making wood cases for 10000 amplifiers

2021/05/21

I would like to ask some questions. Use two smaller transformers and put bridge and caps on amplifier board. help please! Thanks. the rectifier I use other design , 50% more capsitor Or you can calculate the inductanceyourself with this formula: I used 14 AWG magnet wire in my build since its thick andeasyto find. preamps dynaco The power supply wires, speaker output wires, transformer, rectifier diodes, and AC mains wiresare a major source of magnetic fields. I also checked to make sure that sound from my smartphone gets into the amp. The unit looks very professional and the performance is fantastic. Your Tutorial is very nice especially to our novice like me. All the best So myminimum gain is: So Ill need to set thegain to at least 15.1 Vo/Viif I want 38.2Watts output power into 6 speakers with a 1 V input voltage. Thanks a lot for sharing this wonderful job. Is there are substitte that can be used? The Fcof this filter should be set well below the lowest radiobroadcast frequency in your area, and well above the 20 kHz upper limit of human hearing. Hi George do you have still the LM3886 PCB left available? I second the request for component details, such as the voltages of the caps that cant be read, if possible. If that works try setting up the Muting Circuit as designed in the original design, D1 = 16V zener diode, R5 = 10K resistor and C5 = 100uF 63V electrolytic. Diode Technology Silicon Junction Thanks. love the design and want to build the amplifier However, there are good quality audio grade electrolytics like theElna Silmic II or Nichicon KZ series which shouldnt adversely affect the sound quality. I noticed that in the schematic you have a 100nF cap (Csn). 15ppm 21k holco for balance bias current resistors and 15ppm holco everywhere else. At first, the sound stage seemed too narrow to me and some of the songs sounded somehow odd mostly metal tunes, in some the mids sounded somehow hollow. this is unexpected to me because i was expecting to have 32 volts to feed the amp I would not call this basics. Stan, just a few things to keep in mind. Thanks for your advice. I will be using the amp/speaker setup for near-field purposes (mostly music with some gaming). Nice project, good explanations, etc. What kind of transformer are you using btw? thanks, i forgot to add its not on the spec for some reason but the max forward voltage drop on the MURF860G is 1.5volt would this cause a problem With the knowledge and the tools available on this site I have built very modified boards. Cheers. As an electrical engineering student, I love getting the chance to truly understand the process of creating the design. Use low ESR bulk storage caps and minimize inductance lengths. 50V caps should handle that w/o problem. But the question is if the motors operation would generate enough electric fields to start generating noise in the amplifier? Crossed over at 1000 and 7000, thats about it This step is important because if the transformers voltage is too low, the output power of the amplifier will be less than what you expected. sa: The thermal resistance from the heat sink to the ambient air. Setting it too low might make your amplifier too quiet. Ive inserted a nylon screw and two nuts per pair of diodes so they cant touch while youre testing the system. Im a builder, not the editor of this article. Should I use 4 Ohms as my base for the power calculations? There is also a new build-buy forum Unfortunately itcan be hard to find a chassis that fits everything and looks nice too. If that does not fix it, try bypassing the Thiele network . Ive learned a lot from your detailed sections on build and theory. The screws are painted so do not make electrical contact. noticable difference from polyprop, (I know?the rf oscillation fiter makes a difference) hmmm, could be subjective, signal in paralleled 0.2uf silver mica, 1uf teflon and 4uf polystyrene This is my first and through the detailed explanation, Im well able to understand almost all of it. :( when I connect a power supply (tried 2 different ones), voltage slowly rises on both the positive and the negative rail on all power supplies on both channels with no signal through the speakers. http://www.learnabout-electronics.org/Downloads/lm1036-Tone%20control%20IC.pdf. I looked all over for it and cannot find it. V+(L) / GND L = 25v , V-(L)/GND L =-25v thanks for sharing. I have quite a bit of leftover CPU coolers and i have an idea to use those for building an amp based on 3886. Go o top of the article and find a link that says Note, editable PCB files are available here. Click on here. This opens OSHWLabs page. They are easily bent and the backs of the diodes will short if they touch together. Try grounding all return (-) leads from inputs and speaker outputs as a start. However, the bottom was always missing to the music. Thanks for the nice tutorial and beautiful built. I was wondering the same thing. The next step is finding atransformer voltage rating that candeliver this maximum supply voltage. thanks for sharing. Was an electrician in the Navy many moons ago so I am not afraid of this as a hobby and am fully safety oriented. Can you provide more details about your power supply circuit. BE SURE TO TAKE ALL NECESSARY SAFETY PRECAUTIONS, AND NEVER WORK ONA LIVE CIRCUIT!! What is the rating for the fuse at the power switch ? 2. Thanks for reading If you have any questions on this build, be sure to leave it in the comments below and well try to answer it. Ive already bought the pcb and the main electronics circuitry. I think this is an omission in the article. If its not there, then send us a message through our comment form and well make sure you get it: https://www.circuitbasics.com/contact-us/. Gary, optimally it should have been done before soldering the LM3886 onto the board (see the written guide above). Below Ill discuss the guidelines I used to design this PCB layout. This opens EASYEDA. Surprisingly, while searching for Negative Feedback of amps, I came here. First I improved the power supply then I added the zobel and thiele network; Weakest link: Supply large bulk storage caps. The 16 V Zener diode (D1) blocks current flowing out of pin 8 until the diodes breakdown voltage (16 V) has been reached. I like the way you treat ground connections. Right off the bat, I have a doubt/concern. Thank you very much for your detailed explanation, Im searching for the same. The idea is to keep the resistor leads as short as possible. Note: Editable PCB files areavailable for this projecthere. The MAX Input voltage for these particular regulators is 35V. The means to do so have been provided. Thanks. Use the diagram below as a guide for wiring the various parts together: Click on the image to view a larger version. My plan is to power this DC i.e. 1. Thanks in advance. The thermal resistance of the TF version plus thermal paste is about 2.2 C/ case to sink.The thermal resistance of the T version including mica insulator and paste is about 1.4C/W case to sink. Hi! Pete, yes this gainclone was a great project to build and the detailed theory was very instructive. However, as I mentioned before, the hum only exists when the input is left open (without any connection to it). I can enclose pictures with our communications, Hi Scott, Maximum Forward Voltage Drop 1.7V Oops! Im thankful of an Answer if I missunderstand something. I trimmedthe leads of the feedback resistor (Rf1) and soldered it directly to pins 9 and 3 to keep the loop area as small as possible: Inductance inhibits the flow of current and creates resonance witha capacitor thats in series. So my 18 Vtransformer needs to supply the amplifier with at least: The total power can now be used to find a minimum VA rating for your transformer. Start soldering the smallest components first, andwork yourway up to the larger components. There is no 1nF cap on the signal input lines that I can see in the actual build (unless I missed something during my builds of this). Did you mean X7R ceramic capacitors. Can you help please. Peak Reverse Recovery Time 60ns Pretty ironic. To filter this out, you can install a 1 nF capacitor at each input terminal, from the positive side to ground. 1 what would be the effect of using a 18-0-18 transformer (not 0-18, + 0-18) and share the common 0 as ground? Yuval. See page 38? Heres one of the PCBs: High currents flowing through the power supply and output traces will createmagnetic fieldsthat can generate currents in the feedback loop and input traces if theyre routed parallel to each other. using tiny values as mentioned in some forums, produces nothing noticeable , at least not to my ears. I have just finish the buikt Ina high pass filter, frequencies belowthe cutoff frequency will be attenuated (muted). Id like to see what you designed. From then on, I have been trying to improve its performance by making modifications. Ive got the PCB but when I started to put the components , I didnt find the holes for R4. The LM3886 needs a heat sink large enough to dissipate the heat it generates or it will quickly becomedamaged. Garry, R4 (also called Rfi) is soldered directly onto pins 3&9 on the LM3886 chip. Does anyone have a rough cost of building this amp?? Although its a bit more work, I prefer the T version for the 0.8 C/W increase over the other. Wow! There are many circuits on the net but again they do not explain any design aspects completely. Or did you order some other combination of heatsink and case ? What do you think of these changes? If these resistors vary much between the two channels, the gains will be different and one channel will be louder than the other. If you look up page 7 in the LM1036 document below, you will find a schematic for tone/bass/treble/volume controls for stereo amplifiers. Repeating the Fccalculation for a 330 F capacitor gives 0.48 Hz. 2 currents flowing in same direction will have cross interference due to proximity, ideally should be at 90 degrees or have sufficient space, 20.1uf silver mica for rf oscillation filter, sm is the best followed very closely by polystyrene. Second, Im trying to design the amp to go with a pair of Bose Interaudio 4000 speakers, which have a rating of 10-100W and 4-8 ohms. A470F capacitor will set the Fc of myfeedback loop filter to 4.9 times lower than the Fc of myinput filter. A question: If a separate supply is provided for each channel (with separate capacitors bank for each channel, or even possibly with two power transformers), how should grounding be organized? If possible please post on Power Supply, Speaker Protection, Soft Start and Pre-Amp. Its main function is to block any DC present in the audio source, while allowing AC (the audio signal) to pass.

https://www.tindie.com/products/hicoco/audio-input-selector-switch-relay-module-board/, thank you. Then measure theoveralldimensions to make sure the enclosure will fit everything. They will send you a pdf of the parts list and the power supply schematic + Gerber files. Its costly here in India. I also added the decoupling capacitor, Any other suggestions or tips are welcome. I signed up for the partslist but I am not recieving any partslists, can someone upload the partslist, thank you. I built a similar amplifier using the Hi-Fi 2000 Galaxy enclosure. Each one has its own electrically isolated ground plane on the bottom layer. Thanks for the feedback Pete! I wish I had had this guide years ago when I first tried building an LM3886 amp. Metal film resistors with a tolerance of 0.1% or less are ideal. Metal enclosures are the best type because they shield the amplifier from interference caused byfluorescent lights, radios,and cell phones. Heres how I installed everything inside mychassis. You could even add a DIV at the top of the web page with a .print-only class attribute, that is invisible when the page is viewed on a screen/tv, but would be included in the printed version. I will try bypassing the zener diode and check again.. does it means my IC is damaged even after diode jumping doesnt work?? So the question is, if and how much would adding fans to near the circuit affect sound quality? Check out SunFounder, the number one source for Raspberry Pi and Arduino starter kits and many more robotics and DIY electronics modules and accessories. I have this pcb made, and there is no R4?!!!! the pins on the chip are so close and also i dont see this in the video. In this post the author writes about Iphone as input signal source with 1 volt lvl. ;-).

I used solid core 22 AWG, which works well because it can be twisted into a tight coil. Its not fancy audiophile cable but the tight, twisted +&- pair has been used successfully by a lot of builders. Im still fumbling when trying my hand at using the EasyEDA software. 1) The Servo integrator cap (0.47uF) should have a large value resistor in parallel (~ 100 Meg), and not allowed to run open-loop in the real world. I want to use PCs intagrated Realtek sound card as signal source. The datasheet gives a value forTjmaxof 150C. C. Thanks for sharing this! Martin. Now that weve seenhow to calculate the component values, we can startdesigning the PCB layout and wiring scheme. https://www.diyaudio.com/forums/group-buys/330082-my_ref-fremen-edition-gb-13th-gb-6.html I am a total newb so I will take my time so I can fully understand what I am doing and why. I started with a 3 amp Fast Blo and it immediately blew on the first startup due to inrush currents of the 40,000 lytics. That wayCcstill filtersradio frequencies, but italso acts as a low pass filter that willset the upper limit of the amplifiers bandwidth. I found the post about LM3886 amplifier. Thank you for sharing this. From my understanding the 50pf should be C13 and the 680pf the C2?? If I build this my transformer will be one scraped out from an old Audiosource amp. thanks. I get no sound out of the amplifier and its something I cant figure out on my own. The result was good, but not yet satisfactory, Actually you can create a non polarized cap by putting to polarized back to back, i.e. Did I just miss a link or could you make them available. I learn a lot, specially about grounding. I think youve completed the most comprehensive and understandable post on this subject. Let it go. Those are also metalized polypropylene film capacitors, but with a smaller footprint and lower voltage ratings. I wasnt sure if the volume potentiometer should be in the signals input path or the amps output (does it matter?). Since they do not have a specific value, but instead a range, should I make the calculations using the higher values, as a worst case scenario or sorts? (This is where you find air flow holes across the entire top and bottom of enclosure.) Jackson, i cant really make it out but does the blocking side of you D1 have continuity with Pin 8 on the LM3886? Stan. Many many thnx to share this .. Im also going to look at CDE 15000uF caps in the PS to see how that changes the sound. It should read <10mV DC. Rb before Rin or Rin before Rb? Hanger the IC ?? Alessandro Raco on October 27, 2020 at 11:47 am Questions About the transformer: It is hard to resist from building this amp:-). If you just did the wiring of the amp as I just posted, you should only be getting 25V (+&-)to each amp board/channel. You could just put a stereo potentiometer (20-50K?) Also sent to earth ground are the SIG_GND from each board, and all the common (-) lines from the RCA inputs & speaker outputs. The resistor reduces this current and breaks the ground loop. Sorry to hear that Try checking your spam folder. Total power depends on the maximum supplyvoltage output bythe power supply, the amplifiers peak output voltage, and the speaker impedance. NASEOH, Chembur Maitrikunj Building Mumbai - 400071, Maharashtra, India, Carry Bags and Multiutility Bags & Pouches, Shop No. However , is it possible to go directly to EDA with info you posted for the amplifier board? To calculate the output poweryoull get froma particular transformers voltage rating, use this formula: Using the maximum supply voltage I calculated for an18 V transformer (29.6 V), the output power Ill get is: 38.2 Watts of output power is pretty close to my goal of40 Watts, so an 18 Vtransformer willwork fine. So the maximum thermal resistance (sa) of the heat sink for my amplifier with a Pdmaxof 29.6W is: So Ill need a heat sink rated at less than or equal to 2.1C/W to ensure it candissipate the maximum power produced by the LM3886. I would like a kit to same the time to order them. Very similar to Neurochrome design procedure, except Neurochrome uses Crest factor for RMS Power.