Just like monoblocs versus stereo.I'm starting to get a bit confused (not difficult) and need some enlightenment. What exactly is the purpose of the 2 VCC's and how does it improve the performance of the chip? Help greatly appreciated. Cheers
Monoblocs and dual-mono have some advantages:
1). Stereo width separation for greater imaging immersive qualities.
2). When the left channel gets burdened for a bass beat, it doesn't blur the right channel.
3). When the right channel gets burdened for a bass beat, it doesn't blur the left channel.
4). Greater dynamic impact power, at lower distortion than the stereo amplifier.
This can be a significant improvement over the ebay amp board.
These are all power circuit functions, and successful decoupling requires a series element--I think that diode, transistor and regulator are the most attractive series elements for audio power circuits.
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For high end power, check out the Tracking Pre-Regulator application in the ST LM338 datasheet. Be sure to add the protection diodes similar to the simple application. Tracking Pre-Regulator has a colloquial name: "nested regs." This highly filtered power is seen in high end radios and preamplifiers, but it can be done with small power amplifiers too. This can be a significant improvement over the ebay LM338 kit.
Well, if your household voltage fluctuates quite a bit, a regulated voltage supply would be helpful.
Generally speaking, a CLC psu will provide very little ripple voltage, which is great. However, how much benefit will depend on the PSRR of your amp. However, chokes are relatively expensive too.
Regards,
The ouput of these amps are very low if distortion is to be kept to a minimum, so realistically, they require very efficient speakers. I'm not sure that power supplies will alter this fact.
If efficient speakers are not available then would not stepping up to a more powerful chip be the least expensive way to go?
I'm thinking room filling quality sound out of these amps, not little nearfield computer monitors.
If efficient speakers are not available then would not stepping up to a more powerful chip be the least expensive way to go?
I'm thinking room filling quality sound out of these amps, not little nearfield computer monitors.
Agreed 100%. I've put my hands up for some boards, I'm fully aware of the prototype nature, as anyone following the thread is, but this is DIYaudio forum, it's part of the fun! I think it's great.
I've got a tweaked $6 kit board and it's great, but curious to see how far the chip can be taken.
The power supply doesn't alter that.
What the regulated power supply is doing is 1) removing noise and 2) power surge protection.
However, the amplifier board power decoupling circuit can either harm or help transient dynamics, such as bass impact. The amplifier board power circuit shown by Trileru is capable of at least double the dynamic power and it may do more. In this case, speakers with 3db less efficiency could be used and still manage to rattle the windows pleasantly.
From what I understand, a 3db increase, or doubling of power is barely noticeable to the human ear. Also, in recordings, bass is just about always monoed center so there is none of the interaction between channels
mentioned in a previous post.
Well, I am not sure whether the low frequencies are purposely recorded in mono. It is the character of low frequencies that the lower it gets, the more "unipolar/omnipolar" (non-directional) it becomes. That's why for home theater setup, typically only a sub is required. However, there are a few home theater "connoisseur" advocate the use of two subs.
I am sure that in my system, I can detect a doubling of the power of my amp. Also, it is more easily to detect the doubling of power at lower sound levels than at high sound level. I do not think the detection of sound levels by our ears is linear.
Regards,
It isn't linear: http://www.lafavre.us/sound-loudness.jpg
But that has nothing to do with perceiving of increase in sound level I think.
But that has nothing to do with perceiving of increase in sound level I think.
You may detect a 3db increase, which is a doubling of power, but it will not be a doubling volume.
To make a slight noticeable gain on a TDA7297 there must be an increase of 3db at least, which would then increasing the power from 15 to 30w/ch
To achieve this by changing a few components is probably not possible?
There is a drum pingpong effect at the beginning of 'Money for nothing', I would be interested to know how a 3 channel amp would handle it?
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After the original posting and almost 300 replies since last March, you have NOW decided to change the description.Moved to chip amps.. Reported as not being a class D amplifier.
Read somewhere in the website that class AB amp doesn't like regulated supply as it cannot provide the transient and dynamic current when the music required, unlike class A amp which runs on constant current supply... so an unregulated is more suitable? But will this cause problem if supply voltage spike?
Watts versus Effective Watts? This is much different!
However,
Dynamic peak music power is current related AND may deliver high amperage charge in excess of normal capacities, but only for brief moments, such as initial bass impact, indeed the difference between "Fluff!" versus "THUNDERSTRIKE!" which can be effectively much louder than 3db.
Notably, the human ear can detect differences at much greater sensitivity than levels.
The amplifier board power decoupling caps are signal caps and require a series element (resistor or diode or transistor or regulator) to avoid/hinder/block the error of using the entire power supply board as a muddy signal cap. Notably, the series element can also separate the left and right to block crosstalk since we should not have the left channel audio pollute the right channel signal caps nor vise versa and amplifier board power decoupling caps ARE signal caps, so we should treat them as such.
The amplifier board power decoupling caps need sized specifically to support each different design, with neither too small per bad tone nor too large per bad resolution, but right-sized for the task.
If the amplifier board power decoupling caps need to be outside the range of 220u~470u, I suggest to correct the amplifier stability compensation error before proceeding. Maximum scale for normal is approximately 470u in parallel with another 470u of same model. Larger sizes may be used to correct the tone problems of an unstable amplifier at the cost of trading resolution for tone, but it may be better to fix it before proceeding.
When the amplifier board power decoupling is both forced to work (with an effective series element) and Right-Sized (for a specific audio amplifier), then you can expect that amplifier to play louder with lower distortion and greater dynamic impact power and clarity. It is audible.
RMS power is meaningless unless the load and the distortion percentage is expressed with it, such as 10W@8R@1%THD, which is fairly practical. If the Dynamic Peak Music Power is increased so that a given audio amplifier can play louder with less distortion, then an accurate RMS figure also increases, like 14W@8R@1%THD. This figure does not really express the sound of it, since even a small amplifier could cause ripples in the carpet like a rock thrown into a pond.
Non audio example:
Compare a 4000W fan forced electric furnace wasting the radiant energy into a cabinet while creating cold breezes at your legs against a Presto Heat Dish Plus at 1100W giving you a sunburn indoors, to see that Watts is not the same concept as Effective Watts. Electrothermal conversion is 100% in both cases, HOWEVER: The effectiveness difference is 300% nominal, 400% peak. And, there's a stunning difference in the bill. Therefore, I suggest that Watts does nothing other than measure waste exhaust. Watts certainly doesn't measure performance.
RMS power is voltage related, doesn't exceed the rails AND each time you double the wattage, all you get is 3db more from the speaker, so that the difference between a 30W amplifier versus a 60W amplifier is really an unimpressive 3db.
However,
Dynamic peak music power is current related AND may deliver high amperage charge in excess of normal capacities, but only for brief moments, such as initial bass impact, indeed the difference between "Fluff!" versus "THUNDERSTRIKE!" which can be effectively much louder than 3db.
Notably, the human ear can detect differences at much greater sensitivity than levels.
The amplifier board power decoupling caps are signal caps and require a series element (resistor or diode or transistor or regulator) to avoid/hinder/block the error of using the entire power supply board as a muddy signal cap. Notably, the series element can also separate the left and right to block crosstalk since we should not have the left channel audio pollute the right channel signal caps nor vise versa and amplifier board power decoupling caps ARE signal caps, so we should treat them as such.
The amplifier board power decoupling caps need sized specifically to support each different design, with neither too small per bad tone nor too large per bad resolution, but right-sized for the task.
If the amplifier board power decoupling caps need to be outside the range of 220u~470u, I suggest to correct the amplifier stability compensation error before proceeding. Maximum scale for normal is approximately 470u in parallel with another 470u of same model. Larger sizes may be used to correct the tone problems of an unstable amplifier at the cost of trading resolution for tone, but it may be better to fix it before proceeding.
When the amplifier board power decoupling is both forced to work (with an effective series element) and Right-Sized (for a specific audio amplifier), then you can expect that amplifier to play louder with lower distortion and greater dynamic impact power and clarity. It is audible.
RMS power is meaningless unless the load and the distortion percentage is expressed with it, such as 10W@8R@1%THD, which is fairly practical. If the Dynamic Peak Music Power is increased so that a given audio amplifier can play louder with less distortion, then an accurate RMS figure also increases, like 14W@8R@1%THD. This figure does not really express the sound of it, since even a small amplifier could cause ripples in the carpet like a rock thrown into a pond.
Non audio example:
Compare a 4000W fan forced electric furnace wasting the radiant energy into a cabinet while creating cold breezes at your legs against a Presto Heat Dish Plus at 1100W giving you a sunburn indoors, to see that Watts is not the same concept as Effective Watts. Electrothermal conversion is 100% in both cases, HOWEVER: The effectiveness difference is 300% nominal, 400% peak. And, there's a stunning difference in the bill. Therefore, I suggest that Watts does nothing other than measure waste exhaust. Watts certainly doesn't measure performance.
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Regulated is suitable if an effective series element is placed between the power supply and amplifier. For more interesting reading, I suggest the JLH story at startfetch <--link If you're in a hurry, scroll to the circa 2003 example of a practical audiophile amplifier. John eliminates the sound of negative feedback throwing the baby out with the bath water by removing the feedback loops from the power supply. However, I suggest that we could do something almost as effective by using diode isolators so that the sound of the power supply has less effect on the amplifier's sonic signature.
See Trileru's amplifier board designs and in that case, I doubt there would be any lack of dynamics power, even if you use a regulated supply to protect the amplifier reasonably. His boards also show separate left and right series elements, which is really effective.
You're right though, what we wouldn't want to do is apply a regulator's negative feedback loop directly to an audio amplifier because that would form an audio compressor when the signal is forced to resemble the reference.
So, I suggest reviewing the practical information at decibel dungeon. Building an LM3886 Gainclone chip amp with a regulated power supply (PSU). Also see "Tracking Pre-Regulator" Using 3-pin regulators off-piste: part 4 The nested feedback loop is the anti-feedback loop, so the tracking-pre-regulator removes its own noise and doesn't form a compressor.
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Then why does this little amplifier sound so good, they have no high current capabilities? I hear no difference in volume or any sonic deterioration when adjusting the supply voltage from 6v to 18v while in operation.
Could it be my large, efficient speakers? Conducting this test, http://www.diyaudio.com/forums/mult...much-voltage-power-do-your-speakers-need.html
they only draw 0.085w/ch rms or 0.170w/ch peak at my serious listening level.
Way back, audio enthusiasts were quite happy with their 6 or 12 w/ch until America started a crazy power race in amplifier and speakers.
I have an article here on how, in the 50's, at the Royal Festival Hall in London and at Carnegie Hall in the States were the venues for an audio experiment. Live orchestral music was compared to recorded music in an A-B type test.
What is most amazing is that only about 60w of tube amp power was all that was required!
Amps have since got more powerful and less detailed and small inefficient speakers are much cheaper to make, I think there has been a big trade off.
What kind of power supply topology would be most appropriate for this amp? Excluding smps, anything else? Something that I could diy, make a pcb etc. How about a capacitance multiplier since there have been reports of no quality loss when unstable voltage?
I modified my regulator board so it supports a tracking pre-regulator now, but I might just do another design and make pcb for all 3 versions
I also have a ta2020 amp that I'm going to test the PSUs on.
I modified my regulator board so it supports a tracking pre-regulator now, but I might just do another design and make pcb for all 3 versions
I also have a ta2020 amp that I'm going to test the PSUs on.
Way back, high power transitor amps did not exist. Making high power tube amp is no easy task as compare to making efficient speakers those days.
Would you mind telling me where I can find that article please. I found it intriguing. A 60 W amp is "equivalent" to an orchestra of 100 people (estimate)?! I cannot imagine the 60 w amp can deliver the same impact as that when the typamni, the brass instruments and huge drums are going at full force. Could it be the venue that's playing some tricks. Were they simply measuring the SPL at a certain point?
I actually think that amps are getting better and better over the years. Comparing a transistor amp from the 70's to even a "run of the mill" receiver these days will prove my points. Even the remake of vintage design tube amps are sounding better due to better components.
Efficient speakers of the earlier years are mostly horns (speaker make of a single full range driver are quite efficient too). They are efficient no doubt. But not everyone like their sound signature. In comparison, modern day speakers are relatively less efficient due to the type of drivers used and the associated cross-overs needed. However, I personally found that a lot of these "cheap inefficient speakers", such as those from PSB sound quite nice and they can be driven using inexpensive electronics.
Ooops! I think I am way off topics and I better stop here.
Regards,