Author Topic: Weird stereo effect

July 08, 2022, 10:10:21 PM
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igor.moreno

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Hi,

I finally measured my two TS500.
They sound identical, altough one of the units is 1/1,5V "louder" than the other on most measurements.
With the 10kHz sine wave, both units measure 50% less than the reference voltage.  (??)

What is weird though, is that when engaging the units, the ambiance of the sounds seems to disapear.
For exemple, with a drum track, it almost act like a transient designer : Kick and snare become louder, but all the details of the room microphones or overhead are getting lost somwhere. As if it were "mono-ing" the signal.
It's visible on the waveform : when level matched, transients keep the same level, but sustained sounds are way lower.

Is it normal behavior ? It does not seem to be the case on the exemples I found on the internet.

Thanks for your insight !

July 11, 2022, 09:24:44 AM
Reply #1

JPK

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They sound identical, altough one of the units is 1/1,5V "louder" than the other on most measurements.
This doesn't sound right. How did you test?

With the 10kHz sine wave, both units measure 50% less than the reference voltage.  (??)
For what settings and pot position?
JPK

July 11, 2022, 06:21:43 PM
Reply #2

igor.moreno

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This doesn't sound right. How did you test?

I followed the measurement procedure, sending the different sine waves and measuring on output XLR betwenn pins 2 and 3.
I used the same 500 extender, same rack slot.

For what settings and pot position?





input signal = sine 1kHz, 0.4VAC                 TAPE SAT on left                              9.2V        Unit 1   10,6 V              Unit 2     9,3V
(on input XLR between pins 2&3)                TAPE SAT on center                           7.4V       Unit 1     8,27V             Unit 2      7,4V
BIAS on right                                            TAPE SAT on right                              7.1V       Unit 1    7,56V             Unit 2       7,08 V


Input signal = sine 40 Hz – 0.25VAC              SPEED on 7.5'                                9.4V        Unit 1    10,5V               Unit 2    9,9V
TAPE SAT on left                                            SPEED on 15'                                8.5V        Unit 1     9,7V               Unit 2    9,10V
BIAS on center                                              SPEED on 30'                                 7.5V        Unit 1    8,5V               Unit 2    7,95V


Input signal = sine 60 Hz – 0.25VAC                  SPEED on 7.5'                            7.5V          Unit 1    8V                 Unit 2    7,7V
TAPE SAT on left                                              SPEED on 15'                             9.3V           Unit 1    10,4V            Unit 2    10,06V
BIAS on center                                                SPEED on 30'                              8.7V           Unit 1    9,9V             Unti 2    9,46V


Input signal = sine 80 Hz – 0.25VAC                    SPEED on 7.5'                          5.4V              Unit 1    5,7V               Unit 2    5,5V
TAPE SAT on left                                                 SPEED on 15'                           7.9V             Unit 1    8,5V               Unit 2   8,1V
BIAS on center                                                     SPEED on 30'                         9.3V              Unit 1    10,6V            Unit 2   10V
Both pots on 10                                                   BIAS on right                          6.1V              Unit 1   7V                 Unit 2   6,75V


Input signal = sine 10kHz – 0.25VAC             SPEED on 7.5'                                 2.5V            Unit 1   1,34V          Unit 2      1,32V
TAPE SAT on left                                          SPEED on 15'                                  4.1V            Unit 1    2,3V            Unit 2      2,2V
BIAS on left                                                 SPEED on 30'                                  5.1V            Unit 1   2,7V             Unit 2      2,7V
Both pots on 10                                            SPEED on 7.5' and BIAS on right      5.1V            Unit 1   2,75             Unit 2      2,7V


Thanks !

July 13, 2022, 09:43:40 AM
Reply #3

JPK

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Actually the level difference is only 12% which is normal, due to the pot tolerance of 20%.
I misunderstood your 1/1,5V "louder" for 50%.
Your values are in the ballpark except for the 10kHz.

Check the component value, direction and solder joints of:
R33, R34, C35 to C38,
R52 to 58, D8, D9, C62, C63.

What are the DC voltages on U6 pins8 and pin9 for the last 4 settings of the test (10kHz)?
JPK

July 13, 2022, 05:14:02 PM
Reply #4

igor.moreno

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Hi,

Actually the level difference is only 12% which is normal, due to the pot tolerance of 20%.
I misunderstood your 1/1,5V "louder" for 50%.
Your values are in the ballpark except for the 10kHz.


Ok, nice.

Check the component value, direction and solder joints of:
R33, R34, C35 to C38,
R52 to 58, D8, D9, C62, C63.


Everything looks good and is on the right place. I did not reflow the solder joints, but I could try if you think the problem comes from here.
(but as both units sounds really close, I guess a random error would make them sound different ?)


What are the DC voltages on U6 pins8 and pin9 for the last 4 settings of the test (10kHz)?

DC Voltages are 0VDC on the last 4 settings on both units.

Thanks !

Igor




July 13, 2022, 06:20:51 PM
Reply #5

JPK

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DC Voltages are 0VDC on the last 4 settings on both units.
This is the issue. The voltage should go from +12V to -13V on pin 8 and +15V to -13V on pin 9.
Check again without U6 inserted.
Check again R52 to 58, D8, D9, SW3 and SW4. Reflow the solder joints.
Make sure you didn't mix up D1, D2 (zener 2V4) with D8, D9 (1N914).
JPK

July 14, 2022, 12:19:48 PM
Reply #6

igor.moreno

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This is the issue. The voltage should go from +12V to -13V on pin 8 and +15V to -13V on pin 9.

Sorry, I measured AC instead of DC...
I do get the right readings on U6 !

Just to add to the weird "disapearing ambiance" phenomena :
I recorded the output of the TS500 and did a null test with the dry version of the signal (drum track) and the result was ambiance only.

(TS500 = Less / no Ambiance         ///        Dry + TS500 Phase flipped = only Ambiance)

This is weird...


July 14, 2022, 05:32:08 PM
Reply #7

igor.moreno

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OK, so I re-did the measurements with the 10kHz sine wave, but with the multimeter not set to "auto range" and the results I get are much closer to the reference numbers :

Unit 1    2,20          Unit 2      2,16V
Unit 1    3,76          Unit 2      3,7V
Unit 1     4,6           Unit 2      4,5V
Unit 1     4,6           Unit 2      4,5V

I don't really get the difference between the two multimeter modes, I'll try to check with another multimeter.

To bo continued...  :)

Thank !

Igor

July 22, 2022, 10:12:24 AM
Reply #8

roman_cg

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What is weird though, is that when engaging the units, the ambiance of the sounds seems to disapear.
For exemple, with a drum track, it almost act like a transient designer : Kick and snare become louder, but all the details of the room microphones or overhead are getting lost somwhere. As if it were "mono-ing" the signal.
It's visible on the waveform : when level matched, transients keep the same level, but sustained sounds are way lower.
I hear the same effect with my 2 TS500, so I think it's a normal behavior.
The TS500 seems to enhance the transients a lot, so on a drum track when you level match dry and processed signal it's seems normal that the "ambiance" seems lower in volume.

August 01, 2022, 04:59:58 PM
Reply #9

igor.moreno

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Hi,
Thank you for your answer.
Do you get the same effect I get when doing a null test with dry signal + TS500 phase flipped ?

August 22, 2022, 11:43:15 AM
Reply #10

roman_cg

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Hi,
Thank you for your answer.
Do you get the same effect I get when doing a null test with dry signal + TS500 phase flipped ?
I tried a null test with a dry drum mix + drum mix TS500 phase flipped (15ips, Sat in the middle, flat Bias, +9 dbVu), and I didn't get the same result as you. I get a drum mix 20db quieter, not only the room ambiance.
Are you sure you are perfectly time aligned and level match when doing your null test?

January 10, 2023, 12:11:51 PM
Reply #11

igor.moreno

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Hello again,

So I took the time to do a few comparison tests with my TS500 pair regarding this curious "expending" behavior.
I sent a drum track and a full mix to the TS500, and you can clearly hear the ambiance sounds "disapear".
Listen to the reverbs on the "Mix" track, and to the room sound on the "Drums" track.
I also recorded the flipped phase versions of the tracks (null test), and what reamains is mainly reverbs and ambiance.

https://soundcloud.com/igormoreno/sets/ts500-tests

The "tape effect" is often described as compression and saturation, but compression and saturation would make the ambiance sounds more obvious, right ?
This is more like an expander.

So my question is : Is this normal for the TS500 to act like that, or is there something wrong with mine ?

Thanks !

Igor