Sound Skulptor STS help needed

[mesS!eR35]

Hi all,

i am new here, and inspared by this forum i have build my first diy project 8ch summing mixer, so thank you for that!

Now i am trying to build my second project Sound Skulptor STS and i have a problem building. 

Actually the right channel works perfectly, but from the left channel i get this buzzing sound. In bypass everything works fine. If i connect unbalance cable to the output of the problematic channel, the buzzing sound gets weaker, and i can even hear the signal coming trough and i can hear that the 10k lin Input pot works, but not the 10k log Output pot.

I have tried to take out all the op amps and the THAT chip but the noise is still there

Any help would be really appreciated !!

 

[PRR]

> the right channel works perfectly, but from the left channel i get

What's different in Left compared to Right?

Buzz is often a missing ground.

 

[JPK]

Check that all your solders are good.
Check the components values and direction.
Did you have to remove a previously soldered component?
Does the vu-meter work in bypass?
Can you measure the DC voltages on TP1, TP2, TP3?
Can you measure the DC voltages on U1, U2, U3 pins 4 and 8
and on U4 pins 5 and 6?

 

[mesS!eR35]

JPK,

Yes, it is me, the same guy who is mailing, and ones again, i have to say big thanks for your brilliant support!!

PRR,

thanks for responding,

what is diffident is what i am trying to find out also yes, i have some grounding issues on right channel also, but left channel is completely noisy. ..

I go now to mountains over night to clear my head and ween i come back ill try to trace my mistake. In the meantime i have succeed to burn couple of resistors, and have to wait till Monday to by replacements  ;D

Cheers guys, have a beautiful  weekend!





 

 

[Michael Tibes]

I don't know the STS in detail, but I've built the 1073 eq from them and had some serious trouble with hum/buzz which was induced into the filter coils from the mains transformer. Not at all Sound Sculptors fault, it's part of the 1073 design. Mr. Neve put every channel into a separate metal box and had an external power supply which was standing far away... Maybe that rings a bell?

Michael

 

[mesS!eR35]

ok

so i fixed the channel, it was two smoked resistors and bad soldering point and the wrong wiering of in  and outs.

the power transformer is out !

i still have some hum left, caused by bad grounding i ques

but man! this box sound amazing !

 

[mesS!eR35]

hmm..

the power transformer is now placed in a separate plastic box and i am not quite shure what to do with the ground wire?

any suggestions?

 

[mesS!eR35]

pic 1

 

[mesS!eR35]

what is wrong with my STS?
hum at 50, 100, 150 hz..

grounding or power supply or?



pleas help!!

 

[audiomixer]

what is wrong with my STS?
hum at 50, 100, 150 hz..

grounding or power supply or?



pleas help!!

Where is your mains transformer (!)? I See the mains IEC wired to switch and then to the board..... directly, but where is the transformer?

first I wanted to just post a joke about you being in the wrong country, Like move to the US your hum will become to 60Hz, 120Hz, 180Hz..... but your pics made me become worried ;-(

- michael

 

[mesS!eR35]

what is wrong with my STS?
hum at 50, 100, 150 hz..

grounding or power supply or?



pleas help!!

Where is your mains transformer (!)? I See the mains IEC wired to switch and then to the board..... directly, but where is the transformer?

first I wanted to just post a joke about you being in the wrong country, Like move to the US your hum will become to 60Hz, 120Hz, 180Hz..... but your pics made me become worried ;-(

- michael

;D hahaha

don't wory! transformer is outside in the separate box, to left out one of the suspectes.  It's just  the 220V socket with -15 +15 secondary and earth grounding pins

 

[mesS!eR35]

what is wrong with my STS?
hum at 50, 100, 150 hz..

grounding or power supply or?



pleas help!!

Where is your mains transformer (!)? I See the mains IEC wired to switch and then to the board..... directly, but where is the transformer?

first I wanted to just post a joke about you being in the wrong country, Like move to the US your hum will become to 60Hz, 120Hz, 180Hz..... but your pics made me become worried ;-(

- michael

anything else to add ?

you can still help you know ..

 

[mesS!eR35]

Hum was generated by on-board PSU. So i have build a nice little PSU board from sound skulptors schematics, and removed all of the psu components from the main board to that PSU pcb, and now the HUM is GONE 

So for the future references, if anyone have an intention to build  STS, and go with the mini kit, be aware that you will need external PSU, cause this unit is HIGHLY sensitive ( as stated by JPK on his official site!)

thnx