OP
- Thread Starter
- #21
Yes, there is a copper pad on the bottom of the PCB.
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Allo Volt+ D Amplifier Review
- Thread starter amirm
- Start date
Using the PCB as a heat sink from the looks of it.
Oh yes, there is a version that is made for this. Thanks.
Jimster480
Major Contributor
Looks pretty cool, I actually just received an Amazon budget class D amp for testing.
I might mail it in here and see how it compares.
I might mail it in here and see how it compares.
restorer-john
Grand Contributor
It looks like there's just two single ended regulators, likely capacitance multipliers as they mention for other products, one for each channel and the amplifier will be running each chip in BTL.
OP
- Thread Starter
- #26
Most of the tests are at 1 kHz. Performance varies at other frequencies and that is the measurement that shows it.
In general, amplifiers distort more at higher frequencies.
I looked at the product pictures and thought "wt* am I looking at"
But interesting, below 0.01%, shows that TA3116 lives up to its name if done properly. Now I'm curious how the Tripaths perform.
I also remember crosstalk is something that these amplifiers always fall flat on. Although to be fair, you would be lucky to get 60 or 80dB from even a fairly expensive entry level speaker amp too. So that dual mono ish approach is working.
But interesting, below 0.01%, shows that TA3116 lives up to its name if done properly. Now I'm curious how the Tripaths perform.
I also remember crosstalk is something that these amplifiers always fall flat on. Although to be fair, you would be lucky to get 60 or 80dB from even a fairly expensive entry level speaker amp too. So that dual mono ish approach is working.
restorer-john
Grand Contributor
Using two chips, each in BTL, one for each channel and decoupling the common power supply from one another, has paid dividends in this particular case.
Dont understand what they do at the power input. Isnt 31V not to much for a tpa3116? Remember something about max. 26V? But nice that if implemented right this chips can work well. The problem is looks like they often get not implemented right.
That's why I'm thinking that has to be a linear regulator of some sort. A switching reg probably wouldn't need a heatsink when the load doesn't have a heatsink. And the noise performance is too clean to be from a switching reg anyway, plus the simplicity of the circuit.
The adjustable pots are probably to adjust the output voltage which will be necessary when you change the input PSU by too much. But you're still limited by the output capacitor's voltage rating.
- Joined
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Yep, 31V is way too high for this amp based on the info on its website...
OP
- Thread Starter
- #32
There is no documentation on this on Allo other than saying to get 60 watts, you needed nearly 29 volts. So that is already above the spec for the chip. It clearly was happy at 31 volts and the capacitors are rated at whopping 80 volts!
I am confused by the voltage you are supplying to this amplifier @amirm "I used my lab power supply at its max setting of 31 volts and 3 amps." The dashboard says "13.5V Lab Supply", then we are back to 31V on the power v distortion graphs ? Inconsistency like that drives me crazy are there some typos here ? Also, as someone else mentioned, is 31V above the input for this TI chip, because in any case Allo states 19V-26V for the power supply. *edit wrote this during your reply above.
Some additional tests run at 19V would be extremely useful as well, since that is the power supply voltage Allo has as a bundle, and is also a very common laptop power supply voltage.
are there some typos here ? Also, as someone else mentioned, is 31V above the input for this TI chip, because in any case Allo states 19V-26V for the power supply. *edit wrote this during your reply above.Some additional tests run at 19V would be extremely useful as well, since that is the power supply voltage Allo has as a bundle, and is also a very common laptop power supply voltage.
OP
- Thread Starter
- #34
Sorry, should have been more clear. I did run the dashboard at 13.5 volts since that was at 5 watts. For later tests I upped the voltage to 31.
Looking at the website, it seems the Volt + uses the TPA3118D2 -- not the TPA3116. Assuming the Volt D(ouble)+ uses 2 of them, the TI spec sheet: https://www.ti.com/product/TPA3118D2
OP
- Thread Starter
- #36
That's possible. I had a hard time reading the last digit and was too lazy to get my magnifier.
I see. Not sure I agree with the inconsistency between the different measurements then, not to mention neither 13.5V nor 31V are very 'real world' when it comes to the manufacturer-recommended laptop power supplies. If we're going to have a composite rating like SINAD, then later power v distortion, shouldn't they use the same power supply voltage ? Since this is really a pseudo-integrated amplifier with volume control (I believe the line level input is simply attenuated by the volume pot and does not go through an active pre-amp stage), couldn't the dashboard simply be run with 31V power supply as well, then use the volume knob to lower the output to 5W with a 2V line level source ?
sir_frigorifero
Member
- Joined
- Dec 17, 2018
- Messages
- 76
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- 58
Hell Yeah!!
i've been waiting ages for this review to come and see if i really felt right about the qualities of this amplifier.
i'm coming from quite a few class D budget amplifiers (smsl sa-50 and topping PA3) and to be honest the volt+D felt way better than the others right after the first track. at 19db gain it has almost zero hiss and the power felt "cleaner" than other amps, and this seems to be confirmed by measurements.
to my european fellows, this amplifier is available on Audiophonics
i've been waiting ages for this review to come and see if i really felt right about the qualities of this amplifier.
i'm coming from quite a few class D budget amplifiers (smsl sa-50 and topping PA3) and to be honest the volt+D felt way better than the others right after the first track. at 19db gain it has almost zero hiss and the power felt "cleaner" than other amps, and this seems to be confirmed by measurements.
to my european fellows, this amplifier is available on Audiophonics
restorer-john
Grand Contributor
I don't think the manufacturer "recommends" a 19V supply. It's just that they are extremely cheap due to economies of scale and do a reasonable job for most people. So they can sell them as a cheap add-on. A dedicated 120W 30+V regulated SMPS would be very expensive.
I totally agree with Amir's choice of 31V. The regulators and input polarity protection diodes (looks like a bridge) cumulative Vdrops would mean the chip was well within its maximum rating of 30V. And we want to see what it does at the top end of its performance, not the bottom, or somewhere in the middle.
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