Say, I thought I'd ask seeing as I got a little extra money to burn from christmas, anyone got any old/unused car amps they might want to sell to moi? My current sub amp is ever increasingly scaring me and my sub sound's like it's blown a voice coil or something (although I know if it were blown it wouldn't be working as good as it is). What do you got to say Nachomama?

Topic by Punkguyta   |  last reply

Amp to sub amp?

I wanna amp a sub but the only amp I have is a standerd amp how can I make this so audio out of the amp is really bassy part of the music  and with the plugs there 3 wire yellow white and just in there  mid the loos one ground yellow right and white left

Question by R.A.T.M   |  last reply

problem with amp....? Answered

There is power but no sound output,there are relays in side that click on iv have a prob and there is power to about half the board just not out put stage and i know that there is a speaker protection that is probable not letting power through for some unknown reason\r\nsansui au-x410r rated at 180 w   240v does any1 have a surgestions on problem or how to get hold of a service manuel

Question by andybuda   |  last reply

Electromagnet Amp

I need to build an amp circuit for an electromagnetic signal, but I don't know much about amp cicuitry. I am goin to amplify a 7800 Hz siganl from an mp3 player through a coil. I'm making one of those cart locker things. Any ideas?

Topic by gimmelotsarobots   |  last reply

Suggestions for amp? Answered

Hello all, As my question shows, I am looking for suggestions of amps I should use to drIve my speakers. There are 2 speakers RMS rated at 3.7W and 4ohm. Any suggestion is appreciated. Many thanks in advance EDIT: it would be best for the amp to use less than 9v so that it is still portable.  Please suggest 

Question by michalk1   |  last reply

Ruby amp 9v DIY guitar amp

The Ruby amp (by is quite simply the best 9v guitar amp on the planet. Ruby has many shades of sparkly clean all the way up to a great, natural overdrive. Because of its small size and low power consumption its perfect for building your own cigar box amp or mounting into a guitar pedal enclosure. If you have never done a diy electronics project then this is a great way to get started.  The kit comes all the parts you need  - pcb, resistors, caps, jacks, led, 9v battery snap and instruction sheet. Also I have added a couple of parts that you never seem to get included in commercial kits - a toggle switch and a dc jack (so you can run off a wallwart). Its fun, educational and at the end of the buid you have a real great sounding amp that can be used for busking, practicing in the park or for homerecording with a microphone. There are plenty of small output LM386 kits out there - only the Ruby is a real guitar amp as it has a jfet input buffer and a real gain control - oh and thers mods that can be done :) check it out at - heaps of videos and sound samples cheers

Topic by dogbox2012   |  last reply

Which is the better amp? Answered

Hey Guys, I have attached two schematics of two different amps. Can you tell me which is better like  better quality, louder etc,

Question by SA-DIY   |  last reply

10W audio amp?

Ok, so i want to get this one audio amp to work, but i can't seem to figure out how to wire it! the first picture is a schematic, and i have NO idea what the connections are, 1, 2, and 3 the second is a picture of the amplifier chip

Topic by Sandisk1duo   |  last reply

LM386 amp buzz? Answered

Should be an easy question :-) I built my first 386 based amp, and it works great, except for input volume control. Almost every schematic has 10K pot at input (connected to pin 3 on 386). Problem is when I turn pot all the way down I hear buzzing noise, especially if source is off. Also it doesn't cut source volume noticeably so I tried using 10M Pot, and it works except buzz is now super loud. So how would I control volume? 

Question by bratan   |  last reply

Power Amp Build?

I was wondering if there is anyway to turn a set of old computer speakers (the amp inside the computer speakers more particularly) into a power amp? I know it would be a pretty pathetic power amp but I was wondering how I could do it.

Topic by batboy61490   |  last reply

Specialized lm386 amp? Answered

I want to make a amplifier like this but i was wondering if i can make it without the 10k pot as i dont have one.

Question by Kante Tech   |  last reply

Help with OP amps Answered

I'm making an instructable about this circuit, it's a heartbeat detector, it's supposed to beep when a heartbeat is detected. Something weird is going on with the comparator, first of all, the input signal to the comparator seems to get "stuck" at the level of the comparator, like it is an invisible barrier that doesn't allows the signal to cross it easily, this seems to happen with and without the buzzer. Secondly, the comparator "rings", it doesn't displays a clean square signal when the threshold is reached, instead, at the end of the square pulse "ringing" appears. Removing the buzzer or speaker solves the ringing problem.  I tried replacing the buzzer by a 8 ohm speaker, but the problem persists. Then I tried changing the 1k resistor of the transistor by a 10k, but the problem is still the same. I don't know what could be causing this, bad design? A faulty chip? In the second picture it can be seen how the signal "bumps" an invisible barrier when reaches the comparator level, in the third the "ringing" can be seen, the fourth and last picture is how the (previous) comparator signal looks when the load is removed, the problem disappears. Thanks in advance,

Question by Victor805   |  last reply

Fisher amp problem?

I just got a fisher amp for my stereo system. I was playing music fairly loud when i saw a spark and the music stopped playing. I thought i blew my amp but it acts as if nothing happens. the lights light up with the song and all the buttons do what there supposed to but music wont play through any of the speakers. What happened and is there any way to fix this? p.s. i have a fisher integrated stereo amplifier if that helps.

Question by Thelonelysandwitch   |  last reply

OP-Amp Troubles

Hey everyone I was hoping someone here could help me with a problem in having. I've been tinkering with some op-amp circuits with the LM386N-1 namely the one I have pictured. I first assemble them on my prototyping station and they work well using the signal generator but when I connect them to a audio line from my computer nothing comes out the speaker I have tested the cable and speaker and they both work so I am at a loss as to what's not working. I would appreciate any help you guys can give me thanks

Topic by juggalo_assassin183   |  last reply

What amp to use???

I recently made an amplifier based on a TDA2004 chip i salvaged from a car radio but i wanted to get more power and so i planned on making a 20w or more version. Problem is, i don't know what chip to use. Can you guys help me? Criteria: 20w or more (just give me the max wattage the chip can carry) non-SMD chip, preferably on those chips that are on a multiwatt-like package min voltage lower than 6v (around 5v or less) and higher than 6v (obviously) load the chip can carry must be 4-8 ohms About the wattage, just give me the max wattage. I've been running the tda2004 for  some time now on 6v only and it's pretty loud, just not loud enough on open areas (rave party, anyone?) Anyways, just tell me the power amps you know of that'll satisfy the criteria or at least close to it. I need answers in 4 days or so, so please tell me ASAP. Thanks in advance!

Topic by beehard44 

How to increase amps?

I heard ampere could be increased by capacitor. If true then how to do it???

Question by simba1   |  last reply

Tube AND transistor amp? Answered

Question by arhodes18   |  last reply

Tube headphone amp

I want to build a tube headphone amp. Is it possible to make a smps (switch mode power suply) to power it? It would be like a mix between old and new technology!

Topic by dwj300   |  last reply

sony xplode amp

I have an car audio amp that i need the schematics for, the model is: XM-SD22X. was wondering if anyone can help. have been able to find owners manual and such. but not much help.

Topic by waybrane 

millamps vs amps? Answered

I have a mp3 player which uses a 1.5 volt/15 amp AA battery. I would like to use rechargeable battery, but find most are 1.2 volt and 2000 millamps. Would this damage my mp3 p

Question by waynf   |  last reply

Do Amps matter?!?

Ok, I need a charger for my motorolla two way radios. I have the dock, only need a DC power supply. on one of them it states "18Volts DC +/- 20%, 15.3 watts" .Lets say I get 18VDC 1amp power supply, that's 18W,it means it's an overkill? or 15V 2Amps? As I understand, usually amps don't matter, as the item draws as much as it needs, but since it is a charger.. Cheers for the teh help!

Question by zhgutas   |  last reply

Guitar Amp Static

Following up on my other thread with soldering, I managed to get my circuit for a distortion pedal all wired up.  I've got the clean end working, and nothing at all on the distorted end, but I'm not concerned about that just yet.  On the clean end, I get a really annoying buzzing sound, like when you turn the amp on with a cable plugged in with no guitar on the other end.  What would be cause of this?  Possibly outside interference since I haven't actually put this into an enclosure yet?  This is the schematic I followed.. and the sound from my amp is similar to this.. No, it's not the amp that's the problem because it works fine without the circuit.

Topic by MGZero   |  last reply

Op-Amp Help

Hi- So, I made the circuit below to make sound-reactive blinky LEDs for a halloween costume (the round thing on the left is a condenser mic). I think I just got lucky that it worked, because I'm no genius when it comes to op-amp usage or design. Now I want to adapt it to control something else that needs a slightly higher voltage than the LEDs. Basically, I'd like the output to swing as high as V+ when the mic input is "loud" (a relative and possibly adjustable level). I've messed around with various resistor values as well as adding or removing resistors in places it seemed like it would help (according to the LM741 datasheet). All to no avail. Anyone out there who might know what to do? Again, I want the mic input to cause the output to go as hight as V+ (9V in this case) when it's loud, and be more or less at 0V when it's "quiet." Thanks in advance, _mykle

Topic by deadbilly   |  last reply

Portable Amp using MC33171? Answered

Sir, I am really sorry to ask this but i don't know much about electronics but i want to make portable amp for speakers using MC33171 but I don't know which capacitors and resistors to connect to it. Please can you tell me which components i should use. I am gonna use DC current ,around 3.7 to 4.5 voltage. Thank you

Question by harryjone   |  last reply

this bloody amp is going to get bined if i cant sort it out?

The relay in side has switched on to protect the speaker and wont switch back so there must be a fault some where can`t find 1 though..... errrr  not getting any readings via a multimeter on circuit board and i need a servicing manual to know where to prob  any help...

Question by andybuda   |  last reply

Building 5.1 Audio Amp , don't know where to start out with .? Answered

I have 5 Satellite speakers which has a max input power of 60W , rated 30W , 6 ohms impedance , 160 - 20,000 Hz And a passive subwoofer , max input of 140W rated 70W , 8 ohms impedance , 65 - 1,500 Hz (My god , i just searched underneath my bed and i found  Two of those  old but useful JBL GT82 Subs ) Impedance :Single-4Ohm 8" Max power : 200W Rated power : 100W it's a 8" sub Now i'm thinking of , 2 subs (lol)

Question by Thereyouhaveit   |  last reply

i need help with this diagram. Answered

Just the diagram...

Question by xxInSAniACxx   |  last reply

i have got this thing off ebay just need a clue how to connect something to it? Answered

I have a small amp PCB off ebay it has the connectors down the side for the points to connects the parts to it but i just cant work out the connect or plug into the device what i have so far is R+          Speaker right R-           Speaker  right L+           Speaker left L-            Speaker left gnd        power +5v         power sw          switch gnd         switch lin gnd rin thanks for any help you can offer

Question by nonamesleft   |  last reply

d2822 headphone amp build

I have a d2822 op amp and i want to make a headphone pocket amp out of it but i dont know how to wire it. can anyone help?

Topic by heyytraviss   |  last reply

help with lm386 OP amp?

I'm running my guitar's output signal into an Lm386 op amp to light up some LED's, but the amp puts out a constant signal instead of just when I play. What can I do?

Question by spinynormann   |  last reply

Need Help With Amp Instilation

I recently aquired a Infinity 311a Amp and am wanting to install it on a 1994 Chevy Silverado 2500. i can get any wiring i will need i just dont know what to start with  

Topic by torquerat   |  last reply

DIY Ipod Amp Kits

I have all put together all the parts to make your own iPod Amp as seen in ReadyMade magazine issue 23 and Instructables.The kit includes:Velleman Amp kitSpeakerArmy Surplus Case1/8" Stereo JackWireLEDResistorNuts and Bolts to secure speakerPower Switch6AA Battery Holder w/ snap connectorThe price is $45 + $5 for shipping. You can follow the step by step instructions at:,-JoeYou must pay with paypal and I will only ship to the US, sorry I just end up losing money any other way.

Topic by joe   |  last reply

more powerful, portable amp

I was messing around with some op-amps, building variations of the CMoy amp, etc. But I became depressed quickly -- these ICs' data sheets say that at the safe maximum of 15 volts, they can only pump out around 1/4 watt of power on a single channel! Well, i have a full range driver that really needs more power to sound decent. I was wondering what the normal way of constructing an amp would be if I were looking for 5 to 10 watts of power. *edit*: i'm not looking to run this thing off of batteries... i'm sure at 10 watts, a couple of D cells would get drained rather quickly... I recently cracked open an old 4.1 computer sound system (by microlabs) and scrapped the 5 drivers (4 satellites and a 5 inch sub), two big 3700 uF caps, and two JRC4558D dual op-amp ICs from the amplifier. I read up on the JRC chip (actually, just the data sheet from the RC5448D, the texas instruments flavor, i guess the JRC is discontinued) and it seems that this thing only puts out a max of 200 mW per channel, and typically around 90 mW. Ok i know those speakers didn't get THAT loud without distortion, but i am CERTAIN it was more than 800 mW for those 4 satellites. I am a new computer engineering student, so i can understand the physics behind the electronics, but i am nowhere near the level to start reverse-engineering that amp board. So how did these speakers get driven so hard? THANKS for reading!!!!!

Topic by samurai1200   |  last reply

Power amp clipping problem?

I recently bought a Pyramid PTA150 1500 watt power amp, and its clipping led's always seem to be lit when my mixer is set to half volume or higher, even when the amp is unplugged. Could they be powered from the input voltage when it is high enough? Is it bad to push my amp when they are lit? and it has a high volume cooling fan so I dont think it will overheat when pushed.?

Question by macwhiz   |  last reply

Question about speakers and amps? Answered

Okay, so I want to build a set of two-way speakers. BUT, I'm still confused on this one part. Do I need an amp, or some kind of receiver for them to work? Or can I plug them straight into the device? Thanks for your help, sorry if this is a dumb question.

Question by Zem   |  last reply

How Op Amps work? Answered

I was wondering if anyone could explain how an op amp like the LM741 works. I don't mean I want to know what's going on inside it, but more along the lines of "how can it be wired up?" and "what could it be used for?"

Question by tylervitale   |  last reply

need help with lm386 amp? Answered

Hello , i making a little amp.This is the layout: I use a AC to DC adapter (output DC 9V 200mA) as the power source, 8ohm speaker( the sharp 939 speaker).My stratocaster or mp3 player as the input. I have some problem with it : 1.I want to add a volume control , but i don't know what volume control should i use (resistor value) and where to put it (before the cap 220uF or after the cap)? 2.I want to add a gain control(for distortion effect), but some people use capacitor, some people use resistor.What should i use ? 3.When i plug in my Guitar, the speaker starting to noise, but when i touch the guitar string,a metallic or  the GND line, the noise disappear.How can i slove this problem ?? 4.What the pin7(bypass) of the LM386 use for and how can i use it ?? Thank for advance! Sorry for my bad English. :(

Question by login721   |  last reply

op amp as comparator basics? Answered

Well... I'm making this battery charger cum level indicator, which should turn off the battery supply when its voltage drops below 10V. Im using an opamp as a comparator to do that. I have been scratching my head for 3 days but cant get this sorted. From what I have been experiencing for years, on an op amp if the potential on the in+ pin is higher than that on the in- pin, then the output pin goes high, else low. Right?  Now in this particular case (and the first time in my life) the ic gives 4.xx Volts on the output pin when in+ is higher than in- and 11.xx volts when in- is higher. Vcc is 12V.  Im bugged... I have attached the part of the Schematic that shows the IC and its connections. Please have a look. I haven't changed the IC yet, im doing that in a minute anyway. I'll mark this solved if the new IC does the trick. :)

Question by pro2xy   |  last reply

Little Gem Amp Problem

Hi all I am quite new to electronics but I am very interested in it. I have built a couple circuits before but nothing with an IC chip. So now I have decided to move onto slightly more complex projects,  and I found the Little Gem Guitar Amp: I have built it on a veroboard from these diagrams but I changed the layout slightly. Obviously everything is connected the same way I just moved the 100uF cap a little up. I have also added a 10Ohm resistor to the output and used headphones instead of the speaker. When I connect the 9V battery, without an audio source, I can hear is a soft buzz, quite a high frequency. The gain pot makes the noise louder and softer so I assume the LM386N-1 chip is fine. If I put my finger on the ground part of the 1/4 inch jack, the noise become much loader and lower frequency. The same thing happens if I connect an audio source. Is there an obvious cause for this problem that I don't know about? I have connected the jack to the board with shielded twin core wire. I have used the shield as ground and the core as signal. Is this correct? Any help would be appreciated, I would like to get this working.

Topic by geniass   |  last reply

50W amp 60W speakers? Answered

Ive got a 50w dual output Bluetooth only amp, I've also got Two 60w speakers would putting the max volume into the speakers damage them if played for a while. The speakers are 4" and slightly distort at max , could be from slight under power , the amp is rated at 8v to 24v and I am using a 19 v 3.16 amp laptop power supply Speakers 8ohm 60w  Amp dual output Bluetooth only 50w x2 Amp power 8v to 24v

Question by bonze77   |  last reply

Portable Guitar Amp Hiss

Hi all, I have built this design with a few modifications to accommodate for the parts that I already have. I used a stereo 1/4 inch stereo jack, but I connected the 2nd signal to the battery negative and the ground to the circuit ground. This way the circuit switches on when I plug in a guitar. I also used headphones only instead of a speaker, so I don't need a switch. Now the circuit works and it is amplifying the sound, except there is a very load hiss. I am assuming that a certain frequency in not being filtered out but this may not matter when using a medium quality speaker because of its low frequency range. However high quality earphones can play this sound. Is this correct? Does the headphone work for anyone with the hiss? Thanks in advance

Topic by geniass 

How to use an op-amp?

Hi, I've got an op-amp, the part number is OP07CP and I am trying to use it to amplify a voltage by around about 200 times. My set up is 6v going into a voltage divider with one resistor of 100ohm and a variable resistor of 10,000-50,000 ohm, so the output is 10mV-50mv. What I want to do is have the op-amp proportionally increase the voltage, so it goes to a voltage range of 1-5v, which an arduino can read. The power supply is  5v (from the arduino) and the powers both the voltage divider and the op-amp. For some reason, following the simple non-inverting op-amp configuration I just can't get it to work. Do I need a separate power source for the amp? I think it might have something to do with the fact that the amp's ground, input and negative are all just going to the arduino's ground. What can I do to fix it? If someone could help or even give me exact values and configurations of components that would be fantastic. I know that the amp and divider seem like a pointless complication if was just trying to measure the output of the variable resistor, but if you knew the greater extent of my project it would make more sense. Cheers

Question by makincoolstuff   |  last reply

Vacuum tube amp help

I just bought a lot of 125 vacuum tubes on ebay for 30 dollars including shipping (the seller didn't list what tubes were there, just said a crate) I got the following (if the same name is listed 2 times in a row, then I got 2): 10JA8 12AD6 12AE6 12AF6 12AU6 12AX4GTA 12BD6 12BE6 12BG6 12C5 12CN5 12CU6 12J8 12K7GT 12RS 12X4 17AX4GT 17BR3 18FW6 18FX6 18FY6 1B3GT 1G3GT 1G3GT 1S4 1S4 1S5 1T4 1U5 1U5 1X2B 21LR8 2BN4 2BN4A 2CW4 2CY5 32ET5 3S4 3S4 3V4 4BQ7A 4BZ6 4BZ7 4BZ7 50B5 5AT8 5AT8 5AT8 5AT8 5BR8 5T8 5T8 5T8 5T8 5U8 5U8 5U8 5U8 654A 6AB4 6AF4A 6AG5 6AG5 6AL5 6AL5 6AM8 6AQ5 6AQ5A 6AS8 6AT6A 6AU6A 6AU6A 6AU6A 6AV6 6AV6 6AX4GTB 6BA6 6BA6 6BA6 6BA6 6BA6 6BE6 6BE6 6BJ6 6BK7B 6BN4A 6BN4A 6BN6 6BQ7A 6BQ7A 6BQ7A 6BQ7A 6BQ7A 6BU8 6BZ7 6BZ7 6BZ7 6BZT 6CB6 6CB6A 6CF6 6CG8A 6CN7 6CY5 6CY7 6CY7 6CY7 6DQ6A 6DQ6B 6EA8 6FM7 6GN8 6H6GT 6J6A 6J6A 6J6A 6S4A 6SA7 6SJ7 6SK7GT 6U8 6U8A 8FQ7 9A8 I'm thinking about making a small amp (below 5 watts) for my ipod, which one of these would be best?

Topic by guyfrom7up   |  last reply

Equalizer for phono input to amp

Circuit for converting an MP3 player output to input for a phono input on an amp.

Topic by knorrisster   |  last reply

Making a temporary amp with mosfet?

I don't know how to make a amp for my 4ohm 125watt subwoofer? I got heatsink and some Toshiba mosfets.

Question by ShaneR66 

how to make a guitar amp?

Question by originalimiubu   |  last reply

Power supply amp measurement?

My power supply says it can supply 12 Volts @ 10 amps.  It used to power 2 linear actuators drawing max 4.6 amps each, but no longer does. It still supplies 12V measured by multimeter. Is there an easy way to figure out how many amps it now supplies?

Question by thisisted   |  last reply

Whats Better Volts or Amps? Answered

I know the two are completely different, just so you guys don't leave any I'm an idiot comments.  I was wondering if anyone knew what makes a better electromagnet for my coil gun.  Should I look for higher amps or just as many volts as I can find

Question by   |  last reply