Just released from Alcatraz...
That "SMD GC" can't sound good, and there are several reasons why it just can't sound good.
Some reasons are very obvious, really.
Everyone is free to spend the money and try it, why not?
In original form, Brian/PD GC sounds much better, although it has problems driving most "normal" speakers.
I still hope we are free to express our oppinions here.
That "SMD GC" can't sound good, and there are several reasons why it just can't sound good.
Some reasons are very obvious, really.
Everyone is free to spend the money and try it, why not?
In original form, Brian/PD GC sounds much better, although it has problems driving most "normal" speakers.
I still hope we are free to express our oppinions here.
joensd said:
Make a search, I talked about this thousands of times here.
The problem is the very low capacitance PSU.
No, I don't consider 4 ohms "normal" speakers.
Modern 8 ohm speakers (most bass-reflex) can go lower than 4 ohms.
It is quite normal.
That amp is not able to drive my Epos 11 speakers properly, and they are 8 ohms.
Also, it is not my oppinion, I'm completely sure.
I tested a low capacitance unregulated GC with lots of commercial speakers more that a year and a half ago and reported here the results. It couldn't drive most speakers.
Before replying to me in those terms, read my posts, please.
You just look at the chip?
The chip alone can't make an amp.
Dear Carlos, I think there are quite many reports which tell us that a LM3875 and LM3886 actually _can_ drive a normal speaker but with that I didn't say every speaker.carlosfm said:
Before you make very sure judgements it would have been good if you actually had listen and built my amp. You may have been disappointed, you may have not.
roibm started a thread about building my gainclone. Of no particular reason carlosfm thought that LM3886 is not very suited for "normal loudspeakers. This may be true but I don't see in that way. I think LM3886 is surprisingly good.
The thread title is a bit provocative but so was also carlos comment.
Let me add that he thinks that its no good. He is not one of the builders so really certain can he only be when he actually has listened to it.
The LM3886 isn't the salvation to the world but for some (rather many actually) is this the entrance into the DIY world. Let's not look down on those people that find the LM3875/3886 to be a rather good amp.
The thread title is a bit provocative but so was also carlos comment.
Let me add that he thinks that its no good. He is not one of the builders so really certain can he only be when he actually has listened to it.
The LM3886 isn't the salvation to the world but for some (rather many actually) is this the entrance into the DIY world. Let's not look down on those people that find the LM3875/3886 to be a rather good amp.
Well, the point I wanted to make is that you do generalize.
If you wanna make a statement you´ll have to explain.
You can´t just say "the chip can´t handle modern speakers".
And you also can´t assume that everybody reads your posts and concludes what you might mean with what you say.
(Now , how arrogant would that be?)
And it is indeed misleading to newbies (for example) to say that.
That a appropriate PSU is needed is rather trivial and depends on the amp.
Naa, I´ve built my first chip-amplifier in april 97 when ELV-magazine published a project/PCB for the LM3876/3886
and used high capacitance from that point on BTW (except in biamp-setups).
Yes a chip plus a few resistors make an amp. (again assuming that a PSU is needed anyway)
The whole amplifier topology is integrated.
Re: Just released from Alcatraz...
I'll hope you are aware of the you are comparing a LM3886 with LM3875 in two total different setups. Do you mean that the less current capable LM3875 is better to drive speakers than the LM3886?carlosfm said:In original form, Brian/PD GC sounds much better, although it has problems driving most "normal" speakers.
I still hope we are free to express our oppinions here.
Chip amplifiers
I was wondering if there is anything you Chip amplifiers people know
that I don't...
I built my first chip amplifier several years ago with a 3875.... I found
nothing special about this amplifier and I didn't find anything even
more special about the subsquent ones I also built, the 3886 and
recently the 4780.... The supplies were heafty but nothing major happened, the quality of the sound is so so, nothing even close to
true high Fidelity...
On the Solid State forum I'm sure I'm learning here and there several
things that made a lot of sense to improving the quality of some
designs, but here.....
So I've been curious why a lot of people swears by these designs
which are basically the same and based on the National's scematic.
Cost may be?
I'm asking because I would like to learn what moves you guys, if
anything.....
I was wondering if there is anything you Chip amplifiers people know
that I don't...
I built my first chip amplifier several years ago with a 3875.... I found
nothing special about this amplifier and I didn't find anything even
more special about the subsquent ones I also built, the 3886 and
recently the 4780.... The supplies were heafty but nothing major happened, the quality of the sound is so so, nothing even close to
true high Fidelity...
On the Solid State forum I'm sure I'm learning here and there several
things that made a lot of sense to improving the quality of some
designs, but here.....
So I've been curious why a lot of people swears by these designs
which are basically the same and based on the National's scematic.
Cost may be?
I'm asking because I would like to learn what moves you guys, if
anything.....
Re: Chip amplifiers
This question comes up periodically.
The standard answer is something like this:
"Some implementations (DIY or most commercial) using high capacitance standard supplies (non-regulated) produce non exciting sound. A well implemented chipamp using low capacitance supply (arguably creating some limits) or using a regulated supply can sound very very good indeed."
Depending on your tastes your mileage may vary, but the notion in this forum is that the results can be very, very good and people build them seeking that "magic" sound usually find it.
Some don't of course and continue to seek nirvana elsewhere.
jmateus said:
This question comes up periodically.
The standard answer is something like this:
"Some implementations (DIY or most commercial) using high capacitance standard supplies (non-regulated) produce non exciting sound. A well implemented chipamp using low capacitance supply (arguably creating some limits) or using a regulated supply can sound very very good indeed."
Depending on your tastes your mileage may vary, but the notion in this forum is that the results can be very, very good and people build them seeking that "magic" sound usually find it.
Some don't of course and continue to seek nirvana elsewhere.
I think the LM3886 is good
but it all comes down to what you compare it against.
IMO it works great, considering cost & parts-count.
The fact that Jeff Rowland uses them is no guarantee for sound-quality...he also uses icePower & smps...
I have much better transistor and mosfet amps around, driving any load, but also carries hefty price-tags...
Arne K
but it all comes down to what you compare it against.
IMO it works great, considering cost & parts-count.
The fact that Jeff Rowland uses them is no guarantee for sound-quality...he also uses icePower & smps...
I have much better transistor and mosfet amps around, driving any load, but also carries hefty price-tags...
Arne K
Re: Well, P-A......
and so, i'l get back onto the topic then Mr.Homo.
I must personally admit that i'm not impressed by the lmxxxx line of chips so far, but i have only gone so far on teh subject, so i have lots of things to try before i make a definite conclution.
So many people cant be wrong, or at least so i hope.
As for audio Nirvana, i dont think it can be found in a chip.
the search continues.
regards
marius
Jocko Homo said:
and so, i'l get back onto the topic then Mr.Homo.
I must personally admit that i'm not impressed by the lmxxxx line of chips so far, but i have only gone so far on teh subject, so i have lots of things to try before i make a definite conclution.
So many people cant be wrong, or at least so i hope.
As for audio Nirvana, i dont think it can be found in a chip.
the search continues.
regards
marius
Hello.
Since you all are speaking about sound quality and I am new arround here....
I would like to build a Kit..... a kit that could drive my 6 oms speakers!
Now I am using a Pioneer A-702R wich sounds nice!
Building a Amp based on the LM3886 Kit could I achive better quality and drive my Wharfedales?
(compared with the Pioneer A-702R or Audio Analogue Puccini special edition)
Thanks.
Since you all are speaking about sound quality and I am new arround here....
I would like to build a Kit..... a kit that could drive my 6 oms speakers!
Now I am using a Pioneer A-702R wich sounds nice!
Building a Amp based on the LM3886 Kit could I achive better quality and drive my Wharfedales?
(compared with the Pioneer A-702R or Audio Analogue Puccini special edition)
Thanks.
Re: Re: Chip amplifiers
This is conflicting. A high cap supply will appear very close to a regulated supply. A low cap supply will heavily modulate output on peak signals, which both a high cap and a reg supply will do (much) less. Are you sure you haven't switched your statement around?
Jan Didden
moving_electron said:
This is conflicting. A high cap supply will appear very close to a regulated supply. A low cap supply will heavily modulate output on peak signals, which both a high cap and a reg supply will do (much) less. Are you sure you haven't switched your statement around?
Jan Didden
Re: Re: Re: Chip amplifiers
Not with GC's. as everyone who have played with theese chips know, they sound like **** with high large reservoares of capacitance, or rather the inductans that the capacitans brings with it, to more or less extent.
I'm being rather bastant (as in dead certain that my knowledge is aqurate) here now, but this is regarded as a common fact concerning GC's is it not?
regards
marius
janneman said:
Not with GC's. as everyone who have played with theese chips know, they sound like **** with high large reservoares of capacitance, or rather the inductans that the capacitans brings with it, to more or less extent.
I'm being rather bastant (as in dead certain that my knowledge is aqurate) here now, but this is regarded as a common fact concerning GC's is it not?
regards
marius
P-A, you opened this thread in my name?
Wooooowww!
Fair play!!!
Did I ever said that an LM3886 is not a good power IC?
It's what I use!
Your implementation of the LM3886 is not correct.
It doesn't sound good.
High capacitance unregulated with these chips doesn't sound good, and the only thing that improves this with fantastic results is the snubber on the PSU, with the values I reported on this forum.
You can see the snubber on roibm's PCB, can't you?
You can also see some electrolythic caps on the op-amp's PSU pins, can't you?
You can see that I advised him not to use the caps across the diodes, can't you?
You can't see but I tell you: I advised him to remove the servo (and terminate that op-amp's channel).
You can't see but I tell you: without the servo he has 0.2mv DC offset.
You can't see, but I told him to remove the cap from NI to gound (filter) and also the cap across the feedback resistor of the op-amp, can't you?
You can't see but I tell you, he's not using the AD8620 anymore, I advised a much better option.
Your zobel was removed and the output snubber has other component values.
Do I need to say more?
The changes were much more that these, they included changing component values too, and the amp sings now.
For all this work, I would do an amp from scratch.
PS: with a good PSU (and some other tricks) I'm now getting an LM1875 to drive my difficult Epos 11 speakers, with very good results.
So, forget the chip for a while and concentrate on the rest of the amp.
Wooooowww!
Fair play!!!
Did I ever said that an LM3886 is not a good power IC?
It's what I use!
Your implementation of the LM3886 is not correct.
It doesn't sound good.
High capacitance unregulated with these chips doesn't sound good, and the only thing that improves this with fantastic results is the snubber on the PSU, with the values I reported on this forum.
You can see the snubber on roibm's PCB, can't you?
You can also see some electrolythic caps on the op-amp's PSU pins, can't you?
You can see that I advised him not to use the caps across the diodes, can't you?
You can't see but I tell you: I advised him to remove the servo (and terminate that op-amp's channel).
You can't see but I tell you: without the servo he has 0.2mv DC offset.
You can't see, but I told him to remove the cap from NI to gound (filter) and also the cap across the feedback resistor of the op-amp, can't you?
You can't see but I tell you, he's not using the AD8620 anymore, I advised a much better option.
Your zobel was removed and the output snubber has other component values.
Do I need to say more?
The changes were much more that these, they included changing component values too, and the amp sings now.
For all this work, I would do an amp from scratch.
PS: with a good PSU (and some other tricks) I'm now getting an LM1875 to drive my difficult Epos 11 speakers, with very good results.
So, forget the chip for a while and concentrate on the rest of the amp.
A high cap supply will also have greater inductance. The solution is to decouple the power supply with smaller cap. As large caps can resonate with small parallel caps, the small resistors in series with large caps are required. I don't know why Carlos placed them in series with small caps.
Another solution to lower inductance is to put several smaller caps in parallel e.g. 5x2200uF instead one 10000uF. May be Carlos can check it.
Ooops, I think this will appear after Jan post. You are so fast, my friends
Another solution to lower inductance is to put several smaller caps in parallel e.g. 5x2200uF instead one 10000uF. May be Carlos can check it.
Ooops, I think this will appear after Jan post. You are so fast, my friends
dimitri said:
I've tested that.
Of course I use a small film cap after the big ones.
But it isn't a solution, the amp will still not sound good.
Paralleling caps is also not a solution, I've tried that long ago.
Only the snubber makes a "click".
Suddenly the magical midbad and treble that were muted appear from nowhere and then yes, you have a serious amp, not for kids.
With the snubber, the amp sounds as good as the low capacitance one (1000~1500uf per rail/chip) in the midband and treble, but with the added advantage of much better, tight bass and driving ability.
I so look forward to try this snubber of yours, Carlos..
is the wattage value of the resistors very critical? and the caps? i had theese 100-140 pf 1000v condensators i needed to get rid of, but they dont acuratly match the values you posted. Is this critical? common scence tells me no, but then, this is audio, no logic should bhe applyed here.
they were so bothersome to have lying around, so why not put them in the GC?
is the wattage value of the resistors very critical? and the caps? i had theese 100-140 pf 1000v condensators i needed to get rid of, but they dont acuratly match the values you posted. Is this critical? common scence tells me no, but then, this is audio, no logic should bhe applyed here.
they were so bothersome to have lying around, so why not put them in the GC?
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