New adventures in A level audio

[philpoole]

Hi all,

Until now, I haven't done anything with chipamps, always wanting to as it would be a quick and cost effective way into investigating bi amping and active filtering. Or so I had thought...

Then I remembered, back in 93/94, for my A-levels, I built a pseudo-surround sound amp. In those days, I was thoroughly of the opinion that quadrophonic sound would be the future. So I built a project that would take a stereo signal, and completely ruin it using rapid switching and bucket brigade delay between front and rear speakers. It was rubbish!
(That last paragraph was more for your amusement than anything).
Anyway, for the project, I built four tiny amplifiers based on the TDA2030. Quite handy really.
And tonight, I reversed engineered and wired up one of them.
I'm powering it with a +/-15v 78/915 regulated PSU, with about 16,000uF, and its driving one of my 6ohm Mission 751s quite well.

I'm very surprised, mostly that the circuit I made in my youth 14 years ago actually works (its basically the circuit in the datasheet- the real work in the coursework was the 'signal processing' - that was where the originality and flair was demonstrated ), but also that it sounds alright. I can't comment much further because I am only listening to the left channel of an MP3 out of my laptop.

So, my burning question to those far more experienced with chipamps. How good is the TDA2030? For low power setups (like for which the TDA2030 is applied) are there better chips to use?

I'm aware a favourite is the LM3886, and its bigger sibling (the part number escapes me), but they are more powerful chips, how do they compare in lower power systems?

I'll probably use this as a biamp setup anyway, but would I eventually be better off with a different chip?

Cheers,
Phil

PS: In the attached image, you can see the bundle of amp modules I knocked up, cut free from a rat's nest of bad wiring, rescued from the A-level project seen in the far top left of the image. Also, you can see the one module sat on the heatsink, pretty much in middle of the shot, the PSU in the top of the image, and the Alps pot acting as a passive pre amp.
PPS: My skills in electronics have improved VASTLY since then!

[philpoole]

Hopefully, this is it, it was a big file...

[pinkmouse]

Arghh, a Radiohead fan! Run away, run away!

[Nuuk]

I have no experience with the 2030 chip so it looks like you are just going to have to build a chip amp with one of the LM chips and find out if it is better or worse! It's a hard world!

[ratza]

For me TDA2030 sounds rubish. LM has a crisp and detailed sound while TDA sounds like a speaker mounted in a metallic bucket. The best thing at TDA is it's price (here's around 80 cents).

[philpoole]

I was listening to in Rainbows, but at the time of photography, I was listening to Bob Mould.
Maybe someone else has built one of these and is able to offer their opinion? It is a hard life, but I'm too busy developing a discrete IV converter at the moment to build an LM based chipamp at the moment.
For now, I think they'll fill a gap (somewhere between the pre amp and speakers ).

[tangmonster]

offtopic:

radiohead > everything

[Puffin]

I recently bought two boards for the TDA 2030 from RS for £1.50 each. The 2030's were about the same. I configured the board for a single 16v supply, but had big problems with DC offset sucking the cones in ! So put it to one side.

I have recently made a dual rail supply (you have to re-configure the board) and at the moment have only checked that it is all working. DC is down to about .22mv. Initial impressions are that it sounds O.K I will plumb it in to my main system over the next week and report back.

I am currently using an LM3886 amp with which I am very please (mind you it would sound better than anything else I have ever heard) as I built it P2P myself !

[philpoole]

Thanks puffin and ratza for your replies. You see, others are trying this.

This one is dual rail (my dc offset is actually a few mV, a bit more than yours maybe - I shall remeasure - but my load is 6 ohms, not sure if that will affect things).

Let me know how yours goes, and how it compares.

Ratza's not convinced, so I need to investigate further.

My current opinion is that I am surprised how well it sounds for a small chip, I'll reserve judgement until I've setup a sensible layout for it. I'll stick with passive attenuation for now as I'm only testing from a laptop or DAC.
However, as I knocked these up in my teens, I know there's lots that can be wrong with them, earthing layout for starters.

I'm probably going to at least get stereo going and compare to my modded Radford amp (pre A-levels - in fact as old as I am, but sounds lovely) with my LS3/5As and my DAC (rather than a rubbish laptop).
I may well knock up a 4 channel amp and bi amp my missions (albeit with the passive crossovers in place for now), to see what its like (sort of for fun, and because I can really).

Sort of on topic, when I was doing my A-levels I actually saw Radiohead play live in a small bar in Bristol, I think they had just released Creep as a single. It was one of the best gigs I've ever been to (and I did go to loads in a past life). I think the ticket cost £4.

[ratza]

Well I'm not convinced because the sound is highly affected by all the protections inside the chip even at moderate levels. I also have a simple power supply which is just around 16V (at 6A ), so I can't squeeze more than 5W without audible distortions. The comparison was made with a LM3886 at about 2 or 3W on mono music by using left channel in both TDA and LM amplifiers (one channel TDA, one channel LM, separate power supplies).

Anyway, the fact that I don't like it's sound shouldn't stop you to make one. Afterall, it's a personal opinion and what's ugly for me can be beautiful for someone else. For the money you pay for it, you simply cannot find something better than 2030.