1

MP566 Tube microphone preamplifier / Re: MP566 sound, then no sound, just a noise

« on: May 23, 2022, 01:31:34 PM »

Ah just realized today the unit is still shutting off after an hour. I check PTC1, that seems cool, PTC2 area was hot though, but I gave it an empty space on top and below. I think the deactivation might not be normal. Is it most likely the PTC2 or something?

2

MP573 Microphone preamplifier / Mp573 Volume trim to zero

« on: May 23, 2022, 04:11:33 AM »

Hi,

Is there anyway to mod the MP573 to be able to turn the volume to zero?

When I drive the unit into distortion, I can't lower the volume enough to prevent my converters from clipping.

Thanks

3

MP566 Tube microphone preamplifier / Re: MP566 sound, then no sound, just a noise

« on: May 21, 2022, 09:25:46 AM »

Thanks, fixed it, the tube was bad which made the noise, and the HI gain level problem go away. Also replaced the caps that were bad or looked bad. I may pick up another one soon for my summing mixer preamps.

4

MP566 Tube microphone preamplifier / Re: MP566 sound, then no sound, just a noise

« on: May 19, 2022, 03:29:13 AM »

Ok it's been a while since I used this, and I actually opened it up, the signal is loudest on the mid position, in LO, it is lower gain, and HI is lower gain than MID too for some reason.

I tapped the tube today and it is microphonic. Am I safe to try another tube?

I followed the test instructions and got to step 5, no matter how high the test signal is, the LED would never go red, even with everything cranked.

I also took a picture of the unit, one of the electrolytic has orange goo on top, is that normal or is it leaking?

https://ibb.co/Kr3Y54S

Video
https://youtu.be/KSwMZ1qa4JM

5

EQ573 Equaliser / May have overheated rotaries

« on: March 17, 2021, 07:16:37 AM »

Hello,

My Hi band and lo band rotary switches are extremely glitch. I think I may have overheated the rotaries and the solder terminals may have internally shifted. Unless it is a different issue. I did try cleaner but that was ineffective.

https://youtu.be/-pWNooxuCJs

Which replacement rotaries are available for this repair? And is there a much sturdier one available as well?

Thanks

6

MP566 Tube microphone preamplifier / Re: MP566 sound, then no sound, just a noise

« on: March 17, 2021, 07:10:16 AM »

Ok cool I'll leave some space then. Thanks 

7

MP566 Tube microphone preamplifier / Re: MP566 sound, then no sound, just a noise

« on: March 07, 2021, 05:33:24 AM »

Today i left it on the MID, still shut off after 1 hr 15 minutes

8

MP566 Tube microphone preamplifier / Re: MP566 sound, then no sound, just a noise

« on: March 06, 2021, 03:39:15 AM »

Im not sure if turning it to HI makes the tube run a lot hotter, or if it was just averaging on 1 hr, then shutoff. 

9

MP566 Tube microphone preamplifier / Re: MP566 sound, then no sound, just a noise

« on: March 06, 2021, 03:38:11 AM »

Ok just tested it today again. After about 55 minutes on the Mid gain setting, all was OK. I switched it to high, and within 7 minutes, the relay shut off I think.

10

MP566 Tube microphone preamplifier / Re: MP566 sound, then no sound, just a noise

« on: March 05, 2021, 07:14:29 PM »

It's just the MP566 shutting down. Ventilation is questionable?  500 rack is full, and there are units above and below it, but were not on. The face plate was warmer than the rest of the units. I'll test again today to verify how long it lasts.

I am assuming it is going to be impossible to have more than one MP566 in a rack, sitting next to each other? 

There is a good chance it's the relays since I only let it cool about 3 minutes before trying it that second time. 

And just curious, is it normal to need to crank this preamp? Signal to noise gets very noisy below 6/10, output cranked and still a low recording signal. I don't mind because it gets an awesome old sounding tone. I'm using a Blue Bottle

Thanks

11

MP566 Tube microphone preamplifier / MP566 sound, then no sound, just a noise

« on: March 05, 2021, 08:44:13 AM »

Hello,

Ok strange issue. I used my MP566 yesterday, everything worked fine for about 45 minutes, then I heard a click, and then there was no sound, only emitting some intermittent clicks and pops. I include a sample of the sound. 

Then i unplugged the 500 rack for a bit, then turned it on. It worked for about 2 minutes, then the same click, and back to the problem.

I am using a Bento 10, and the rack is filled. Could it be a current problem? Which is strange because the first power up worked for 45 minutes, then only 2 minutes and then the same issue arises.

I was on the High gain setting, cranked input, output on 3.5. 

Also, there is a ton of noise when the preamp is at 5 or below on the mid setting, and even more noise on high when input is on 8 or less.

Is it overheated and shutting down?

Thanks

https://soundcloud.com/vcs-verchrona/mp566-issue