81

MC624 Monitor Controller / Re: No function of -12db over inputs ans outputs

« Last post by JPK on February 14, 2025, 11:39:13 AM »

To check that the unit is working do the following:
1. 
- send a low level audio signal (preferably a constant sine wave) to the input,
- set the level of the MC624 at 0dB, note the audio volume.
- bypass the MC624 completely and check that you get the same audio level.
2.
- send a strong audio signal (preferably a constant sine wave) to the input,
- set the level of the MC624 at -63dB, note the audio volume.
- Lower the audio signal by -63dB at the source,
- increase the level of the MC624 to 0dB and check that you get the same audio level than before.

82

MC624 Monitor Controller / Re: No function of -12db over inputs ans outputs

« Last post by audiosoldering on February 13, 2025, 10:47:55 PM »

Thanks for explaining the functions. 

Listening to a loud source, "Mastered Music," I find it to be 14db louder than some of my lowest listening levels when set to the maximum attenuation of -63. 

If I pull my DAW fader down an additional 42db then the signal is inaudible.  

83

MP573 Microphone preamplifier / Re: No DI input: what did I forgot in the calib prodedure? [SOLVED]

« Last post by JPK on February 13, 2025, 04:27:16 PM »

84

MC624 Monitor Controller / Re: No function of -12db over inputs ans outputs

« Last post by JPK on February 13, 2025, 04:26:11 PM »

Check that the in/out offsets are set to 0.
If one input or output is offseted by +5dB the the max level will be reached at -5 on the display.

85

MP573 Microphone preamplifier / Re: No DI input: what did I forgot in the calib prodedure?

« Last post by batchas on February 13, 2025, 02:10:34 PM »

I wanted to inform you that the DI input is now working.
I traced this morning a short between 2 points on the DI board. A tiny blob of solder between 2 pins on 2SK170 that I did oversee when cleaning the board.

86

MC624 Monitor Controller / Re: No function of -12db over inputs ans outputs

« Last post by audiosoldering on February 12, 2025, 03:53:40 PM »

Understood on the attenuation.   

When I run a tone into the input of the MC624 and back into my DAW I observe the following.

-63 on MC624 set to -63db db on daw meter.  A 1db increase is observed until -5.  After this, there are no more level increases or relay clicks. 

Thanks

87

MC624 Monitor Controller / Re: No function of -12db over inputs ans outputs

« Last post by JPK on February 12, 2025, 12:07:32 PM »

I can add +12db of gain on all i/o but I don't get any attenuation.
When you are at -63dB attenuation, it is not possible to add more attenuation. This is normal. The offsets are added to the main level but the main level cannot go above 0dB or below -63dB.

Also at -63 I have level louder than I would expect.
Do you have all the -1dB steps from 0 to -63?

88

MC624 Monitor Controller / No function of -12db over inputs ans outputs

« Last post by audiosoldering on February 11, 2025, 11:04:34 AM »

Finished the build and everything sounds great.  I'm just having two issue. 

The attenuation of inputs and outputs.  I can add +12db of gain on all i/o but I don't get any attenuation.  Also at -63 I have level louder than I would expect. 

The relays are not clicking,  Which relays and IC deal with the i/p and o/p attenuation? 

thanks

89

AB528 Microphone preamplifier / Re: 2e unité: Pas de son et voltages sur F et I problématiques

« Last post by JPK on February 08, 2025, 10:02:09 AM »

90

AB528 Microphone preamplifier / Re: 2e unité: Pas de son et voltages sur F et I problématiques

« Last post by lp@kyer.ca on February 08, 2025, 05:15:54 AM »

La pin 2-3 du pot 10k donnait 0M peu importe la position. 1-2 fonctionne bien.
J'ai donc ressoudé les 3 pins du pot.

Problème résolu.

Je vais le laisser tourner quelques temps encore pour m'assurer qu'il n'y a pas un problème inhérent au pot. Si c'est le cas, je le remplacerai.

Gros, gros merci JPK.
Très hâte aux prochains kits...