1

First Aid / Re: MP512 Outputs random static

« Last post by JPK on July 19, 2024, 08:34:29 AM »

I don't believe the tranformer can become faulty. Try reflowing the solders.
Reinsert the DOA to make sure the connections are good.
Try tapping on the large caps to check if it increases the noise.
Also do the same on the pad potentiometer.

2

First Aid / MP512 Outputs random static

« Last post by jmauz on July 18, 2024, 12:39:20 AM »

Hello, I have an MP512 unit that's several years old. It's worked flawlessly up until recently. When I turn on the lunchbox, the mic pre outputs random static, and tapping on the input transformer makes it worse. Eventually it goes away and all is well. 

I can't see any solder joint issues. Could the transformer be bad?

Thanks in advance for any help!

3

MP566 Tube microphone preamplifier / Re: C4 and R51 specs

« Last post by TomT on July 17, 2024, 04:47:31 PM »

I figured it would be ok.

Thank you very much!
Better to be sure 

T

4

MP566 Tube microphone preamplifier / Re: C4 and R51 specs

« Last post by JPK on July 17, 2024, 11:20:40 AM »

No problem, you can move forward.
The 315V is still well above our B+  which is at 225V.
If the colour code on the resistor is correct (violet, green, black, silver) then the resisor is correct within 1%. The typical ohmmeters are generally not very acurate for the extreme values (very small or very large). Also, it adds the resistance of the leads, and connections to the resistor value.

5

MP566 Tube microphone preamplifier / C4 and R51 specs

« Last post by TomT on July 16, 2024, 02:05:23 PM »

Hi,

This is the first MP566 I'm putting together.

I have two questions about some parts.

In the 'parts list' C4 is described as 22uF350v.
However, the (only 22uF) capacitor I received indicates 22uF315v.

R51 indicates 7R5 on the 'parts list', but when measuring I get 8R9.

Can I go ahead and just install both of these?

Thanks in advance!
Tom

6

MP573 Microphone preamplifier / Re: Bias Adjust

« Last post by Gavin1393 on July 15, 2024, 05:43:32 PM »

Did you get your issue solved Evan? I had a similar problem, my MP just kept droppong indefinitely. Turns out my Q6 (one with the 90 degree bent legs) wasnt contacting the PCB...a little more solder sorted it!

7

Discussions about the products / Re: Preamp suggestion

« Last post by Gavin1393 on July 15, 2024, 05:30:42 PM »

Hey Jasper, I have the same Cranborne Setup you have. Was wondering if you experience the same "issue" I do with the Sound Skulptors I have running in the ADAT, I have to physically switch the link switch off and then on to link Pre-EQ-comp. Whereas, with the R8 the summing mixer seems to retain the setting when switched off and then back on. The ADAT seems to "turn off?

8

Discussions about the products / noise in mp(5)73

« Last post by JanPa on July 13, 2024, 01:53:23 PM »

I build the MP573 and everything works fine, but I find the output quite noisy and at the same time it has a very high output level (compared to other Skulptor pre amps I have). The class A output stage BA283AM has the right bias, but I am wondering why this stage is amplifying the signal with at least 15 dB. I made the feedback resistor R63 lower, 1k, and the signal level and noise level indeed drop. Why is there so much gain in this stage?

9

CP4500 Stereo Bus Compressor / Re: Meter Light not working

« Last post by yudamn on July 13, 2024, 03:21:49 AM »

Update for anyone that may experience the same issue.  Replacing Q1 and D18 did the trick.  Everything is working now.

Thank you JPK!

10

CP4500 Stereo Bus Compressor / Re: Meter Light not working

« Last post by JPK on July 09, 2024, 08:39:49 AM »

Be carefull to ground your body when handling the 2N7000 (removing your shoes does the trick). It is very sensitive to static electricity.