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Old 24th June 2013, 01:33 PM   #131
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Originally Posted by pkozul View Post
Hi again,

Thanks for the comments. I tried to keep the project as neat as possible since the amp will be sitting in our study on the desk, so there's a bit of FAF involved (family acceptance factor).

It's funny when you get more and more into this hobby and you start noticing potential enclosures in all shapes and sizes :-)

Daniel, the power supply (SMPS) I have has a 3 prong plug. The amp is connected to the laptop via an Edirol USB audio interface. I found that the hum only really kicks in when the volume pot is turned up to about 80 or 90% of its range. Since it's a linear 100k pot, I guess that level is really out of the listenable range. Could it be a faulty pot? In any case, I will try adding some resistors between the pot's pins, to turn it into a more of a log pot. Currently, the volume pot is not very useful since there is such a fine line between quiet and loud, as some people here noticed with the original pot.

Cheers.
Could be your laptop? my laptop produces a slight hum when either asleep or off.
I have a selector box connected to my laptop, cd player, fm tuner and minidisc player. The laptop is the only component that produces this hum, but not when running. Try connecting your amp to another component.
At my usual listening level with the laptop in sleep mode, the room has to be quiet and my sitting close to a speaker for me to hear the hum.
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Old 28th June 2013, 01:48 AM   #132
von Ah is offline von Ah  United States
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So where would one acquire an equivalent board now? Does anyone know of a source for one with RCAs?
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Old 28th June 2013, 06:43 AM   #133
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Originally Posted by von.ah View Post
So where would one acquire an equivalent board now? Does anyone know of a source for one with RCAs?
Many hits on Ebay but can't say I've seen any with RCA's.
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Old 1st July 2013, 04:38 PM   #134
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Seeking some advice on a smallish boombox. I recently got my TDA7297 and want to make a portable boombox. I was considering pairing it with 2 HiWave BMR12s
HiWave BMR12 Compact 2" Full-Range Square Speaker 12W 8 Ohm 299-208
This would be running off a CCTV Li-ion I already have. Ideally, Im looking for something reasonably inexpensive that I could carry with one hand.
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Old 31st August 2013, 05:02 AM   #135
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Hey Guys,

I've been using one of a "Mini Amplifier Board 10W+10W Class D Amplifier 12V"
http://www.ebay.com.au/itm/280917627145?ssPageName=STRK:MEWNX:IT&_trksid=p398 4.m1497.l2649
but even with ferite cores on the speakers, it just gives to much feedback, buzzing at idle and interfers with my FM radio. So i've put the money down for a
TDA7297F Amplike everyone seems to have here.

I am going to de-solder the Volume pot add some wire and move it to another location on the case, Is there any way i can introduce an Of//On switch to this?

Also any other tips from existing users?

Cheers Rob.
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Old 31st August 2013, 05:11 AM   #136
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Hey Guys,

Looking at the datasheet

TDA7297 datasheet(2/9 Pages) STMICROELECTRONICS | 15+15W DUAL BRIDGE AMPLIFIER

Looks like Pin 7 is standby, so would you just ground that to put it into standby mode?
Is it that simple?

Cheers Rob.
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Old 31st August 2013, 09:14 AM   #137
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Almost. Pin 7 needs to be >1V to put the chip in standby mode. Have a look at the datasheet, though. You'll probably want the RC delay on pin 7 to avoid turn-on thump. A small current-limiting resistor in series with the switch, placed in parallel with the capacitor, should work.
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Old 31st August 2013, 12:31 PM   #138
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Hello sofaspud,

Thank you so every much, will give that a try.

Thanks Rob.
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Old 10th October 2013, 03:46 PM   #139
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Still very happy with my lunch money amp. It's now housed with a USB/MP3 player with FM tuner and it all works very nicely. This module was hopeless with a class D amp as the high speed switching caused interference on FM drowning out all but the strongest stations.

Click the image to open in full size.
Hi,
is that little FM tuner STEREO?
I have since purchased a 3116 board plus a 2.1 deluxe version but have swopped back to the 7297, it just sounds so much better on my setup, and not just FM.
Time to take the 7297 seriously and house it.
I have a spare RS Minimus-7 speaker and I'm thinking that if I remove the guts and use the aluminium box to house the 7297 and a small FM tuner, as pictured, it would look smart?
I have given up with D-amps, just too much RF interference.
There are some interesting discussions on the web about d-amp car radios and interference.
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Old 10th October 2013, 05:02 PM   #140
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Yes, that little FM module is stereo. Reception is OK with a metre length of wire but I'm in a fairly high signal strength area. It has memory presets too

I still can't quite believe how good that 7297 sounds!

Cheers
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