The TPA3251/3255 are 4 single amplifiers. To drive the "other half" of the bridge you need the opposite polarity signal: balanced drive.
If you want only to drive a BTL amplifier with a unbalanced drive then look at the TPA3116/8 series. These can be driven unbalanced and still operate as a BTL output...lower output power though.
I have and he seems very good. He's replied to my questions in a couple of days or less.
To answer some of my own questions (with help from the supplier):
1. Still haven't tried this one...
2. I use a 12V foam mounted PC fan to cool module and PSU and it runs into 4ohm 85db speakers at good levels without issue.
3. I use Conexant/HIFIMEDIY SMPS600RS 48V and there are no turn on or turn off sounds. I always turn off without signal however.
4. The TPA3255 has built in speaker protection against DC if not run in SE mode. The #e Audio is in BTL so we should be fine.
Extra notes: I have run without signal and load momentarily to check fan operation. Seller says it should be ok without a load just to check things like that.
The pin headers do not allow for external LED for clipping etc. You need to either parallel with onboard LED or pick up LED via nearby via and use another ground.
I have tried driving this balanced with a transformer but I only had 600:600 and so got little bass but very sweet sound. I loaded the secondary with increasing load until about 4kohm whereupon I got bass back but there was some sibilance that wasn't there with less loading - and maybe less detail too. Maybe I have some resonance now? I don't know whether putting the load across the primary or secondary makes a difference.. I have even seen series R with the primary in some schematics but I don't know how that might help. I am an input transformer virgin. I am driving it with a NAD M51 which uses TL082 output op-amps which can drive down to 600ohm at line level pretty well.
Perhaps one of the transformer gurus can make a suggestion? I may also try the 20k pot and twiddling as was suggested earlier. So far it was just 3 different resistors. Mine are also line isolation transformers technically, albeit with good bandwidth at reasonable level according to their published specs, but no shielding. I took them from a talkback radio board. I heard no noise though.
Do you think it would be worth buying some of the taobao 10k models to try? I am happy to go back to single ended if people don't think there's an improvement. I just thought the transformers might add a bit of harmonic enrichment and flesh out the imaging. I'm also a bit confused frankly as to whether the transformers (such as 600:600, 10k:10k etc) are directional or not and whether they might behave differently driven from one winding or the other. Any guidance is welcomed. 8)
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I just received and setup the 140w version of the tpa3251 from 3eAudio and I am impressed.
For the time being, I am using it with a 24v supply (from the FX-Audio 502 actually - so nothing fancy).
I have tried quite a few chip amps and to my ears this one is clearly head and shoulders above the others.
In my main system I use hypex Ncore, and have not had a chance to go back and forth between the two, but unlike other budget chip amps this one seems to do everything well and there are no obvious weaknesses.
For the time being, I am using it with a 24v supply (from the FX-Audio 502 actually - so nothing fancy).
I have tried quite a few chip amps and to my ears this one is clearly head and shoulders above the others.
In my main system I use hypex Ncore, and have not had a chance to go back and forth between the two, but unlike other budget chip amps this one seems to do everything well and there are no obvious weaknesses.
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G'day Hopkins, Do you drive yours single-ended or balanced? How do you find the sibilance aspect? I am, as yet undecided on that point but I'm running the more powerful TPA3255 module from him. My speakers are Dynaudio S1.4LEs and so level out at 6ohm I believe at the treble end. I don't know what effect, if any, that has on the frequency response with the inductors that 3e Audio chose. My system has digital eq and the speakers in my environment are hot at the top end anyway so I may have to go elsewhere with the amp to test it out and compare to get a better overall impression. Other than a *possible* very high sibilance sound I think mine sounds wonderful. I will investigate further and report back my findings. I wouldn't take this impression as any kind of putting down of the module as I may be hearing phase issues with my digital eq or the speakers themselves at this point!
I use it single ended. I did not notice any sibilance. I have Harbeth P3ESR speakers.
Hello,
I consider different options, and one of them is this 4 channels board: TPA3251-4CH-100W | 3e Audio
I understand that it is composed of 2x TPA3251. Why is the power limited to 100W per channel (instead of the 2x140W of the stereo board) ?.
I need to pull at least 2x50W to 2x60W in 8R with low THD (and 2x25W in 4R on the other channels). Is it a suitable board for this purpose ?
In that case, what would be an advised power supply (Voltage, power, model if possible).
Best regards,
JMF
I consider different options, and one of them is this 4 channels board: TPA3251-4CH-100W | 3e Audio
I understand that it is composed of 2x TPA3251. Why is the power limited to 100W per channel (instead of the 2x140W of the stereo board) ?.
I need to pull at least 2x50W to 2x60W in 8R with low THD (and 2x25W in 4R on the other channels). Is it a suitable board for this purpose ?
In that case, what would be an advised power supply (Voltage, power, model if possible).
Best regards,
JMF
I also found that when i had some questions, a short, snappy,simple english email got a very helpful response with answers to my questions.
Like it is safe (or fairly safe) to switch between unbalanced and balanced while the board is powered up. so i have a 4 way switch to switch between diff and sd mode + input contacts.
Like it is safe (or fairly safe) to switch between unbalanced and balanced while the board is powered up. so i have a 4 way switch to switch between diff and sd mode + input contacts.
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