1

TS500 Tape Simulator / Re: Testing The Unit For Correct VAC

« on: April 12, 2021, 11:16:54 PM »

Hi,
These are the results I got when testing the TS500 as described in the "Testing Your TS500" topic. Not sure if they are within bounds for a perfect running unit:

-----------------------------------------------
Test 1) sine 1KHz @ .4VAC

I could not get my DMM exactly at .4VAC, I got it to .384VAC with the following results:

BIAS on right
TS500 ON
Both pots on 10

TAPE SAT left : 9.62VAC
TAPE SAT center :  7.73
TAPE SAT right : 7.36

----------------------------------------------

Test 2) sine 40Hz @ .25VAC

I could not get my DMM exactly at .25VAC, I got it to .262VAC with the following results:

TAPE SAT on left
BIAS on center
Both pots on 10

SPEED on 7.5 : 11.26VAC
SPEED on 15 : 7.73
SPEED on 30 : 7.36
---------------------------------------------------

Test 3) sine 60Hz @ .25VAC


I could not get my DMM exactly at .25VAC, I got it to .262VAC with the following results:

TAPE SAT on left

BIAS on center

Both pots on 10



SPEED on 7.5 : 9.12VAC

SPEED on 15 : 11.44

SPEED on 30 : 10.77
---------------------------------------------------



Test 3) sine 80Hz @ .25VAC


I could not get my DMM exactly at .25VAC, I got it to .264VAC with the following results:

TAPE SAT on left

BIAS on center

Both pots on 10



SPEED on 7.5 : 6.59VAC

SPEED on 15 : 9.63

SPEED on 30 : 11.38

BIAS on right : 7.76

---------------------------------------------------


Are these readings within range...if not, what should I look for.


Thanks,

Rob

2

TS500 Tape Simulator / Testing The Unit For Correct VAC

« on: April 11, 2021, 11:38:19 PM »

Hi,
Just a couple of questions to make sure my unit is working correctly:

1) I'm trying to check the VAC specified in "Testing your TS500" topic. In the first "Conditions" I set a 1kHz at .04VAC ? This is measured by attaching my DMM to the output XLR connector on my chasis?  Also, what do you mean by "in Bypass"?

2) Am I using TP2 and TP0 for testing the VAC for all the test conditions?

Thanks,

Rob

3

EQP501 Passive Equalizer / Re: VAC and VDC Readings Not Right

« on: March 16, 2021, 07:17:13 PM »

HI JP,

I think the problem is solved...I had mixed up R9 on the SK25 with R25 on the Potentiometer circuit board.
Everything seems to be workng.

I do have on e question...when I measure DC resistance between TP1 and TP3 on one of the units I get 11.06K at 0. Is that ok? The other unit is 10.41K. Is 11.06K ok?

Thanks for your help.

Rob

4

EQP501 Passive Equalizer / Re: VAC and VDC Readings Not Right

« on: March 12, 2021, 05:37:26 PM »

Hi JP,

I think I might have found the problem. On the Potentiometer circuit board R25 is the wrong resister. Its Red Red Black Black Brown with a reading of 181.1 ohms. I think it should be Brown Black Black Red Brown with a reading of 10K. If this is the problem, I should have checked the resistance with my DMM before I installed it. Having said that though, I think it was the last resister left in the build and I installed it. 

Anyway, can you send me the right resistor if this is indeed the issue.

Thanks,
 
Rob

5

EQP501 Passive Equalizer / Re: VAC and VDC Readings Not Right

« on: March 11, 2021, 02:52:15 PM »

Hi JP,

My readings were:
 
10.41k with pots at o
11.60k with low freq attenuation at 10.

Thanks,

Rob

6

EQP501 Passive Equalizer / Re: VAC and VDC Readings Not Right

« on: March 10, 2021, 10:49:08 PM »

Hi,

I re-soldered the joints on the pots and connectors on the switches. At 2VAC I am getting .010VAC on TP3. What else can I check?

On my other unit I am getting .09VAC at 2VAC on TP3. Is that ok?

Thanks,

Rob

7

EQP501 Passive Equalizer / Re: VAC and VDC Readings Not Right

« on: March 10, 2021, 03:57:08 PM »

Hi JP,

Without the DOA inserted, at 4VAC I am getting .039VAC on the top pin of P5. What does that tell me?

Thanks again,

Rob

8

EQP501 Passive Equalizer / Question About R14 And R15

« on: March 08, 2021, 05:33:06 PM »

Hi JP,

I had initially made a mistake when building the SK25 which caused R14 and R15 to burn up. I replaced R14 and R15 and replaced the SK25. In a previous post I stated that I am getting a reading of .227VAC on TP2 when sending a 100Hz 2VAC signal. Could that reading of .227VAC be a result of the previous issue? Could I have affected other components besides R!4 and R15 due to the mistake I made with the SK25? If so, which components might have also been affected?

The mistake i made with the SK25 was reversing Q9 and Q10.

Thanks,

Rob Lanter

9

EQP501 Passive Equalizer / Re: VAC and VDC Readings Not Right

« on: March 08, 2021, 11:01:05 AM »

When i take my readings of TP2, all the pots are set to 0. I am getting .227vac on TP2 ...that can't be right. What else can I check?

10

EQP501 Passive Equalizer / VAC and VDC Readings Not Right

« on: March 08, 2021, 01:16:01 AM »

Hi JP,

I have built two EQ501 units.

With unit 1 I am getting a reading of .227 VAC on TP2 when sending 2VAC 100hz signal, TP1 is ok at 1.3VAC

With unit 2 I am getting in the setup Step 4 DOA Check, I get  -.7 Millivolts on TP2. Is that ok?

Also with unit 2, in the "In case your EQP501 doesn't work as expected" I am getting some strange readings. When sending 2VAC 100hz signal I am getting .947VAC on TP2, not 1.15VAC. TP1 is ok at 1.3VAC on TP1.

What can the problem be?

Thanks,

Rob

11

EQP501 Passive Equalizer / Re: R14, R15 Started Smoking After Inserting SK25 DOA

« on: March 08, 2021, 01:14:15 AM »

My problem is solved. I had flipped Q9 and Q10...thanks.

I have another post with some other issues with the EQ501 unit.

Rob

12

EQP501 Passive Equalizer / Re: R14, R15 Started Smoking After Inserting SK25 DOA

« on: February 14, 2021, 09:30:48 PM »

I was trying to be very careful when I built the SK25 since it was the second one I had built. Can you tell me what I might have done wrong on the SK25 to have caused R14 and R15 on the 501 Passive EQ to burn up?

Thanks,
Rob

13

EQP501 Passive Equalizer / Re: R14, R15 Started Smoking After Inserting SK25 DOA

« on: February 14, 2021, 04:13:49 PM »

Hi JP,
 
Is there a reason why a defective SK25 DOA would affect resisters R14, and R15 on the 501 Passive EQ? As soon as I installed the SK25 DOA, R14 and R15 started smoking. 

Thanks,
Rob

14

EQP501 Passive Equalizer / R14, R15 Started Smoking After Inserting SK25 DOA

« on: February 12, 2021, 11:15:48 PM »

Hi JP,

R14 and R15 started to burn up when I inserted the SK25 DOA during the testing phase after the build. All the voltages checked out before I inserted the DOA.

I sent you an email asking for replacement parts.

Thank,

Rob 

15

CP4500 Stereo Bus Compressor / Re: Channel A Distorted

« on: February 12, 2021, 05:45:23 PM »

Hi JP,

Good news...I was able to move the distortion to the other side...the 1646 chip is bad...I will replace it and hopefully the problem will be solved. I am going to wait to replace it after I finish building the two 501 eq's I purchased in case I need to order more than just the IC 1646 chip. 

Thanks for your help.

Rob Lanter

16

CP4500 Stereo Bus Compressor / Re: Channel A Distorted

« on: February 12, 2021, 02:55:57 PM »

Also, the meter needle does move when compressing. It moves as I would expect it to move when changing the Threshold.

Rob

17

CP4500 Stereo Bus Compressor / Re: Channel A Distorted

« on: February 11, 2021, 04:03:28 PM »

Hi,

I am getting +4.6VDC on TP11. 
I switched U1 with U11...same problem.

I am definitely getting compression on both channels. Though Channel A has some slight distortion. 

I am attaching a short audio file so that you can hear what I am talking about.

https://www.dropbox.com/s/7yil2tongebu5gp/DistortionExample.mp3?dl=0

Any other suggestions as too what might be causing distortion?

Thanks,
Rob

18

CP4500 Stereo Bus Compressor / Re: Channel A Distorted

« on: February 10, 2021, 04:53:30 PM »

Hi,

I get compression on Channel B.  I am not sure about channel A because of the distortion.

I had a typo in the previous reply...TP11 was 6.5VDC, NOT -6.5VDC, Then the second time I measured TP11 was 4.3DC.

Rob

19

CP4500 Stereo Bus Compressor / Re: Channel A Distorted

« on: February 10, 2021, 02:43:28 PM »

Hi JP,

Can you please help me debug this issue? 

Thanks,

Rob Lanter

20

CP4500 Stereo Bus Compressor / Re: Channel A Distorted

« on: February 09, 2021, 03:36:50 PM »

Hi JP,

Usual suspects are fine, IC's are in the right place, I am getting +16.15V, all others are between 15V and 16V

I removed all IC's except U21, TP11 = 4.3DC

I am getting sound in channel A and all the controls are working, there is  just some distortion, where as Channel B is perfectly clean.

Thanks,

Rob

21

CP4500 Stereo Bus Compressor / Channel A Distorted

« on: February 06, 2021, 11:31:33 PM »

Hi JP,

I am getting distortion in channel A. I followed the tests in the "In case your CP4500 doesn't work as expected" I got some strange readings:

Step2:
TP2: -.7 VDC
TP4: -1.1 VDC
TP11: -6.5 VDC
TP12: - 6.0 VDC

Step 6:
U6 pin 1: -.7

Any suggestions?

Thanks,
Rob

22

CP4500 Stereo Bus Compressor / How can I test the Side Chain HF Lift?

« on: January 31, 2021, 06:00:46 PM »

How can I test the Side Chain HF Lift?

Thanks,

Rob

23

CP4500 Stereo Bus Compressor / Re: No Signal On 2nd Channel of the CP4500

« on: January 30, 2021, 11:08:56 PM »

Hi JP,
Good news.. I think.the unit is working perfectly...still need to verify the side chain functionality ratio and release, but so far my test has indicated everything is working...I had some bad solder joints. Re soldered all the IC's and some other points that looked bad and now it all seems to work...thanks for you help.

Rob

24

CP4500 Stereo Bus Compressor / Re: No Signal On 2nd Channel of the CP4500

« on: January 30, 2021, 02:58:26 PM »

Hi JP,

I can confirm 1.5VAC on TP7, TP8. TP9 is .06VAC.

For U17 I get:
pin1 - 2.9VDC
pin 4 - 1.0
pin 8 - 1.1

Thanks,
Rob

25

CP4500 Stereo Bus Compressor / Re: No Signal On 2nd Channel of the CP4500

« on: January 29, 2021, 07:22:27 PM »

Hi,

Thanks for getting back to me...I just replaced all the ICs on Channel B with newly bought chips.

I get a reading of 0.000 on the DMM on channel B. I can't get any VAC at all, so I really can't perform the test you suggested in the thread. On Channel A, I can set 3VAC from my DAW, but when I attach my DMM to the output XLR on channel B, I get 0.000VAC.

Thanks,

Rob Lanter