1

MP566 Tube microphone preamplifier / Re: No Mic Input And Saturation on DI

« on: March 03, 2021, 07:30:13 AM »

Q1 is a component with 3 pins in a row. I mean between the 2 pins which are not the center pin.

Alright! So I did it, but I don't hear the mic relay clicking. Does that mean that the Q1 is damaged?

2

MP566 Tube microphone preamplifier / Re: No Mic Input And Saturation on DI

« on: February 28, 2021, 04:37:18 AM »

You can check this by creating a short between the 2 extreme pins of this component.

By the two extreme pins of the component, do you mean the 0V and the V+ ?

Do you have a gain variation between the mid and high gain?
Check the DC voltage on TP4. it should be close to 0.

I have a big difference of dB between the three of them. The Low gain is the loudest and the Hi Gain the least loud. But I don't really hear a lot of difference in terms of saturation between the three of them.

Do I have to put the black probe on the 0V and the red probe on the TP4? If yes, I am getting 0V

3

MP566 Tube microphone preamplifier / No Mic Input And Saturation on DI

« on: February 25, 2021, 08:30:23 AM »

Hi! I just finished a MP566, but I don't have any Mic Input. The signal on the DI seems to work but there's a lot of saturation on it, its almost distortion. I checked the click on the gain switch and I have a click between the Low and the Mid but nothing for the High. I also have no click when I insert a jack in the DI. 

Thanks!

4

MP573 Microphone preamplifier / Re: 100 Hz Hum And No Input

« on: February 12, 2021, 05:59:09 PM »

Alright, can I order them from you guys?

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MP573 Microphone preamplifier / Re: 100 Hz Hum And No Input

« on: February 11, 2021, 09:48:33 PM »

Thank you, I was doing it wrong ahah. So I redid It and now I have 4k? for the V+ and 0? for the V-

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MP573 Microphone preamplifier / Re: 100 Hz Hum And No Input

« on: February 11, 2021, 09:58:32 AM »

I am getting nothing for the both of them.

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MP573 Microphone preamplifier / Re: 100 Hz Hum And No Input

« on: February 10, 2021, 04:29:53 PM »

But if RLY1 is dead, wouldn't the DI not work because its is RLY? Because right now the DI is working perfectly on both of the modules.

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MP573 Microphone preamplifier / Re: 100 Hz Hum And No Input

« on: February 10, 2021, 03:52:07 PM »

I redid the soldering on the JMP3, the R28 and the D5 just to be sure. The R28 is 1.2K and I'm getting 2.9k for the RLY1 across D5.

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MP573 Microphone preamplifier / Re: 100 Hz Hum And No Input

« on: February 09, 2021, 09:04:07 PM »

Alright, so I redid all the soldering on the three RLY but the issue is still there on both of the preamp. I don't hear the clicking when I insert JMP3.

10

MP573 Microphone preamplifier / Re: 100 Hz Hum And No Input

« on: February 09, 2021, 09:07:53 AM »

I hear a click between the 1200 and the line but not with the 300 and the DI. Also, I checked my relays, and they are all in the right direction.

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MP573 Microphone preamplifier / Re: 100 Hz Hum And No Input

« on: February 08, 2021, 07:32:31 PM »

Yes it is

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MP573 Microphone preamplifier / Re: 100 Hz Hum And No Input

« on: February 08, 2021, 07:05:28 PM »

I am not sure that would be it, because the problem is still there even when the DI board isn't plugged into the main PCB board.

13

MP573 Microphone preamplifier / 100 Hz Hum And No Input

« on: February 07, 2021, 05:31:01 PM »

Hi, I recently built two MP573 but I have the exact same problem on both of them. There is a 100 Hz hum and no mic input signal. The DI works fine though. At first, I thought that the problem was with the input transformer, so I redid all the solder on it, but the problem is still there. I also checked all of the components and they all seemed at the right place and on the good side.