Most of them can be connected to power amps directly and will play beautifully on them. The voltages on the 7805 will be minus 18.6v and minus 25v. can i use +-90 v supply? R1 = 33Ω (5W) and R2 could have values between 10Ω and 3.9Ω (3W to 5W) depending on how much attenuation you want/need. I have tried other sources but they all assume a little more initial knowledge than I possess. This table is for headphones with power ratings ranging from 200mW (0.2W) to 500mW (0.5W). Again, thank you for taking your time to give your feedback, I truly appreciate it. resistors don’t cost that much. So.. yes and no depending on the circumstances. As can be seen there are no connectors specified. It varies greatly (100-150W) depending on your power supply. I wanted to give a look at the KiCad files but the link gives me “Error 404 This could lead to damage of the connected source. We want to filter frequencies that are higher than 20 kHz. It would be possible in theory if you use the rectangular signal before the filtering (the last inductor and capacitors), which can be used with a transformer, but I do not know after that what needs to be done. I’ll be using same design with appropriate component values. There’s V going into the HIN, -30V. The reason for that is that there is no standard and not everyone uses the same pinning. The table below is for the same types of headphones (200mW) but with a series resistor of 120Ω (3W rating). The input signal has its own connector and there are two spade terminals for ground: one for the power supply and one for the speaker. Real nice project and well documented. You are better of using either KiCad (Which is open-source - free and easy to learn) or start a new project with Eagle. It won’t reach 15V on 4 Ohm speakers though as it would be pumping out 2x56W. If you want to build your own amplifier, then this is for you! Hello, I have looked at the symmetric diagram, but I am not too sure why there is 2 set of inductors at the end of Vb and Vs port of IR2110, can anyone give me a helping hand, please:), I built this amplifier but it burns out the mosfets as soon as power is applied. An input signal of 4.6Vmax would be enough for the full output swing. Any higher than this and we will run into trouble because the comparator and the MOSFET driver are not the fastest devices. If you want to use other ICs, just be careful to check that the pins match or you will have to modify the PCB design. First of all, did you use my pcb or did you build in on a perfboard? BECAUSE WE HAVE ALREADY 100N PARALLEL TO POWER CAPS. When there is no audio input how does this circuit prevent the carrier PMW signal from entering the speaker. So I removed the MOSFETS and measure pulses at pins 1 and 7. A real filter, not an ideal one, does not have a perfect "brick-wall" transition from passband to stopband, so we want the triangle signal to have a frequency at least 10 times higher than 20KHz, which is the upper human hearing limit. Amplifiers that drive headphones need to be able to deliver enough voltage to drive the headphones but not too much to fry them. In this case it is safe to connect the – outputs together. Neither of the voltages will be stable as the minus 30v rail (line) is not stable. For the low-pass filter, you can use a 680nF capacitor to get as close as possible to the calculated value, but you can also use a 1µF capacitor without any trouble (I designed the PCB so that you can use two capacitors in parallel to mix and match). Your email address will not be published. Also you may not be able to turn up the volume and get the ‘tube sound’ Basics Of Class D Class D is an amplifier topology. Sounding loud already when the volpot is barely turned away from its minimum setting. I always go to Ian’s ‘Welcome’ post then on from there, or am I missing something? When unsure do NOT connect the ground (-) connections of these amplifiers together. Hi Cezar, i have a power supply of +100v 0 -100v would i be able to use this circuit if i use IRFP260 . For the sake of illustration below a table for a 680Ω (5W rated) series resistor. Hi, I´m using a Audio-Technica ATH-ADX 5000 on a JJ 322 SE Tube-Amp. Hey Cezar, I had a few questions about this project: I am trying to build it at home. One could easily make an attenuator with just 2 resistors which will work just as well. All the best! With this simple trick the output voltage of the amplifier is lowered by voltage division, similar to what is described above, BUT because 2 resistors are used we can lower the output resistance ‘seen’ by the headphone. checking that page should tell you what has been added or updated. The actual frequency of the triangle signal is much higher, on the order of hundreds of kHz, so that we can later extract our original signal. Can I use the speaker output terminals of a power amp to drive headphones ? The current limiter will kick in and the output stages will dissipate a lot of power (thus heat), I have a pair of Sennheiser HD558’s and I’m if I can hook them up to the amp I’m looking to buy. Depends on the frequency, but keep in mind that this is an amplifier designed to go well with frequencies under 20kHz. Is the voltage divider update still going to be written? The charging and discharging of the capacitor produces a nice triangle, which is not perfect (it rises and falls exponentially) but if the rise and fall times are equal, it works perfectly. You can buy one already made but I would suggest that you wind your own—this is a DIY project after all. Its model number is yamaha mcr-b142 with 15W output to 6 ohm load from each side. The 4-pin XLR is not used that much in audio but is gaining in popularity for balanced headphones as you need just one (professional quality) connector. Sorry this took so long. These amp build instructions from StewMac are very good: StewMac_15_Watt_Build_instructions WARNING : A tube amplifier chassis contains lethal high voltage even when unplugged --sometimes over 700 volts AC and 500 volts DC. When soldering wires onto these plugs you must realize what the pin numbering is on the solder side (mirrored from the plug side !). JVC – 150mV (1979) I am tempted to try adding some other values (higher) and check the sound then. This site uses Akismet to reduce spam. If the signal is 0v and the triangle wave oscillates between +/-5v a 200KHz square wave is outputted from the comparator. SO… the power tables below are thus made to ensure you don’t blow up your headphone and NOT to reach loud levels at the end of the volpot range. (resistor value) Most of the common headphones have these kind of power ratings, the smaller IEM’s may have power ratings of just a few mW so NONE of those should EVER be connected directly. For the comparator, you can use whichever component you want—it just needs to be fast. Beware that here too you will have to pick the right one for the job. This basically means that the input is encoded into the duty cycle of the rectangular pulses. There are many things that can be improved in this project. I will give this a try. I would suggest to operate with the LM5104 for the half bridge driver together with the STP16NF06 NMOS transistors to operate at 500 kHz. Probably balanced (negative ground not short circuit!). The amplifier stage is based on the Compact Hi-Fi Power Amplifier. To get a better volpot range a reduction of 20dB (10x attenuation) may possibly be better though. $399.96. Indeed, amp noise will go down in case of attenuator at output. HI IS IT NECESSARY TO HAVE 220N AT +TO G AND -TO G ??? Welcome to TubeDepot Javascript must be enabled to use this site. A typical 5 V linear regulator (such as the LM7805) will make the output voltage 5 V higher than the "ground" voltage. All you need to add is an enclosure with the proper input and output connectors, power … Am I correct? In case someone would use only an input attenuator to get the proper volume control range and connect headphones directly to speaker outputs one could still blow up the headphone when selecting another connected and not attenuated input for instance or might be hearing background noise from the amp with sensitive headphones. I am trying to build one myself and I have a few issues. I will now tell you some design choices and how the components work with each other. This is standardized and all XLR sockets in (pro) audio equipment is usually connected that way. 2x6W Stereo Amp – Hi-Fi spec’d stereo power amplifier based around TDA1521A; 3W Tube Power Amp – 6AK6 power amp with 6021 submini tube and LND150 stage; 5W Soldano SLO – 5 watt version of the famous Soldano amp, with EL91 output tubes; AX84 Firefly – self split 12AU7 amp with cascode boost With it you can drive high impedance headphones (300 Ohm) and most planars directly without the need to attenuate. The complete Bill of Materials can be found in the files below, where you can also find the PCB files both in PDF format and as KiCAD files. To prevent this, we need to insert some dead-time between the signals that drive the high and low side MOSFETs. Will this setup work as expected ? Good circuit and a good DIY project from you….... Hello, I have been working on this circuit for quite some time. The rest of the capacitors in the design also need to have an appropiate voltage rating. Most (balanced) high-end equipment often uses this plug. Another plug that is sometimes used for headphones is the 3-pin XLR (or mini XLR) or the 4-pin (mini) XLR. It plays quite loud already in that case. The output can be 25 ohm impendance, no problem, you would just (again) need to adjust the output filter accordingly. I hope it also gets you excited about building your own amplifier. You can try it but need to lower the volume when it distorts or when the amp get’s too hot. Had started on it a long time ago but other projects required more attention. So you have, look at the reference design he used from infereon, that is something you might wanna use. Your attenuators seem well designed and made and will certainly help when connecting modern DAC’s to old DIN and RCA inputs of vintage gears as the ‘line levels’ were much lower in those days. Don't worry about the +-5V, that is regulated from the +-30V power supply using the two Zenner diodes D1 and D2. Green cells show the headphone with that specific impedance can be connected directly to the speaker terminals and will give no risk of drivers being damaged by too much power, the orange cells show the upper range of the power ratings of the most common headphones. I have an EL34 tube amp, 8w. However, I do not think that having -25V going out of a 5V regulator is right. I would be the only one in this house trying this (no kids etc ). One thing about DIY audio is that it is a journey, not a … On the left column the specified power of an amplifier into 4Ω, one column to the right of it specified into 8Ω, next to it the output VOLTAGE that belongs to those powers and is the important thing here as the maximum voltage a headphone can handle depends on its impedance and power rating. the headphones range from 32 to 250 ohms. I'm guessing there is a whole lot of distortion, since there isn't any negative feedback to compensate for all the imperfections in the triangle wave and comparators and output stage; it should be fine for signals with no dynamic range like a siren, or a compressed speech over a bullhorn. The answer is that building a hand-wired tube amp is within the reach of most players. When the same signal is sent out balanced the ‘other’ amp that is now connected also will have a 1V output signal but in opposite phase. I was a bit hesitant for blowing up my valued tube amplifier which has balanced outputs. (1/R1) = (1/R2) = 1/Rout. Hello john12, really you can't get the voltage value at the HO of IR2110, unless you connect the output MOSFETS, remember its a floating ground at VS, HO voltage can be achieved when the Lower MOSFET turns on. On integrated amps: on one they also lacked bass, power was there (Denon PMA700V, 100wpc/8ohm). Below the most common usages for this plug. If me measure "+12V", on the multimeter it reads +12V. Yes, because some ortho-dynamic headphones need a lot of ‘power’ which can be delivered easily with power amplifiers. You have all the necessary information and files, but you do not need to follow them to the letter. But in order to fully understand how one works, I need to teach you all its nooks and crannies.Let's start with that first sentence. With a single ended amplifier the output voltage, for instance, would be 1V (just a random number used here for illustrative purposes only) and this would be 31mW in 32Ω. A: The balanced signal stays perfectly balanced If you want to know how much power your headphones can handle (NEVER connect earbuds and IEM’s to an amplifiers output !) You could build in a small switch (1A rated is enough) that lets you switch the headphone socket between the two end of the 6.8 Resistor. A couple of points though.. PA150), and then I use the DRV134 to bridge 2 of the PA150 PCB boards. Also could you link me the heatsink you used?, I opened the files in kicad and it said that a lot of the libraries you used are missing, is it possible to send me your kicad libraries in a zip? Somewhere between 120-140W. Just not with balanced outputs. Why power the input side of the IR2110 with -30 and -25 V? The there is the question do we really need deafening levels when the volpot is at maximum setting ? HiFi Class AB Tube Power Amplifier DIY Kit Push-pull Stereo Audio Amp 12W+12W. One way to achieve this is to use a specialized MOSFET driver from International Rectifier (Infineon), such as the IR2110S or IR2011S. Very interesting, thank you. http://audio.rightmark.org/products/rmaa.shtml. The amp is a mono guitar amp… When it has a Jack output (cannot see on the pics) it is likely mono. On the reguatlor you have got 18 volt on the input and 25 volt on the output. yeah I’m Dutch alright, although i haven’t been living in the Netherlands for quite some years. 0 volts. This whole area is excellent but is it readily ‘discoverable’ to newcomers? Hey Cezar, I had a few questions about this project: I am trying to build it at home. This last thing i mentioned would imo be quite important addition to your truly great article: alot of people will probably test this on “old / vintage” integrateds. The voltage difference between the 2 amp outputs (where the headphone is connected to) thus is 2Vrms. When the load decreases, the amplifier's output increases. Cezar's design is more of an entry level or for hobbyist. I am having the same issue, have burned two sets of MOSFET, and 12V Zenner, and so on...I am almost giving up on this one. Preferably the output resistance should remain below 120Ω although some headphones like the K701 for instance may sound a lot better from an amplifier with 330Ω or even 680Ω output resistance. You are right that they will not be stable in regards to 0V, they will, however, be stable in regards to the negative rail, which is how the IR2110 is referenced. Theory is one aspect and practice is another. Brilliant – thanks a million! I am using them nearfield so I don’t need them to be too loud. I look in this bit from time to time but finally decided to ask. 18 sold. These MOSFETs have low gate charge for faster switching and low RDS(on) for lower power consumption. Another approach is to use a comparator that has two outputs, such as the LT1016 from Linear Technology. please let me know and thanks a bunch for your help. At the time, he wrote: “I feel that it’s important to support AudioXpress, a magazine with which I have a 35 year history, and which also serves as a mainstay for the DIY community. Hi, all looks really great! There is only a pulse at pin 7 but nothing at pin 1. Buy a T106-2 toroid. At the positive peak of the sine wave, the duty cycle of the rectangular pulse is 100% whilst at the negative peak it is 0%. Hello. Hey Cezar, I had few more questions, I substituted 2n5401 with MPS751 bc it is unavailable in the market now. Yes, because high impedance (> 300Ω)  headphones can be connected directly to power amplifiers without damage Most balanced amps (by design) would have to be able to provide double the current as well though. Is it before the input of the amplifier? If that is the case (depends on the used headphone) simply calculate resistor values for max headphone power that is at least 10x lower than the max power rating. Hello, what modifications will be necessary. The power amp attenuator should never be connected to the headphone out connector of any amplifier and is intended for speaker terminals only.