Why are TI's chip amps (OPA549) six times the price of National's (LM38xx)?

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Jump to Latest
kinser

kinser

Member
Joined 2004
Hi guys,
This might be of toppic but...
My name is David im 14 years old, here in Israel at one shop the price of an LM3886 was 60NIS ($13.3) THE OPAxxx would be cheaper to order from over seas!:D:cool:
Alaso the price diffrence between the $90 TO-3 packege and the $11 TO-220 (I think:xeye:) its crazy!:hot: :mad:
Kinser
 
C

carlosfm

Banned
Joined 2003
rabstg said:
Hey Carlos-

"They are so cooool."

Enlighten us... What are you using them for, and how do they sound compared to the LM38 75/86?
Click to expand...

I'm not using them at the moment, but I have made tests.
Actually, I have two of them mounted on heatsiks (10 holes to mount each of these things:bawling: ), fully assembled in P2P, inverting, gain of 22x.
I tested them with input OPA627 buffers (gain of 1), as a power amp.
The sound is different from the LMs, it's somewhat smoother.
Very good, but not up to the LMs (for my taste, of course).
BTW, bass is very good indeed.
I didn't make any more changes, but I'm quite sure that BB power op-amps need a different implementation, because of the lower bandwidth.
They would be better used at lower gains (no more than 10x), with an input gain stage.
That's a test I will make someday, when I have the time.:xeye:
 
P

paulb

Member
Joined 2001
peranders said:
The LM38xx is aimed for a consumer market and the OPA541 for a professional market and has nothing to do with performance. I think this is the simple explanation.
Click to expand...
Right. Also, the OPA came from Burr-Brown, who were a smaller company that charged more, who were bought by TI. I believe the OPA was developed before the National parts and probably costs more to fab.
 
bigparsnip

bigparsnip

Member
Joined 2003
owlstone.co.uk
Probably one of the reasons (appart from the hugely expensive metal packageing allredy mentioned) is the fact that the ti parts have FET input transistors, whereas the national parts are all bipolar. And, as it costs a lot more to mix bipolar and MOSFET technologies on the same piece of silicone, this will probably account for the majority of the price increace.
 
jackinnj

jackinnj

Member
Joined 2002
tech-diy.com
paulb said:

Right. Also, the OPA came from Burr-Brown, who were a smaller company that charged more, who were bought by TI. I believe the OPA was developed before the National parts and probably costs more to fab.
Click to expand...
the OPA chips are great for programmable power supplies, high power oscillators -- like an opamp on steroids -- the LM3886 etc. are really designed with a specific gain in mind, SPIKE protection etc.

Burr-Brown -- I am pretty surprised that TI has kept most of this intact -- they were the "ne plus ultra" of linear design...
 
jan.didden

jan.didden

AX tech editor
Joined 2002
linearaudio.net
Paid Member
Upupa Epops said:
TO 3 notoriosly expensive than others . Why ? 2 N3055 is in classical TO 3 and mostly cost 0.3 buck. Are several holes up more in case TO 3 so expensive ? Where is the problem ? Or have this manufacturers so bad technology,that they must trow away tree of four chips ?
Click to expand...


No, it's all in mass production. The modern plastic things can be very cheaply produced in relatively cheap machines. The metal parts are made in less quantities, and the machines are more expensive, so the price per part goes up even if the die inside is identical.

I would expect you will find that on average a TO3 2N3055 will be more expensive than a plastic MJ3055.

Edit: Digikey prices: 2N3055 TO3 $2.10 or $1,68 (depends on brand)
Plastic MJE3055 $0,84 or $1.01
All single prices, and MJE3055 is higher spec than 2N3055

Jan Didden
 
jan.didden

jan.didden

AX tech editor
Joined 2002
linearaudio.net
Paid Member
nick_g_evans said:


quote:
Originally posted by peranders
The LM38xx is aimed for a consumer market and the OPA541 for a professional market and has nothing to do with performance. I think this is the simple explanation.


This makes sense. Maybe they just don't sell very many of them.
Click to expand...

No it doesn't make sense. If they had the same performance, they would be the same and the price would be the same. If you built it for the professional market at a higher price that means you can only sell it if it performs better.

Jan Didden
 
C

carlosfm

Banned
Joined 2003
The TO3 version I was talking about has 8 legs and two holes.
10 holes to mount them on a heatsink, and I did this.
Painful job, without the right tools.
The metal can must really be more expensive to produce, specially because they also have a "normal" version, wich is much easier to use and must as a consequense sell more, and again, if it sells more, it is produced in much more quantities, and gets cheaper to produce.

The beauty of these chips (even the TO3) is that the metal case (or tab) is isolated.
I made the wholes on the heatsinks and didn't use isolators, just thermal paste.
BB (now TI) even has sockets for the TO3 version.:cool:
Oh, yes, they are Fet inputs.
You will not have more than 1~2mv DC-offset on the outputs, as I do.:cool:
But LM chips sound better to me.:xeye:
Oh, a pic of the chips:
 

Attachments

  • opa541.jpg
    opa541.jpg
    3.5 KB · Views: 341
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Top Bottom