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MOX-like crossover and discrete opamp group buy

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#283
Hi,

I’m working on a complete parts list that I can send to the supplier for a price on a complete component kit.

The resistors will be 1% or 0.1% TK=100ppm all metalfilm.

Caps will be standard PP or PE 10% or better in a housing that fits the boards.

Pots will be what ever they have in stock.

Sockets for the opamps will be gold tulip types

Should I also get the jumpers and Headers for them?

Should I get a price for the big elektrolytic caps?

Did I miss anything?

\Jens
 
#285
Sort of a parts list

Hello,

The list is not finished yet, but these are the resistor values I plan to get for my own boards. Tell me if these resistors are ok, and also let me know if anybody would want a set of resistors and possebly a component kit.

I know the kit is a lot of work, but it might be the only way of getting the resistors that really is needed for optimal performance

EDIT: please follow the list from left to right, there was supposed to be cells for everything but somthing went wrong.... sorry for the bad pic.

\Jens
 

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#289
Hello,

Yes the frequencies you refer to are the ones implemented on this version of the board.

However I added an option for 0.1* freq, because this way you can HP the signal to a subweefer and ues the filter Q to EQ the response.

Please refer to the manual, I hope everything is mentioned in it. If not I'd really like you all to tell me what I missed.

\Jens
 
#290
JensRasmussen said:
Hello,

Yes the frequencies you refer to are the ones implemented on this version of the board.

However I added an option for 0.1* freq, because this way you can HP the signal to a subweefer and ues the filter Q to EQ the response.

Please refer to the manual, I hope everything is mentioned in it. If not I'd really like you all to tell me what I missed.

\Jens
Click to expand...
Thanks Duck, Jens,

These freq's will work fine, particularly with the *.1 factor.

BTW Jens, is a "subweefer" a cross between a subwoofer and a tweeter?😉 I wouldn't think you'd need a x-over for that speaker.🙂
 
#293
weakest link in a chain

I must admit that my ability to contribute in choosing and arranging components for the discrete opamp is SO limited.
I began by starting my own list of dip-8 chips to understand how their sound relates to measurements. THEN I read the thread on the discrete opamp. I found there is a point where the measurements have less meaning, ie. they can help me along in the right direction only so far. See http://members.cox.net/alexhardware/opa.htm
and the linked preceeding post. Also http://www.passdiy.com/pdf/diyopamp.pdf
I am very interested in the use of the discrete opamp. I have a sense that the quality of my power supply could limit a synergistic combination of parts to do their best.

So, to the question: What degree of filtering or regulation should I plan for my power supply? I prefer not to re-do this later.

And secondly, a statement of purpose: I will be trying a variety of combinations of parts to find that "synergistic" match

Yee Ha!
 
#294
Hello all,

I seem to have promised more than I can deliver. The resistor supplier I talked to can get all the values we need, but only if I get 20000 of each and in only 20 weeks – aauchh!!!

However there is another fellow that might be able to get all the values in the list for the filter – I’ll check back when I know more – however I already know that the price will be somewhat higher…. Stay tuned

\Jens
 
#296
JensRasmussen said:
Hello all,

I seem to have promised more than I can deliver. The resistor supplier I talked to can get all the values we need, but only if I get 20000 of each and in only 20 weeks – aauchh!!!

However there is another fellow that might be able to get all the values in the list for the filter – I’ll check back when I know more – however I already know that the price will be somewhat higher…. Stay tuned

\Jens
Click to expand...
Thanx for your efforts, Jens

Peronally I think a a bit higher price is not a big problem, as long as the quality is okay.
 
#297
Hello,

More measurements:

An externally hosted image should be here but it was not working when we last tested it.


Red graphs are calculated response, Black are measured.

As for resistors, the values are NOT avalible in Denmark, so there will be no group order for this one - sorry. The third supplier just told me that he can not get all values - because the don't get imported into Denmark.

I don't know if anybody else will give it a go?

The manual is also updated further.

\Jens
 
#298
resistors

OK
I'm considering purchasing Vishay CMF/RN resistors for this project. However, some values aren't available. I can use 2, 1/8W units in parallel to obtain near optimal value in 3 or 4 places.
The worst case is 1.3% off-value.
Should I keep looking for a closer match to optimal?
 
#299
Hi Ed,

Sorry for the delay, I have been on a small holiday during this weekend.

The resistor values I have used for the measurement are in the manual. I think that 1.3% tolerances are pretty great, be sure to measure you caps also to get a good result.

\Jens
 
#300
And sorry for my post on that any supplier should be able to provide the resistors. I read the table which says "Standard E96" value which *everybody* has but some of the values in the table are E192 and NOT E96 values which makes it quite a lot harder...

Sticking to E96 would make it a breeze...
 
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