Show Posts

This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.

Messages - JPK

Pages: [1] 2 3 ... 43
1
MU524 Vari-Mu Tube Compressor / Re: AudioPath Test Question
« on: June 19, 2024, 11:12:16 AM »
TP1 290 mV VDC
TP2 203 mV VDC

These pins should be above 30VDC, against 0V.
Check the solder joints on R8.

2
CP4500 Stereo Bus Compressor / Re: Meter Light not working
« on: June 19, 2024, 10:57:39 AM »
Yes, after disconnecting the meter connector.

3
MU524 Vari-Mu Tube Compressor / Re: AudioPath Test Question
« on: June 17, 2024, 11:58:32 AM »
What is the DC voltage, against 0V, on the test pin B+.
It should be around 45V.

5
CP4500 Stereo Bus Compressor / Re: Meter Light not working
« on: June 17, 2024, 11:52:10 AM »
First check that the meter is working by measuring its internal resistance (connector unplugged). This should move the needle. Around 600 ohms.

6
MU524 Vari-Mu Tube Compressor / Re: AudioPath Test Question
« on: June 13, 2024, 10:53:11 AM »
What AC value do you read when directly connected to the source at 0.0dB, without the MU524 connected.

7
Check the usual suspects:
  • Check you didn't leave the polarity switch on the center position (=mute),
  • Forgotten solder joint,
  • Bad solder joint (reflow suspicious joints),
  • Reversed components (electrolytics, diodes, transistors, IC's). In case of IC's, probably destroyed, better replace,
  • Flipped IC's or transistors,
  • Trim all the component leads and test pins as short as possible. Nothing must touch the chassis plate.

Check the DC voltages:
First check the supply voltages as described in the setup guide.
Next, without any input signal, connect the voltmeter black probe to the 0V test pin and note the DC voltages you get at the points shown on the attached picture. Compare with the expected results (more or less 10%).


8
AB528 Microphone preamplifier / Re: Preampli AB528
« on: June 12, 2024, 04:08:10 PM »
Le problème se situe dans l'étage de sortie.
Vérifiez valeur, direction et soudures des composants Q3, Q4, Q5, Q6, R22...R29, C13...C18.

J'ai ajouté un topic pour les tests :
https://www.soundskulptor.com/forum/index.php?topic=498.msg2966#msg2966

9
MP566 Tube microphone preamplifier / Re: Solder bridge on C9 and C10?
« on: June 10, 2024, 12:18:19 PM »
or is it harmless, and better to leave it this way?
Yes harmless. These pads are already connected together. They are only there to allow the use of capacitors having a different distance between pins.

10
MU524 Vari-Mu Tube Compressor / Re: AudioPath Test Question
« on: June 10, 2024, 11:10:39 AM »
No matter what I change in my daw I can't get it close to 1.0 vac.
Do you mean when bypassed?
If true, it is either a connection issue: check your connections from your audio source,
or you have a bad solder joint on the relay.
Do you hear the relay clicking when you move the bypass switch?

11
AB528 Microphone preamplifier / Re: Preampli AB528
« on: June 09, 2024, 09:56:07 AM »
Voyez-vous le signal sur TP4 avec le voltmètre en alternatif, par rapport au 0V.
Le maximum que je mesure est 5 mV.

Même question pour TP3, TP2 et TP1.

12
AB528 Microphone preamplifier / Re: Preampli AB528
« on: June 07, 2024, 05:40:17 PM »
Voyez-vous le signal sur TP4 avec le voltmètre en alternatif, par rapport au 0V.
Quelle est la tension continue sur la vis des transistors de sortie Q5 et Q6, par rapport au 0V.
Vérifiez les connexion du transfo de sortie.
Vérifiez que vous n'avez pas laissé le commutateur de polarité sur la position centrale (=mute).

13
The transformers are OK.
There is something wrong around Q4, Q5, Q6.
Check all the solder joints around there.

14
First Aid / Re: Need help with 573EQ, solder on gold connectors
« on: June 01, 2024, 06:09:56 PM »
Just remove as much solder as you can with a desoldering pump or solder braid.
You won't be able to restore the gold layer but it should still work.

15
Can you do the measurements shown here : DC voltages, and output transformer check?
We will add a new relay to your new order.

16
There is something wrong in both channels.
The pins 6 & 7 should be at 0VDC.
Does it change something in the voltages if you remove the ribbon cables going to CN24 and CN25.
What are the DC voltages on TP9 and TP10, against 0V? Should be 0VDC.
Same question after removing U6 and U8 but with a wire connected between pin 7 and 0V.
Look for bad solder joints or solder bridges in the area U6 to U9.

17
Do you have this issue in both ears?
Please report the DC voltages on every pins of U6 and U8 against 0V.

18
CP554 Diode bridge compressor / Re: Attack times
« on: May 21, 2024, 04:10:20 PM »
The front pannel attack times are more realistic in the 6 or 12 ratios.
In the lower ratios they are slower because they depend on the side chain signal level and this is by design.
The CP554 1ms position matches the originial Neve circuit which doesn't have an attack time switch. 
You can reduce all the attack times proportionnally by reducing the value of C37 but this will increase the distortion in the lower frequencies.

19
I think you should statrt here: https://www.soundskulptor.com/forum/index.php?topic=5.msg5#msg5

22
MP573 Microphone preamplifier / Re: No Output
« on: May 20, 2024, 11:14:00 AM »
Try to follow the signal as shown here.

23
DI503J Triple DI and Re-Amp / Re: Extremely low output
« on: May 20, 2024, 10:26:46 AM »
👍

25
TR1 is a 2k trimmer so the marking 202 is correct (the third digit is the number of zeros to add).
The partslist is correct. Where did you see 203?

Were you able to set the balance 1 in step 7 ?
Can you do the voltage checks described here:
https://www.soundskulptor.com/forum/index.php?topic=347.msg1907#msg1907

Check the component value and solder joints of R3, R4, TR1.

Pages: [1] 2 3 ... 43