Indeed Hi Fi Labs 6N11 Tube Class A Headphone Amplifier

The review is a double review between the Indeed 6N11 Tube Class A Headphone Amplifier Versus the Qinpu Q1 + Indeed L-top 6N3 Buffer Amplifier combo. First off the Indeed Hi Fi Labs 6N11 Headphone amplifier is a Hybrid amplifier using a Chinese military grade class tube, if you see a J on any Chinese tube it means that this is military grade. The indeed amplifier is a combo of the 6N11 tube and the IRF63o Mosfet.

There are no op-amps in the chain. Regulation is accomplished by way of a LM317 and what immediately comes to mind is the replacement of this item with a higher grade equivalent from Linear Technologies (a possible note for upgrade in the future). The design is a cute design and what I would call an open board, with only two clear acrylic covers for the top and bottom. The workmanship of the boards is very good and the class of components used is also good employing nichicon caps and dale resistors.

Below is the circuit of the 6N11 tube amplifier (with permission from Indeed):

The power supply for the 6N11 tbe amplifier is a seperate switching supply supply with an output of 24 Volts rated at 2A and a ferrite choke on the output cable for removal of noise. During operation of the amplifier, the supply ran warm but was not hot. The power cord is detachable, so those who like to play around with power cords can do so, I did not change the power cord for the purpose of this evaluation since the power cord on the Qinpu Q1 is fixed and not detachable which is a pity! The mini audio pot appears to be either a alps or matsushita audio grade pot and I did not detect any imbalances to channels at various levels.

The circuit diagram resembles one drawn by Sijosae, first shown by this Korean on headwize/zerosoft some time ago.

The outlook of the Indeed 6N11 is quite cute and in some ways reminds me of the Earmax although the outlook is different, the size is somewhat similar. It would be nice to have a review of the Indeed versus the Earmax but this is not possible as I do not have the latter anymore. But from my memory, the Earmax would probably still win hands down.

Okay, here are the general manufacturer’s specs.:

In Put Power: DC24V 400mA
Input Sensitivity:50mV
Input Impedance: 100KOhm
Out-Put Impedance:16~600 Ohm
Dynamic range: 84.6dBA((300 ohm) 89.8dBA(33 ohm)
Gain:20dB
Frequency response:10Hz-60KHz +/- 0.25dB
Minimum THD: 0.016%(300 ohm) 0.45%(13 ohm)
Signal/Noise Ratio >90dB
RCA 2CH Input X1
6.3mm 2CH Output X1
Shipping Weight: 1kg
Transformers AC100V ~AC240V\50~60Hz 1.8A
Dimension:80mm (D) X 80mm (W) X 48mm (H)

500 Watt High Power MOSFET Amplifier

Amplifier circuit these days,We would like to musical you pro the MOSFET 500 watt amplifier is amplifier on my kW shares the same circuit and main PCB design. The barely real difference is the figure of output procedure to the device. We encompass using The IRFP448 design while the MOSFET amplifier 14 O / P procedure. These amplifiers can live used used for almost a few effort with the aim of requires in high performance, low apply din, distortion and brilliant sound quality.

Examples would be subwoofer amplifier be supposed to FOH stage Amplifiers, surround a inland waterway a very powerful sound amplifier, et cetera. The 500W MOSFET-amplifier has four tone stages of amplification. We are looking to start several stage appropriate list.

400Watt IRFP448 Power Amplifier Circuit Diagram. The bias and bumper stage in the role of the entitle suggests All Q ,C and ZD the Bias and buffer phases. Its major goal is to provide a firm MOSFET Gates and offset voltage and the voltage memory amplifier stage of the extraordinary Resource scope. pardon? would engage in devoid of the period response and the effect Slew rate is indeed very bad. The flip part of the coin is not the spare step Introduction of an bonus dominant pole trendy the amplifier opinion disk.

Power amp 500 Watt IRFP448 PCB and the electronic components layout

500 Watt High Power MOSFET Amplifier PCB Layout

Bridge Your Stereo Amplifier to Double Subwoofer Power Amp

A stereo power amplifier is limited in its output power by two main factors – the impedance of the load and the internal power supply voltage. To obtain more power, one has very limited choices – other than the purchase of a more powerful amp.

The load impedance can be lowered, but if the load happens to be a pair of standard loudspeakers this is not viable, since the impedance is set by the drivers themselves. Increasing the power supply voltage is generally a bad idea, since most commercial amps do not have a wide safety margin with component ratings, and will probably be destroyed if the voltage were to be raised sufficiently to obtain even 50% more power.

The bridging adapter shown can make an amplifier produce almost 4 times the power for the same impedance – but beware of the pitfalls.

The amplifier must be rated to drive a load impedance which is half that of the speakers to be connected
Although some forms of distortion will cancel, the primary form of amplifier non-linearity – crossover distortion – will be worse because …
Both amplifiers in bridge will cross the zero volt point at the same time
The impedance is lower, there is more current, so each amplifier’s contribution will be greater

Construction is not critical, and the adapter has unity gain for each output. Naturally, 1% metal film resistors should be used, and the choice of opamp is not too critical – the TL072 is perfectly acceptable in this configuration, and will have low noise and a wide bandwidth. Note that if interconnect leads are to be used from the adapter to the power amp, the 100 Ohm resistors shown must be placed in series with each output to prevent instability – this is important, as an oscillating adapter will inject an AC voltage of perhaps hundreds of kiloHertz into the amp’s input, with the very real possibility of destruction of the output transistors.

The power supply may be taken from the preamp supply (this should be +/-12V to +/-15V). The preamp output is connected to the adapter’s input, and for the sake of convention, connect the +OUT to the Left power amp’s input, and the -OUT to the Right amp’s input. For opamp pinouts, go to the link on the main projects page, or have a look at one of the other projects (such as the Audio Preamp – Project 02) where this information is to be found.

Naturally, for stereo two circuits are needed, as well as a second (preferably identical) stereo power amp. This arrangement is also very useful to convert an otherwise mediocre stereo power amp into a perfectly acceptable sub-woofer amplifier, having plenty of power (depending on the power of the original, of course).

Quality is not so much of an issue for a sub, since only the low frequencies are reproduced, and amplifier distortion is as nothing to the distortion generated by a loudspeaker at low frequencies.

100 Watts Simple HiFi Mosfet Amplifier 2SK1058 2SJ162

My friend Gianfranco was looking for a project amplifier powerful sound and warm. Fixed point had to be HEXFET. I did see some of the proposals with both bipolar and with HEXFET, with some front-end valve but the realization challenging and the relatively high cost of running without anything negative feedback or low feedback had focused on something more affordable. I did not agree. But the end had to have it and then he was master of his choice.

I submitted a pattern, the usual operational discrete controreazionato, in the form of kits FT15 Future Electronics . I told him I had to change at least the two electrolytic capacitors signal (one input and one on the counter-reaction) with two polypropylene decouple the power supply between the output transistors and the rest that precedes them and that after all, even after the upgrade, still did not like it. But the very affordable cost, power exuberant, the easy availability of your equipment and the provision of a kit ready they were right.

I did not want to participate in various stages of construction and declined invitations to the various test sessions, I went to him only finished work already premeditating the inevitable negative judgment.

He greeted me with a “Mo feel.” It was all lit, very hot. I always considered my friend Gianfranco as a holder of a good ear, I have much more confidence in his ear than they riponga in mine. I found it difficult to interpret his attitude somewhat sly. She put a CD in the drive and behold, to my surprise, ethereal but almost palpable in front of me I could hear an orchestra playing a qualified no better song unknown to me. Good reach to extremes, powerful punch, fine detail, good engraving. Never heard something so well at home (because the previous sound was entrusted to the LX139 – 60 Watt in darlington New Electronics). but the music on that cd was for me quite insignificant and anonymous.

To judge had to try something more exciting, I had no chance with me “Jacques Loussier Trio play Bach” and a compilation of Joan Baez. We put in the first CD and here in the room takes up a size so real that it almost could not walk around. Full focus of the sound stage, all the details in good evidence. Sound kind, gentle and dynamic impact significant, unexpected. Let Joan Baez, the incision is of good quality and the amplification chain works fine. That disappears hint of bitterness that characterizes my system (my final) to give place to the breath of the singer. A little ‘envy. Gianfranco had center. Nothing miraculous, of course, if you do not think about the fraction of the cost of the whole.

What can I say? Rather than put his tail between his legs, as I still maintain my point and find fault with the new creature of my friend, I said dryly: “Yes, it sounds very good, but suffered from a perfectionist like you I would have expected a realization container with a slim top two, but not a single unit. “” But it would not be possible, the cooling fin, hardware circuits, the toroidal transformer ……. “I answered him. “Want to see?” I say.
I already knew that I had to revise my old final change all the capacitors in the power supply and to make some improvements, then I would stay for a while ‘walk without wanting to consider dusting my very old Williamson aside for a slight lack the extreme high . The challenge happened at the right time to give me a shrug.

Said and done, the day after I was already in possession of two modulini FT15, I ordered two toroidal transformers New Electronics (mod. TT12.975) and I sent an email to Mauro AudioKit to order the container HiFi2000 slim line height 1 unit depth 280 mm, two signal capacitors (47 uF to 10 uF and counter-polypropylene Digital input for the polypropylene ERO), the electrolytic filter (16 x 4700uF 100V Nippon Chemicon) and the great silver plated OFC copper cable and Teflon coated to make the wiring.

Ten days later (we are in mid-July, unbearable heat) the end cap was already playing on my rack. So well that, in the certainty of not running out of music, I went immediately to the next order Mauro relating to materials needed to rebuild my final one.

I must say that perhaps my FT15 is a bit ‘better than that of my friend Gianfranco perhaps because the eye of the master fattens the horse forever, maybe because of good nutrition capacitors instead of commercial ones and because of the two bridges rectifier formed by diodes fast instead of a single integrated bridge, perhaps for the reason that it is supplied with 24 volts too. When Gianfranco saw it finished, judging from his expression, he must have felt a twinge of pain, the aesthetics of the container undoubtedly attractive slim tall one unit within which beats the heart of a 144 Watt (calculated) for the channel has very bad mood because he has to make (!) 100-Watt declared by the House. After listening carefully is insisting on a comparison between his and mine and is already making a shopping list for the transformation.
Let the mounting considerations.

I will not repeat what has already been reported in the literature concerning the Futura Electronic schematic and assembly of modulini. I assume that the installation has already been performed according to the instructions of the House, including the changes described in these notes. Just read the document that accompanies the kit or notes prepared by the House on the site also reported here in pdf (advise you to check the website for updates of the House).

Place that the container is the slim line of HiFi200 high units and a 280 mm deep and place that we purchased dissipation fins of a height not exceeding 40 mm and two cooling fans also of 40 mm side (if they are of two types: a type often over 10 mm looking reassuring, 4 blades and 1.2 Watts of power but it is too noisy, the other often about 5 mm blades thinner and more numerous, 0.8 watts, very quiet) proceed by measuring the dimensions of the two angular aluminum that are part of the kit, intended to function as heat conductors between the HEXFET end and the dissipation fins, and then to transport the heat that will be disposed by the fins: 40 mm side. Soon, just enter in the height of the container useful. So it is not possible to assemble the two module as required by the instructions of Future Electronics, the thickness of the printed circuit board, welding and fixing screws not allow us to close the lid for a good 5 mm.

But just change the mounting arrangement of modulini and re-enter in the fateful 40 mm. Here’s how it works:
- work the two aluminum angles flaring holes for attaching the two HEXFET, the flare should be practiced in the outer side of the L with depth equal to the screw head 3 MA countersunk head that there will be inserted; the head must be completely embedded in ‘aluminum without sticking,
- Slip the two screws 3 MA countersunk from below and above on the side we put two micas silpad (I also use insert above and below the silpad a thin layer of silicone grease), we place the two HEXFET, say a washer and self-locking nut on each of the two screws and we close permanently maintaining the two HEXFET in the correct position;
- The circuit board, we should have already installed (having cut all the surplus of the leads of the components with the exception of those of the lugs on the input, output and supply, we will need surpluses ), except for the two signal capacitors and the two HEXFET end, should now be able to slide in the two screws through the holes already present and rest on the nuts that secure the two HEXFET; the distance between the plate and the body of vetronite L of aluminum is, however, a bit ‘to leave little quiet ; unthread the printout and interpose a thickness of about 5 mm for each screw (not to use all the washers available I used a self-locking nut 4 MA flowing on the screw 3 MA without impanarsi).
- Slip the printed circuit on the two screws, above the two thicknesses and measure perform well where the fold upwards of the leads of the two HEXFET end;
- We ride the plate vetronite, perform the fold of the leads of the HEXFET, slip the plate again leading the six leads into the holes provided on the printed circuit board;
- We put a washer and nut on each of the two screws that protrude from the plate vetronite and we close gently (no need to tighten) not to loosen the tightness of the two HEXFET;
- Perform the welds of the six leads of HEXFET;
- Do not cut the excess of the leads, we come in handy later;
- Check now that no component exceeds the height of the top edge of the aluminum L, if everything was done as described control will be passed without problems.

components:
R1:2,2 Kohm
R2:47 Kohm
R3:47 Kohm
R4:3,9 Kohm
R5:3,9 Kohm
R6:1 Kohm
R7:33 Kohm
R8:12 Kohm 1 Watt
R9:100 ohm
R10:100 ohm
R11:47 ohm
R12:100 ohm
R13:220 ohm trimmer m.o. p.5
R14:100 ohm
R15:100 ohm
R16:100 ohm
R17:4,7 ohm 2 Watt
(I resistori sono da 1/4 watt 5%
salvo diversa indicazione)
C1:10 µF 50 V elettrolitico rad.
C2:47 pF ceramico
C3:47 µF 50 V elettrolitico rad.
C4:6,8 nF ceramico
C5:33 pF ceramico
C6:33 pF ceramico
C7:100 nF 100 V poliestere
C8:220 µF 50 V elettrolitico rad.
C9:100 nF multistrato
C10:220 µF 50 V elettrolitico rad.
C11:100 nF multistrato
D1:1N4002
T1:MPSA92
T2:MPSA92
T3:MPSA92
T4:MPSA42
T5:MPSA42
T6:2SK1058
T7:2SJ162

NAD 3020 VS NuForce

No doubt about it, Nuforce makes audiophile products that don’t conform to the old paradigms. Take a look at the Dia digital integrated amplifier. It’s downright tiny, accepts only digital sources like CD, DVD, or Blu-ray players, or an Apple TV, flat-screen TV, game, or cable box. How tiny is the Dia? Just 6 inches by 4.5 inches by 1 inch; and man that’s really small. It has one RCA coaxial and two Toslink optical digital inputs. The onboard digital-to analog converter accepts up to 192kHz/24-bit sources, and the analog switching stereo 24 watt per channel amplifier runs cool to the touch. I assumed the front panel’s 3.5 mm jack was for headphones, but no, it’s a subwoofer/line-level output. The $299 Dia weighs 1 pound. Nice!

We live in a time where most people take it on faith that new technology is always better than old tech. I don’t subscribe to that theory. To my ears good-sounding LPs sound better than most CDs but what about amplifiers? How do old amps compare with the latest gear? For this shootout I compared the Dia with a 32-year-old NAD 3020 integrated amp I bought on eBay last year for $66. The 3020 is 16 inches by 3.75 inches by 10 inches and is rated at 20 watts a channel. The little Dia delivers 24 watts per channel, so despite the gigantic size differential the two amps were fairly matched. I used a pair of Dynaudio Contour 1.1 speakers for all of my listening tests.

The Dia sounded really nice, sweet, and not at all “digital” with a broad range of music. The tonal balance was slightly warm, which I like, but my only concern about the sound was it lacked get up and go. The dynamics were laid back and a bit blah for my tastes. Switching over to the 3020, the sound was livelier, and more three-dimensional and therefore more realistic. The 3020′s bass definition was better, so I could hear more of the “pluck” on jazz recordings with acoustic basses. The Dia was softer and mellower, which wasn’t what I expected. Acoustic guitars sounded more like themselves over the 3020. The music engaged me more, so one tune led to the next. I respected what the Dia did–the little thing is so cute–but on an emotional basis, sorry, I’d rather spend time with the 3020.

Those impressions were based on listening to CDs, so I went ahead and tried some high-resolution 96 KHz/24-bit recordings, like Paul Simon’s recent “So Beautiful or So What” album. The Dia was decidedly brighter and more forward sounding; the 3020 was richer. I had an even stronger preference for the 3020 with high-resolution audio (that was decoded by my Oppo BDP-95 Blu-ray player). So in any case I’d rather listen to the NAD 3020, which also has a really nice built-in phono preamp. Yes, the 3020 is a lot bigger than the Dia. It runs hotter, doesn’t have a remote, and finding a working 3020 isn’t necessarily easy. But newer vintage all-analog amps from NAD, Rotel, Creek, and Onkyo won’t be too hard to find. Of course, they would be even bigger than the 3020; the Dia was designed for folks looking for something that doesn’t take up a lot of valuable shelf space.

TIP3055 TIP2955 75W Class AB Amplifier Circuit

75Watts amplifier does not claim “state of the art”, and in fact, the basic design is now more than 20 years. It is a simple amp to build, uses standard parts and is stable and reliable. The recommended design is a slight adaptation amp I originally designed many years ago, the red dog were built., most of them were small PA or instrument amplifier power, but words have found their way into home hi-fi. amplifier is capable of driving 4 ohms, but it begins, however, the limits of the transistor, even when used at 4 Ohms found very few errors.

Circuit. Note that no output short circuit protection, so that when the speakers are shorted while the amp is working (with signal), there is a very real danger that the transistors are destroyed.

TIP3055 TIP2955 75W Class AB Amplifier PCB Layout

This amp was built commercially, the savings were worth it – most of these amplifiers were installed in the box speaker have so little was probably not (unless the coil loudspeaker few times short-circuit). be used because of the cost of the equipment (at least), it does not cost much to repair amplifier, even if you manage to blow

Amplifier Specs
Sensitivity to 74 Watts of output power – just under 1V (1V is 75W)
Gain – 27 dB
Frequency range (-3dB) – 10Hz to 23kHz @ 1W
THD at 1 kHz – 0.05% (typical maximum)
Open loop gain – 125dB (without load), 80dB (8 ohms)
Input Impedance – 22k ohms
DC offset – less than 100 mV (<20 mV typical **)
Noise - <2 mV at the output (-80dB ref 50W unweighted)
Changes to the original design ...

Increase the value of the bootstrap capacitor 100uF
Stabilization reduces 100pF cap (220pF used)
Adding the output coil and the damping resistor (see news)
It is conceivable that ** number of transistors can not the value of 560 ohms is correct. If it is found, you may need "fine tuning" to maintain the resistance at least DC offset. If you really wanted, you could even use a pot (2k), and put DC offset minimum. It is best to wait until the temperature stabilizes at first, but it should not even change much.

TIP3055 TIP2955 75W Class AB Amplifier PCB with Component Assembly

Assembly set to show the image. 75W Class AB TIP3055-layout. Apart from these changes, the amplifier is almost original, with delivery + /-35V (open circuit voltage), as indicated, provide 70W into 8 ohms very satisfied. In their lives, most mods above are anyway, that because I’ve never been able to find the wiring diagram when I needed it, it was so often I went along! It is. An honest testimony of the amplifier resistor and a capacitor that various substitutions can be made, and it still works well

The numbers of noise and distortion are a bit pessimistic – there is so little distortion at 1V (or 20 for that matter) that my rate of deformation is struggling to measure readable. The oscilloscope output indicates that most of what I see is noise – the integration of the output (see my field “bogus) to eliminate noise reveals little of everything

Take The Best Speaker, Amplifier And Enclosure Audio Project

The three most important components of your boombox is your amplifier and speakers. The three of them are considered as the most important factors which can affect the performance of the speaker. In this step, I’m going to give advice in selecting the best type of speaker. An amplifier and speakers for your project and other options that you can use for your alternate If you are well-informed about the amplifier and speakers, you can skip this step.

Plan to collect and screen information:
Make sure to plan everything before you buy your wood, speakers, amplifiers and everything. Also place on where you place your limited boombox. Try to do some research before you buy anything. According to research, write doen your plans
Speakers:
Before buying a pair of speakers, you try to do some research on the different brands that are reliable and have been known to do to produce speakers with excellent quality, such as brands Dayton, Tangband, Focal, Seas, Fostex and crown (only in the Philippines). I chose the brand of the Crown, as he is known for cheap speakers with excellent sound quality, I had also made good experiences with it. Try speaker 80W audio power exceeds can buy. Not by the maximum power of the speaker fool, depending on the audio quality.

Also try speaker, find the achieve a wide range of frequency response. For woofers, frequency response 60Hz – 6kHz are good for a start, and a frequency response of 200Hz – 20kHz Speaker for broadband recommended. The more, the better! Mine has a two-way design has cross so that both speakers should reach in combination 45Hz – 20kHz (no frequency shift)

Note that the human ear can not hear 20Hz – 20kHz audio frequency, not to get upset when you can find speakers go above or below the audible frequencies, this would be a great lack of realism.

You can easily judge a speaker by its appearance, size, magnet, cone material, the size of the rubber surround, the wieght, size and beauty of the design.

The first time I took my speakers in the store, I easily GOTY happy to buy, when I discovered the larger size magnet and rubber surround design with a thick polypropylene cone, I told myself that I buy today. When I checked the specs and the price, I was very impressed, surpassed all my expectations.

Amplifier:
It is better to make your own amp I built an amplifier with TDA8569 chip amp (2x40W BTL) and a circuit connected TDA1524 EQ (bass, treble, balance and volume button). Chip power amplifiers are much more efficient than the MOSFET amplifier. You can choose to make one or buy one if you are experienced in the manufacture of amplifiers, I suggest this one, TDA1554 (2x22W), TDA7394 (2×30) and TDA8560 (2x40W) sounds great and also try TDA1524 chip equalizer. If you do not know about how to create circuits, you can try to find a car amplifier ready. Make is cheaper than buying a finished.

Accessories
If your amplifier and speakers are good, but your speakers is poorly designed, the sound quality will be significantly affected. There are two widely used speaker is inclined and the other is closed. Try of the tightening, the strut of the additional support structure is added to the inner edges of the speaker housing can be arranged in this way oscillations outside the chamber to a give best audio experience.

The sealed housing is ideal for small speakers, it is obvious payback of sound. Advantages is that this case can be used for small and compact housing and is a too soft and wet, while disadvantages is that this design requires a sealed 100% to be effective. The bass reflex enclosure is ideal for large housing (6.5 inch “) with large enclosures.

You can use a bass reflex enclosure and simply plug in a thick lather in the harbor, making it a closed, even though the air was still escaping.

300B Danji Tube Amplifier Good Sound Single-Ended

Today popular Liangsheng amplifier 300B tube amp, amplifier tubes 300B tube amp sound permeability, slender, analytical sound natural, beautiful, some people think that listening to addictive, so many fans want to have. 300B has been speculation the price is very expensive, 300B commodity machines of course, expensive. And commodity machines due to cost reasons, the next material had to compromise to consider the sense of hearing is not necessarily to reach a higher level, sometimes they would go to Mount buy back.

Therefore, the ability of those who own welder, homemade 300B tube amp, even with compare components fever, the cost can be reduced by more than one-third, and well-produced, but also can get decent playback.

300B push-pull amplifier circuit and single-ended output circuit, a push-pull output amplifier output power and sense of speed than the husband, dynamic. Single-ended output circuit due to work in the Group work state, pure tone, no crossover distortion, good linearity, output power is slightly smaller, but smooth and warm tone, listen to the human voice is more charming, more beautiful string.

300B is a direct thermal pull tube, more suitable for single-ended output power amplifier, so most of the popular 300B machine is a single-ended output amplifier. 300B tube amp, how to make a good sound single-ended output this article to talk about the experience in the production, for your reference.

300B direct thermal tri-polar power amplifier tube is generally believed that the directly heated triode making single-ended output machine hum (push-pull output stage output transformer primary two plate coil suppress hum can be obtained with low hum), but because the the 300B filament is improved, and other direct thermal transistor (eg, 2A3, etc.) of the filament structure is not the same, is a long filament, filament both connected to one end, an intermediate The head is the other end, so that the filament is short and thick, low sound when lit with AC, AC 300B tube amps are much lower than the 2A3 hum.

Amateur the conditions under welder, the signal-to-noise ratio can reach more than 85dB ear close to the speaker can identify a little hum.

TDA2009 BTL Amplifier with TL084 Low Noise Pre Op-Amp

Introduce a need to debug, high-fidelity, low-cost BTL power amplifier circuit final amplifier integrated circuit, and can be selected according to their own situation and a great convenience, versatility, production audio enthusiasts DIY audio.

The working principle of the device circuit shown in Figure 1 (click here to download the schematic). Here is given only a circuit diagram of a one of the channels , and another channel is exactly the same. Audio signal input from the A-side of the circuit, the amplification of the op amp IC1 (magnification by R1, R2 decision), all the way through IC2 inverting amplifier with a gain of 1; another pass through IC3, IC4 is for two inverting amplifier gain remains 1, and its essence is IC3 is, IC4 together constitute the positive-phase amplifier with a gain of 1, so the two equal and opposite phase to an audio signal obtained at the C-terminus of the B end of IC2 and IC4.

Two mutually inverted audio signal respectively through R9, C5 and R10, C6 applied to the dual audio power amplifier IC IC5 (TDA2009) and foot end of the two inputs is a noninverting input and the inverting input promote the speaker BL, respectively, from the side, so the the IC5 internal power amplifier IC5 ? feet and ? pin output. Component selection and commissioning of components Parts list below.

IC1-IC4 can use a quad op amp IC TL084 differential amplifier’s wide frequency response, low noise, high transient indicators. Power integrated amplifier in addition to using the TDA2009 can also choose other similar integrated circuits, no special requirements.

The resistors used in all low-noise, precision metal film resistors, which aims to reduce the pre-stage noise should make the B, C two points is equal to the amplitude of the signal, used in the pre-stage coupling capacitors precision tantalum capacitors.

Power transistor VT should be depending on the circuit current required and sufficient capacity reserves in order to obtain good transient characteristics and sufficient dynamic range.
Due to the versatility of the design of this circuit, therefore, any OTL, or OCL output dual power amplifier integrated circuit can be put with Poor amplifier B, C ends SPIDERS, thereby constituting the BTL amplifier. The reader interested, you can also insert the RC attenuation Tone control circuit will receive better.

TDA1521A Minimalism Amplifier Circuit with Fewer External Components

Hi-fi amplifier the IC TDA1521A production amplifier circuit with fewer external components, without debugging, one mounted on the ring characteristics. Suitable for home-made for the continuation of the power Walkman, or for the transformation of low-grade computer powered speakers.

TDA1521A nine-pin single in-line plastic packages with output power, two-channel gain difference, the switch machine speaker and impact sound and reliable thermal overload and short circuit protection. Of TDA1521A use both positive and negative power supply, can also be used a single power supply, circuit schematic see Figure 1 (a), (b) (Click here to download the schematic ). Dual power supply, eliminating the need for the two audio output capacitance, high bass sound quality is better.

Single power supply, the power supply filter capacitor should be as close as possible to the power terminal of the integrated circuit, circuit internal to avoid self-excited. Production must give Manifold mounted on the heat sink can be energized audition otherwise easily damaged Manifold. The cooling plate is not less than 200 × 100 × 2 mm.