TDA7297 - What are you looking to see, for DIY?

radolang · « **Reply #40 on:** 29 Jan 2015, 03:07 pm »

Quote from: Salis Audio on 29 Jan 2015, 01:09 am

Would you believe another amp is on the table?

You mean you found a better sounding chip amp, Salis?

So I assume there is no difference between TYPE A and TYPE B approach I mentioned above, or is there?

Folsom · « **Reply #41 on:** 29 Jan 2015, 03:32 pm »

Type B maybe. I wouldn't worry, just go with what you like afterward without switch.

The next amp I'm looking at will have more power, so less efficient speakers will match better. It'll be different, and more complicated.

happyrabbit · « **Reply #42 on:** 30 Jan 2015, 09:51 pm »

Board Looks Great ! Looking forward to seeing it populated

Dwight

Folsom · « **Reply #43 on:** 31 Jan 2015, 12:31 am »

Within a day or two, prototype boards for demo are in. They don't have gold immersion but the kits and PCB will.

radolang · « **Reply #44 on:** 31 Jan 2015, 07:46 am »

Quote from: mboxler on 28 Jan 2015, 02:37 am

So...there will be two input caps per amp. One amp (the one driving the K-22-E woofer) will have no volume control, as it's rated at
104db sensitivity. I'll wire the input signal wires straight to the middle holes where the pot would have been.

Hi Mike.

Thanks for your answers.

I did not realize you could use one board for woofers and second board for tweeters (I'm assuming you are talking stereo). Yes, you answered my question for your configuration.

I thought I'd bi amp one channel, woofer+tweeter, from one board, and second channel from the other board. And in that case I was not sure how to feed the input to one board. Would it be better to have separate coupling caps for tweeter and woofer on one board? Or just one coupling capacitor, and from there feed both input pins on the chip? I guess that was my question.

Rado

radolang · « **Reply #45 on:** 31 Jan 2015, 07:47 am »

Quote from: Salis Audio on 29 Jan 2015, 03:32 pm

Type B maybe. I wouldn't worry, just go with what you like afterward without switch.

The next amp I'm looking at will have more power, so less efficient speakers will match better. It'll be different, and more complicated.

Hi Salis,

Ok, I'll consider option B then. Thank you!

On another note - is there any benefit to point-to-point wiring for these chips?

radolang · « **Reply #46 on:** 31 Jan 2015, 07:54 am »

Quote from: Salis Audio on 29 Jan 2015, 03:32 pm

Type B maybe. I wouldn't worry, just go with what you like afterward without switch.

The next amp I'm looking at will have more power, so less efficient speakers will match better. It'll be different, and more complicated.

Salis, regarding the other amp - I stumbled upon TDA7265, which seems to be advertised as "designed for high quality sound application as Hi-Fi music centers and stereo TV sets.". Have you ever played with that one? According to specs it should be even better than 7297, and it's 2x25W.

Nick77 · « **Reply #47 on:** 31 Jan 2015, 11:32 am »

Subscribe.

mboxler · « **Reply #48 on:** 31 Jan 2015, 01:42 pm »

Quote from: radolang on 31 Jan 2015, 07:46 am

Hi Mike.

Thanks for your answers.

I did not realize you could use one board for woofers and second board for tweeters (I'm assuming you are talking stereo). Yes, you answered my question for your configuration.

I thought I'd bi amp one channel, woofer+tweeter, from one board, and second channel from the other board. And in that case I was not sure how to feed the input to one board. Would it be better to have separate coupling caps for tweeter and woofer on one board? Or just one coupling capacitor, and from there feed both input pins on the chip? I guess that was my question.

Rado

Hey Rado

What are your speakers? Are they Bi-wired, with your plan to drive the separated crossovers with each amp, or do they have no
crossovers, which will require an active crossover ahead of each amp?

I'd be glad to help with the connections. As far as coupling caps, I used them for all channels, as my Marchand XM9's don't have
coupling caps on the output to the amps.

I guess the main questions are...

1) Will you be needing volume controls?
2) Does the component driving the amps already have a coupling caps on it's outputs?

Cheers!

Mike

Folsom · « **Reply #49 on:** 31 Jan 2015, 06:08 pm »

Quote from: radolang on 31 Jan 2015, 07:54 am

Salis, regarding the other amp - I stumbled upon TDA7265, which seems to be advertised as "designed for high quality sound application as Hi-Fi music centers and stereo TV sets.". Have you ever played with that one? According to specs it should be even better than 7297, and it's 2x25W.

Not yet. Specs don't tell you much about sound aside from how loud it'll get.

radolang · « **Reply #50 on:** 31 Jan 2015, 10:47 pm »

Quote from: mboxler on 31 Jan 2015, 01:42 pm

I guess the main questions are...
1) Will you be needing volume controls?
2) Does the component driving the amps already have a coupling caps on it's outputs?

Hi Mike, I'll probably leave out volume control and use sources that have variable output. I'll need the input caps as I don't know if all my sources will have output coupling caps. My speakers are bi-wired with crossovers - older Klipsch bookshelves.

I like the idea of using each board as a "mono block", with separate brick power supplies, located just behind the speakers. I thought it could be fun to try different caps in tweeter and woofer paths - that way I could try optimizing each path for corresponding speaker. Woofer path could use an input cap close 2uF, while tweeter should be ok with something close to .22uF (or even less?). I don't know if this could have any audible and beneficial effect, could it? But it seems like a fun project..

Thanks again,
Rado

Folsom · « **Reply #51 on:** 1 Feb 2015, 01:54 am »

The PSU board minus some caps (misorder). It's good for many more applications. Current is only limited by CMC, as it can be outfitted with a diode bridge for 22a, and at least 40kuf worth of caps.

Folsom · « **Reply #52 on:** 7 Feb 2015, 04:49 pm »

Someone just stole the enclosure before I got home a couple days ago

JDUBS · « **Reply #53 on:** 10 Mar 2015, 09:07 pm »

Is this amp still happening?

-Jim

Folsom · « **Reply #54 on:** 11 Mar 2015, 12:35 am »

Oh ya!

I got a replacement enclosure. The demo is making a hop to my neighboring state for a bunch of holes and what not.

As much as I want to rush it to be done, the reality is that holding off so long has allowed multiple developments in quality without hiking up the parts requirements.

JDUBS · « **Reply #55 on:** 12 Mar 2015, 12:51 am »

Quote from: Salis Audio on 11 Mar 2015, 12:35 am

Oh ya!

I got a replacement enclosure. The demo is making a hop to my neighboring state for a bunch of holes and what not.

As much as I want to rush it to be done, the reality is that holding off so long has allowed multiple developments in quality without hiking up the parts requirements.

Cool. Just looking forward to it. Any idea when it might be available? Trying to think through my next diy project.

-Jim

Folsom · « **Reply #56 on:** 12 Mar 2015, 01:01 am »

I had planned to start a group buy immediately as the tour started. The plan is for the tour to start, or rather a review, first week of April.

The group buy is to include everything you need but input wire, power wire, connectors and chassis. In other words you'll get everything you need to populate an amp board and PSU board fed by an included transformer. The parts are very nice and work together well. I even plan to include the output wire, as shielded is preferred and there aren't a lot of options.

JDUBS · « **Reply #57 on:** 17 Mar 2015, 12:26 am »

Quote from: Salis Audio on 12 Mar 2015, 01:01 am

I had planned to start a group buy immediately as the tour started. The plan is for the tour to start, or rather a review, first week of April.

The group buy is to include everything you need but input wire, power wire, connectors and chassis. In other words you'll get everything you need to populate an amp board and PSU board fed by an included transformer. The parts are very nice and work together well. I even plan to include the output wire, as shielded is preferred and there aren't a lot of options.

Sweet. Looking forward to it. Do you have a targeted price yet?

-Jim

Folsom · « **Reply #58 on:** 17 Mar 2015, 01:04 am »

I was wrong, right now it's $181. The price may change by a few dollars, but it came out lower than I'd even hoped for

Folsom · « **Reply #59 on:** 26 Mar 2015, 02:18 am »

A little bit of wiring.... some feet....