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Messages - JPK

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CP4500 Stereo Bus Compressor / Re: Issues with Midas L10
« on: December 02, 2022, 04:01:20 pm »
Check if you do not have a bad connection on the meter wire connector.

LA502 Optical Compressor / Re: Hissing LA502
« on: December 02, 2022, 03:52:10 pm »
What is your PCB revision number?

CP4500 Stereo Bus Compressor / Re: Issues with Midas L10
« on: November 30, 2022, 10:16:48 am »
It doesn't sound like a lack of power.
Maybe a earthing issue that injected some mains voltage leak into the chassis.
Check the V+, V- voltages.
Remove the input/output interface IC's U1, U7, U11, U17 and check again.
Check the LED D3 with your DMM.
What is your PCB revision number?

First Aid / Re: AB528 Noisy in Bento 10S
« on: November 28, 2022, 10:02:34 am »
The external noise may come from 2 sources:
- radiated on short distances,
- from the power rails.
On our Bento6, the noise cannot be heard at the maximum gain.

First Aid / Re: 2-slot modules such as CP554
« on: November 28, 2022, 10:01:28 am »
This will work from the left module to the CP554 input but it won't work CP554 output to right module input because the right side connector output is not connected.
You must use an external connector here.
On the other hand, the stereo link does work.

CP5176 FET compressor / Re: Pop sound and some smoke upon testing
« on: November 23, 2022, 08:34:12 am »
Simply measure the value of the resistor with your DMM in Ohm position without de-soldering the resistor from the PCB.
If it shows a higher value than 5.6 ohms then it is probably dead.

CP5176 FET compressor / Re: Pop sound and some smoke upon testing
« on: November 22, 2022, 07:42:09 am »
Remove the DOA.
Check that R56 and R57 are measuring OK in circuit.
One of them may have burnt. If not conducting anymore, you need to replace one or both.
Then power up again. Turn off quickly the LED's does not light up.

Heat the 3 pins together with a big blob of solder.

Can you check the DC voltages as shown here?

Try removing Q1, it might be damaged (Its function is to stop the meter moving when the compressor is bypassed).

I donĀ“t get any VDC on pin1 of JMP1
12.336 VDC at Threshold set to -9dB
These 2 lines seem contradictory.
Do you mean it is only at Threshold -6 that you get no DC on pin1?

Is there anything specific that goes bad on these after a while?
No. This sounds like a random component failure.
If you have some electronics competencies you should start here.
If not you will need to send it to us. Please contact me here (jpk).

THRESHOLD adjust :
input 1kHz 6.15 VAC
Threshold -6dB
Bypassed: 6.151 VAC OK

In the THRESHOLD adjust conditions, with 6.15VAC at the input :

With JMP1 removed:
AC volts on TP4 : 2.8V (varying with trimmer TR3)
AC volts on TP5 : 2.8V (varying with trimmer TR3)

With JMP1 back in position 1-2:
DC volts on JMP1-pin1 : 4.7 VDC

CP4500 Stereo Bus Compressor / Re: Stereo image changes
« on: November 04, 2022, 06:35:35 pm »
Good news!

What is the DC voltage on TP5 and TP11 (only channel 1 installed)?
Check that the resistors R5 to R9 are in the correct position.

Have you added the four 4mm spacers under the transformer?
If so, you could try to add some washers on the side that sticks out from the chassis.

CP4500 Stereo Bus Compressor / Re: Stereo image changes
« on: October 29, 2022, 12:02:46 pm »
Is the side that stays loud compressing? Check by disconnecting the other side input signal.

Discussions about the products / Re: CP554, I need some guidance
« on: October 29, 2022, 09:53:45 am »
I can only approve! :)

Not sure for the isopropyl. The issue would be there for the 3 ratios.
Do you get the same meter shift without the channel 2 installed?
Do installing channel 2 modifies the shift level?

Is it only the display with the sound being compressed normally in 2:1?
Does the meter needle move from the +4 position when audio is sent?

You could check that diodes D1 and D2 are in the correct direction.

Discussions about the products / Re: CP554, I need some guidance
« on: October 24, 2022, 09:58:16 am »
Thank you for the kind words!

You can start with one CP554 then add another one later, no problem.
The matching is done with the settings.
Any 2 units can be perfectly matched because the diodes have a very predictable behaviour.

I wonder if it makes sense to get 5176 + LA502 instead of the 2nd channel for now.
I think both approaches are valid. It's your own strategy.

Discussions about the products / Re: CP554, I need some guidance
« on: October 17, 2022, 05:09:21 pm »
1. What sets the Sound Skulptor CP554 appart from the other compressors you mention isn't really the diodes but the 3 Carnhill transformers in the signal path and the Neve output stage. It does give a richness to the sound which is not present on other compressors. In particular, if you try it on a drum bus, you will never remove it.

2. I don't believe there is so much difference in the attack times because these units all have the same origin. It is more a matter of how you measure the attack time: Is it when the signal gets to 100% or 90% or 70% (3dB) of the final level?

We plan making a demo video someday.

CP4500 Stereo Bus Compressor / Re: Stereo Linking
« on: October 17, 2022, 04:48:44 pm »
No need of stereo link. The 2 channels are permanently linked.

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