TDA7297 Build Guide

Danny Richie · « **Reply #100 on:** 9 Apr 2014, 03:25 pm »

Quote from: wushuliu on 9 Apr 2014, 02:28 pm

Your review aside, I'm surprised that the TDA7297 doesn't blow the TPA away in general given how few parts it uses. Unfortunately it looks only suitable for 8 ohms so it would not be suitable for my speakers to test.

I drove it into some 4 ohm loads and it was very stable and played well with no issues.

wushuliu · « **Reply #101 on:** 9 Apr 2014, 05:12 pm »

Quote from: Danny Richie on 9 Apr 2014, 03:25 pm

I drove it into some 4 ohm loads and it was very stable and played well with no issues.

OK good to know. I've got one sitting in a drawer I'll do the usual mods and give it a whirl.

elb · « **Reply #102 on:** 9 Apr 2014, 06:57 pm »

Quote from: wushuliu on 9 Apr 2014, 02:28 pm

Your review aside, I'm surprised that the TDA7297 doesn't blow the TPA away in general given how few parts it uses. Unfortunately it looks only suitable for 8 ohms so it would not be suitable for my speakers to test.

My speakers are M.J .King H frames with Eminence Alpha 15/L-Cao 8 inch.
Started out with the Alpha/Fostex FE103en combination,tried Visaton B200 and Mark Audio Alpair 12.

The present set up is best for me.

Regards.

gychang · « **Reply #103 on:** 21 Aug 2014, 06:35 pm »

Quote from: Salis Audio on 15 Dec 2013, 09:27 pm

Alright guys, here it is! First the parts you need. *C4 amended.

From Mouser.

Input caps, order 10x because it's cheaper than 4x (yes you'll need 4x)

647-UES1H010MDM
UES1H010MDM
50volts 1uF

Power cap 1x

661-EKZH250E222MK30S
EKZH250ELL222MK30S
25Volts 2200uF

Shunt/Mute Power cap

661-EKY500ETC220ME1
EKY-500ETC220ME11D
50volts 22uF

Building

Ok, so first I recommend getting to this point, the naked board of all the parts you don't need. That is unless you want the volume pot, but I wouldn't recommend it.

Here's a clear board, I've labeled the R and L inputs, and their grounds. R1, D1, D2, C1, C2, C3, C4 (not shown removed) C5, CN4, and RP 50k have been removed.

Install a wire for the bypass of the diode (D2), I did this on the bottom.

Install the Shunt/Mute cap (C3) 22uf, negative side (short lead) goes to the striped pattern on the board.

Install the upside C1 and C2 capacitors, 1uf Nichicon Muse. Long leads go toward the input (as circled)

Install on the bottom 1uf capacitors with the reverse orientation of the first two (long leads towards the chip), on C1 and C2. This is very important, and can only be done with non-polar caps. Without doing this your amplifier won't be that great unless you got some very nice film caps for the inputs.

Install C5, the big 2200uf cap, again stripe to stripes.

That's it! My next post here will be about advanced options, this is the simple, but very good build.

Use only DC power supply after removing the diode.

*do not replace C4, it's a worthless snubber that causes ringing.

this is great, thanks for putting this together with pictures even I was able to get this done and listening to sweet quartet as I am writing this. Your instructions are excellent, since I did not listen to nonmod version extensively I can not tell, but as I am listening in garage sounds nice.

Folsom · « **Reply #104 on:** 22 Aug 2014, 10:08 pm »

Hey I'm glad it's working.

I recommended a few other potential changes to another guy. The biggest issue is the board is the OPPOSITE of compatible of using different power caps. The input caps are going to remain as a very transparent, balanced, recommendation. You can spend $480 on V-cap input caps if you want... a piece!

Bang for buck, I'd like to know how far my input capacitor method can go.

What PSU are you using? An Astron like the guys with the TPA3116 guys are using would be a great choice. They do well with minor capacitor mods too.

gychang · « **Reply #105 on:** 22 Aug 2014, 11:04 pm »

Quote from: Salis Audio on 22 Aug 2014, 10:08 pm

Hey I'm glad it's working.

I recommended a few other potential changes to another guy. The biggest issue is the board is the OPPOSITE of compatible of using different power caps. The input caps are going to remain as a very transparent, balanced, recommendation. You can spend $480 on V-cap input caps if you want... a piece!

Bang for buck, I'd like to know how far my input capacitor method can go.

What PSU are you using? An Astron like the guys with the TPA3116 guys are using would be a great choice. They do well with minor capacitor mods too.

I was using a cheap 2A, 12V wallwart.

Folsom · « **Reply #106 on:** 22 Aug 2014, 11:13 pm »

You have so much more amp to enjoy when you switch that out!

gychang · « **Reply #107 on:** 23 Aug 2014, 11:53 pm »

Quote from: Salis Audio on 15 Dec 2013, 09:27 pm

Alright guys, here it is!

is there any chance on continuing the pictorial steps in putting the modded unit in the case with power connector, pot/volume, DC connector etc? This tutorial has been very helpful.

Folsom · « **Reply #108 on:** 24 Aug 2014, 12:29 am »

I'd have to get all that stuff

.

I've been mounting all these little amps on a piece of plywood for testing.

There's some decent guides to volume out there. Generally any DC jack uses the center pin for power.

gychang · « **Reply #109 on:** 24 Aug 2014, 01:58 pm »

I am confused about the proper soldering of signal inputs, original suggestion was the common ground is the single hole in the front as pictured. There are 4 holes (2 for R/L). Can either hole be used for each channel? or is the ground the outer holes and each signal must be soldered on inner holes?

Danny Richie · « **Reply #110 on:** 24 Aug 2014, 02:08 pm »

Just flip the board over and look at the back side of the traces. The ones that are ground will be apparent.

Folsom · « **Reply #111 on:** 25 Aug 2014, 10:12 pm »

Quote from: Danny Richie on 24 Aug 2014, 02:08 pm

Just flip the board over and look at the back side of the traces. The ones that are ground will be apparent.

Yes, and they connect to the same plane. You can connect both ground wires to the board, or make a Y shaped cable so that only one wire runs away from the RCA jacks.

gychang · « **Reply #112 on:** 26 Aug 2014, 01:32 am »

can someone verify whether this is correct connection of audio input after ridding of the volume pot?

Folsom · « **Reply #113 on:** 26 Aug 2014, 01:53 am »

We need to see the underside, it appears to be a different board.

keith_correa · « **Reply #114 on:** 26 Aug 2014, 10:46 am »

gychang · « **Reply #115 on:** 31 Aug 2014, 07:49 pm »

I have a audio input signal that intermittenly cuts out on one channel, corrects if I wiggle the input line at the terminal. I want to solder lines on the bottom to bypass the loose connection but I am little confused about the orientation.

a: I am guessing is the R input, but 2 solder teminals are connected, looks like it is shorted? (on picture does not show well since angle is not correct)
b: likely ground
c: prob L input, but 2 solder terminals are not shorted.

I like to take the input jack out but not clear on exactly which holes I should solder to. Can anyone explain

?

Folsom · « **Reply #116 on:** 1 Sep 2014, 06:56 pm »

I think these caps would work well for the inputs, two of them, keith. Don't worry about the 22uf cap, you can leave it as is if you want. Two of these will work great for replacing the 2200uf.

gychange, you're correct that they are the input signals. They're not bypassed, that's just the cheap 1/8 jack's way of mounting. First try re-touching the solder joints with a tiny bit of lead solder. It's most likely either a cold solder or a jack that's too cheap.

keith_correa · « **Reply #117 on:** 2 Sep 2014, 05:28 am »

Quote from: Salis Audio on 1 Sep 2014, 06:56 pm

I think these caps would work well for the inputs, two of them, keith. Don't worry about the 22uf cap, you can leave it as is if you want. Two of these will work great for replacing the 2200uf.

Thank you! Are you sure about this to replace the 2200uF cap? It is only 100uF. Won't even 2 of them paralleled be inadequate?

Folsom · « **Reply #118 on:** 2 Sep 2014, 05:52 am »

Darn, you are right. I thought they were 1000uf.

I'm not sure how to search sites for your location so I was just looking on those two.

http://theaudiocrafts.com/index.php?route=product/product&path=124_146&product_id=278

Those will work if you can't find Nichicon KG or FG.

keith_correa · « **Reply #119 on:** 2 Sep 2014, 07:24 am »

Quote from: Salis Audio on 2 Sep 2014, 05:52 am

Darn, you are right. I thought they were 1000uf.

I'm not sure how to search sites for your location so I was just looking on those two.

http://theaudiocrafts.com/index.php?route=product/product&path=124_146&product_id=278

Those will work if you can't find Nichicon KG or FG.

Thank you!