chip amps: Almost everything you ever wanted to know

[DizRotus]

Rich,
My mother warned me about hanging with bad influences. Now you made me risk $5.98 on another chip amp. That makes 2 Lepai TA-2020s, 1 SMSL SA-S1 & 1 SMSL SA-50 and now this.

I see the makings of a reality TV show.

Now that I bought it, it's not clear whether it's two channels or one. Which is it? I don't know what I'll do if I need to protect my $5.98 investment by buying another one.

SOLD to CECAA850 I must thin the herd. For $15, I'll ship one of the Lepais to a member in U.S. Send a PM if interested.

Edited November 13, 2013 by DizRotus

[rhing]

Rich,

My mother warned me about hanging with bad influences. Now you made me risk $5.98 on another chip amp. That makes 2 Lepai TA-2020s, 1 SMSL SA-S1 & 1 SMSL SA-50.

I see the makings of a reality TV show.

Now that I bought it, it's not clear whether it's two channels or one. Which is it? I don't know what I'll do if I need to protect my $5.98 investment by buying another one.

I must thin the herd. For $15, I'll ship one of the Lepais to a member in U.S. Send a PM if interested.

It is a slippery slope indeed. The low costs of these fine low power amps makes it a fun adventure to experiment and improve the audio chain with a low budget.

The TDA7297 amp is a stereo amp. The amp I purchased has a 1/8" stereo jack. I bypassed this by soldering hook-up wire between my RCA connectors and the PCB where the stereo jack is mounted. I also recently replaced the 2,200uF/25V power supply cap with a better 2,200uF/25V Panasonic FM electrolytic cap that has further improved dynamic response and bass extension. I might replace the cheap Polyester film caps at the inputs with better Polypropylene film caps.

By the way, besides the TDA7297 chip, the only other passive components in the signal path are the two input caps. The other handful of components are tied into the Mute and Standby circuits of the chip along with the two caps in the power supply. This amp is almost like a straight wire with gain.

I don't want to give the impression this amp trounces the SMSL T-amp, because they do sound similar and they are both very good in their own right. What's impressive though is that this amp is only $6 and has a very low parts count making upgrades easy and affordable. On top of that, the sound is more immediate and perhaps less colored, because the circuit is so minimalist. With good, efficient speakers like Klipsch speakers a very nice amplification system can be built on a shoestring budget.

Edited November 7, 2013 by rhing

[DizRotus]

After I posted above, I re-read the description and was comfortable that I didn't need to risk another $5.98 to get a second channel.

I'm looking forward to getting this thing and sharing my impressions.

[onlysleeping]

I am interested in trying the TDA7297. I found the home mart usa seller and plan to purchase one . Any recommendation on power supply? I'm looking for a wall wart.

I have used a Dayton DTA-1 with my Klipschorns. Without my preamp (mcintosh MX113) the bass is a bit weak.

[rhing]

I am interested in trying the TDA7297. I found the home mart usa seller and plan to purchase one . Any recommendation on power supply? I'm looking for a wall wart.

I have used a Dayton DTA-1 with my Klipschorns. Without my preamp (mcintosh MX113) the bass is a bit weak.

The recommended power supply should be capable of providing 12V DC and 2A. I use a modified 110 watt Switch Mode Power Supply (SMPS) that has a regulated 12-13V DC and 3-4A output. The amp can actually be driven with anything from 12 to 16V DC. If you can find a laptop power supply or an LED monitor power supply that fits this range, that should be good for starters. These are usually SMPS and should work well.

If you are a DIY audio person -- especially with working safely with power supplies -- I would recommend the Mean Well RS-100-12 SMPS. You will need to put this in an enclosure and also add the following:

• Power switch
• IEC inlet
• DC power cable

With the right power supply, this amp will provide more bass and musical body than the Dayton DTA-1 amp. From what I know, the Dayton DTA-1 is basically the same as the original Sonic Impact T-amp using the Tripath TA2024 Class D chip. I have a Sonic Impact Gen 2 T-amp, which I have modified, and it still doesn't sound as good as the TDA7297 amp in stock form.

I have since replaced the stock Polyester input coupling caps with Panasonic Propylene film and foil caps, and the sound quality has reached a new level. I have some Mundorf Supreme film caps and an SMD resistor-based stepped attenuator on the way. I have high expectations for taking this amp even further.

I've even connected this little amp to my Audio Research PH5 phono stage, and I've obtained great results. This is a very musical amp, and it's so inexpensive. It doesn't beat my Audio Research LS7 and restored and modified Dynakit Stereo 35, but it's able to hold its own.

[billybob]

I am interested in trying the TDA7297. I found the home mart usa seller and plan to purchase one . Any recommendation on power supply? I'm looking for a wall wart.

I have used a Dayton DTA-1 with my Klipschorns. Without my preamp (mcintosh MX113) the bass is a bit weak.

I found the seller on e-bay but am unable to find the TDA7297 module there. Are there any amps already using this?

Thanks

[DizRotus]

I am interested in trying the TDA7297. I found the home mart usa seller and plan to purchase one . Any recommendation on power supply? I'm looking for a wall wart.

I have used a Dayton DTA-1 with my Klipschorns. Without my preamp (mcintosh MX113) the bass is a bit weak.

I found the seller on e-bay but am unable to find the TDA7297 module there. Are there any amps already using this?

Thanks

Is this what you're looking for? http://www.ebay.com/itm/151144420264?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

I risked a whole $5.98 on this amp from this seller. It hasn't yet arrived.

Neil

TDA7297F.pdf

Edited November 13, 2013 by DizRotus

[billybob]

Thanks yes it is! I have now read the 6 pages in this thread up to this point. I have toyed with the idea of T-Amps for some time now and may just get my feet wet. Will be following this and other threads where the conversation continues. Most interested to find out if this is a good building block module from which all things good will flow. Getting more anxious as time goes on to do some exploring.

Thanks again

[billybob]

Thanks yes it is! I have now read the 6 pages in this thread up to this point. I have toyed with the idea of T-Amps for some time now and may just get my feet wet. Will be following this and other threads where the conversation continues. Most interested to find out if this is a good building block module from which all things good will flow. Getting more anxious as time goes on to do some exploring.

Thanks again

And I see the link is to the B version which compared to the A version already has the power supply DC adapter in place.

[rhing]

Thanks yes it is! I have now read the 6 pages in this thread up to this point. I have toyed with the idea of T-Amps for some time now and may just get my feet wet. Will be following this and other threads where the conversation continues. Most interested to find out if this is a good building block module from which all things good will flow. Getting more anxious as time goes on to do some exploring.

Thanks again

And I see the link is to the B version which compared to the A version already has the power supply DC adapter in place.

That's correct. I have the A version with the screw down terminals for the DC input. They're saving everyone time by including the DC power connector on the B version board now. They still offer the A version board. Just search for "TDA7297f" on eBay, and you'll find it.

This amp seems to like more current. Using my modified SMPS, when I adjust the output voltage to 12V vs. 13.4V, the output current increases and the soundstage is a bit larger. My friend uses a Mean Well RS-100-12 SMPS with his TDA7297 amp, and when he dials the voltage down to 12V DC with a slightly higher output current, he gets a richer sound from this little amp. If you can use a power supply with 12+V DC and 5+A output, I think the results are very impressive.

DizRotus, you should have received some tracking information from homemart.usa. My amp came within a week. I live in California, and my friend lives in Huntsville, AL, and he got his before I did.

I'm still waiting on my 0.22uF Mundorf Supreme film caps and stepped attenuator. Once I get those, I'll post photos and listening impressions. I think I'll buy another TDA7297 to use as a baseline to gauge the effects of any component upgrades I make.

[DizRotus]

Thanks yes it is! I have now read the 6 pages in this thread up to this point. I have toyed with the idea of T-Amps for some time now and may just get my feet wet. Will be following this and other threads where the conversation continues. Most interested to find out if this is a good building block module from which all things good will flow. Getting more anxious as time goes on to do some exploring.

Thanks again

And I see the link is to the B version which compared to the A version already has the power supply DC adapter in place.

That's correct. I have the A version with the screw down terminals for the DC input. They're saving everyone time by including the DC power connector on the B version board now. They still offer the A version board. Just search for "TDA7297f" on eBay, and you'll find it.

This amp seems to like more current. Using my modified SMPS, when I adjust the output voltage to 12V vs. 13.4V, the output current increases and the soundstage is a bit larger. My friend uses a Mean Well RS-100-12 SMPS with his TDA7297 amp, and when he dials the voltage down to 12V DC with a slightly higher output current, he gets a richer sound from this little amp. If you can use a power supply with 12+V DC and 5+A output, I think the results are very impressive.

DizRotus, you should have received some tracking information from homemart.usa. My amp came within a week. I live in California, and my friend lives in Huntsville, AL, and he got his before I did.

I'm still waiting on my 0.22uF Mundorf Supreme film caps and stepped attenuator. Once I get those, I'll post photos and listening impressions. I think I'll buy another TDA7297 to use as a baseline to gauge the effects of any component upgrades I make.

Rich-

Thanks for the reminder to check for a tracking number. Looks like it is in Chicago now and headed to Motown.

Neil

Edited November 14, 2013 by DizRotus

[onlysleeping]

I am interested in trying the TDA7297. I found the home mart usa seller and plan to purchase one . Any recommendation on power supply? I'm looking for a wall wart.

I have used a Dayton DTA-1 with my Klipschorns. Without my preamp (mcintosh MX113) the bass is a bit weak.

The recommended power supply should be capable of providing 12V DC and 2A. I use a modified 110 watt Switch Mode Power Supply (SMPS) that has a regulated 12-13V DC and 3-4A output. The amp can actually be driven with anything from 12 to 16V DC. If you can find a laptop power supply or an LED monitor power supply that fits this range, that should be good for starters. These are usually SMPS and should work well.

If you are a DIY audio person -- especially with working safely with power supplies -- I would recommend the Mean Well RS-100-12 SMPS. You will need to put this in an enclosure and also add the following:

• Power switch
• IEC inlet
• DC power cable

With the right power supply, this amp will provide more bass and musical body than the Dayton DTA-1 amp. From what I know, the Dayton DTA-1 is basically the same as the original Sonic Impact T-amp using the Tripath TA2024 Class D chip. I have a Sonic Impact Gen 2 T-amp, which I have modified, and it still doesn't sound as good as the TDA7297 amp in stock form.

I have since replaced the stock Polyester input coupling caps with Panasonic Propylene film and foil caps, and the sound quality has reached a new level. I have some Mundorf Supreme film caps and an SMD resistor-based stepped attenuator on the way. I have high expectations for taking this amp even further.

I've even connected this little amp to my Audio Research PH5 phono stage, and I've obtained great results. This is a very musical amp, and it's so inexpensive. It doesn't beat my Audio Research LS7 and restored and modified Dynakit Stereo 35, but it's able to hold its own.

Thanks! I am looking forward to trying it out in few weeks when it arrives. Do you think the power supply that came with the Dayton DTA-1 would work? I probably have a laptop power supply laying around somewhere.

[rhing]

The DTA-1 power supply should work. Can you share the specs that are usually written on the bottom of the unit?

[billybob]

Anxious now to receive my TDA unit and revive my novice soldering skill. Power supply should be not a problem what with what I have here. Will be fun to check it out!

[DizRotus]

I'm eager to receive my TCC TC-760LC from Billy Bob. Without that phono preamp, I can't combine my two latest addictions; vinyl and chip amps.

Thanks Billy,

Neil

[onlysleeping]

The DTA-1 power supply should work. Can you share the specs that are usually written on the bottom of the unit?

Input 100-240V 50-60hz .6a

Output is 12v 2amp .

Model number is ksas0241200200d5

Looks like this - http://www.google.com/imgres?imgurl=http://azsurplus.com/images/KTEC_KSAS0241200200D5.jpg&imgrefurl=http://azsurplus.com/index.php?main_page%3Dproduct_info%26cPath%3D1_14%26products_id%3D6818&h=768&w=554&sz=47&tbnid=Di7qmv8UAhMYsM:&tbnh=90&tbnw=65&zoom=1&usg=__jU-EMyL6IZduNtgShqVCJ46D_nE=&docid=iQEAB6tcEVcyDM&sa=X&ei=j4-FUqjvE4bhyQHiyYCQDA&sqi=2&ved=0CEkQ9QEwAw

I wasn't sure if the plug would fit. Hope it does!

[rhing]

The plug should work fine. Try it out and enjoy.

[ClaudeJ1]

As shown in the photo, I powered all four single driver BR speakers with two 8 ohm speakers in parallel on each channel for a nominal 4 ohm load. The tendency to stridency in the high frequencies seemed to disappear. The results are consistent with Dean's comments.

The reviews for this amp on the Parts Express site are extremely favorable. On the basis of value, it's hard to fault this little amp.

I use a T-amp on my woofer section of the stack in my Avatar. I measure 10 Milliwatts at 85 db in my sweet spot from the receiver amps, which are reduced by -12 db and run on the -23 db setting. It's a Lepai and it does about 6 Watts per ch. before distortion rises. People are amazed. I use the big Bryston 4B and Adcom 555 on my new twin DTS-10's. I'm in bass heaven right now.

[DizRotus]

Claude-

How's Indy treating you?

I can testify to the abundance of tight clean controlled bass in Claude's system.

Edited November 15, 2013 by DizRotus

[DizRotus]

At the recommendation of some people on the diyAudio.com Class D amplifier forums, I decided to purchase a TDA7297 Class AB chip amp from an auction seller, Homemart.USA. The amp only cost $4.99 plus $1.00 shipping from Hong Kong. Several people claimed that this amp sounds better than the SMSL SA-S1 TA2020 Tripath Class D (i.e., Class T) amp. I've wasted $6 on bad lunches before, so I figured what could I lose.

Within a week, the amp module came in a padded envelope from Hong Kong. It was wrapped in Saran Wrap and bubble wrap. The amp has a 2" x 2" footprint. The heat sink, which is the largest component on the printed circuit board is a bit less than 2" high. This amp is tiny. I wired it up in a makeshift test bed with 5-way binding posts and good quality RCA connectors. I hooked up my Klipsch Forte IIs, my Sony SACD/CD player and powered up the amp with the same modified power supply I used with my SMSL T-amp. I've been listening to music the last two evenings using this tiny amp, and I am amazed that this amp really does sound better than the SMSL amp. It digs deeper in the bass and sounds clearer than the SMSL amp. The tonality is balanced, the timbral detail is nice, and the amp has plenty of headroom despite its low power spec. I've listened to rock, classical and jazz, and I am impressed with the size of the soundstage and well defined imaging.

The funny thing is the data sheet from STM, the chip's manufacturer, states that applications for this chip include televisions and portable audio.

My example of this tiny amp arrived today. It's a cute little thing. If I don't like how it sounds, it could be used as an audio themed key-chain.

I'll probably wait until the phono stage arrives from billybob before I insert this into a system.

Edited November 16, 2013 by DizRotus