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Possible OPA2134 Group Buy

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#3
Does anyone know if it is possible to buy the OPA's straight from TI?

I know the MOQ is 1000 pcs, but ti.com quotes a price of $1.10 each vs. digikey's $1.4125/$1.365 each for 500+/1000+ quantities, meaning that we get 780 opamps at digikey for the same cost as 1000 from TI. If I could get more opamps for my money I wouldn't complain :smash:


/U.
 
#9
I'm all in favor of getting the cheapest price. I'm skeptical that they would deal with us for a 1-shot 1KU order.

Bob--have you actually talked to anyone at TI to see if they can do anything for us?

I'm adding my interest to the WIKI, and that should put us squarely above 1K.

--Greg
 
#15
I am not clear on the wiki GB for OPA2134's.

Is that just EU members, and is that in euros?

And if so. will another be likely to be run for US members?

It would pay me and others in this region to jump on one or other of the GB.
 
#16
Re: better ?

BobEllis said:
so with OPA2134s you'll have to be careful to keep the crossover frequency below 800 KHz, although distortion does hit .001% by 20 KHz.
Click to expand...

Cobra2 said:
6172 is a fancier opamp than 2134, but more difficult to work with, (oscillates easier), and therefore need a better layout & psu.

:hot: I actually prefer 2132 to 2134... :devilr:

Arne K
Click to expand...

Please forgive my ignorance; not being an op-amp expert, these statements confuse me a bit. I'm looking at a 3-way x-over with 2 boards (on each side), should I not use the 2134 for the Mid-Tweet cross (~1500)? With these boards and the associated PSU you guys are putting together, is the 6172 ok or should I be concerned with oscillation problems? :scratch:

Thanks
John
 
#17
John,

With any circuit you should be concerned with oscillation. The 6172s are more prone to problems than the 2134s. Board layout is a factor.

Given Jens' board design experience and day job, I suspect that 6172s will be fine. However, the only way to know for sure is to build up a set.

You should have no problems using OPA2134s for all positions. Some people like the bottom end of the NE5532 better than the 2134, and build bass sections with them.
 
#20
Re: Re: better ?

BobEllis said:

so with OPA2134s you'll have to be careful to keep the crossover frequency below 800 KHz, although distortion does hit .001% by 20 KHz.
Click to expand...

JohnL said:

...should I not use the 2134 for the Mid-Tweet cross (~1500)?
Click to expand...

JohnL--

I also think you might have missed the joke, somewhat. There was a comment in the "Active Filter GB" thread about using an opamp with a gain-bandwidth product (sometimes referred to as "unity gain frequency") that's 10x the highest frequency in use. This implies a conservative GBWP of ~200kHz (10x above 20kHz audio).

Bob's somewhat tongue-in-cheek comment was that since the OP2134 has a GBWP of 8MHz that it would be useful up to about 800 kiloHertz, so the bats in your attic can enjoy their Hi-Fi, too.

John, don't feel bad about not getting all of this. I have a BSEE and still learn something new almost every time I'm on this board. Welcome to the world of DIY electronics. Here's to always learning something new.:cheers:

--Greg
 
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