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Amp using TDA2030

Started by trialabc, July 23, 2010, 02:07:51 AM

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trialabc

Dear all,

   I was planning to use TDA2030 to build an amp which have separate frequency band amplification. In this way, I can get higher power output without using ICs like LM3886 together with large heat sink. I plan to use TD2040's datasheet's suggested circuit to give two output : one to woofer and one to tweeter. Or maybe I can cascade several TDA2040 to give higher power output.
   The problem is that this IC is for Hi-fi, and the suggested frequency band of interest is not suitable for a guitar amp. I would like to know what frequency band are of interest to guitar so that I can keep using that circuit.

Thanks in advance!


J M Fahey

Hi trialabc.
Don't worry too much about that, the frequency shaping and sound characteristics will come from the preamp.
The power amp will faithfully reproduce what you feed it.
As of the heatsinks, you will still need them, even if they end up being a flat sheet of aluminum (even the chassis itself )
No matter what the chip, it will dissipate around 40% of its rated power output as heat, which must go somewhere.
A tda2030 will dissipate less heat (and require a smaller/simpler heat sink) than a 3886, only because it provides 15W compared to 60.
Any special reason for biamping?
Good luck.

rowdy_riemer

Also, keep in mind that a proper guitar speaker will cut the higher frequencies appropriately. LM3886's are also Hi-Fi chips, but work great as guitar power amplification.

trialabc

#3
I choose to use TDA2030 simply because I can easily find it in stores.

I have used TDA2030 before and I know that it still require a heat sink, otherwise it will still burnt out even if I am just using two 9v batteries!!

I wanna bi-amping is because I still wanna try make a battery-powered amp which can sustain outdoor for at least 3~4 hours. Using this scheme, I hope the overall power could be large enough for outdoor activity. LM3886 seems so large that I am afraid that a lot of heat would be produced. It would be better if there is a way to cascade small power amp to produce large power output.
Well, to me, the heat produced by SS components is hardly bearable and I have not tried tube amp which one could fry eggs on them.

I thought I just need a power amp. Is a preamp necessary?

Thanks in advance!

rowdy_riemer

Don't misunderstand my point about the lm3886. I was just saying that lm3886 designs prove that using a hi-fi chip for a power amp is no problem. Of course, there are several tda2040 guitar amp designs that prove the same thing, so maybe mentioning the lm3886 was unnecessary all together. A tda2030 or tda2040 is fine.

You might run into a problem with running the amp from two 9v batteries. I could be wrong, but I bet that a 9V battery will not supply the current you need. If you want a battery-based +- 9V supply, consider using a couple of 12V motorcycle batteries (or any lead-acid batteries with a weight you consider acceptable). That will give you more than +-9V and will supply all the current you need.

And yes, you do need a preamp. There are many suitable preamp designs on this sight and elsewhere on the net. Also, if you get a decent guitar speaker, you do not need to worry about a woofer and a tweeter. If budget is an issue, I suggest one of the Jensen Mod speakers. While using HiFi power amp chips is plenty ok, using Hi Fi speakers for a guitar amp isn't a great idea (Except, I guess, for accoustic guitar amps).

bry melvin

There is at the moment another source of good budget guitar speakers.

Carvinguitars.com is currently selling their "british" speaker, which was their speaker for the SS SX series fro a long time for $29

Carivn on EBAY is selling the vintage 12 for about the same price. This is the belair (vintage tube) speaker

Both speakers have identical electrical specs. Not sure if there is any difference at all other than label.

They are rates at 70 watts

trialabc

Speaker is not my main concern at the moment. For preamp, I don't really know what it is.... So I don't know how to kick start.

Perhaps a little help? I think equalizer is not a preamp but a effect within preamp?

rowdy_riemer

The speaker might not be your main concern at the moment, but be sure not to dismiss speaker choice as being trivial. The main purpose of a preamp is to provide at least enough voltage gain for the signal to be useable by the power amp. And yes, preamps often incorporate eq's and other effects. Many preamps are made to be overdriven while others are made to be run clean. Many distortion pedals qualify as preamps. Amps with multiple channels basically have multiple preamps. With preamps, you're not to concerned with power gain. On the other hand, power amps provide significant current gain as well as a little voltage gain to produce power.

You should really read Teemuk's book to become familiar with different guitar amp concepts. His book really kicks lots of ass and it's free. Then, decide what kind of sound you want. Then choose a preamp design that will produce that sound. Letting us know what kind of sound you're looking for will help us recommend a preamp design.

trialabc

Thanks for the reply. Well, I just need to have clean sound. There is no need to have any effects.

Therefore, I thought I just need a power gain. As you have mentioned, preamp is used to tune the signal to the desired voltage signal level, I think for my case it is not really a big deal. Perhaps just use a CMOS N-channel will do. Hopefully I am not thinking too ideal.

Of course, I think having a equalizer in the preamp will be good. But for this experimental moment, I thought the most simplest preamp design will do.

I do think up of using a 12V lead acid battery. However, I will have to make up a charger before hand so that I can charge it up. Since power issue is not really quite a big deal and can be easily solved my money, it is not a critical concern for this moment.

J M Fahey

Please define what you want to do, as a 12V amp is very different from an AC powered one, unless 5 or 6 W are enough for you.
A TDA 2030 or better will give you even less than that, because they are optimized for higher voltages.
A TDA2003/LM383 will provide 5 or 6W into 4 ohms, 10W into 2 ohms.
To get 16/20W into 4 ohms you'll need a bridged TDA2005; for higher outputs you'll need a switching converter to rise those 12V up to what the circuit needs.

rowdy_riemer

That's why I had suggested two lead acid batteries, though bridged tda2005's might be better (and much lighter with just one battery).

trialabc

I miss out the important part about the power output upon the voltage given. After reading through the specification of TDA2030, I think it is likely that I will try out using two lead acid batteries. +- 12V with bridge configuration should give me 16W for a 8ohm speaker. Hope that it would be enough.

Now I understand why so many of us like the chip LM3886. Hopefully in the future I should give it a try.

Thanks guys for the reminder about the power supply. I really miss its importance.

J M Fahey

Well, a single TDA2005 and a single 12V7A gel battery will give you 16 very clean watts into 4 ohms, and will be much lighter and portable.
I've sold *many* of them in different configurations.
Similar commercial amps are the Peavey Solo and the Fender AmpCan.
Search and study them, they'll give you many good ideas.
Both are relatively simple, tried and true designs, and very popular.
And believe me, the difference between one and two batteries, is abismal, much more than what you imagine.
Remember you'll also carry your guitar, maybe a microphone stand, some pedals, an MP3 player for backing tracks, maybe a folding stool ... weight always adds up, never substracts.
Good luck.

trialabc

Oh.... how about the preamp part? What do I need? Which design I can use as reference if I just wanna have clean sound?

rowdy_riemer

I've got a jfet preamp design that works well for clean. But you may do just as well with a simple textbook op amp gain stage. You might check out this thread: http://www.ssguitar.com/index.php?topic=1426.0;wap2.