GSSL HELP THREAD!!!

[main repairman]

I want just to know to calculate correctly the voltage to Op Amp. I do not have any problem with GSSL. I want just to know correctly voltage nothing more. Thanks

 

[Gustav]

I want just to know to calculate correctly the voltage to Op Amp. I do not have any problem with GSSL. I want just to know correctly voltage nothing more. Thanks

Someone would have to open up a unit and check those exact spots for you. I doubt anyone before you cared what they were at those spots.

What matter is, that you check the supply voltage pins, and check the signal path (knowing the voltage you spit into the unit) to see if it behaves.

Just curious - why are you interested in those specific spots? (I might learn something!)

Gustav

 

[main repairman]

OK once again.
I need to calculate the voltage output op amp, nothing more.

TL 074 pin 7 = 0,14VAC ---- (2*0,1VAC in voltage*33/47= 0,14VAC) OK
TL074 pin  1 = 0,42VAC  --- 0,14VAC in voltage*20/20=0,14VAC BAD  why????
Junction  20k, 10k, kat. diode = 0,1 VAC why?

 

[Gustav]

OK once again.
I need to calculate the voltage output op amp, nothing more.

TL 074 pin 7 = 0,14VAC ---- (2*0,1VAC in voltage*33/47= 0,14VAC) OK
TL074 pin  1 = 0,42VAC  --- 0,14VAC in voltage*20/20=0,14VAC BAD  why????
Junction  20k, 10k, kat. diode = 0,1 VAC why?

I am not sure I follow (maybe you could try setting it up differently to get different answers instead of just repeating the same), but would you mind trying to measure on pin 1 at each of the three ratio settings?

 

[main repairman]

I think if someone has posted the correct voltage at points it would be a big help to all.
From the beginning thread in year 2004 nobody did not write support for the construction.
It is a pity.

 

[Majestic12]

I think if someone has posted the correct voltage at points it would be a big help to all.
From the beginning thread in year 2004 nobody did not write support for the construction.
It is a pity.

As I said before, this is a rectifier circuit and the voltages there aren't only AC and depend on the settings of your unit as well as the audio input signal. You'll need to use a scope and look on the pins itself to see what's going on. Simply posting AC voltage values does not really help to check for any faults here.

 

[patzo]

Hi.  On the output 5532 the schematic shows a 10K and 470R resistor from pin 5 to 0v and 3 to 0. But on pcb both are 470R, Which is right?

And the input - and + on PCB and schematic are inversed. Which is right too ?

 

[main repairman]

The correct voltage at the input and output units are:

Input signal 1KHz sine,  0dBV  = 1VAC RMS (1,414VAC pk). 
Power down, pull both audio VCAs and temporary link pins 1-8 with a piece of wire.

INPUT      -  NE5534,  pin6 =      1VAC    (1AVC*22k/22k = 1VAC)
OUTPUT - NE5532, pin1 = 0,55VAC    (1VAC*15K/27K = 0.55VAC)    same output molex +
OUTPUT - NE5532, pin7 = 0,55VAC    (0,55VAC*10K/10K = 0.55VAC)  invert phase    same output molex -

Voltage output molex connector pin + - = 1,1VAC    (pin7 - 0,55 + pin1 - 0,55 = 1,1VAC)

 

[Dinomight]

Helle there, i have a few problems,


I have 14,5 Volts on Pin 5 of the right VCA, can not find a short,  it should be about 2.5

Does anyone know where to search?

Thanks for your help.

Dino

 

[Gustav]

Helle there, i have a few problems,


I have 14,5 Volts on Pin 5 of the right VCA, can not find a short,  it should be about 2.5

Does anyone know where to search?

Thanks for your help.

Dino

Try swapping the VCAs. My guess is a dead VCA, and dead VCAs dont draw current, so voltage is not dropping ( V = I x R, and I = 0). If my guess is right, the problem will move to the left channel

 

[innercityman]

Hi every one, simple question... when installing DBX202C gold can instead of the THAT 2180 on GSSL Gustav's pcb, is there some resistor values that needs to be changed ?

Thanks for your help.

 

[Gustav]

Hi every one, simple question... when installing DBX202C gold can instead of the THAT 2180 on GSSL Gustav's pcb, is there some resistor values that needs to be changed ?

Thanks for your help.

Unfortunately, I dont have the answer, but I do know its been discussed numerous times. Try typing "202 black" into  the search (http://groupdiy.com/index.php?topic=41338.msg513353;topicseen#msg513353 There are plenty more hits where that came from.

Gustav

 

[Dinomight]

Well, okay, next Problem:

On + 15  are 14.9 Volts, seems to be ok,
Ob -15 are 14.4 Volts, thats weird? Any suggestions?

Thanks again

 

[Gustav]

Well, okay, next Problem:

On + 15  are 14.9 Volts, seems to be ok,
Ob -15 are 14.4 Volts, thats weird? Any suggestions?

Thanks again

If you check  the data sheet, you'll see the tolerance is 4% on the 7915 regulator under good conditions (spec is given at 25 degrees, P < 15Watts).

15 x 0.96 = 14.4.

Within the spec of the part, so not exactly weird, but more off than I've usually seen.

I'd check the voltage on the input pin, just for the hell of it. (Spec calls for at least -17.5VDC on the input pin for regulation). If thats fine, maybe try swapping the part to get closer if its a concern.

Gustav

 

[pstcho]

Hi guys, i tried to find the answer, but didnt find ...

I just finished my second GSSL  the new boards at pcbgrinder.com  are incredible quality and goes etremely fast to mount all the components ( took me  5 hours ) AMAZING

anyway

I got a transformer  2x18V  2x1A, i was wondering how many GSSL i can power with this transformer?

I guess 2 but i am not really sure

Anybody got an idea ?

thanks  

 

[innercityman]

Hey Gustav, thanks for the answer.

Try typing "202 black" into  the search

In fact I'm not installing "Black Can 202" but a pair of 202C GOLD CAN, but even when doing some research on groupdiy, I can't find any answer... Maybe that means that no value needs to be changed. I'm sure Jacob should be able to answer me, if there's a chance that he can read this post.

 

[Gustav]

Hey Gustav, thanks for the answer.

Try typing "202 black" into  the search

In fact I'm not installing "Black Can 202" but a pair of 202C GOLD CAN, but even when doing some research on groupdiy, I can't find any answer... Maybe that means that no value needs to be changed. I'm sure Jacob should be able to answer me, if there's a chance that he can read this post.

Sorry for misreading your post. "Gold can"

http://groupdiy.com/index.php?topic=47.msg703950#msg703950

Gustav

 

[Gustav]

I got a transformer  2x18V  2x1A, i was wondering how many GSSL i can power with this transformer?

I guess 2 but i am not really sure

I haven't measured, but Id guesstimate the current draw of the circuit with no mods or light bulbs is no more than 100mA total.

Sometimes, splitting the AC/trafo secondaries into two PSUs will work, but most often, it will cause  problems. I would leave one PSU section unpopulated and jump the supply rails from one (used as a hub), and probably even add a cap on input node of the receiving board  - but I dont know enough theory to back this up with anything but experiments with other circuits.

Gustav

 

[pstcho]

Thanks for your reply Gustav

So far,  i just ran my classic 48hours full power to see if it warms up too much or anything goes wrong, and in the middle of the test, still no problem !!!

I just plugged both GSSL in serial on the same transformer and it seems not to have any weird behavior

 

[Harpo]

Hey Gustav, thanks for the answer.

Try typing "202 black" into  the search

In fact I'm not installing "Black Can 202" but a pair of 202C GOLD CAN, but even when doing some research on groupdiy, I can't find any answer... Maybe that means that no value needs to be changed. I'm sure Jacob should be able to answer me, if there's a chance that he can read this post.

Sorry for misreading your post. "Gold can"

http://groupdiy.com/index.php?topic=47.msg703950#msg703950

Gustav

Go to section "The Lab" and/or section "Dynamic Processors" (in order to leave out the white/black market threads) and type in the smart search field "202c" for lots of hopefully useful results ...