TDA7297 Build Guide V.2 Updated SG Change

Odal3 · « **Reply #20 on:** 7 Dec 2015, 06:06 pm »

Thanks for the input and the patience walking a newbie through this.

I'm still not sure I understand it fully and probably mixing things up. So pin 1 is a chassis ground on the crown, but only connect positive and negative on the tda7297 side?

How would the resistor dropping network look like?

Folsom · « **Reply #21 on:** 7 Dec 2015, 07:53 pm »

Yes.

pin1 works when both appliances have the shield connected, for signal. Using two wires will work correctly. The pin1 wire isn't required for balanced operation to function when being used normally, but when used correctly is good for noise attenuation.

sts9fan · « **Reply #22 on:** 7 Dec 2015, 09:46 pm »

Maybe I am missing something. Where does this board come from? Maybe have some history in the first post?

Folsom · « **Reply #23 on:** 7 Dec 2015, 09:47 pm »

China, found on eBay. Also on Amazon (reply #7).

sts9fan · « **Reply #24 on:** 7 Dec 2015, 09:57 pm »

seems like it would go nicely in the first post.

Odal3 · « **Reply #25 on:** 9 Dec 2015, 06:45 am »

Many thanks.

cyclops13 · « **Reply #26 on:** 12 Apr 2016, 08:12 pm »

Hi All,

I recently got introduced to the world of cheap-chip amps and been trying to learn more and more about them.
So far I never thought I would be able to afford a nice music system given the other priorities I got. But recently I found some good options.

So I got the insignia bookshelf speakers from best buy in a awesome deal and while finding an amp I stumbled upon the TDA7297.
I have received the amp and it sounds great when paired with my speakers. Even with the puny 9V 1A wall wart I am using to feed it.

I am not very good at soldering but have some experience as I am also into RC and had worked on modifying my radio.

Given the limited skills/budget I got, I have planned the following upgrades -

1. Getting a DC step down regulator so that I can use my 20V laptop charger to feed 16v to the amp http://www.aliexpress.com/item/LM2596-LM2596S-ADJ-DC-DC-Step-down-Step-Down-Adjustable-Power-Supply-Modulefor-Arduino/32646984800.html?spm=2114.13010208.99999999.304.kWJEL8
2. Bridging the diode as I will never use AC power with this amp - does this makes big difference? Do I need to remove the diode completely and then bridge? What can I use for bridging?

The board which I got is having different layout as seen in the attached image. Am I correct in identifying the diode and proposed bridge?

You can also refer to this ebay page http://www.ebay.com/itm/AC-DC-12V-TDA7297-2x15W-Digital-Audio-Amplifier-DIY-Kit-Dual-Channel-Module-/371499351808?hash=item567f163f00:g:ISIAAOSwAKxWXutU

Folsom · « **Reply #27 on:** 13 Apr 2016, 12:36 am »

Yes, that's the diode. The little black can with a stripe at one end. The bridge can be made with any wire. 18-20ga would be plenty big (and common). But you could also use a lead you cut off from a new electronic part that's somewhat thick. I prefer larger than resistor lead. Sometimes large caps and inductors have large leads I've used for bridging things.

cyclops13 · « **Reply #28 on:** 13 Apr 2016, 02:30 pm »

Quote from: Folsom on 13 Apr 2016, 12:36 am

Yes, that's the diode. The little black can with a stripe at one end. The bridge can be made with any wire. 18-20ga would be plenty big (and common). But you could also use a lead you cut off from a new electronic part that's somewhat thick. I prefer larger than resistor lead. Sometimes large caps and inductors have large leads I've used for bridging things.

Thanks for confirming. I will remove the diode and bridge it. Once my step down arrives, will supply higher voltage. Really excited to experience the change in sound..

Next step would be to remove the potentiometer.

Just curious, did anyone else used the amp with this board layout? If its a bad design, should I get another one? Most of the pictures here show the headphone jack on the front, while mine is on the side.

cyclops13 · « **Reply #29 on:** 18 Apr 2016, 05:53 pm »

Okay. So I removed the diode past weekend and to be honest, I did not notice much difference in sound.

Probably because I am not feeding enough power to it? I am still waiting for the step down converter to see if it makes a difference.

Folsom · « **Reply #30 on:** 18 Apr 2016, 06:05 pm »

There's too many variables for me to confidently answer that. Keep in mind all the small stuff that may not seem to make a particularly noticeable difference at first can add up to a big difference.

cyclops13 · « **Reply #31 on:** 20 Apr 2016, 08:29 pm »

Quote from: Folsom on 18 Apr 2016, 06:05 pm

There's too many variables for me to confidently answer that. Keep in mind all the small stuff that may not seem to make a particularly noticeable difference at first can add up to a big difference.

I agree. Once I am able to feed 14v to it, lets see how it goes. Thanks again for your advise.

thebob · « **Reply #32 on:** 1 Oct 2016, 03:07 am »

Quote from: cyclops13 on 13 Apr 2016, 02:30 pm

Thanks for confirming. I will remove the diode and bridge it. Once my step down arrives, will supply higher voltage. Really excited to experience the change in sound..

Next step would be to remove the potentiometer.

Just curious, did anyone else used the amp with this board layout? If its a bad design, should I get another one? Most of the pictures here show the headphone jack on the front, while mine is on the side.

Great thread. I've just followed through from the first part.

I have 2 of these boards with the jack on the side. I'm powering with 16V AC at 1.1A from an AC/AC wall wart.

I'm using Pioneer S-S9 (16 ohm) speakers. Just modded one with 1uf polyester box caps.

http://www.ebay.com/itm/3-x-1uF-100V-5-Polyester-Film-Box-Type-Capacitor-/260820441937?hash=item3cba1c1b51:g:J7wAAOxyY3ZRzFP0

Well worth the extra dollar to plunge the bass down to where it should be. I had to use a drill to enlarge the holes. Just spun it gently by hand so as not to damage the pad, after desoldering the tiny ceramics.

As I've got 2 of these boards I'm able to A-B each mod to see what works for me.

Next is changing the 10uf electro for a 470uf 50V to try hand help the bass a bit.

( There are only 4 fingers on one hand!)

Folsom · « **Reply #33 on:** 9 Oct 2016, 02:47 am »

If the output is 1.1a it's light by a fair bit, if the input is 1.1a you're all good.

Sakujin · « **Reply #34 on:** 25 Jan 2017, 10:59 pm »

Hi,

I was wondering if there's a failsafe way to mod this amp into a headphone amp for 32ohm? has anyone tried this? thanks in advance.

Folsom · « **Reply #35 on:** 26 Jan 2017, 01:22 am »

There's a few solutions floating around the net. The most important part is that they have no grounds to share, so you have to use two cords or it won't work. (TDA7297 doesn't use ground on speaker outputs, it's balanced so both + & - are hot)

Dunk_c · « **Reply #36 on:** 9 Aug 2017, 11:46 pm »

Hi,
Could I have advice for cap replacements for this board config, it has a different layout to the one shown in the guides.

Dunk_c · « **Reply #37 on:** 10 Aug 2017, 08:55 pm »

I was a bit lazy. Worked it out but was unsure about joining capacitors back to back reversed in exchange for for the nonpolarised originals. Worked a treat. Pictures attached. What benefit will I get from replacing volume pot? Sounds fine to me.

Skegsi · « **Reply #38 on:** 20 Jan 2020, 04:35 pm »

Hi there. I know I'm reviving am old thread, but just wondering what is meant by "having more capacitance off the board" as per the guide.

Also, a lot of the parts are on backorder from mouser, for the input capacitors will 1.0 vs 1.5 uf make a difference?

Can anyone suggest a good value Bluetooth module that could pair with this?

Sorry for multiple questions.

Thanks in advance
Tim

Nahuelitsn · « **Reply #39 on:** 15 Mar 2021, 03:09 am »

Hi guys. I make all the changes. First build guide 1 amazing sound. Put to Shame some vintage amplifiers of friends. And now build guide v2. I have big problems. I put more capacitance off the board (8500uf )
And bypass the 1.5uf dc iinput caps. But when i connect my amp to the battery i see a spark and the amp stays mute. Then if i connect again start playing only in left channel and the right doesnt produce sound at all but i can see the speaker stay stuck forward like if receive DC power. Please help!!

TDA7297 Build Guide V.2 **Updated SG Change**

TDA7297 Build Guide V.2 Updated SG Change