good morning,
this may be opening an entirely new can of worms... but, i'm not entirely sure what using feedback before the lowpass [filter] means. i am not married to using the TK2050, is there another D-Amp you would recommend? i don't know how critical a feature this might be, surely yet another subject of contention among audio enthusiasts
before i immediately begin asking questions about the best way to add electrolytics to the incoming power, i want to make sure i understand the principals of what you are saying :
correct?
that brings up a few questions for me...
first question -
you have mentioned a few different possible input voltages, as well as suggesting a "weaker" supply for 25 watts RMS. but i feel like you have not specifically recommended a voltage/amperage formula for this amp and the speakers i'm planning on using. did i miss it in your reply?
for reference, i am considering using one of these for my power supply :
24volt 150watt LED supply
or
25volt 200watt DROK power supply for audio
i feel like the LED supply would be more noisy, but that might just be an uninformed bias. obviously since this conversation is about not oversizing the power supply, maybe the 200watt DROK is too much? there is also a 100watt LED supply of similar construction from the same vendor.
second question -
how does volume control work? would i be limited to changing my source volume, and leaving the amp just "on". so the amp would always be putting out 25 watts? it seems like changing the volume would lower / raise the wattage being sent to the speakers.
now i'm thinking that i should consider the RMS of a speaker to be the highest sustained level of power they take... and that they will be fine with anything lower than 25 watts (as in, playing music at a quiet volume in the evening), and that peak rating means the upper limit of short-burst volume?
so many things to learn
thanks again for your continuing help.
this may be opening an entirely new can of worms... but, i'm not entirely sure what using feedback before the lowpass [filter] means. i am not married to using the TK2050, is there another D-Amp you would recommend? i don't know how critical a feature this might be, surely yet another subject of contention among audio enthusiasts
before i immediately begin asking questions about the best way to add electrolytics to the incoming power, i want to make sure i understand the principals of what you are saying :
it sounds like your recommendation is that i provide the amp the right power for it to function at continuous duty (to use a term i am more familiar with) outputting 25 watts. that would give me matching RMS output from my amp and what my speakers want.
but by sizing the power supply so that the amp is basically at the limit of its capacity outputting 25 watts. then add electrolytics into the equation to cover short duration bursts of higher output.
but by sizing the power supply so that the amp is basically at the limit of its capacity outputting 25 watts. then add electrolytics into the equation to cover short duration bursts of higher output.
correct?
that brings up a few questions for me...
first question -
you have mentioned a few different possible input voltages, as well as suggesting a "weaker" supply for 25 watts RMS. but i feel like you have not specifically recommended a voltage/amperage formula for this amp and the speakers i'm planning on using. did i miss it in your reply?
for reference, i am considering using one of these for my power supply :
24volt 150watt LED supply
or
25volt 200watt DROK power supply for audio
i feel like the LED supply would be more noisy, but that might just be an uninformed bias. obviously since this conversation is about not oversizing the power supply, maybe the 200watt DROK is too much? there is also a 100watt LED supply of similar construction from the same vendor.
second question -
how does volume control work? would i be limited to changing my source volume, and leaving the amp just "on". so the amp would always be putting out 25 watts? it seems like changing the volume would lower / raise the wattage being sent to the speakers.
now i'm thinking that i should consider the RMS of a speaker to be the highest sustained level of power they take... and that they will be fine with anything lower than 25 watts (as in, playing music at a quiet volume in the evening), and that peak rating means the upper limit of short-burst volume?
so many things to learn
thanks again for your continuing help.
To quote my earlier message:
So no input signal amplitude (no music) - no output power. A low input signal amplitude (quiet music) - low power on the output. Full input signal amplitude (music at full volume) - max output power. If power supply is limited to less than full power, full peak power is only achieved for a short time, supplied by the capacitors.
good morning,
thanks for responding
so, the RMS output (which i always considered the lowest output) is more accurately described as the maximum continuous output from the amp. with peak power (which manufacturers are always sure to mention) really just a more transient level, and mostly mentioned to tell you what the amp can provide without self-damage. correct?
if my speakers are rated as 25 watts RMS, i should consider that to be the wattage they will use while playing at the highest listening level?
so i should size my power supply to drive the amp at 25 watts, when my input source it at full volume?
any listening at lower levels will happen at under the 25 watts, below the RMS rating for the speakers. is that ok?
thanks for responding
so, the RMS output (which i always considered the lowest output) is more accurately described as the maximum continuous output from the amp. with peak power (which manufacturers are always sure to mention) really just a more transient level, and mostly mentioned to tell you what the amp can provide without self-damage. correct?
if my speakers are rated as 25 watts RMS, i should consider that to be the wattage they will use while playing at the highest listening level?
so i should size my power supply to drive the amp at 25 watts, when my input source it at full volume?
any listening at lower levels will happen at under the 25 watts, below the RMS rating for the speakers. is that ok?
Morning!
Correct - well, the peak power is pretty much limited by the amp supply voltage, without any danger of damage to the amp.
Analog sources are a bit trickier, in that there isn't a hard limit to the maximum signal - you just get more clipping/distortion, but on the other hand, your 25 W spec for the speaker is approximate anyway, and the speaker can survive much more as long as it is only short peaks.
There are two different common failure modes for speakers - one is the voice coil overheating and burning due to too much continuous power (usually an issue with mids and tweeters) and the other is mechanical overextension and breakage due to excessive cone excursion (caused by really excessive peaks, usually with woofers).
Correct - well, the peak power is pretty much limited by the amp supply voltage, without any danger of damage to the amp.
It is the highest power you can keep playing at without damaging the speaker.
Yes. A lot depends on your source. Digital sources have an easily defined maximum level ("full scale") and they simply can't exceed that. I have a 400 W amp driving a 50 W-rated speaker, but I have limited the gain so that even at full input signal, the output doesn't exceed 50 W or so, even if both the amp and the power supply are capable of much more.
Analog sources are a bit trickier, in that there isn't a hard limit to the maximum signal - you just get more clipping/distortion, but on the other hand, your 25 W spec for the speaker is approximate anyway, and the speaker can survive much more as long as it is only short peaks.
There are two different common failure modes for speakers - one is the voice coil overheating and burning due to too much continuous power (usually an issue with mids and tweeters) and the other is mechanical overextension and breakage due to excessive cone excursion (caused by really excessive peaks, usually with woofers).
good afternoon,
after doing some skimming online for gain control, i came across the SainSmart NE5532, which is advertised as a volume (gain) and tone pre-amp.
would this be a suitable candidate for getting at least some kind of control over analog sources?
i would assume that the "volume" control function is directly limiting the signal voltage delivered to the amp.
could it possibly be as simple as :
1. install this pre-amp card inside the receiver housing, so it can't be accidentally adjusted.
2. supply a music source to the pre-amp, at maximum listening volume.
3. meter the output from the d-amp, and turn the "volume" knob on the pre-amp up until i get 25watts.
4. volume control is provided by source, but d-amp output should not exceed 25watts.
after doing some skimming online for gain control, i came across the SainSmart NE5532, which is advertised as a volume (gain) and tone pre-amp.
would this be a suitable candidate for getting at least some kind of control over analog sources?
i would assume that the "volume" control function is directly limiting the signal voltage delivered to the amp.
could it possibly be as simple as :
1. install this pre-amp card inside the receiver housing, so it can't be accidentally adjusted.
2. supply a music source to the pre-amp, at maximum listening volume.
3. meter the output from the d-amp, and turn the "volume" knob on the pre-amp up until i get 25watts.
4. volume control is provided by source, but d-amp output should not exceed 25watts.
Do you have a preamp? How are you going to adjust volume in general?
Instead of a separate volume control stage set for a "fixed", pre-adjusted gain, you are probably OK with just a couple of resistors.
Technically no. It is not limiting voltage, it is regulating gain. If the analog source gives out a 2V peak over a nominally-1V-output (tape recorded too "hot', scratches on vinyl, etc.), it won't really help. What are your sources?
good afternoon, thanks for continuing help
i was just planning on controlling the source volume, since controlling the input volume is lower on my priorities than figuring out the right power-supply. i'm open to suggestions, including a PCB pre-amp if a decent one exists for under $30.
i rather like the look of this LM3886TF*, which has an integrated NE5532.
should i consider the NE5532 as more of a general volume control, rather than a gain control?
just for the volume control feature, it might be worth considering the LM3886TF as a superior option to the TK25050.
*please forgive the ebay link, i can't find the same part elsewhere.
this will be a complete stand-alone system for my girlfriend. since she has nothing to play music on, except for woeful laptop speakers. source will be from the 3.5mm audio-out on her laptop or ipod. until such time as i can add a proper DAC to the my project, and then that will be the primary source.
would installing two nice potentiometers (one for each channel) between the input RCA jacks on the outside of the housing, and the input on the D-amp, serve just as well for gain control? the main goal is to have them be adjustable... but not accidentally so.
trying to design this so that nothing can be hurt by one of her friends plugging in their own phone and turning the volume on everything all the way up.
i would definitely like to have an external volume control knob on the receiver, in addition to the gain limiting ... device
i was just planning on controlling the source volume, since controlling the input volume is lower on my priorities than figuring out the right power-supply. i'm open to suggestions, including a PCB pre-amp if a decent one exists for under $30.
i rather like the look of this LM3886TF*, which has an integrated NE5532.
should i consider the NE5532 as more of a general volume control, rather than a gain control?
just for the volume control feature, it might be worth considering the LM3886TF as a superior option to the TK25050.
*please forgive the ebay link, i can't find the same part elsewhere.
this will be a complete stand-alone system for my girlfriend. since she has nothing to play music on, except for woeful laptop speakers. source will be from the 3.5mm audio-out on her laptop or ipod. until such time as i can add a proper DAC to the my project, and then that will be the primary source.
would installing two nice potentiometers (one for each channel) between the input RCA jacks on the outside of the housing, and the input on the D-amp, serve just as well for gain control? the main goal is to have them be adjustable... but not accidentally so.
trying to design this so that nothing can be hurt by one of her friends plugging in their own phone and turning the volume on everything all the way up.
i would definitely like to have an external volume control knob on the receiver, in addition to the gain limiting ... device
You worry about the number of zeroes after the THD comma and you are using the crappy analog laptop output - that does not fit.
A cheap USB interface will typically improve the situation noise-wise, a set of active speakers can solve all the amp power power supply limiter etc.. troubles for you with or without USB interface........
A cheap USB interface will typically improve the situation noise-wise, a set of active speakers can solve all the amp power power supply limiter etc.. troubles for you with or without USB interface........
Well, Ijason does write:
So sounds like it will be a temporary arrangement (and the ipod audio out is not that bad) until a proper DAC.
A USB DAC won't help with the ipod.
i was mostly interested in the fact that, however you select the mode, the "audiophile" setting on the TK2050 provided 1. low THD - which i think we can all agree is a design goal, and 2. 30 watts of power - which is exactly what my speakers want.
which is why the topic of my thread is "how to find the RMS rating for D amps? speaker matching help". because i have found the speakers i would prefer to use, and am seeking advice about how to know the RMS rating so that i can properly drive them.
further research indicated that lower-powered D-amps could not push 30 watts without getting upwards of 10% THD. i refer to my first point, about low THD being a goal.
in my inexperienced opinion... passive drivers have a much longer life than active drivers. and are more generally reusable: if your needs change you can still add them to an existing system. plus, it seems like every active monitor (in the ~$200 a pair range) is peppered with reviews about speaker hum. there is also the option of adding an A/B switch to whatever receiver i build, and having the feature of driving two different sets of speakers in different locations in the apartment.
if you are done giving me advice on this d-amp, i think you for your very gracious efforts thus far. your advice is both appreciated, and helpful.
if you have decided that you're done helping me with this project and that i should be better off just buying a pair of powered speakers, a usb DAC box, and calling it finished... i will certainly consider than an informed opinion.
i still want to learn more about the advantages of building my own stereo, you know - a DIYAUDIO project, if you will - before i call it quits and just buy everything pre-made. i'm hoping to learn on this project and perhaps build other receivers in the future.
thanks
good afternoon,
after further looking online, would the TDA89x0SMPS from Connexelectronic be a better solution for me?
it includes a SMPS, so there is no question of needing to pair the right power supply to the amp
another advantage is that within all specs, the operating capacity of the amp fits the operating capacity of the speakers i would most prefer to use.
thanks.
after further looking online, would the TDA89x0SMPS from Connexelectronic be a better solution for me?
it includes a SMPS, so there is no question of needing to pair the right power supply to the amp
another advantage is that within all specs, the operating capacity of the amp fits the operating capacity of the speakers i would most prefer to use.
thanks.
good evening,
i think this amp is definitely more closely sized for the speakers i want to use....
the first question that comes to mind, is which would be best - between the TDA8950 (rated at 35watts, 8Ω) or the TDA8950 (rated at 55watts, 8Ω)?
my first instinct is that the TDA8950 would be the right choice, because it is rated just slightly higher than the peak of my speakers - so theoretically the amp should never suffer from clipping, even at full volume.
but i've already learned that my instincts are often incorrect, and i remember that these D-Amps are generally described at their RMS value. in which case the TDA8920 would be the better match, since 35watts RMS is a perfect match for my speakers. but what about clipping the amp?
would volume control be most easily managed by potentiometers between the amp output and the speakers?
thanks.
i think this amp is definitely more closely sized for the speakers i want to use....
the first question that comes to mind, is which would be best - between the TDA8950 (rated at 35watts, 8Ω) or the TDA8950 (rated at 55watts, 8Ω)?
my first instinct is that the TDA8950 would be the right choice, because it is rated just slightly higher than the peak of my speakers - so theoretically the amp should never suffer from clipping, even at full volume.
but i've already learned that my instincts are often incorrect, and i remember that these D-Amps are generally described at their RMS value. in which case the TDA8920 would be the better match, since 35watts RMS is a perfect match for my speakers. but what about clipping the amp?
would volume control be most easily managed by potentiometers between the amp output and the speakers?
thanks.
The amp clipping has nothing to do with the speakers as such. It only has to do with not reaching "flat out" at your maximum listening volume.
You should limit the gain/volume of your system to the point where the amp doesn't clip. With the 55W amp that can be at a louder volume than with the 35 W one, but then your speaker becomes the limiting factor.
The difference in actual loudness between 35 and 55 W is pretty small, so I would go for the 35 W one, leaving a nice safety margin for your speaker.
No - the pots should be at the inputs of the amps - otherwise you end up going full volume all the time, but then burning off most of the power in the pots. They would get rather hot...
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