformer with somewhat limited primary inductance. The high voltage amplification factor is in itself almost a prerequisite for a one-stage power amplifier. Output power and distortion, self bias A test circuit was set up for electrical evaluation and listening tests. The circuit was wired point-to-point on a couple of bookshelf boards. This route is fast and easy, and allows for quick changes. Figure 6 shows harmonic distortion (THD) of a 1 kHz signal versus output power. Figure 6: THD of 1 kHz versus output power in the three different operating points Theoretically, the quiescent 500 mA will limit current swing to an output power of 8 watts. 600 mA and 700 mA will limit output power to 11 and 16 watts, respectively. These limitations are apparent in the diagram. Onset of clipping is asymmetrical and very gentle, and as with any good SET amp, second order THD thus generated is benign to our hearing. The diagram confirms that the PASS-SIT-1 appears more linear at higher VDS. As usual in SET design, however, the tradeoff between low THD and high output power is also quite obvious. Output power and distortion, fixed bias The above measurements were repeated with the test circuit using fixed bias. Compared to the auto-bias scheme there is only a very minor reduction in THD and no increase in output power. Choice of operating point Increasing VDS above 70 volts with a 64 ohm load will result in dissipation above 40 watts during positive signal half cycles. While this may be entirely acceptable (lower dissipation during negative half cycles will keep average dissipation slightly below 40 watts) I'd recommend against setting reliability at risk. If load line slope can be made smaller (lighter load) it will keep dissipation below 40 watts also when moving VDS to even higher voltages. This may induce other problems, however. I repeated the above measurements with a 128 ohm load and the outcome was immediate; maximum output power doubles and THD quite more than doubles - the cut off region is reached way too quickly. For further evaluation an operating point close to 60 volts, 600 mA and a 64 ohm primary load (4 ohm secondary windings) was chosen. This choice gives a 10 watt amplifier with promising data. Frequency response The frequency response of the SIT Nemesis is strongly governed by the output transformer. A transformer wound for currents in the Ampere range will use the corresponding wire gauges, effectively lowering the number of turns that can be practically fitted on the bobbin. This obviously limits winding inductance. As mentioned above, the low frequency range is primarily governed by the primary winding inductance. Despite the low inductance of this output transformer the resulting low frequency response is quite respectable. The frequency response at 100 mV input signal is shown in Figure 7. The low drain resistance of the PASS-SIT-1 is indeed very helpful in this case, but a transformer with some more turns of wire will further extend the low end. The high frequency response is very good thanks to the low number of winding sections and layers. Figure 7: Frequency response at 100 mV input. The - 3 dB points are 27.1 Hz and 60.6 kHz. Listening impressions The SIT Nemesis amplifier is listened to by myself and two friends, both experienced with SET amplifiers. Various music is played and special attention is given to the presentation of voices and instruments, the depth and spaciousness of the sound stage and, of course, to the musicality and ability to engage. During evaluation a pair of relatively large, high-sensitivity (96 dB/W/m), 3-way, loudspeakers are used. The first thing that really strikes is about resolution, contour and dynamics. We unanimously comment on the immediate attack, the liveliness of transients, and the extraordinary dynamics. The transients of string instruments such as the guitar, the cello, and the piano are presented with stunning realism. Energy distribution is excellent. If a singer in a band suddenly increases the strength of her voice, only her voice releases that energy, nothing else. We can clearly see the individual instruments. A voice and a piano are presented as just that, a voice and a piano - not a sum of the two. The bass and the kick-drum are physically separated also on the sound stage (provided they are separated on the recording, of course). The separation of voices and instruments is very convincing and easily conveys the impression of individual musicians performing together. Many of the recordings we listened to have many small sounds generated by the artists, the instruments, and the background; they are reproduced with surprising clarity. The concept of Downward Dynamic Range, as introduced by late Allen Wright, captures the requirement of an amplifier to allow us to hear low level sounds while louder ones are playing. The SIT Nemesis really does this and the sense of 'live' is fascinating. The sound stage is very three-dimensional. Its width easily extends outside the speakers with no tendency of splitting up. Depth is presented seemingly limitless. Interestingly, it's also easy to see instruments at different heights; a guitar at waist height and a trumpet at mouth height. Not all recordings contain this height information, I guess it depends on the production process. A contrabass is difficult to record due of its sheer size, but a recording done right presents the contrabass as a two-meter tall instrument. Airiness of the sound stage and (recorded) reverberation are impressive. The sound stage is perceived as 'big' and the presence of the venue very realistic. I know from previous experience that these properties are quite difficult to preserve in amplifier design, but the SIT Nemesis does a very good job here. There is no doubt during listening that the music reproduction is engaging. None of us is completely still during listening. Although a strictly subjective experience, it's easy to engage in the music to the extent that the setup actually "disappears". Concluding remarks The PASS-SIT-1 is nothing less than an extraordinary device. The triode-like characteristics, low internal resistance, high amplification factor, and distortion signature offered by the SIT Nemesis circuit makes it a very competent performer for anyone interested in a solid-state version of single-ended amplifier qualities. Despite the electrical similarities between the PASS-SIT-1 and the power triode, the evaluated circuit does not sound like a triode amplifier. There's a slight lack of body and warmth when compared to a serious SE 300B amplifier. The transient and dynamic abilities, on the other hand, appear to be more pronounced than with the SE 300B. Following the above listening impressions, however, it brings most of the SET qualities. I tend to believe that the output transformer, in combination with the distortion signature of the PASS-SIT-1, plays a vital role in achieving this. Much has been said about transformer performance in audio amplification, but its contribution to subjectively pleasing listening should not be underestimated. Nor does it sound like a modern (push-pull, high power, NFB) transistor amplifier. Its character appears to constitute a blend of single-ended triode qualities with qualities of modern solid-state amplifiers. Considering the classic circuit and its musical potentials, however, the SIT Nemesis performs more closely to the SET than any of the very few one-stage, solid-state, non-feedback amplifiers I have previously come across. No intermodulation, clipping, frequency range, or other distortion effects were detected during listening sessions. Unfortunately, the PASS-SIT-1 cannot yet be bought in the local store. But apart from this, the major concern will be the sourcing of a suitable output transformer. Its size, weight, and cost is likely to limit the number of future owners, but anyone lucky enough to listen to the SIT Nemesis will find it truly amazing! Acknowledgements I owe special debts to Nelson Pass for providing the PASS-SIT-1 transistors, Jan Didden for providing the output transformers, Anders Björklund and Eive Skoog for invaluable support and criticism in listening evaluations and discussions. References [1]  Nelson Pass; "The Arch Nemesis"; Linear Audio, Vol. 0, September 2010; pp. 20-30. [2]  Nelson Pass; "SIT Nemesis!"; Linear Audio, Vol. 1, September 2011; pp.141-148. [3]  Jean Hiraga; "L'amplificateur Némésis ou l'hommage au WE 25 B"; L'Audiophile, January 1985. [4]  Jean Hiraga; "L'amplificateur Némésis, 2. Montage et mise au point"; L'Audiophile, spring 1985.

Hakintoš amp

nema bez Vangelisa ništa (ovo je zadnji album rossetta)....kakav Hans Zimmer, kakve pm...

pouzdan švercer je majka u ovom hobiju. plus ko uzima redovno preko modushop.biz ima kupone za popust. . .

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kralj !

Cinemag.

Nema ni W11CY001... to je stari model. ima sličnih. ali je isto gatanje kad nemaš identične drajvere.

ali i od cene spadaju https://www.hificollective.co.uk/components/morel-mdt-33-dome-tweeter.html

Ali cone nije od ovog.... sa sajma... sa sajma je iz sonus fabera klona SEAS EXCEL W11CY001 rokneš morel mtd33 i spadaju gaće