pinkmouse said:
A little snobbish don't you think?
A well built chip amp can beat most budget/midrange commercial discrete designs. They do lose out to higher end commercial or well designed diy though, my Krellclone drives loads that the chip amps would give up on, and my Symasym easily beats them in SQ. However, I would willingly put a chip amp up against an ESP P3a for instance.
Hi Pinkmouse,
Snobbery seems to be in the order of the day especially in the DIY environment, someone always has something to say about another persons pride and joy because they have heard, seen, read did better.
There is absolutely nothing wrong or inadequite about single chip devices, it in fact will outperform anything of the same specification per dollar discreet.
Maybe Burntfingers would prefer it if his PC was built using discreet components.
Moreover, in DoD, Aerospace and most vehicle industries I have served in, the fewer components you have the higher your reliability.
I designed, built and owned some very high-end amps in my day and in 1979 built a 20 watt amplifier using a TDA 2020 from Telefunken and a pair of 8" Philips dual cone speakers for my little brother on his 17 th birthday.
Switching between my then highly acclaimed Pioneer SA9100 driving KEF Concertos and fed from my Thorens TD150, was quite a revelation. The TDA 2020 did not sound that much different besides lacking a few watts.
My brother eventually replaced the speakers with a second hand pair of JBL L150 and added a Rotel CD player. He used it until giving it to his son in 2002 on his 17 th birthday.
This was a well spent $ 2.50 at the time, I suppose and it still sounds pretty good even by today's standards.
burnedfingers said:
I revisited the history and my wife confirmed that it was 1973 when my little brother turned 17, I get a little forgetful these days.
Yes, believe it or not. It was highly acclaimed and won almost every best systems award at the time.
I was a audio DIY since the early sixties and I imported my first real commercial amp from Pioneer based purely on reviews at the time and used it another two years before earnestly becoming involved in audio design for commercial gain.
Unfortunately, at the time there was little money in it, only love and most had to have day jobs as well.
Yes, I agree with Pinkmouse, most successful audio designers started somewhere. In my dyas it was a single ended EL34.
I guess I cannot claim the same vanity, since I never worked in a shop or finding the time teaching my dog to apreciate music.
Those who undestand the complete audio chain, from inception through the recording processes and eventually ending with your ears will confirm that an amplifier makes very little difference in the complete chain.
What your dog is listening to in the shop is a far cry from what the musician intended to convey.
It is only your dog's perception of what he thinks it could sound like.
Maybe the dog would prefer listeng to a chip amp. Have you even considered asking your dog or is your opinion the only opinion?
burnedfingers said:
After achieving a D.Sc in electronics I became design engineer at HP signal analysis division in Spokane.
I developed an "audio" amplifier I see is still used throughout their range of function generators having a slew of 200 V/uS, THD15MHz and IMD of less than -97dBc and gain flatness of 0.001 dB with phase non-lineariry of 0.1 dgree over the range 1mHz to 15 MHz.
Later years I still use the knowledge gained from this experience in my own audio amplifier designs regardless of what the gurus say. I have performed designs for other "reputable" companies I consulted for, who are believe it or not still in exixtance other than some esotric companies that builds "high-end" audio equipment in their kitchens.
I believe in amplifiers measuring perfectly. Should you not agree with what you hear I would suggest consulting an ear specialist, if your dog does not agree with it have him put down, he is deaf.
National semiconductors was a fair client of ours and sported more that $ 120M of test equipment from our division only let alone other divisions and manufacturers.
I would like to conclude, working in a shop has little benefit to one who seeks to learn and experience.
A "gain clone", I must admit that I have never built or heard one. It has not crossed my mind even to try, it is not in my interest.
It is as difficult building a discreet product with more that 500 componets than it is building something with a few components.
It has to do with the level of comfortability of the constructor, not his capability. A a solder joint is good or bad regardless of the number of components.
Considering your regard of other DIY memebers indicates only that you have no idea what it is all about except for your own opinion which is most likely founded on what you have experienced in a shop.
Fixing a product is a far cry from designing a product that actually does what one set out to be design. If you fix something, it has been working before so you only have to find what component went wrong it is a simple procedure of elimination.
Well good for you then! I wish I could pat you on the back and boost your ego a little more.
Yet this still makes you an expert, right? But wait!! You do have experience with chip amps.
Isn't the TDA classed as a chip amp? I believe it is.
Personally I would say that if a person cannot solder it does indeed say something about his capability.
Now it would seem that you are an expert in the field of repair also. Oh, thats because your an engineer right?
Well, the drab job of fixing does take into consideration that you have to re-think what some engineer has done and some of the time make corrections to the circuit in order for it to function correctly.
I'm not an engineer and I will be the first to admit this. I have had numerous experience bugging out problems in specific product lines for various companies. Problems that their "engineers" didn't see or didn't want to see.
I'm sorry that you didn't like what I posted and felt compelled to post for all the uncomfortable people out there that cannot solder. I'm also sorry that you needed to take a pot shot at me dispite the fact that you have never built this particular amplifier.
Just for your knowledge...The dog likes the sound of tube amps. He will tolerate the world of solid state somewhat and he shares my opinion for the most part.
Let just take this to email shall we?
I dont understand why people argue about what amp or dac or speaker...etc sounds better. Differant strokes for differant folks. Some like chipamps and some dont. Everyone hears differant and likes a differant kind of sound. All that matters is that you like the sound of the amp, who cares what some person on an internet forum says? I dont play favorites, iveheard good sounding amps of all differant designs from chip amps to tubes and everything in between. It has more to do with how a design is implemented. A well built chip amp will most likely sound better than a poorly built tube amp and vice versa. So how about we stop with the childish arguements, and focus on what people actually come here for which is to have fun and learn about the hobby we love.
rightimperfectcircle said:
no problem nico ras
maybe one of u can anwer to my post on site 2... the one with the picture included.
would be nice
thx
_____________
i want to use this layout for my power supply
An externally hosted image should be here but it was not working when we last tested it.
not my design and not my engineering
but i want to substitute the 6.800µF caps by 10.000µF and 250VA torodial per channel
thx
The design is fine and you can substitutethe capacitors for higher values. It may be more economical to use two 4700uF in stead of one 10 000uF, there is another advantage to be had from this method which would increase the ripple current capability over that of a single cap. The impedance would also be somwhat lower, which is good.student said:
right
no problem nico ras
maybe one of u can anwer to my post on site 2... the one with the picture included.
would be nice
thx
_____________
i want to use this layout for my power supply
An externally hosted image should be here but it was not working when we last tested it.
not my design and not my engineering
but i want to substitute the 6.800µF caps by 10.000µF and 250VA torodial per channel
thx
Make sure that the 1 Ohm resistors are rated to dissipate the heat which is at maximum when the amplifier is turned on and the capacitors are fully discharged. For a short period they will dissipate 30 watts so 10 watt ceramic types should be fine. The resistors does not work hard during operation and will only work when the diodes conduct.
I am not convinced that using two positive regulators are a very good idea, it would work better for a class A type amplifier that draws constant current, but in this amplication and with class B operation your nrgative supply draw may be modulating the positive supply.
I know that National stopped making their negative regulator but it might be worth finding one from another source.
There are more but the main two reasons for regulation is to ensure a stable voltage regarless of the transformer and secondly to reduce the ripple superimposed on the DC rails. As for this configuration, there is no ripple reduction on the negative line and probably will cause rail imbalance and essentially output off-set.
The amp you are using has excellent PSRR and ripple is not really a concern. Should you only want to improve the regulation a simple series pass transistor with zener reference is more than adequit, again the chip has excellent common mode rejection and the noisy zeners will not be a problem either.
This is only an opinion, but I would like to convince you to find a negative regulator for the bottom rail, the results will be far more satisfactory.
Kind regards
Nico
Hi,
the PSRR of the chip amp is specified as being very high, but I suspect PSRR at high frequency is falling to quite mediocre.
Although I do not champion regulated supplies for power amps I can understand the benefits when done correctly.
The chipamps are reputed to sound better on a regulated supply and to me that indicates that PSRR is indeed poor. They are relying on the low impedance, low noise source to get clean audio.
The dual positive regs work just as well from dual secondaries as pos+neg regs working from a centre tapped transformer.
the PSRR of the chip amp is specified as being very high, but I suspect PSRR at high frequency is falling to quite mediocre.
Although I do not champion regulated supplies for power amps I can understand the benefits when done correctly.
The chipamps are reputed to sound better on a regulated supply and to me that indicates that PSRR is indeed poor. They are relying on the low impedance, low noise source to get clean audio.
The dual positive regs work just as well from dual secondaries as pos+neg regs working from a centre tapped transformer.
Hi student,
It's more important to have those bypass capacitors as close to the IC as possible.
I've built alot of IC amps and I cannot confirm those argumenting that only 2200µF is enough, but thats rather philosophical.... For using those little caps, as mentioned before, you have to use higher supply rails to prevent the amp from clipping in the case of large transients. With +-24V at the LM3886 I wouldn't go under 10.000µF.
Grüsse,
Markus, auch aus Wien
It's more important to have those bypass capacitors as close to the IC as possible.
I've built alot of IC amps and I cannot confirm those argumenting that only 2200µF is enough, but thats rather philosophical.... For using those little caps, as mentioned before, you have to use higher supply rails to prevent the amp from clipping in the case of large transients. With +-24V at the LM3886 I wouldn't go under 10.000µF.
Grüsse,
Markus, auch aus Wien
Student:
If you dig up old threads here, you'll find that using a regulated power supply like the diagram you showed (Nuuk's or Pedjarogic's?) appears to be the key to be able to use big capacitance with GCs. Peter Daniel's (AudioSector) comments about maximum recommended capacitance are in the context of using unregulated power supplies.
If you dig up old threads here, you'll find that using a regulated power supply like the diagram you showed (Nuuk's or Pedjarogic's?) appears to be the key to be able to use big capacitance with GCs. Peter Daniel's (AudioSector) comments about maximum recommended capacitance are in the context of using unregulated power supplies.
CarlosT said:
Hey, Nico...maybe it's time you give it a try
I am becoming more and more interested in knocking up a LM3886 chip amp. The reports I read contiually makes me think that I may (and maybe the gurus) are missing something.
I have always opted to build something complex but maybe I have just been biased because it seems too simple.
Thank you for the challenge Carlos, I am starting a PCB layout this evening and will get the buyer to order a few LM3886s in the morning.
I will report back to this thread when finished hopefully by the weekend because I am now very curious to what I a, going to find.
I guess I am goin to be very p#@#ed-off if I like it better than what I am running now.
I am wondering if the output devices in the LM3886 will handle bridged mode, because I have very inefficient and power hungry speakers. Has anyone tried it bridged?
Kindest regards
Nico
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