651

MP566 Tube microphone preamplifier / Re: signal check fail

« on: January 18, 2022, 10:16:33 AM »

What DC resistance do you measure between pins 8 & 10 on the extender, with the gain switch on LOW (module powered).
Do you see any resistance between pin 8 and pin 5 (0V).
Do you see any resistance between pin 10 and pin 5 (0V).

652

MP566 Tube microphone preamplifier / Re: Noise when switching form MID to HIGH gain

« on: January 17, 2022, 04:50:17 PM »

Do you get the click with no input signal?
Some clicking is normal here.
You could try to reduce it by using a higher voltage cap in C5 (watch out the size).
Also reducing the value of R15 (by 1/2 or 1/3) might reduce the clicking.
(not tested).

653

MP566 Tube microphone preamplifier / Re: signal check fail

« on: January 17, 2022, 03:52:10 PM »

Check the value (by color code) and solder joints of R38 to R44.
Are you sure your meter is OK, with a fresh battery?

654

CP4500 Stereo Bus Compressor / Re: No output on L-channel when engaged ("In" pressed) - right channel fine

« on: January 17, 2022, 03:42:37 PM »

In step 6 of the voltages tests, you said you got 1.5VAC on TP2. This means that the signal is present just before the output amp U7. 
Check the solder joints on C23, C24, C25, U7.
In the same conditions as step 6 check the AC signal level on TP2, U7-pins 4, 1, 8.

655

CP4500 Stereo Bus Compressor / Re: Second Channel not working

« on: January 17, 2022, 03:31:55 PM »

There is an issue there.
Check the value, solder joints and direction of
D2, D13 to D17, R14 to  R18, R85 to R88, L2, RSW1, U18, U20.
Can you report the DC voltages on U20 pins 1, 2, 3 and U18 pins 5, 6, 7.

656

CP4500 Stereo Bus Compressor / Re: Second Channel not working

« on: January 17, 2022, 10:46:16 AM »

Please measure the DC voltage on TP10.

657

CP4500 Stereo Bus Compressor / Re: No output on L-channel when engaged ("In" pressed) - right channel fine

« on: January 17, 2022, 10:19:21 AM »

Try putting U17 (THAT1646 from right channel) into U7 (left channel), in case U7 is damaged.

658

MP566 Tube microphone preamplifier / Re: signal check fail

« on: January 17, 2022, 10:12:10 AM »

The input impedance of the MP566 is around 1k2.
Which can be low for some sound cards, creating an voltage attenuator. 
Check the output impedance and max level of your sound card (from the specs sheet).

Now going from 1VAC to 0.086VAC seems really too much loading. Make sure the 48V is off, check the cable.
Check with the gain switch set to LOW.

659

MP566 Tube microphone preamplifier / Re: signal check fail

« on: January 15, 2022, 01:16:49 PM »

On the extender it is between pins 8 and 10.
Without an extender you must remove the cover of the XLR plug to get to the contacts.

660

MP566 Tube microphone preamplifier / Re: L1 and L2 different radial inductance ?

« on: January 15, 2022, 01:14:03 PM »

Not a problem.
The 2 inductors are from a different batch but they both are 22uH.
No need for matching here.

661

MP566 Tube microphone preamplifier / Re: signal check fail

« on: January 13, 2022, 08:38:15 AM »

Did you measure the input voltage (1VAC) with the source connected to the pre? The input impedance of the pre may load the source and reduce the input voltage when connected.

662

EQ573 Equaliser / Re: EQ-573II dropouts in PRE Mode when linked to an MP573

« on: January 12, 2022, 12:20:35 PM »

The Bento 2 overall got 900mA, that means 450mA per slot right?
It should be OK.

But is it an issue caused by the Rack or is it "just there" because of the slow start of the MP?
Some rack PSU's can't stand the high inrush current of the MP573 this is why we had to add a slow start.

Shortening the legs at L1 without a linked EQ Module would be also no prob?
It is not shortening but shorting and it is not L1 but U1. If it works it will work in any configuration.

663

EQ573 Equaliser / Re: EQ-573II dropouts in PRE Mode when linked to an MP573

« on: January 12, 2022, 08:35:35 AM »

It is a problem of 0V reference between the MP and the EQ during the power up.
One solution, if your lunchbox has enough juice is to remove the slow start on the MP573 by shorting the 2 side pins of U1 (LM317T). You can leave U1 in place.

664

MP566 Tube microphone preamplifier / Re: signal check fail

« on: January 10, 2022, 12:05:33 PM »

Probably Q1 (2N7000) is dead.
This device is sensitive to static electricity and is preferably handled with the body grounded (shoes removed).

665

MP566 Tube microphone preamplifier / Re: signal check fail

« on: January 09, 2022, 08:55:06 AM »

but I also don't see the tube light up
You must be in total darkness to see the tube glowing.

Do you hear the DI relay clicking when you insert a plug into the DI socket?

666

MP566 Tube microphone preamplifier / Re: Noise when switching form MID to HIGH gain

« on: January 09, 2022, 08:49:20 AM »

Check the direction of capacitor C5 and the solder joints on R15.

667

MP566 Tube microphone preamplifier / Re: No audio from preamp

« on: January 09, 2022, 08:47:33 AM »

Start here : https://www.soundskulptor.com/docs/mp566-test-guide-01.pdf

668

LA502 Optical Compressor / Re: La502 doesnt reach 15V AC

« on: January 09, 2022, 08:45:09 AM »

In step 5 what is the maximum voltage you can get?
Can you reach 15V if you increase the input signal?
Do you confirm that your input is actually 1VAC?

669

First Aid / Re: Lunchbox voltage

« on: January 09, 2022, 08:37:08 AM »

Ça n'est pas un problème à +/-10%.

670

TS500 Tape Simulator / Re: High Distortion

« on: December 23, 2021, 12:18:37 PM »

Check if you have any DC voltage on TP1, U2-pin1, TP2, TP3, TP4, TP5, U11-pin1, TP7.
There should be no more than a few millivolts.

671

LA502 Optical Compressor / Re: irregular output level

« on: December 20, 2021, 06:16:50 PM »

Great!

672

TS500 Tape Simulator / Re: High Distortion

« on: December 17, 2021, 09:55:25 AM »

Does the DRIVE pot have any effect on the gain?
Check the solder joints on the resistors and IC's.
Reflow any suspicious joint.

673

CP4500 Stereo Bus Compressor / Re: Have I ruined my PCB ?

« on: December 16, 2021, 10:28:47 AM »

You should also check the connections shown in the attached pic.

674

LA502 Optical Compressor / Re: irregular output level

« on: December 15, 2021, 05:05:03 PM »

It sounds like a bad solder joint making an intermittent connection.
Can you get the volume shifting by pressing or tapping the gain knob? This would show a defective potentiometer.
Next you need to visually check the solder joints and reflow the ones that look suspicious.

675

CP4500 Stereo Bus Compressor / Re: Have I ruined my PCB ?

« on: December 15, 2021, 04:59:28 PM »

Check that the vias are OK. They connect the top and bottom pads.
What is your PCB revision?