Jeez, I had no idea of what you had achieved until I took delivery of my ready made tpa3123 board. Was this just a one off challenge or do you intend to build other tpa31xx amps?
The dead bug looks more like a cancerous growth, I mean that in a nice way
I'm appreciating the sound of this amp, perhaps more than the ta2020 whch I have several of. I cannot see there being any difference in sound quality between the tpa31xx amps?
I just need to chase down some faceplate lamps before putting my old McIntosh ss amp on Craigslist, I'm a d-amp convert.
Hey thanks for the kind words - cancer is a good way to describe it
Glad to see we have another class D convert! The dead bug was a one-off challenge to myself to see if I could "McGyver" an SMD amp from parts and nothing more than SMD "fleas", paper, glue, and wire. Indeed it works but thinking back how painstaking the wire-bonding process was to get those 0.6 mm pitch pins soldered and leads to go out to usable wires I am not sure I would do it again. Especially after building the TPA3116D2 using a PCB - boy that was like child's play to solder SMD components to the fat nicely tinned solder pads after working with the dead bug style.So I have built both the 3118 and 3116, and really, they sound very much alike - wonderful, dynamic, and superb resolution/clarity and definition. The 3116 goes a little louder (50 watts max) but not sure if it is that big a deal. The 3118 has an advantage of being able to select a modulation at up to 1.2 MHz whereas the 3116 is only 600 kHz max. The use of extra capacitors on the power supply pins makes a big difference in the bass.
The next ones I build I will design my own PCB using Eagle, then send the Gerber files off to China for cheap boards (Itead does 10 for $10 double-sided as long as it is under 2 in x 3 in). Have not used Eagle yet but looking at demo teaching vids on YouTube it doesn't look too hard.
If I dead bug again, it will be to make an active cross-over/pre-amp for my two TPA amps so I can bi-amp a FAST system without any passive speaker level x-overs. I have located a nice ultra-low distortion audio quad op-amp from TI for this. Just need to get some resistors, bypass caps, pots, and I am good to go...
Although, when I did the dead bug, I did not have the proper smallest soldering iron tip available - I was using an 0.035 in vs 0.015 in. I also had fat 0.035 in solder instead of the 0.015 in solder. That may make a difference in ease of wire bonding.
$6 amp - impressions after about a week
This post is for anyone still considering buying this amp.
After a week of listening...I still pronounce it excellent. I'm still really happy with the musicality of this amp and glad I've purchased it.
It's got terrific bass, and a non-murky, very transparent presentation. Everything seems very "fast" - attack time of instruments. Vocals excellent. No complaints at all. It's very enjoyable.
This amp is dead quiet at idle. You can't even tell it's on. I put my ear right up to the La Scalas. No hiss, no nothing. This is THE quietest amp out of the dozen and a half or so amps I own: tube, solid state, D, chip, you name it. This one is spooky quiet so therefore there's nothing bugging you in those quieter music passages.
I forgot to mention -- zero turn on noise. Upon power down/turn off --a tiny little noise. On a scale of 1-100, that turn-off noise would be about a 4. It's a very low volume thing, not loud at all.
Per every discussion on every Internet forum, much babble ad nauseum about "specs" and how this thing cannot be any good or will or won't do this or that because of the specs. HMMMM.........
I don't care what all the specifications say:
1) NO. It doesn't run hot. I can touch the heat sink.
2) NO. It doesn't need any special power supply. I'm just using a simple computer type power supply. 12VDC, 2 amp. XRK, in a link earlier in this thread found a similar one on Amazon for even less money than I paid, and 5 amp.
This amp is being used with my Klipsch LaScalas, Emotiva CD player, Magnum Dynalab FM tuner, the E.A.R. phono preamp with a Technics SP-25. And just a simple $9 switchbox.
I guess the only thing I'd nit-pick on the amp is this: The volume pot on the amp is a tad touchy. It's 100K. And I don't have much "throw" to it before it gets really loud. I'm wondering if I were to pull it and run a different "K" would that help that "too loud, too soon" situation? As you guys no doubt understand La Scalas are very efficient and on other speakers this may not be a problem.
Try it and enjoy! Hide it under a big cardboard box and have a buddy over for a listen. Then ask his impressions and how much he thinks the amp under the box should cost.
Mark
This post is for anyone still considering buying this amp.
After a week of listening...I still pronounce it excellent. I'm still really happy with the musicality of this amp and glad I've purchased it.
It's got terrific bass, and a non-murky, very transparent presentation. Everything seems very "fast" - attack time of instruments. Vocals excellent. No complaints at all. It's very enjoyable.
This amp is dead quiet at idle. You can't even tell it's on. I put my ear right up to the La Scalas. No hiss, no nothing. This is THE quietest amp out of the dozen and a half or so amps I own: tube, solid state, D, chip, you name it. This one is spooky quiet so therefore there's nothing bugging you in those quieter music passages.
I forgot to mention -- zero turn on noise. Upon power down/turn off --a tiny little noise. On a scale of 1-100, that turn-off noise would be about a 4. It's a very low volume thing, not loud at all.
Per every discussion on every Internet forum, much babble ad nauseum about "specs" and how this thing cannot be any good or will or won't do this or that because of the specs. HMMMM.........
I don't care what all the specifications say:
1) NO. It doesn't run hot. I can touch the heat sink.
2) NO. It doesn't need any special power supply. I'm just using a simple computer type power supply. 12VDC, 2 amp. XRK, in a link earlier in this thread found a similar one on Amazon for even less money than I paid, and 5 amp.
This amp is being used with my Klipsch LaScalas, Emotiva CD player, Magnum Dynalab FM tuner, the E.A.R. phono preamp with a Technics SP-25. And just a simple $9 switchbox.
I guess the only thing I'd nit-pick on the amp is this: The volume pot on the amp is a tad touchy. It's 100K. And I don't have much "throw" to it before it gets really loud. I'm wondering if I were to pull it and run a different "K" would that help that "too loud, too soon" situation? As you guys no doubt understand La Scalas are very efficient and on other speakers this may not be a problem.
Try it and enjoy! Hide it under a big cardboard box and have a buddy over for a listen. Then ask his impressions and how much he thinks the amp under the box should cost.
Mark
Mark,
Glad this is working out for you. Too bad these are sold out now. I looked at the spec sheet for this chip, it is one of the fewest external parts required for any amp and if you operate it under 5 watts output it is under 1% THD so not bad. Since your are using very nice speakers the LaScalas will be very loud at 5 watts power so there is the reason they sound good: 75% of sound quality is the speakers. I like how they are quiet and simple. I think these are an excellent alternative for desktop pc speaker builds or something that is plugged in as they are not super efficient not being class D. If you want to improve volume controllability try using a logarithmic pot. Keep it at 100k though.
Glad this is working out for you. Too bad these are sold out now. I looked at the spec sheet for this chip, it is one of the fewest external parts required for any amp and if you operate it under 5 watts output it is under 1% THD so not bad. Since your are using very nice speakers the LaScalas will be very loud at 5 watts power so there is the reason they sound good: 75% of sound quality is the speakers. I like how they are quiet and simple. I think these are an excellent alternative for desktop pc speaker builds or something that is plugged in as they are not super efficient not being class D. If you want to improve volume controllability try using a logarithmic pot. Keep it at 100k though.
A most interesting website, I remember those fashions, we thought we looked so cool. At least we could cast them off as fashions changed, unlike tattoos.
With all your years of experience in the audio industry you look have a regard for the d-amp technology?
For those interested, the little amps are still available.tda7297f | eBay
Looking back, I think those 70's fashions are best forgotten!
Well I try to keep up with the latest trends and have tinkered a bit with class D. I'm not entirely convinced about sound quality although it does have other virtues which can't be ignored.
The TDA7297 board is up and running, looks a little lost in the case which originally house a TA2022 board and toroidal transformer. With a hole pre-drilled for a volume pot mounting the board should be straight forward.
An externally hosted image should be here but it was not working when we last tested it.
Not quite as easy as I thought. I wanted to remove the 3.5mm socket from the front edge but desoldering the blighter defeated me.
An externally hosted image should be here but it was not working when we last tested it.
As for performance of this little board I have to agree with everything that Mark2727 has already said. My speakers are a DIY effort using 8" woofers and Tang Band W3-871 for mid and top end, efficiency I guess is average, about 88dB. The amp appears to have no problem driving them at levels which are quite loud enough for me.
To sum up:
It's silent.
It runs cool.
It has good strong bass
It has clear, dynamic mid and top end
It has a volume control that's more like an on/off switch, silent or loud!
It's remarkable for the price
Get one today, you won't regret it!
(Anyone know why the images have the wrong aspect ratio?)
Last edited:
What, you have found something even cheaper?
There is this
1.99 British pounds or about 3 USD including shipping. At 3W+3W I doubt that it's serious competition for the TDA7297
I didn't do it for the price. I bought the TDA7297 to check it out. I have some unusual approaches and applications for which it may be suited. And, two "normal" uses for it as well--surround channels at home or upgrade the front speakers in the pickup truck with a decent amplifier. That would be really nice. And, yeah, the convenience is unbeatable.
You could add resistor between input and wiper, or between input and ground. I can't remember at the moment, so you'd have to check. My first try would be with 100k resistors, and if that's insufficient then try other values. Anyway, no need to desolder the pot.
I don't have one to play with at the moment--it hasn't arrived yet.
For the TDA7297? A whole bench? Howabout a music collection and a fun little speaker project? Also, laptop based measurement and a hard drive packed full of tunes. The "something to do" could be updating that music collection with lots of exploring and listening.But I can't take my whole bench with me!
Meanwhile, where's the cute little woofers, neo magnets, at least 90db efficient (preferably better), 8 ohms, can actually handle 15W, grace 65hz flat and wants a small portable box? Does not exist?