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TS500 Tape Simulator / level problems
« on: June 04, 2021, 03:30:05 PM »
Hello,
I assembled two TS500 and they sounded great and identical at first. Suddenly I recognized a level jump of + 2.5/3 dB on one unit, which was also confirmed by the LED Meter.
I went through the level testing routine, and the defective unit had too much level of 2.5-3V on the 1kHz and all low frequency measurements. At 10k the results were fine.
I also noticed, that with no signal at the input and Drive on max., the first 3-4 green LED show a constantly "pumping" signal, whithout anything hearable at the output.
Ich checked the test pins with a 1kHz sine at 0.4V and got the following results:
Pin 1: 1.4V (+0.25V compared to the working unit)
Pin 2: 6.1V (+1V)
Pin 3-5: 3V (+0.7V)
Pin 6: 2.8V (+0.7V)
Pin 7 5.6V (+1.4V)
I swapped ICs and LED boards between the units, I double checked the parts, resoldered and cleaned the whole board. No Success
I really appreciate any help!
Thanks!
Christoph
I assembled two TS500 and they sounded great and identical at first. Suddenly I recognized a level jump of + 2.5/3 dB on one unit, which was also confirmed by the LED Meter.
I went through the level testing routine, and the defective unit had too much level of 2.5-3V on the 1kHz and all low frequency measurements. At 10k the results were fine.
I also noticed, that with no signal at the input and Drive on max., the first 3-4 green LED show a constantly "pumping" signal, whithout anything hearable at the output.
Ich checked the test pins with a 1kHz sine at 0.4V and got the following results:
Pin 1: 1.4V (+0.25V compared to the working unit)
Pin 2: 6.1V (+1V)
Pin 3-5: 3V (+0.7V)
Pin 6: 2.8V (+0.7V)
Pin 7 5.6V (+1.4V)
I swapped ICs and LED boards between the units, I double checked the parts, resoldered and cleaned the whole board. No Success

I really appreciate any help!
Thanks!
Christoph