Author Topic: EQ531T build

June 30, 2025, 10:54:43 AM
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Lud

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Hi everyone, I have started building the 531T and there's three 470 condensers and one 470 KAK listed. I have four KAK. Is that an Issue?

Cheers.

June 30, 2025, 03:06:04 PM
Reply #1

JPK

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No issue there.
We have supplied all the 47pF in 250V to avoid mistakes.
JPK

June 30, 2025, 03:21:06 PM
Reply #2

Lud

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Ok, thanks a lot.

July 02, 2025, 11:06:56 AM
Reply #3

Lud

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I've done the build and i have strong dirty noises parasites in, unit off or on, around -30/-25 dbfs. Everything was good when testing exept with TR1 that i can't match the 1vAC, it only goes to 0,88v.

Have you got an idea what the first thing i've got to check?

Cheers.

July 02, 2025, 05:17:32 PM
Reply #4

JPK

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I added a Try to follow the signal section in this thread: https://www.soundskulptor.com/forum/index.php?topic=7346.0
Try it!
JPK

Today at 10:45:39 AM
Reply #5

Lud

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Ok, so this is what i got :

TP1 : 0,75
TP2 : 0,7
TP3 : 0,7
TP4 : 0,65
TP5 : 0,65
TP6 : 0,65

Those cracklings are actually always there, even when the Lunch box is off.

I've removed the face, the IC's and there is still that noises crackling. I remade some solder joints, I checked the caps polarities. It seems to me that it cames from a ground issue and/or a cap but i can't see from where. I also wonder if Q2 is well placed?

« Last Edit: Today at 03:47:54 PM by Lud »

Today at 05:22:20 PM
Reply #6

JPK

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Check the output transformer connections: You should read around 35ohms between the output XLR pins 2 & 3, Power on, EQ on, no input signal.
JPK

Today at 05:28:50 PM
Reply #7

Lud

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I have 36 ohms.

 

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