Barry Porter "Net EQ"

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This may seem a little dumb, but whats a good way to shop for resistors for the switches?

I went to Farnell.com, and by the time I got to the 5th value, I already had.

1. 1 pcs 3 euro resistor to cover one value
2. bag of 50 pcs (minimum) for a second value
3. One value missing
4. One value "ships from the US, add a gazillion dollars for shipping"

Mouser/RS etc results in a similar mess.

Basicly asking if there is a shop that covers the E96 range

Gustav
 
Gustav said:
This may seem a little dumb, but whats a good way to shop for resistors for the switches?

I went to Farnell.com, and by the time I got to the 5th value, I already had.

1. 1 pcs 3 euro resistor to cover one value
2. bag of 50 pcs (minimum) for a second value
3. One value missing
4. One value "ships from the US, add a gazillion dollars for shipping"

Mouser/RS etc results in a similar mess.

Basicly asking if there is a shop that covers the E96 range

Gustav

Hi Gustav,

I ordered every resistor for all my switches (as per Harpos spreadsheet) from Farnell (called Element14 in Australia... Same thing).

Look for the multicomp brand, they often are cheapest and come in MOQs that aren't too insane.
Also, you can save a few dollars by not getting too pedantic about the resistor values, give or take an ohm here or there. I.e. A 499ohm resistor might be 3x the price of a 500ohm resistor. (Maybe a bad example but you get the idea). This makes a significant difference to the price. Ordering very obscure resistor values is an expensive process... Hope that helps
 
frazzman said:
Gustav said:
This may seem a little dumb, but whats a good way to shop for resistors for the switches?

I went to Farnell.com, and by the time I got to the 5th value, I already had.

1. 1 pcs 3 euro resistor to cover one value
2. bag of 50 pcs (minimum) for a second value
3. One value missing
4. One value "ships from the US, add a gazillion dollars for shipping"

Mouser/RS etc results in a similar mess.

Basicly asking if there is a shop that covers the E96 range

Gustav

Hi Gustav,

I ordered every resistor for all my switches (as per Harpos spreadsheet) from Farnell (called Element14 in Australia... Same thing).

Look for the multicomp brand, they often are cheapest and come in MOQs that aren't too insane.
Also, you can save a few dollars by not getting too pedantic about the resistor values, give or take an ohm here or there. I.e. A 499ohm resistor might be 3x the price of a 500ohm resistor. (Maybe a bad example but you get the idea). This makes a significant difference to the price. Ordering very obscure resistor values is an expensive process... Hope that helps

Thanks. I was a little worried about going off-value, because the differences will add up the way the switch is built, but Ill go for it :)

Gustav
 
Gustav said:
frazzman said:
Gustav said:
This may seem a little dumb, but whats a good way to shop for resistors for the switches?

I went to Farnell.com, and by the time I got to the 5th value, I already had.

1. 1 pcs 3 euro resistor to cover one value
2. bag of 50 pcs (minimum) for a second value
3. One value missing
4. One value "ships from the US, add a gazillion dollars for shipping"

Mouser/RS etc results in a similar mess.

Basicly asking if there is a shop that covers the E96 range

Gustav

Hi Gustav,

I ordered every resistor for all my switches (as per Harpos spreadsheet) from Farnell (called Element14 in Australia... Same thing).

Look for the multicomp brand, they often are cheapest and come in MOQs that aren't too insane.
Also, you can save a few dollars by not getting too pedantic about the resistor values, give or take an ohm here or there. I.e. A 499ohm resistor might be 3x the price of a 500ohm resistor. (Maybe a bad example but you get the idea). This makes a significant difference to the price. Ordering very obscure resistor values is an expensive process... Hope that helps

Thanks. I was a little worried about going off-value, because the differences will add up the way the switch is built, but Ill go for it :)

Gustav

I still stayed pretty close to the spec, most of mine were exact as per Harpos spreadsheet for 23 pos switches. But a few ohms here or there is still probably going to put you within a -/+ 1% tolerence. For gain switches you'll have 500ohms the whole way around...
For freqs I guess a ohm deviation here or there would change your actual frequencies but I don't think my ears could hear the difference between say 1980hz or 1985hz
(I might add that I haven't assembled my switches yet so this is all in theroy, but I've ordered everything from element14 regardless)
 
This is what I got for the 23 step...

Not sure I did it right.

If so, could someone explain how it works? I am confused about the large jump for the final value for an RC filter in the given frequency steps.

Edit:link removed to avoid confusion. (values were wrong).

Gustav
 
Gustav said:
This is what I got for the 23 step...

Not sure I did it right.
references mixed up, negative resistor parts values, ...
Maybe try this calc sheet for X step positions.

// excel file errors in text corrected
 
Harpo said:
Gustav said:
This is what I got for the 23 step...

Not sure I did it right.
references mixed up, negative resistor parts values, ...
Maybe try this calc sheet for X step positions.

Thanks, Harpo! (Thought the negative value was just an accumulated rounding error :) )

Gustav
 
I think I did a basket for all the resistors from Harpo's sheets. It is with mouser 1% tolerance. I'll have a look see.

Edit: Am not sure how accurate it is been some time since I did it. Some are out of stock. It has free postage to Europe.

https://ie.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=26ecaa8ea4
 
petermontg said:
I think I did a basket for all the resistors from Harpo's sheets. It is with mouser 1% tolerance. I'll have a look see.

Edit: Am not sure how accurate it is been some time since I did it. Some are out of stock. It has free postage to Europe.

https://ie.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=26ecaa8ea4

I started one the other day - quantities are off, but I wanted a roll of each value.

http://www.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=f66bec5e1e

Gustav
 
Noone could stop you to edit the calculated closest parts values from column 'J' with your availible parts values, beginning with the highest step position, and the calcsheet will give you the recalculated values for the steps above in order to minimize total errors. ;)
 
Harpo did the thinking part - I did the monkey part...I like doing the monkey part.

This is a fun project, but way over my head  ;D

Gustav
 

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hey guys, since i am new to this project i could need some help. is there a complete bom or documentation for the net eq? i think of a dual mono unit like domc used in their studio, but i dind't find any information on the jlm website (https://scontent-a-ams.xx.fbcdn.net/hphotos-xpa1/v/t1.0-9/10376288_10152150017372544_2675178422037116930_n.jpg?oh=43071c0c0e25ceac39f18554f4b72959&oe=54411A6B)
 
Weiss send me a PM I will pass along the info. what exactly are you missing?

Has anybody given thought to sticking in some input/output transformers? Is that even possible?
 
Harpo, the calculator sheet is just fantastic...

Is it possible to extend it with the HPF, the same way, when I can change freqs and steps?

Would be welcomed:)

BTW, is there info about how to separate the peak and shelving bands?

 
prescott said:
Harpo, the calculator sheet is just fantastic...

Is it possible to extend it with the HPF, the same way, when I can change freqs and steps?
my pleasure, but this is just a quick and dirty tool, far from perfect/foolproof.

Maybe reload updated calcsheet with your request.

BTW, is there info about how to separate the peak and shelving bands?
Look at the headlines or part numbers...
 
Thanks a lot Harpo!

But how do you mean "look at the headlines"?

Its just putting the peak and shelving bands to separated rotary switches and thats it?
 
prescott said:
But how do you mean "look at the headlines"?
Its just putting the peak and shelving bands to separated rotary switches and thats it?
Look FI at calcsheet row17 and row 200 to get the relation to the 'headline and parts numbers' for the low band.
Separate switches or separate decks at the same switch, IE pot 15a and pot 15b (row 17) get substituted by a 2deck switch, each deck with required resistor values for the peaking low band. Pot 15c (row 200) get substituted by a 3rd.switch deck (with different from peaking band resistor values) on either the same switch (=3deck switch required) or at an additional separate switch (1deck switch) for the shelfing low band.
 
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