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Old 12th December 2004, 01:49 PM   #1
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Arrow 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.
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Old 12th December 2004, 02:54 PM   #2
joensd is offline joensd  Germany
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Quote:
I still hope we are free to express our oppinions here.
And your opinion is based on...?

IMO a LM3875 is perfect for 8Ohms, if you call 4Ohms is normal, well that´s your opinion but you can´t say it like you do as it is very misleading and a "non-technical" argument.
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Old 12th December 2004, 05:33 PM   #3
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Quote:
Originally posted by joensd

And your opinion is based on...?

IMO a LM3875 is perfect for 8Ohms, if you call 4Ohms is normal, well that´s your opinion but you can´t say it like you do as it is very misleading and a "non-technical" argument.
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.
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Old 13th December 2004, 05:08 AM   #4
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Quote:
Originally posted by carlosfm
It couldn't drive most speakers.
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.

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.
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Old 13th December 2004, 01:23 PM   #5
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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.
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Old 13th December 2004, 01:27 PM   #6
joensd is offline joensd  Germany
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Quote:
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.
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.

Quote:
You just look at the chip?
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).

Quote:
The chip alone can't make an amp.
Yes a chip plus a few resistors make an amp. (again assuming that a PSU is needed anyway)
The whole amplifier topology is integrated.
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Old 13th December 2004, 03:28 PM   #7
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Default Re: Just released from Alcatraz...

Quote:
Originally posted by carlosfm
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.
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?
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Old 13th December 2004, 03:30 PM   #8
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Default 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.....
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Old 13th December 2004, 03:40 PM   #9
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Default Re: Chip amplifiers

Quote:
Originally posted by jmateus
I was wondering if there is anything you Chip amplifiers people know that I don't...

I'm asking because I would like to learn what moves you guys, if
anything.....
[open commercial]

buying stock of chipamp components = $100

investigating permutation/combinations of low-parts-count amps = 100 hours

claiming to be an amp designer = priceless

[end commercial]

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Old 13th December 2004, 03:44 PM   #10
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Default Re: Chip amplifiers

Quote:
Originally posted by jmateus
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.
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.
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