1

TS500 Tape Simulator / No Output - solved!

« on: December 08, 2022, 08:25:11 PM »

Hi,

I've built two TS500's. One is working with correct output voltages. The other has no output.
- Correct power voltages (+16/-16 VDC).
- Peak-meter is working and I can set it correctly.
- I've swapped all IC's, on both units, but still no output.
- I've Re-touched solder joints, still no output.
- I've compared continuity on the transformers of both units, but both were still in circuit.

Where should I look?

2

CP4500 Stereo Bus Compressor / Stereo Linking

« on: October 16, 2022, 11:52:27 PM »

Question:
Do I need to use a stereo linking switch on my 500 series rack?

I have a Midas Legend L10 rack. This switch s called "COMP BUS" switch. In the manual is stated:

"COMP BUS - These switches are
used for those compressors that
allow linking together for stereo
or multi-channel compressor
applications. Only certain
compressors have this feature,
and our current MIDAS 522
compressor/limiter does not."


When I did the calibration, I used two extenders but I don't know if the switch was "in" or not...

3

CP4500 Stereo Bus Compressor / CP4500 Setup trouble

« on: November 25, 2021, 10:27:42 AM »

Hi there,

The first time I was ready to fire up the the CP4500, it was with only the 1st channel in (PCB-A).
No IC's plugged in. Compressor was off.
When I turned it on, I saw a short light flash in the meter and than a super high high pitch and than C18 exploded. Was the wrong way in. First time that happened to me.

I cleaned the board and I saw that I forgot to pull out U7 (THAT 1646) before turning on for the first time. I put a new capacitor in C18. Checked all solder joint and re-flowed some of them. Cleaned again all the flux.

Measured all the voltages without any IC's in:
• V+ =+15 to +16VDC, +16.04
• V-  =-15 to -16VDC), -16.13
• +12V = +11.1 to +12.9VDC, +11.89
• -12V  = -11.1 to -12.9VDC -11.84


Now I'm going through the setup guide:

Channel 1

Step.....	Conditions	Result
1	Mix = 100% Ratio = 10 Attack = 0.1 Release =1.2 IN button pressed HF lift, 100Hz, 50Hz buttons released Negative meter probe on 0V	• V+ =+15 to +16VDC, +16.04  • V-  =-15 to -16VDC), -16.13 • +12V = +11.1 to +12.9VDC, +11.89 • -12V  = -11.1 to -12.9VDC -11.84

2

Step 1 conditions plus: Input signal = 0V Threshold on +15 Makeup on 0

TP1, TP2, TP3, TP4, TP11, TP12 = 0VDC TP1= 0V, TP2= 0V, TP3= 0V, TP4= +15.6V, TP11= -15.17V, TP12= +14.26V (all VDC)

I'm stuck in the this step of the setup. Only TP1, TP2 and TP3 gave 0VDC.
I don't know if anything else got damaged when C18 exploded? Or IC U7 got damaged? I don't know.

Also: When I turn compressor on (IN pressed), the meter light turns on and the meter hits MAX, way passed 20dB compression.

Can someone point me in the right direction?

Cheers!

EDIT:
From datasheet OPA2134:
1 out A
2 -in A
3 +in A
4 V-
5 +in B
6 -in B
7 out B
8 V+

From the CP4500 schematic:

TP4 --> IC U10 (OPA2134) pin7 = out B
R40 = measured in circuit = 33k?

TP11 --> IC U21 (OPA2134) pin1 & pin2 = out A & -in A

TP12 --> IC U22 (OPA2134) pin2 & pin1 = -in A & out A --> ACV1

Why do I get DC voltage on TP4, TP11 en TP12 when input signal = 0V?