digital reverb or delay

[ingrast]

Originally posted by davesaudio
did this project die a quiet death?

It is sleeping for a while for I am working on an important amplifier topology developement which may eventually lead to publication on one hand, and comercial products on the other.

It was shortly after my last post here I came across the idea, made the initial analysis and filed for a patent.

I hope to be able to resume this as soon as practical, apologies to those who had expectations on a quick result.

Rodolfo

[davesaudio]

EPE magazine had a project called the "polywotsit", which used a PIC with ADC built in and an external DAC. Several effects are switch-selectable, all implemented in firmware. It uses 8bit converters, not state-of-the-art but probably equivalent to a bucket brigade chip. You might get some ideas from it, link is here

EPE have published "cybervox" project in july 2005.
Reverb via PIC and external DAC (sound familiar?), though they have upgraded to an 18F252.

amazing how simple the 18F pic code has become...

[-_nando-_]

It's time to this topic become alive again !

[-_nando-_]

Originally posted by ingrast



It is sleeping for a while for I am working on an important amplifier topology developement which may eventually lead to publication on one hand, and comercial products on the other.

It was shortly after my last post here I came across the idea, made the initial analysis and filed for a patent.

I hope to be able to resume this as soon as practical, apologies to those who had expectations on a quick result.

Rodolfo

Ingrast ! Did it work ?



I'm very curious !

You have already done all this, so let's get a conclusion


Thanks !

[ingrast]

Thanks for your interest _nando_.

Yes, the project is going on. Attached are some shots, and I will be posting more soon.

At the moment I have 2 boxes working and have accumulated about 50 hs. of listening time with different material from classics to rock, and am quite satisfied. I will be presenting them for evaluation to knowledgeable people to get impressions and critique.

In the next post are the measurement results.

Rodolfo

[ingrast]

These are measurements performed on the prototype amplifier.

Due to differences among the audio nboard right and left channels, it seems amplifier output has actually less distortion than the input signal !. Of course this is not so, but underscores the fact the amplifier contribution is about an order of magnitude lower than the measurement baseline.

Rodolfo

[neazoi]

Are these TDA1097 chips available from you? I cannot find them in the local stores or ebay

In reply to:

I think you have to buy a reprint.. but no matter, I have the article and can scan it. The software (maybe should be firmware) can be downloaded free from the site, as you have seen. The PCBs (1 analogue & 1 digital) are available for only £7.61 for the pair according to the magazine with the article.

If anyone is interested, send me an e-mail from the link on my user info. There is no way to include attachments there, but it will generate a normal e-mail that will accept attachments in a reply. It's fairly large, 8 sides of A4, and includes PCB patterns. I'll see if I can send it uncompressed.

I have two TDA1097, made by Mullard, 1536 stage BBD chips that I never got round to using. They are pre-production prototypes. I have the datasheet too, and I have two TDA1022. I experimented with the latter but found them noisy, almost certainly due to the spaghetti layout I used. My layouts are better now. If you want to experiment with them, send your address in the e-mail. I have no time for it now.