simple bass, treble, volume for a chip amp

[darkczar]

I've started to make a stereo amplifier using a couple kits from Maplin that have the TDA2050 chips. (I've got an Airlink brand 18v, 160 Va transformer). I got one channel running briefly the other day. I was way excited, but also realized that I am someone who loves to twiddle the bass and treble knobs.

Can someone point me to some simple instructions for adding some eq controls? I bookmarked a description of adding a volume control - seems doable, but I'd love to know more about that too.

I will to be happy to end up with a working amplifier, on a budget. Yes, I like to fiddle with eq, but I'm not an audiophile, per se... I don't want to have to buy another transformer, and more stuff to build a pre-amp. Mostly I'm going to play my ipod through it, and maybe the audio from the TV.

thanks

[stratus46]

Originally Posted by darkczar

I've started to make a stereo amplifier using a couple kits from Maplin that have the TDA2050 chips. (I've got an Airlink brand 18v, 160 Va transformer). I got one channel running briefly the other day. I was way excited, but also realized that I am someone who loves to twiddle the bass and treble knobs.

Can someone point me to some simple instructions for adding some eq controls? I bookmarked a description of adding a volume control - seems doable, but I'd love to know more about that too.

I will to be happy to end up with a working amplifier, on a budget. Yes, I like to fiddle with eq, but I'm not an audiophile, per se... I don't want to have to buy another transformer, and more stuff to build a pre-amp. Mostly I'm going to play my ipod through it, and maybe the audio from the TV.

thanks

Go to Elliot Sound Products and check out projects 2 and 97. You will end up with an 'integrated' amplifier when you add those modules to your chip amp.

G²

[hd220]

Ditto for Elliot Sound Products. Good informative site with lots of good articles.

I made Rod's Project 06 Phono (RIAA) Preamp (which I haven't yet tested) and Project 97 Hi-Fi Preamp (with bass, treble, balance, volume and tone defeat) which is currently playing beautiful music on a pre-construction breadboard LM3886 gainclone assembly. I constructed both projects on perf-board using NE5532's. The site and projects are well recommended.

Unless you are capable of assembling his circuits on your own perf-board, I recommend purchasing his printed circuit boards.

Can't go wrong with this if you know what you are doing.

Regarding powering the pre-amp. I'm using (2 x) 44VCT transformers, so designed a very simple LM317 and LM337 dual regulated +/- 15VDC power supply for the pre-amp. Also assembled on perf-board. I could post this if you are interested.

Rod's site for the pre-amp is: Hi-Fi Preamplifier

Cheers and good luck.

[darkczar]

Cool - thanks. I was hoping I could just throw a couple potentiometers in there somewhere, but I see there's a little more to it. After I get the amplifier up and running, and let it break in for a few days, I'll see what it really sounds like, then maybe I'll start selling my kids' toys to raise money for the eq.

[asad_asad]

İf your project stereo pt 2316 / if quag pt2317 amazing.
not hifi but. digitaly controllled eq. very simple and avesome

[ChicagoJTW]

Doug Self's Small Signal book has about four different variations on powered tone controls, including Baxandall, which works very well. The OpAmp powered one is preferable, as the passive version sucks quite a few dB out of the signal. There are a couple of examples at the Headwize site, also. The circuits are quite easy to build on perf board.

[Tajmahallbal]

I did some research on these active filters and decided to build them. To my amazement I found that they sounded a lot beter than the passive ones. Its a lot of calculations and the mid range filter does require two biquads for a nice sharp cutt off. Ill try to find the documents that I used.