Sound Skulptor forums

Build help and troubleshooting => TS500 Tape Simulator => Topic started by: igor.moreno on December 16, 2021, 07:44:03 PM

Title: High Distortion
Post by: igor.moreno on December 16, 2021, 07:44:03 PM

Hi,

I've just finished my second TS500 (the first one worked at first try).
I have very high, almost gate-like distortion when the unit is on. On bypass, the signal is just fine.
What can I do to check the unit and solve this mystery ?

Thanks !

Igor

Title: Re: High Distortion
Post by: JPK on December 17, 2021, 09:55:25 AM

Does the DRIVE pot have any effect on the gain?
Check the solder joints on the resistors and IC's.
Reflow any suspicious joint.

Title: Re: High Distortion
Post by: igor.moreno on December 20, 2021, 02:01:03 PM

Hi,

I've checked every solder joint and reflowed a few suspicious ones, but the problem is still there.

At low drive settings, the signal is gated (on a drums track for exemple, only the highest peaks pass through.)
At higher drive setitngs, the gate effect disapear, but the distortion is so high, the signal is completely destroyed.

Any idea ?

Thanks,

Igor

Title: Re: High Distortion
Post by: JPK on December 23, 2021, 12:18:37 PM

Check if you have any DC voltage on TP1, U2-pin1, TP2, TP3, TP4, TP5, U11-pin1, TP7.
There should be no more than a few millivolts.

Title: Re: High Distortion
Post by: igor.moreno on April 05, 2022, 01:33:33 PM

Hi,

So I finally found the time to test my TS500.

Here are the results :

TP1 = 0V
TP2 = 0V
U2 Pin 1 = 0V
TP3 = 10,38V
TP4 = 10,39 V
TP5 = 10,60 V
U11 Pin 1 = -10,60V
TP7 = 0V

Any idea ?

Thanks,

Igor

Title: Re: High Distortion
Post by: JPK on April 06, 2022, 11:59:35 AM

You must have a bad or forgotten solder joint on one of:
U2, R19, R20.
Or a badly inserted U2?

Title: Re: High Distortion
Post by: igor.moreno on April 06, 2022, 04:06:27 PM

Hi,

Thank you for your reactivity !
So I've just checked my TS-500, and .......... R20 is missing ! ::) (I don't know how I did not see it before...)

I searched in the packaging, and did not find any reminding resistor, so either I lost it, or it was missing in the first place.

I'm just concerned the absence of R20 may have damage some components in the cirtcuit (nothing smoked or smelled like burned component, though)

Would you mind sendind a 180k resistor ? I would happily pay for the stamp, etc.

Thanks again,

Igor

Title: Re: High Distortion
Post by: igor.moreno on April 26, 2022, 10:58:15 AM

Hi,

Thank you for the fast shipping of the resistor (and for your patience) !
Everything works as expected now !

I now have quite a big difference in level between my two TS500.
I'll take the time to go through the testing procedure, and I'll create a new post if needed.

Thanks again,

Igor