Thanks for these explanations. 😉
I was looking for a T Amp with a good headphone output but it's not easy to find one.
TeddyK,
I that think the "no common output leads" limitation I mentioned applies to nearly all (if not all) Class D amps so that's probably why you won't see any headphone output. You need to go with a different topology in a separate amp or added into a Class D amp (but I don't know if anyone even makes that added function in a Class D amp).
You'll probably need a separate headphone amp. The headphone amps I mentioned (Crack and FiiO) are both really good - the small, portable FiiO is under $60 as I recall. Of course you can also build a DIY headphone amp, and there are quite a few kits as well.
Les
I that think the "no common output leads" limitation I mentioned applies to nearly all (if not all) Class D amps so that's probably why you won't see any headphone output. You need to go with a different topology in a separate amp or added into a Class D amp (but I don't know if anyone even makes that added function in a Class D amp).
You'll probably need a separate headphone amp. The headphone amps I mentioned (Crack and FiiO) are both really good - the small, portable FiiO is under $60 as I recall. Of course you can also build a DIY headphone amp, and there are quite a few kits as well.
Les
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TeddyK - fit a step-down trafo on the output of any classD amp. You won't look back, dynamics will be to-die-for. Using a trafo means you can common up the grounds (for 3-wire cans) even when the amp's output is BTL.
I think one of the best headphone amps you can buy is the Objective 2 or O2. It comes as kit for $40 or built for $130. Look at the designer's website he has data showing how well it works. It is a great preamp for regular amps too.
NWAVGuy'a website discussing design:
NwAvGuy: O2 Headphone Amp
Can buy it here:
JDS Labs - Objective2 Headphone Amplifier
The best money can buy for 40$. Otherwise it lacks dynamics in sound for my taste.
Thanks for your responses about Headphones on Classe D amp.
I 'm interested in Building O2 amp kit if it's not too difficult.
I 'm interested in Building O2 amp kit if it's not too difficult.
Hi, please give me an example of such a ready available transformer that would fit such purpose (and also the wiring diagram that could permit that common GND on the output), I would like to try your sugestion
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No ready-made ones that I'm aware of - this needs DIY winding. I've used PQ ferrite cores for my headphone trafos and they're available from Mouser, though for some reason they don't stock bobbins for them. RM14 cores though should be just as good and Mouser stock the full range of hardware - rm14 ferrite Ferrite Cores & Accessories | Mouser
<edit> If you'd like some hand-holding for how to design the trafo I'll be happy to do that - best open a new thread for it though.
<edit> If you'd like some hand-holding for how to design the trafo I'll be happy to do that - best open a new thread for it though.
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The O2 was my first build. It isn't too difficult, but I'd suggest practicing your soldering first. It's a rewarding project.
There are headphone amps with fewer parts, but if you have the patience to solder more components onto the PCB, the O2 is no more difficult.
BTW, the kit is $70.
JDS Labs - Objective2 DIY Kit
Another option may be Audio Poutine, providing he still stocks O2 kits. A very helpful guy.
https://www.facebook.com/AudioPoutine
multiple pop issues
Hi all,
Yesterday came a new issue I never had while modding a yj 3116 blue board:
With this modded board, when turning on, I have not a single 'pop' in my speakers, but 3 pop, 1 big pop, 1 second later another one, and 1 second later another one.
I don't know if it comes from a bad soldier, or bad component,
the difference with my other boards is I have 7.8uf at input dc decoupling cap
1 wima MKP 1uf 250v and 1 k73-16 6.8uf 250v
my other mods are:
tdk x7r as bootstrap capacitors
panasonic oscon as dc power caps
330pf/10R bootstrap mod
despite this bad pops, sound is very good.
any help to understand why 3 pops at start up ?
Hi all,
Yesterday came a new issue I never had while modding a yj 3116 blue board:
With this modded board, when turning on, I have not a single 'pop' in my speakers, but 3 pop, 1 big pop, 1 second later another one, and 1 second later another one.
I don't know if it comes from a bad soldier, or bad component,
the difference with my other boards is I have 7.8uf at input dc decoupling cap
1 wima MKP 1uf 250v and 1 k73-16 6.8uf 250v
my other mods are:
tdk x7r as bootstrap capacitors
panasonic oscon as dc power caps
330pf/10R bootstrap mod
despite this bad pops, sound is very good.
any help to understand why 3 pops at start up ?
A number of weeks ago I reported that my Ybdz boards did this from the get go but the popping for me didn't stop after a while. I replaced the main capacitors and it did nothing. So I too am eager to hear any more insights on the issue.
From data sheet "SLOS708C –APRIL 2012–REVISED NOVEMBER 2013"
"The impedance seen at the inputs should be limited to an RC time constant of 1 ms or less if possible. This is to allow the input dc blocking capacitors to become completely charged during the 10 ms power-up time. If the input capacitors are not allowed to completely charge, there will be some additional sensitivity to component matching which can result in pop if the input components are not well matched."
So there is a probability that larger input caps will produce pop issues.
The use of a power-up mute circuit should let the amp settle without speaker pops.
🙂
"The impedance seen at the inputs should be limited to an RC time constant of 1 ms or less if possible. This is to allow the input dc blocking capacitors to become completely charged during the 10 ms power-up time. If the input capacitors are not allowed to completely charge, there will be some additional sensitivity to component matching which can result in pop if the input components are not well matched."
So there is a probability that larger input caps will produce pop issues.
The use of a power-up mute circuit should let the amp settle without speaker pops.
🙂
Attachments
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I use 10uF/16V ceramic.
IMHO a smaller physical size of cap closer to the ground plane picks up less radiated interference.
If you like the sound of something different then do that.
Table 2 in the data sheet provides some examples of various values.
TI suggests that:
"If a flat bass response is required down to 20 Hz the recommended cut-off frequency is a tenth of that, 2 Hz."
Input impedance depends on the gain selected...and that works with the coupling cap to calculate the cut-off.
Doug
As this thread is kind of longish by now the question might have been asked before: Is it possible to run two TPA 3116 boards from one PS?
Any feedback will be appreciated - thx.
dubai
Any feedback will be appreciated - thx.
dubai
***
"Possible" yes but whether it's advisable is a different question. Unless the power supply is powerful enough for both amplifiers running at the same time it will compromise the performance of both amps. I've found that amplifiers like to have their own dedicated power supply, so that keeping them completely independent normally results in better sound quality. As usual, there's a trade-off, in this case between better sound quality and optimum performance vs. convenience and cost savings. Only you can decide the best way to resolve those competing factors.