I got a tda7240 ic from a friend and Im planning to build an amp for my '59 lp..please give me a simple schematic to build using the tda7240..thanks!
Well, there is one in the datasheet. Just add a 10K pot to the input for a volume control.
http://www.datasheetcatalog.org/datasheets/105/378745_DS.pdf (http://www.datasheetcatalog.org/datasheets/105/378745_DS.pdf)
Then maybe throw something in front like a preamp? Maybe runoffgrooves tonemender?
Edit; I'm not familiar with this chip but I have seen a lot of TDA20X0 chips being used in this way.
cant read the file.,maybe post a pic?
Search here for "Tiny Giant"
tiny giant looks pretty interesting but can be quite a hassle for me... Any more suggestions? Im thinking of getting something like the tda2003..
Sometimes when yo have to work on a computer with no Acrobat Reader, you can google something like "online pdf viewer google" or thereabouts
does this ic requires a preamp before I can play my guitar or I can directly plug my guitar on?
Quote from: jogina111 on September 14, 2012, 09:35:37 PM
tiny giant looks pretty interesting but can be quite a hassle for me... Any more suggestions? Im thinking of getting something like the tda2003..
I'm confused about what it is you are wanting to do. Your initial post said that you got a TDA7240, so Keeb gave you the data sheet that has the schematic on it. It seems that you can't read pdf's. Next, Waltk recommended the Tiny Giant and you said it's a hassle for you. Then you said you want more suggestions and you're thinking about the TDA2003.
I don't mean to be rude, but it appears that you want others to do your research for you as you throw out moving targets. Asking for help is fine, and there are a lot of people here who are very eager to help, but you need to do some of your own legwork and not have people shooting ideas at you until something grabs your fancy.
I did an image search on "TDA2003 practice amp" and found lots of schematics with minimal parts. You might want to give that search a try and then ask the forumites any questions you have about it.
My comments here are not intended to insult you, but to help you move toward being better at researching your project and knowing how to get useful help here on the forum. :)
jogina111,
After reviewing some of your other posts it looks like it's difficult to get parts shipped at decent prices to where you live. This may be why your posts sometimes seem scattered as you look for projects you can build with what you have on hand.
I'll send you a parts kit for a musicpcb.com Tiny Giant amp (http://musicpcb.com/wp-content/uploads/2011/02/Tiny-Giant-Build-PDF-rev2.pdf) including the PCB, heat sinks, and offboard components. No charge to you.
You will need to supply:
TDA7240 IC (which you already have)
~17-20vdc power supply
Speaker
Enclosure
Knobs
Wire, solder, and other building supplies
If you're agreeable to this, send me a personal message with your address.
What a cool thing to do John :icon_cool:
is there any other way to power up the tiny giant amp except through a laptop power supply?
The short answer is yes. Any DC power supply that has an output of 15-32VDC and is rated at 4A or greater will work. However, the higher you go above 15V, the more heat is dissipated at the LM338T regulator. If you need to go lower than 15V, you'll need to do some tweeking as described below.
As PRR has pointed out on another thread, most of the TDA amps are made for automobile sound systems. Voltage in a car would typically be ~14V when the engine is running, ~12V with the engine off, and ~18V with a malfunctioning voltage regulator (a bad situation as your car battery fluid begins to boil!). So the TDA amp is designed to handle this voltage range without damage.
However, the Tiny Giant was designed to operate at 14V and has a variable voltage regulator (LM338T) that is fixed at ~14V with a 1k resistor. In order to work, the regulator needs an input voltage higher than the regulated output voltage. You could go with a lower supply voltage, but you'd need to adjust the output of the LM338T by changing the 1k resistor to another value. You could substitute a 1k trim pot for the 1k fixed resistor. If you do this, there are a few things to consider:
1) You still need a 4A supply.
2) The amp's output power (volume) will be reduced if you have <14V output at the LM338T or increased if you go higher. (See the chart below from the TDA7240 datasheet). Be careful not to fry other components if you adjust the LM338T higher than 14V.
3) You may have some bias voltage issues if you change the LM338T output voltage. Maybe this has been covered in the Tiny Giant thread, or else someone smarter than I can educate us.
(http://i1160.photobucket.com/albums/q485/jdansti/BB546628-B05B-4569-908E-446CD5BD9D8E-1365-000001D92F9C4CFE.jpg)
I went to some stores checking out for dc adaptors but they all have a 12v max..
I'll keep on looking tomorrow..
Watch the output current. You need 4A (4000 mA).
Two alternatives:
1) Use a 12VDC, > 4A adapter and modify the Tiny Giant regulator output.
2) If you can find an AC adapter or bare transformer with an output (secondary coil) between 16-35VAC, > 4A, I can help you convert it to DC fairly cheaply.
With 4 ohm load, 1.2 Amps is marginal, 2 Amps should be ample.
With 8 ohm load, 0.6 Amps is marginal, 1 Amps should be ample.
The 4 Amp number comes from the fact that laptop owners expect fast re-charge, and it takes that much power to fill a large laptop battery in an hour or so; and in some places old laptop power suplies are VERY cheap. It is more than the Tiny Giant would ever demand.
if paul is right, then I could get that 12v 800mA-900mA DC adaptor and modify the TG to make it run on 12volts. right?
Shop owner said when I asked him if they have a dc adaptor that can produce 14-18v 4A: "what?! Car batteries only have 12v and 24v means 2 batteries, your looking for something very complicated mister!"
Thanks Paul for clarifying the current requirement.
Could you please help us out with the voltage issue? The LM338T on the TG amp cannot provide regulated output greater than approximately Vi minus 1 to 2 volts. If jogina111 can only find a 12VDC power supply, and we change the adjustment resistor on the LM338T so that it regulates the output somewhere around 10-11V instead of 14V, would we have to change the value of any of the resistors on the TL072?
I don't think that musicpcb.com allows posting of their schematic, so here's the link:
http://musicpcb.com/wp-content/uploads/2011/02/Tiny-Giant-Build-PDF-rev2.pdf
No there's no changes needed to any of the resistors on the TL072. The way it is set up with the two 1Meg resistors connected to the non inverting input mean it is correctly biased to half of whatever the supply voltage is.
If you know the supply is 12 volts then you could omit the LM338T, this is there in part so you can use power supplies that would otherwise fry the 7240.
Quote from: slacker on September 17, 2012, 04:42:20 PM
No there's no changes needed to any of the resistors on the TL072. The way it is set up with the two 1Meg resistors connected to the non inverting input mean it is correctly biased to half of whatever the supply voltage is.
does that mean if I used 12volts with the lm338 stage on, i am only supplying it with 6 volts?
No. Biasing the audio signal is different to powering the chip. It puts your audio halfway between ground and the PSU voltage for the best possible headroom.
> help us out with the voltage issue?
"If you know the supply is 12 volts then you could omit the LM338T" -Ian M.
The power-amp uses a "12V" chip. Taylor found an inexpensive yet ample 17V power supply. The LM338 is an ADD-ON to drop 17V down to 12V. If Mark has found a nice 12V supply, there is NO need for the LM338, just take positive 12V to the power-amp chip. There is NO need for any other changes, since 12V is the way it is supposed to work.
And BTW "any" car-sound chip could be used instead. They are all much the same. Some detail differences in external parts.... follow the data-sheet (yes you usually need a PDF reader).
(http://circuits.datasheetdir.com/344/TDA7240A-pinout.jpg)
Car-sound chips need a stronger signal than comes out of guitar. You need another stage. You also want a volume control. Taylor's TL072 stage and volume control is a fine example.
> i am only supplying it with 6 volts?
No. The supply is zero V and 12V. The signal must stay between these voltages; actually, between about 2V and 10V. Taylor set the DC voltage on the signal pins to half of the supply, 6V, which is correct or optimal.
Thanks for the information and good news Slacker and Paul!
So looking at the LM338T pin out and Taylor's PCB, Mark will need to place a jumper between where the regulator's Vin and Vout pins would go on the PCB and omit the 120R and 1k resistors that would normally connect to the Vout and Adj. He could leave the 100nf capacitor on the Vin. Correct? Should he substitute a larger electrolytic for the 100nf on the Vin to help filter the power supply?
what would the effect if no tweaks, replacements, etc. are done, and just putting in that 12v 800mA powes supply directly on the TG? Will the regulator chip malfunction?
I mean even without skipping the regulator chip. What would happen if the regulator chip was supplied with a lower voltage than the voltage it supposed to regulate.? Would it still cut some volts or just let it pass?
I think the differential between Vin and Vout is around 1.25V, so 12V in would at most give you around 10.75V out. The value of the adjustment resistor was chosen to give 14V out when supplied with >15V in. If you decide to leave the regulator in, you might need to change the adjustment resistor to maximize the Vout given Vin~12V. Either way, I'll ship you all of the parts so you'll have an option.
BTW, the kit comes with a TDA7240, so I'll include it even though you already have one. I probably have all of the other parts in my stock to build another amp except for the LM338T, so I'll send you those too. You'll have enough stuff to build a second amp if you leave off the regulator and do your own PCB or perf. A suggestion: use the extras I send to build a second one and sell it. Use the proceeds to stock up on parts for more projects. Rinse and repeat. :)
Another suggestion: Once you get the ball rolling on selling a few pedals and reinvesting in parts, you might be able to supplement your household income. :) :)
man, I cant wait for the package to come...
Patience young Grasshoppa! I still need to receive it and re-ship it. :D
(http://i1160.photobucket.com/albums/q485/jdansti/C76E2D94-4C03-4391-8836-5A86015DB85E-3110-0000044BB3D76FBE_zps055d1cd9.jpg)
I found some wall warts but theyre all 12v 500mA..dang! :-) why do the TG need that much current?
Quote from: jogina111 on September 20, 2012, 04:13:30 AM
I found some wall warts but theyre all 12v 500mA..dang! :-) why do the TG need that much current?
I reckon that would work with an 8 ohm speaker
Back of a cigarette packet calculations...
12V rail ...at this voltage the most 'signal' you'll likely get across the load is 10pk to peak, which is 3.56V RMS (of course this assumes a sine wave).
For an 8 Ohm speaker 3.56/8 = 445mA max current required .....not much spare capacity there for a 500mA PSU, but hey, if you're pushed it'll likely work.
Have a search for CCTV PSUs...they're often 12V & normally are spec'ed for high-ish current delivery.
what does higher spare capacity means?
Quote from: jogina111 on September 20, 2012, 07:08:56 AM
what does higher spare capacity means?
The PSU you mentioned will supply up to 500mA, but my (rough) calculations shows that the amplifier circuit will draw about 450ma when operating at max (in fact a touch higher due to the quiescent current of the other components on the circuit) that means the circuit will be operating at very close to the maximum amount of current the PSU can supply ...ideally you'd want the PSU to have more current delivery capacity spare/in reserve, but like I say if you're pushed - and don't clip the amplifier (ie don't use this amp to distort the signal), it'll likely work.
does that mean I cant use effects pedals? Would the amp distort by itself? And would higher current prevent the amp from distorting or it will give it more headroom? Sorry for the ignorance, still a noob noob in electronics.
Quote from: jogina111 on September 20, 2012, 09:58:50 AM
does that mean I cant use effects pedals? Would the amp distort by itself? And would higher current prevent the amp from distorting or it will give it more headroom? Sorry for the ignorance, still a noob noob in electronics.
Yes you can use effect pedals (distortion etc)...what I meant was, if using an 8 Ohm speaker, 12V PSU & a 12V 500mA PSU, you are best not using the TDA IC to do the distortion by pushing it to the max (else this will be too much for your 500mA PSU)
Gurner-I was typing this at the same time that you posted. :)
Quote from: jogina111 on September 20, 2012, 09:58:50 AM
does that mean I cant use effects pedals? Would the amp distort by itself? And would higher current prevent the amp from distorting or it will give it more headroom? Sorry for the ignorance, still a noob noob in electronics.
Distortion in can be created in at least a couple of ways.
1) You can use a pedal that distorts the signal shape before it gets to the amp. In this case, you would normally still have a "normal" signal amplitude going into the amp and shouldn't cause any problems.
2). Amps can have "built in" distortion where the preamp overdrives the power amp. I haven't built a TG amp, but I suspect that like most amp designs, as you crank the volume closer to max, the preamp begins to push the power amp into distortion. The TDA amps are solid state and would not sound nice like a tube amp if overdriven. Furthemore, as Gurner said, the more you push the TDA amp (by cranking up the volume), the more current it will draw. He calculated that you would max out in normal conditions at 450mA. If you use a 500mA PS, you don't have much spare current capacity in your PS to handle the current if you cause the amp to draw more than 450mA. Keep in mind that the 450mA is an estimate. The 500mA capacity rating is also subject to error just like all components. If we assume that the PS current rating has an error of +/- 10%, then that tells us that we could max out somewhere between 450mA and 550mA. You could probably use the 500mA PS and avoid cranking up the volume near max. Ideally, you would use a PS that has more capacity than 500mA.
I looked at sending you a spare laptop PS that could do the job, but the shipping would be outrageous due to the weight. Member 3hree6ixty in Singapore offered to help you with parts here: http://www.diystompboxes.com/smfforum/index.php?topic=98540.msg867594;topicseen#new. You might ask him what it would cost to send you a used or new laptop PS.
Edit: Fixed hyperlink.
thanks for the explaination guys..john,yeah Iv'e pm'ed him for the psu and some lm386 and jfets. Maybe the shipping fee would be much cheaper since Philippines and Singapore is just a one way plane ride away.
> 12V rail ... 10V pk to peak, which is 3.56V RMS
The chip is two amplifiers in _bridge_ configuration. You get nearly 4V rms at each output, out-of-phase, so 8V rms across the speaker.
This is roughly 8 Watts in 8 ohms, 16 Watts in 4 ohms. (The chip is rated for 14.4V use, a hot car battery, and specs are taken with significant distortion, so it may say more on the data-sheet.)
> why do the TG need that much current?
It is a POWER amplifier, and significant power.
Your 12V 500mA (0.5A) supply only has 12V*0.5A= 6 Watts of DC power. With losses and sine-wave output, a linear audio amplifier can only deliver 3 or 4 Watts of undistorted output.
Quote from: PRR on September 20, 2012, 11:12:46 PM
> 12V rail ... 10V pk to peak, which is 3.56V RMS
The chip is two amplifiers in _bridge_ configuration. You get nearly 4V rms at each output, out-of-phase, so 8V rms across the speaker.
Good spot! I'd leaped into the maths overlooking that the TDA7240
is a BTL amp,Therefore the aforementioned 10V is actually peak signal voltage across the load, or 7.07V RMS ........8(ohms)/7.07 =
1132mA ( therefore a 500mA PSU @12V *will* be
totally insufficient - I'd be lookig to use a 12V 1.5A PSU at the least)
would this thing help? : www.extremecircuits.net/2009/08/ampere-or-current-booster-circuit.html?m=1
Quote from: jogina111 on September 21, 2012, 10:55:43 AM
would this thing help? : www.extremecircuits.net/2009/08/ampere-or-current-booster-circuit.html?m=1
No, that would not help. You'd use such a circuit if you had a voltage regulator and your load pulled more current than the
regulator could handle. Your actual power supply would still have to be able to supply the current.
Desktop PC power supplies will give you 12 volts at a few amps, if you can find an old one of those you could use that, It just takes a little work to make them work without the rest of the PC attached. They can be noisy, but for a chip designed to be used in cars this probably won't be a problem.
yeah, Im still looking for a psu...so far, 800mA is the highes I can find...
BTW- There is another option if you can find an AC to AC wall adapter that has 12-35VAC out and is rated at 2A or more. With a few diodes and capacitors, we can easily get you fixed up with the DC power you need. You'd need to put the extra components on a separate small board. It'd be a good learning experience about power supplies too.
maybe I could... I need to earn some money first so I could buy a bare transformer. I already got one here but its a 9 volt transformer..
Quote from: jogina111 on September 21, 2012, 10:19:45 PM
maybe I could... I need to earn some money first so I could buy a bare transformer. I already got one here but its a 9 volt transformer..
Or scavenge one from an old radio or something. Just be careful of the capacitors when you're cannibalizing. They can hold a charge for a long time after they were last powered up.
The reason I mentioned an AC to AC wall adapter is that you won't have to get near the mains power. You could build a plug-in power supply from the ground up, but you better know what you're doing to keep things safe!
oh! I found one it says:
HT 4098
2A/28VDC
1A/220VAC
COIL:12VDC
Could it be that this is a dc to ac transformer? And I dont even know which poles should go to the mains...
The "mains" refers to the voltage at the wall plugs in your country. I understand that you have 220VAC or 230VAC at 60HZ there in the Philippines.
The adapter you found takes 220VAC from the wall and puts out 12VDC (I think). I'm a little confused by the specs showing two different DC outputs, but only one AC input. Do you have a URL that you could post so I could look at it?
you mean a picture? I'll try to upload it tomorrow...
Quote from: jogina111 on September 22, 2012, 09:17:22 AM
you mean a picture? I'll try to upload it tomorrow...
I was hoping to get a URL (web address) for the item and look at a data sheet. I searched for HT 4098 and couldn't find anything.
I guess that you're looking at a model at a store. If you could get a photo of the specs on the package, insert sheet, or the unit, that might work. The more detailed, the better. The manufacturer's name would help too.
oh..i just found it..Not at a store. Its just a scrap.
maybe a transformer from cfl's will do, since a cfl can deliver 18 to 23 watts?
I don't think so. Too small.
I=P/V
I=23W/220V
I=0.1A or 100mA
Nice try. :)
Actually, I may be wrong in my last post. If we assume that the secondary is 12V (I have no idea what it really is), then it might handle close to 2A.
I'm just not able to intelligently help you with the CFl transformer idea given that I don't have the actual specs of the transformer in the CFl. I'm not going to guess due to the danger of being wrong and getting someone hurt or burning your home down! Maybe someone else knows.
Compact Fluorescent Lamps do not have anything like a conventional transformer.
I'm real nervous about *any* line-power work by an electrical novice. A mistake on a signal jack gives bad/no sound. A mistake in wall-wiring burns the house down, or stops your heart.
What about a car battery charger? 12V 2 Ampere is a common car-batt charger, is isolated, is polarity-marked. Car-batts do not need filtering, audio does, so you hang a 3,300 uFd 25V capacitor on the "12V DC" output and get around 16V DC no-load.
Great idea Paul!
Okay! I got one! 12volts, 2.1 Amp wallwart... I just hope its not noisy..
Good news! We can do things about noise. Is the output 12VAC or 12VDC?
it says ac-dc adaptor/charger input:220v-60Hz
output:12v 2.1Ah
Are there any symbols next to output labeling such as
______
---------- or ~
yes the--- under ____ is between 12v and 2.1A
and its 220v~60Hz..
Good, that's 12VDC. So now we just need to decide whether you keep the LM338T voltage regulator in the circuit or just use the raw 12V from the power supply. If you use the regulator, the circuit will have around 10V at the regulator output, which will reduce the amp's output volume. I like Paul's suggestion of leaving it out.
> output:12v 2.1Ah
"Ah" ?? The "h" generally implies "hour". A battery has a discharge time; a wall-supply works forever (no specific hours).
Yes, it could be a typo. The people who write manuals and labels often don't know electricity.
does wallwarts supply exactly 12 volts? Or it has some excess voltage? The TG schematic shows that its powered by 11.6 volts. Does that makes any difference using 12v?
Quote from: jogina111 on September 24, 2012, 10:45:22 AM
it says ac-dc adaptor/charger input:220v-60Hz
output:12v 2.1Ah
Does it really say 2.1A
h or just 2.1A?
Thanks for the catch, Paul.
shop says "its designed for batteries..thats a typo. That charger doesn't discharge."
> The TG schematic shows that its powered by 11.6 volts
Read the chip spec-sheet.
It is made for CARS. Car radio etc.
A car's electrical voltage may be 12.6V full battery engine off, 10V on a weak battery on a cold dark night, 13.6V-14.4V when engine is revved or cruised on a full battery. You expect the radio to play in all these cases.
(A car's voltage can also fall below 10V when cranking a cold engine, or be jump-started with 24V... you don't expect the radio to play right in these cases, but the chip must survive. The TDA series will shut-down at 18V; in shut-down they will survive 40V for a little while.)
It is "legal" to run the TDA7240 with up to 18V supply. However at 18V it can get VERY hot; and if you touch 18.1V for an instant it may shut-down. Taylor decided it did not need to work that hard, or that close to shut-down, with laptop supplies which may range from 16V to 20V. That's why he added-on the voltage regulator chip. It could be tuned for 10V out and be fairly loud, 14.4V to match the factory show-off specs (except 14.4V is too close to the 16V of some laptop supplies). He probably penciled "12V", then when he calculated standard low-cost resistor-values to set the regulator, it came out as 11.6V.
Without the regulator you may run 10V to 16V, although at the higher end of that range with lower-ohm speakers you may run into over-heating. Power output rises with voltage, but 10V to 16V is not a "big WOW!" kind of change.
Quote from: jogina111 on September 24, 2012, 08:06:57 PM
does wallwarts supply exactly 12 volts? Or it has some excess voltage?
Along with what Paul said, we don't know at this time whether your wallwart is regulated or unregulated. Most inexpensive models are unregulated, which means that the voltage
without a load could be the stated voltage or even a little higher. This will change once you apply a load. Depending on the current draw of the load, the voltage could drop below the stated voltage.
The purpose of the 338 regulator on the TG is to make sure a laptop PSU, which could put out as much as 20V, doesn't damage the TDA amp (or cause it to shut down due to heat). If I understand Paul correctly, the TG will not be in danger of overvoltage from your PSU rated at 12V, even without the 338 regulator. If it were me, I would bypass the 338 regulator if I were using a 12V PSU. One reason for doing this is that the PSU might not be able to deliver 12V to the input of the 338 regulator. If we assume that the PSU output drops to about 10V when powering the TG, you're going to lose as much as a couple more volts due to the operation of the 338 regulator. Now you've only got around 8V to power your TDA, which would not be optimal.
Please help me out, Paul, if I've misstated anything.
oh! I'm going to my granma next week and Im gonna get a laptop psu.. She got an old one that she isnt using anymore!
Good news! Grandma to the rescue! You'll be set once the parts come in. :)
The laptop psu was damaged. I brought it to the best repairman I know but it cant be done... I dont know why...so Im stucked with a 12v 3A wallwart...which components should I ommit or what should I add?
Quote from: jogina111 on October 19, 2012, 09:43:37 PM
The laptop psu was damaged. I brought it to the best repairman I know but it cant be done... I dont know why...so Im stucked with a 12v 3A wallwart...which components should I ommit or what should I add?
I'll look at it shortly and let you know what changes you'll need. Did the package arrive yet, or are you just preparing?
Here's what you'll need to do.
-Omit the LM338T.
-Install a wire jumper between the LM338T Vin and Vout pads as shown. Do not connect anything to the third ADJ pad.
-Omit the regulator's 1k resistor.
-Omit the regulator's 120R resistor.
-Supply +12VDC to the + pad.
(http://i1160.photobucket.com/albums/q485/jdansti/0AB0651D-D4B0-46A7-A5F8-BDE5DD767627-12822-00000C36B2650DE0.jpg)
thanks! Im just preparing the power supply and the enclosure... Theres no mails today because its weekend..
If you get a notice to go to the post office to pick up your package, you should not have to pay taxes on it. Tell them it is a gift (which it is) from someone you know in the USA who has the same hobby as you do. Be persistent! I've read horror stories about people being cheated by corrupt postal workers in the Philippines.
I hate the postal system!
I've been tracking the package with the TG kit and a bunch of other parts that I thought you could use to build other pedals. Your package was clearly addressed to your address in the Philippines on the Express Mail form, the Customs form, and on the package itself. Somehow, it was sent to Poland and it is sitting in a post office there waiting for you to pick it up. Grrrrr!!! >:(
I spoke with a person today that handles international shipping problems at the US Postal Service, and they have started an investigation. They are going to ask the Polish postal service to forward the package to the Philippines. It is possible that it could be sent back to the USPS, who would then try again to ship it to you.
Sorry for the extended delay. I'll stay on top of the investigation and keep you updated.
thanks John. Thats quite disappointing. I thought its on the way to the philippines. I hope it wouldnt get stucked to other places where it would stop over..
Yeah, it wasn't even supposed to go through Poland. Some one in Chicago must have thrown it in the wrong bin. The Philippines and Poland bins are probably right next to each other. It should have been routed east through California, not west. I'll stay on top of it.
no need. I've just recieved the package.... I'll open it later. Thanks a lot John...
What??? Either it's been in the Philippines for over a week, or someone in Poland forwarded it to you. Glad you got it! Hope you didn't have to pay anything to receive it.
actually, I did... 40 pesos or 0.90$..
actually, I did... 40 pesos or 0.90$..
That doesn't sound too bad if it were in the US, but hopefully it didn't affect your budget too much.
ok, I built the TG but it sounded like an arriving ferry. It hums like a giant.. What could be wrong, Im sure the components are in correct places.
It could be your power supply. As a test, take the largest electrolytic cap you have and just hold it in your fingers and put the + lead on the +12v pad and the (-)lead on the negative pad and see if that helps. If it does, I'll tell you where you can solder it permanently.
it didnt helped...
it didnt helped a lot. The humming is still too loud and .. The 2200uf cap eases it like 10%
Can you temporarily hook the power up to a 12V car battery and see if the hum goes away?
if a power supplx is noisy, could it be on the transformer or the filter? Im looking on building a power supply..
I'm not an expert on power supplies, but my guess is that you need more filtering.
The thing to watch out for, whether you add a filter to your current PSU, or you build one, is the TG could potentially draw 1-3 amps depending on the PSU voltage. You need to make sure your caps, resistors, and diodes in your filter are rated properly to avoid frying them.
To reiterate what several of us have said, building a PSU from scratch is potentially a deadly act, especially for noobs. Hopefully someone can give you some guidance on filtering your factory-built PSU. It might be as simple as building a beefed up Huminator that can handle the current draw of the TG.
I connected my guitar to the tg and the hum dissappeared and its really a good amp.. But when my guitar is removed, it hums loudly again...is that normal?
I believe that most amps hum when there isn't a complete circuit at the input (no instrument plugged in). I know that my amps do. This usually isn't a problem because there's no reason to crank up the amp when there's no instrument plugged in. ;)
Glad you got it going. Is it loud? :icon_eek: If someone has told you to turn it down, it should be loud enough. :D
yeah, its pretty loud...my brother and sister came shouting at me to turn it down...haha i thinks its done... I just need a better power supply and use some of the parts you sent me to build an overdrive channel..
Cool! On to the next project! 8)
just cant decide on what to build next..
just cant decide on what to build next..
How about an echo?
How about an echo?
;D
thats pretty complex...Im thinking of a booster, distortion, compressor and /or reverb.
thats pretty complex...Im thinking of a booster, distortion, compressor and /or reverb.
Quote from: Jdansti on October 25, 2012, 04:35:52 AM
I believe that most amps hum when there isn't a complete circuit at the input (no instrument plugged in). I know that my amps do. This usually isn't a problem because there's no reason to crank up the amp when there's no instrument plugged in. ;)
Glad you got it going. Is it loud? :icon_eek: If someone has told you to turn it down, it should be loud enough. :D
Most commerical amps use switching jacks to ground the input if there isn't any 1/4" plug inserted (though the silence doesn't apply if a cable is plugged in without a gutiar at the other end)