I also want to try those TPA3116D2 boards. But I'm not a fan of 2.1 system nor those with additional tone circuit. I also prefer output inductors to be red toroid type. But those boards with plain L/R stereo don't come with toroid inductors. I hope there will be new boards next year that use toroid...
As for FM, what about digital FM ? It should not be affected much as regular analog FM.
Still enjoying the 7297 amp...........
As for FM, what about digital FM ? It should not be affected much as regular analog FM.
Still enjoying the 7297 amp...........
I don't listen to FM radio here since I don't care for many of the stations here, and the ones I do listen to don't have great signals. I would not recommend this amp for radio listening as noise I hear is RFI. It's too bad this amp has this noise, because it is a great sounding amp. I think the situation might improve if I put this amp in a metal enclosure to minimize RFI from the circuit.
The TDA7297 is a fine amp in itself. It's not like the Sure amp wipes the floor with it. Both amps are great, and it is always a good thing to have choices.
I do not think most serious audio enthusiast are interested in the least in these amplifiers, the Tannoy list show complete indifference. It is just audio on the cheap at present.
I use large corner speakers with my equipment against an adjacent wall so the leads are long, one lead runs under the floor, through the basement and up.
With all the switching amps I have purchased I picked up lots of RF interference, which I learned was through the long speaker leads. This problem is well documented, even TI mention the importance of short speaker leads.
I still enjoy fm and there are a couple of classical stations here in Montreal that are particularly good.
I am using the 7297 with a cheap ebay fm tuner module, same as yours without bluetooth, with 18 inches of wire for an antenna HANGING DOWN and the reception is crystal clear and quiet.
It's not just me, see post #119 of this thread. Note the tuner.
I was hosting a Christmas party the other day with me entertaining my guests with music. I usually play my acoustic guitar and condenser mic through an acoustic guitar amplifier (Acoustic AC30, which I like very much). But I decided to use the 7297 amplifier with the Tannoys instead. I plugged my MXL 990 condenser mic into the Behringer Xenyx 1202FX mixer and then RCA L/R linked to the 7297 amp. The single mic picked up both the vocal and guitar nicely. I dialed in a little bit of echo on the mixer and I had nothing but praise.
With moderate level of volume, the amp didn't get hot at all. It was at most lukewarm. Then one of the friends indicated he wants one too. I gave away to him my spare unit (bought two of them)......
So far my total cost on the amp has been very minimal:
Amp-$4.5
Aluminum chassis-$2 (the wooden base was given by my neighbor)
Input caps-$1
Tank cap-$1
Speaker terminals - $4
RatShack power switch - $3
Volume knob - $1
SMPS-$7.5
The rest of the needed parts or hook up wires etc were from salvage.
-AC
With moderate level of volume, the amp didn't get hot at all. It was at most lukewarm. Then one of the friends indicated he wants one too. I gave away to him my spare unit (bought two of them)......
So far my total cost on the amp has been very minimal:
Amp-$4.5
Aluminum chassis-$2 (the wooden base was given by my neighbor)
Input caps-$1
Tank cap-$1
Speaker terminals - $4
RatShack power switch - $3
Volume knob - $1
SMPS-$7.5
The rest of the needed parts or hook up wires etc were from salvage.
-AC
Well, I wouldn't want to do without the matching tuner, so I bought one in Silver. It was $9 and comes with mp3 SD playback, chip voltage regulator and remote control. Thanks for the tip!
I found a very small sort of 70's looking alloy case covered in some vinyl woodgrain, and I turned the front panel to bright silver brushed aluminum. Next, the silver colored plastic tuner (with red led display), and see what happens.
Maybe LED VU meter up each side?I found a very small sort of 70's looking alloy case covered in some vinyl woodgrain, and I turned the front panel to bright silver brushed aluminum. Next, the silver colored plastic tuner (with red led display), and see what happens.
Sounds cool, how about posting a pic.
I should really find a box, the wife is getting annoyed, but even she admits It all sounds so good.
http://s20.postimg.org/h0zeml30d/pieces.jpg
http://s20.postimg.org/h0zeml30d/pieces.jpg
I have been fuzzing (messing) around this amp on and off past few days. I didn't like the salvaged pot so I decided to use the stock pot. I also removed the diode and shorted it with a link...
I feel a bigger sound stage. Bass is strong and tight. The amp is very comfortable to listen to. The wife is shopping and the volume is up now....
I recently removed the diodes from my two TDA7297 amps, and replaced them with solid Copper core jumpers. The improvements were subtle, but worth the time to do it. The diode protects against a wrong polarity connection to the power supply. It's not even on the STM data sheet circuit, but the diodes are added by the manufacturers to keep people from damaging the chip. Time to look into a regulated linear power supply.
IMHO, the diode does nothing except to guard against wrong polarity connection. Some might just connects to a transformer and let the diode rectify to DC. The 2200uF tank then acts as the smoothing cap after rectification. I am sure one will not get good sound quality from this setup.
I first tried with my linear PS then I moved to SMPS. They are very close but the linear PS gives a little more "old" sound (maybe a little relaxed sound, I'm loosing words here), sort of like the same feeling of listening to a quality 1955' tube FM radio. The SMPS is not inferior but gives a little bit more speed for the sound.
I really like this amp and have been using it daily.
The two kits I ordered from ebay have shown up.
One of them is short a wima cap.. but then I cant be sure I didnt lose it when I opened the envelope at the mailbox.
But anyway they look OK.. planning to assemble one almost stock, and one with different bits. I think I'll bypass the voume pot and 3.5mm jack on both though.
(pic shows parts from one kit, bit PCB from both to show each side of the board).
One of them is short a wima cap.. but then I cant be sure I didnt lose it when I opened the envelope at the mailbox.
But anyway they look OK.. planning to assemble one almost stock, and one with different bits. I think I'll bypass the voume pot and 3.5mm jack on both though.
(pic shows parts from one kit, bit PCB from both to show each side of the board).
And here it is.. quickly assembled into a 60cent plastic tray thing from the discount shop.. the slots handy for adding sockets without drilling and ventilation as well...
I've got a 12VDC 18W linear PSU and a 12V battery to play with, now it;s sounding OK on my test speakers running full range I'll try it as the HF amp in my active system (miniDSP into compression drivers).
With the 12V linear PU it uses 4.7W mains power running idle and about 5-7W playing music quietly. Not bad at all.
maybe!
Though the closest I've got in testing it so far is some Sonic Youth
I've been running it a few days now and it's sounding very pleasant. I replaced a hifimediy T2 amplifier doing high frequency duties in my active setup after matching adjusting to match levels closely using the miniDSP tools.
I have assembled unit #1 with the stock parts the kit came with, though I have left off the volume control and 3.5mm jack.
I'm using 110dB sensitive compression drivers, with about 7dB of LPAD attenuation and a protection cap, so at 103 dB sensitivity I dont need much power but I do need the amp to run quiet. Crossover point is 600hz.
I tried two 12VDC SMPS and a lead acid battery, and a 20VDC SMPS with an LM317 regulator to drop voltage to 12.7 VDC.
The two 12VDC SMPS turned out to be quite noisy once they warmed up (some kind of interference) even though one works very quietly normally with a Lepai TA2020 amp. Battery power very quiet - but I dont want to keep recharging the battery.
The 20VDC SMPS with the regulator so far is maybe even quieter than the battery.
Neither are as quiet as the hifimediy T2 amp (TK2050 based), but it is quiet enough to not be audible at the listening position, I have to put my ear within 30cm of the waveguide to hear the hiss.
Soundwise it is easily on par, and possibly a bit better, I think.
An extra bonus is the 20VDC SMPS only uses 2W idle, which is about the lowest of any of my amps I've measured. Even when playing power consumption only climbs slightly (as I'm only playing back frequencies over 600hz).
Next step I'm planning to assemble the other board, but with with 0.47uF WIMA mks2 (5mm spacing) coupling caps and a 4700uF low esr cap.
I have one unit with 0.22uF Mundorf Supreme input caps and one unit with 1.0uF Black Gate N input caps. Using the Alan Parsons test CD with 1/2 octave band tones ranging from 20Hz to 20,000Hz, I do not notice a difference between both TDA7297 amps where the bass rolls off, 40-45Hz on my Klipsch Forte IIs in my listening room. What I do notice is that the bass rolls off at lower frequencies with my restored Dynakit Stereo 35 tube amp and Sure TPA3110D2 Class D amp at 31.5Hz. In reviewing the TDA7297 datasheet (Figure 7), the frequency rolls off -1dB at 40Hz and -3dB at 20Hz.
The 7297 is only 15 watts/channel @ 10% THD, so require very efficient speakers to operate well at .1% THD which is about 8W/ch
If you have modern, 4ohm inefficient speakers then the 3116 will sound better.
From what I can remember reading, the Klipsch Forte needs to be driven, so perhaps the 7297 just runs out of steam at the low end where the current is needed?
I don't think it's an issue of enough drive or current from the TDA7297. I've easily exceeded 95dB SPL in my listening room with plenty to spare. As I pointed out before, the frequency response of the amp itself is not flat down to 20Hz. This is clearly cited on the datasheet and I verified it in my listening room with a sound meter and test CD. That said, I still really like the TDA7297 and I would recommend it to people who don't like the Class D amps for whatever reasons, but still want a great-sounding budget amp. In fact, I like both amps than many more expensive amps I've heard, SS and tubes. It basically just comes down to personal preference. Some will like it more than the TPA31xx Class D amps, and some won't. To my ears, these amps are more similar than different.