Help with adding resistors

Mattrox217 · 1361

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Offline Mattrox217

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on: June 12, 2018, 10:47:50 AM
Hi all,

I'm running a stock Crack+Speedball. I've been running this for a few years with HD 600, 6xxs, and various IEMs. I'm not sure if I just like to listen at unuaually low levels, but I've noticed that with all of the headphones I use, I have to turn my source volume down significantly because I have some imbalance at the low end of my volume pot.

I've been looking into this and I realize now that this issue is part of the Crack FAQ. Doc's response is here:

Quote
3.  I can barely turn my Crack up at all before it's far too loud, what do I do?

Disconnect the white wire at the pot that originated at the left RCA jack.  Install a 75K resistor between this wire and where it connected on the pot. 
Repeat this step for the red wire coming from the right RCA jack.
Attach and solder one 33K resistor between each outer pair of lugs on each level of the volume pot and the ground lugs on the pot.
Resistor wattage is unimportant, 1/10 Watt or greater will work nicely.

I'd like to do this small mod so that I can put system volume to max and use more of my crack volume. Now my question is:

Would anyone be willing to help me source these resistors?

I will need two 75k resistors and one 33k resistor. I'm just not familiar enough with what to search on Digikey (or elsewhere) to get the items I need. I can only seem to find chip/surface mount resistors...

Thank you in advance!



Offline Paul Birkeland

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Reply #1 on: June 12, 2018, 11:03:03 AM
On Digikey, search for:

"CMF55 33K"

and

"CMF55 75K"

They usually have two different items depending on quantity, so if you end up on a page with a minimum of 1000-5000 pieces, that's for a whole reel, and you just need to go back and look for the same item in quantity 1.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Tom-s

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Reply #2 on: June 12, 2018, 11:25:09 AM

I will need two 75k resistors and one 33k resistor.


For FAQ#3 you need two of each if i'm correct.



Offline Mattrox217

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Reply #3 on: June 12, 2018, 12:58:13 PM
Paul - thank you. These look different than the resistors that are used in the kit, I assume that's fine?

Tom - thanks you're totally right, I mis-read it the first time through!



Offline Paul Birkeland

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Reply #4 on: June 13, 2018, 03:53:20 AM
Paul - thank you. These look different than the resistors that are used in the kit, I assume that's fine?
Yes, these are an acceptable choice.

If you search

"CCF55 33.2K"

and

"CCF 75K"

Those will look similar to the 2.49K resistors on the headphone jack.  (I'd rather have the other parts I picked for you)

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Mike1590

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Reply #5 on: August 20, 2022, 04:03:30 AM
Hoping I can resuscitate this thread. I’m having the same issue with sensitive volume and want to install these resistors. However, I’m overwhelmed with the number of choices on Digikey when I search the keywords Paul mentioned. Would anyone mind linking me to the exact resistors I should be buying?

Thanks in advance!




Offline Mike1590

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Reply #7 on: August 20, 2022, 05:58:45 PM
Awesome. Thanks a bunch, Paul!