AD825 module from LC Audio

Bom

Member
2002-07-16 12:35 pm
Thailand
Hello everybody,

I am new in here. Nice to meet you all. I have question regarding to the AD825 module from LC Audio. For analog circuit in cd player, does the module really superior to the AD825 opamp? I mean comparing between the module and the AD825 opamp (just only the chip) Is it worth more money to spend? AD825AR from Newark is about $4 each which AD825 module from LC Audio is about $14.

Thanks
 

gromanswe

Disabled Account
2002-07-08 8:42 am
North
www.google.com
No, It is not worth it!

As you use AD825 OPamp in both cases,
the result will be the same,
to such a degree, that noone will notice
the difference.

And you could upgrade to any high performance
Audio OP.
Does not have to be AD825.
Just select one that fits in circuit.
Ask, in new thread maybe in Digital or Amplifiers,
if anyone have modified CDplayer XXXXXX.
XXXXX is the name of your CD player.

I am sure you get advice which OP
you should buy.
It will save you money, not much however.
But it will be a lot easier just to change an OPamp.

Does AD825 have a specially filtered/regulated
power supply?
Is your CDplayers power supply of the cheap type,
and AD825 is somewhat better?

That could have some importance.
Maybe even more than what OP amp you use.

As I only can give you some general advice
do as I said here above
 

gromanswe

Disabled Account
2002-07-08 8:42 am
North
www.google.com
ok, that was a little more

NE5534 is a single Amp. If we say mono amp. Not a dual.
It is also bipolar. That means it uses bipolar
input transistors. Not JFET transistors.

Also AD825 comes only in SMD. Surface mount device.
SMD does not go through board into holes.
It is mounted on boards surface. Has pins bended out from body
so that sits on board like the legs of a fly.
That means one AD825 is only half the size of NE5534.
Distance between PINS is half of 2.54 millimeters.
So an AD825 does not fit into your circuit board.
That is why they found a market for a module that
converts to normal PIN IC. DIP o DIL.

http://www.octave-electronics.com/lcaudio/ad825.shtml

This module just contains 2 capacitors and one OP.
No regulated power supply.
It can be seen from picture.
Type 4 is the one you chose, if you decide to buy.
It could improve sound. But if you will notice
any difference, I do not know.

It is not like changing your Loudspeakers.
OPA134, single version of OPA2134
OPA604, single version of OPA2604
are both very cheap and popular replacements
that would fit into your board.
They are said to sound much better,
than NE5534. NE5534 is single version of NE5532.
Even some chose OPA134/OPA604 before AD825.

Somewhat higher in price, but you only need 2 pieces,
is AD627. That one is really "HIGHEST FASHION" today.
It has better in DATA than AD825, it is not listed
to compare with AD825 !:( !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!:( !
Why? I really do not know........

You are always welcome to ask me questions.
My YAHOO Messenger(FREE) ID is "gromanswe"
Install it and see when I am online,
and talk to me.
Maybe we could play a game of Chess
and exchange mp3-files? From my CD-collection.
And enjoy some music. For FREE!!!

http://messenger.yahoo.com/
 
BTW, most of the Burr Brown opamps gromanswe was talking about are no where near as good as the high end Analog Devices opamps I mentioned. Also, I think (or at least hope) he was referring to the OPA627, not the AD627. The AD627 is a micropower instrumentation amplifier totally inappropriate for audio use. The OPA627 is a decent but pricey older high end opamp that is good for audio but has been eclipsed by more modern designs.

I strongly urge you to search the forums before making any decisions based upon this one thread.
 

gromanswe

Disabled Account
2002-07-08 8:42 am
North
www.google.com
morsel

If you have the real interest in Bom's need,
you would have noticed that he need SINGLE DIP OP.
The adapter you mention wouldn't work to well.

About the OPA627, you are right, thank you.
That is the one.
These are easy to find worldwide on market
for normal consumers.
New product takes some time to spread to other
than to the "expertise".

About Bom thread.
I find it good thing that subjects are repeated.
Someone will catch some useful information.
New observations will be added.

Eventually Diyaudio.com would be a dead archive,
sooner or later, if we draw out the consecvenses
of your reasoning.
And I know that few of us here would object,
to repeated threads. That doesn't exclude using
the versatile search engine we have.
You like "law and order". Okay, but humans
making threads fullfill other needs, too, than
only finding answers to questions.
It is to me a "social thing".
Something to gather round, during this time
we call a lifetime.
 

Wombat

Member
2002-07-09 4:14 am
Germany
Hello all here on this board!

I have read and listened a bit about OPs in the last time.
There i stumbled across a side where someone still swears on the 55xx
types.

http://www.dself.demon.co.uk/webbop/opamp.htm

There aren´t many actual ones listed but it might be interesting.

A friend of mine also had some Philips 5532 in his hearing field
and seconds that a 55xx can sound extremly good still even if papers
differ.

So get rid of the 5534s does not perfectly means it gets better.


regards

Wombat
 
I am a NE5534 man.

The only OPamps I have at home is 20 NE5532
and 10 NE5534. And a bunch of 741 for nonaudio use.
LM324 is useful for many purposes,
can be driven from lower voltages.

Performance/price of 5534 will probably never
be reached by any other device.

It was not many years ago 5534/32 was the replacement
for other OPs.

It has almost no really bad variable.
That makes it very allround useful in Audio Designs.
So I must agree with you Wombat.

To have any improvement that you can HEAR
you must spend maybe 20 times the money.
 

Wombat

Member
2002-07-09 4:14 am
Germany
To add a small bit of substance.

I have a Sony digital processor EP90ES
around here that has 4 OPs in the filtering
stage and 1 in the exit. I still can´t believe
Sony uses Mitsubishis 5218A types, i think
just to save money cause all channels together
need 15 OPs.

So i looked what SO-8 types i could get. I was
able to get some OPA2134UA. I only modified the
Front channel. First i switched the 4 OPs into
the digital filtering section and the result was
amazingly better! Very good imaging and a very
precise bass.

(i use my Burr Brown PCM63P-K with OPA627 as
reference so far)

So i thought i throw in the last one into the
exit and a new listening feeling will come in.

But to my surprise "nearly nothing" has changed,
nothing for better.
May be due to the capacitors around!?

Thats why i think only switching to ones with
better specs into an existing piece doesn´t
always mean it gets better!

btw. i will try a 5532 in the exit as soon i
can get my fingers on a SO-8 version.

Wombat
 

Bom

Member
2002-07-16 12:35 pm
Thailand
Thank you everybody for your good opinions.

Here is my understanding. I can replace the 5534 with any single opamp which has same leg (DIP, I guess). Not talking about the difference in sound, all opamp will work properly by doing so right? I mean without any other mod.

The website Wombat recommended is very useful but currently I don't have time to read all topics. I will have time to read them all by this weekend.

Thanks
 
The adapters that morsel point out are good, however i still prefer the LC audio ones because of the 2 decoupling caps on it. If you do get those brown dog ones, there is no reson why you shouldn't solder the caps on top (just a bit fiddly).

The caps are there to smooth and filter the power, as a last ditch effort to try and stop (maybe present) digital hash on the power supply line comming in to the op-amp. They also allow the op-amp to see a very low impedence supply which is useful to keep the bass tought and the trebels smooth especially under heavy loading (for example input on a ZEN amp). The caps are not essential but prefrable.
 
Zappin'

Hey, I was looking at the LC site and they have the Zapfilter device. It uses discrete componants instead of opamp chips.

I understand that opamps are pretty darned good but it might be a decent idea, especially if you listen to people's opinions about op amp chips on the Pass site :D

The think that caught my eye was that it can be configured to be a balanced output. Since I use the Pass balanced pre and power amps this would be cool, Balanced outputs on players tend to be available on only the top models.

Now, my ignorance of electronics will be only too clear!!!

I have 2 ideas:

Is there a simple way to make a balanced output module with premium op amp chips? This would be a useful project, and probably not too difficult?

Can you use a pre-amp design such as the Pass balanced line stage to replace the output opamps in a SACD player? (If you keep it right next to the SACD circuitry? Or I suppose you can make a discrete op amp circuit as Mr. Pass describes on his web site to substitute, i.e. make your own zap filter.

These sound like projects that you clever folks could whip out in a trice -or maybe a quint, especialy the chip based balanced. Or has this been discussed to death in a thread I missed?

Thanks, Mark

Still hasn't finished his Son o Zen
(O my God!!, Gromanswe you are contagious )
:D :) Actually I like the tagline idea
 
Helix, the bypass caps are rarely needed and their presence makes the LC Audio modules too big to fit in many applications. Air wiring the caps is a messy kludge, a waste of time, and to really imitate the LC audio module you would need a ground tether from the main pcb ground to the junction of the two caps, which is an even worse kludge.

Bypass caps are generally too small to be power supply reservoirs, so they will do nothing for the bass, treble, or power supply ripple, for that matter. The actual purpose of these caps is to prevent finicky high bandwidth opamps from oscillating under certain circumstances. True fast reservoir caps, such as the 6.8-10µF Wima polyester box caps, are too big to air wire onto the adapter.