GSSL HELP THREAD!!!

[warpboy]

Hi Scottcfp,
I'm actually debugging my SSL like I say in my last post.

I'm having trouble passing audio

, How can you define your problem : saturation, no sound, what is good ( threshold,attack,release....)

Personally one of the two channel works correctly, but the other one is saturated...

I have a few infos about the VCA (mine are2180LA)
First important parameter : the That 2180 are current in/current out components!!
then what I know :
Pin 1 : current input
pin 2 :gnd
pin 3 : signal coming from the NE5534 output
pin 4 : not connected
pin 5 : -vcc
pin 6 : gnd
pin 7 : +vcc
pin 8 : current output

If these infos can help you.....

 

[scottCFP]

warpboy,

Thanks for the reply! Sounds like you are further along than I

How can you define your problem : saturation, no sound, what is good ( threshold,attack,release....)

My problem is No Sound, No Hum. LED works!! so it must be 'on' right!!??

Anyway, I have scrapbooked this thread and am pretty sure you are not alone in the distortion realm. Have you figured out the FireFox Scrapbook thing? full text search of ENTIRE thread only? Let me know if you need some help with it, it makes things really easy.

Like I said, I know I've ran into some folks with a similar problem to yours.

Scott

 

[warpboy]

Scott, do you have an oscilloscope?
with it you could look at :

input Ne5534 :

1) pin 2&3
2) output pin 6


Ne5534 before the THAT218X

1) pin 3
2) pin 6


NE 5532

1) pin 2
2) pin 1
3) pin 6
4) pin 7


Normally for all these pins you will see an audio signal.I'll hope that I don't give you false infos.

 

[warpboy]

hello,
back with my problem :
One channel sounds good, but the other one is distorted (much more db)
I've checked the component placement and the only thing I can see is the placement of the 15k/27k (unity gain resistor) betwwen the left vca and the xfmr.

On mine this resistor is like shown on gyraf pdf.....not like on this picture

.....What is the correct solution..?

 

[warpboy]

Ok, I've looked at the component placement and this resistor isn't the problem...
I'm looking at the left output Ne5532 :
the NE5532 is composed of two opamp. The first output works correctly, but the second does not. With an oscilloscope the signal that I see at the output of the second one has an amplitude going from -15v to +15v (this is the reason of the distorted sound)
I will check a new time all the components values, but I have really no idea
:?

 

[Bluzzi]

Have you tried swapping the good channel ICs into the bad one? One at a time? That should eliminate or point to those components at least.

jim

 

[warpboy]

Hi Bluzzi, yes, I have swapped the two IC without success...
I have looked at the different pins of the Ne5532 (left channel)where the problem seems to be.
It seems that the signal is correct till the ouput of the first opamp (that includes the ne5532). when I look at the second output (pin1) the audio signal is really bigger (Amplitude : -15V to +15v)
Resistors values are corrects....I have really no idea :?

 

[Bluzzi]

I have 1 GSSL finished but I haven't had the time to put audio through it! I won't again tonight! I'll do it soon though. If (and that is a big if) mine works as it should I can take voltages for you if you want.

Also have you tried looking at the resistor color codes on the good channel and that they match bad one? Maybe an incorrect resistor?

Just giving you ideas in case you haven't done tried yet.

If you have 1 channel working the other is not that far behind I'm sure. hang in there and don't get discouraged.

Bonne fêtes

jim

 

[warpboy]

Thank you Jim for your encouragements :wink: . I think I'm not so far from the end (imho...), but now there is something that I can't understand.
I'm am almost sure the problem stays in the second stage of the ne5532 : two much gain!!!

Bonnes Fetes à toi aussi :wink:

 

[vertiges]

warpboy,

If you tried to swap the 5532 and the 2180 between the left channel and the right channel, and if the problem doesn't move from left to right, your 5532 and your 2180 must be ok.

Have you tried to bypass the VCAs ? Take off the 2180s and put a wire between pin and pin 8. If you get your audio undistorted on the two channels, your input and output stages are ok.

eD

 

[vertiges]

Jim,

I just can't believe you haven't found a few minutes to put audio through you GSSL :shock:

eD :wink:

 

[Bluzzi]

vertiges - believe it! I just got in, I'm tired and I have to dismantle whats left of my bedroom as I have furniture coming tomorrow. Yes I have 15minutes here and there but I want uninterrupted hours! If there is a problem I want time to deal with it.

Soon!

jim

 

[vertiges]

Jim,

I was kidding... I understand very well.
15 minutes it's not enough ! If it doesn't work you'll will need time for troubleshooting and if it does work (And I'm sure it will !!!) you will need more than 15 minutes for playing with it ! :green:

eD

 

[Nadege]

Hello

I've made what vertiges and bluzzi suggested, moving the diode bridge from the centre of the pcb to the upper left corner, and.... Succes :razz: no more buzz on two of my gssl and on the third, the buzz is still there but as loud as the noise floor of my system (so I don't care..)

Thanks a lot to you two guys, I almost became nuts with this annoying buzz issue :evil:

By the way, Vertiges, I've had a look at your website and saw, that you studied in Belgium!, In fact we are coming out of the same sound ingeneering school ... What a small world.

Regards

And thanks again :thumb:

 

[vertiges]

Nadege,

That's a great news !!! :thumb: :thumb: :thumb:

What a small world indeed... :wink:
I met Pascal a few times in the past by the way (the owner of the Cara... ). I'm sure he doesn't remember me.

eD

 

[warpboy]

hello,

Vertiges said:

If you tried to swap the 5532 and the 2180 between the left channel and the right channel, and if the problem doesn't move from left to right, your 5532 and your 2180 must be ok.

and

Have you tried to bypass the VCAs ? Take off the 2180s and put a wire between pin and pin 8. If you get your audio undistorted on the two channels, your input and output stages are ok.

I tried all these possibilities because I have seen these infos in an old post (maybe written by you....)

I have taken a few time only to think what could be the reason of the distorted channel.
I think that I will changed the resistor and the capacitor between the input and the output of the second opamp of the NE5532.
If i'm right I think for the second stage of the NE5532 : G=-1
If one of the resistors (or the capaitor) is out of order Gain will changed and in my case increase..

 

[Harpo]

[quote author="warpboy"]I tried all these possibilities because I have seen these infos in an old post (maybe written by you....)

I have taken a few time only to think what could be the reason of the distorted channel.
I think that I will changed the resistor and the capacitor between the input and the output of the second opamp of the NE5532.
If i'm right I think for the second stage of the NE5532 : G=-1
If one of the resistors (or the capaitor) is out of order Gain will changed and in my case increase..[/quote]
Doublecheck the 10k input resistor between pin 7 and pin 2 and check for shorts to the 100R next to it (resulting G=-100). Otherwise replace the broken 10k feedback resistor between pin 1 and pin 2 of this inverting buffer. No need to change the 100pF cap.

 

[warpboy]

Harpo wrote :

check for shorts to the 100R next to it (resulting G=-100)

Really good idea. I had not thought to do that :wink:
Tomorrow I'll try
Thank you!

 

[Miska]

Happy New Year everybody!

I have a bunch of these EAO swithes which I would like to use in my GSSL compressor. I guess the model is old 'cause I can't find any datasheets on the internet...
http://www.mikkimusic.com/LAB/EAO-Switch.jpg

On the switch it says:

01-262-025

Questions:
1. Since these switches are latching, can I use them to power and bypass WITHOUT relays/relayboard?

2. They have 8 (4X2) solder contacts on the sides and 2 on the end (probably for the lamp). Is the switch DTDP, DTSP, 4TSP or what is it?

I've never used this kind of a switches and I would appreciate any kind of info or help to solve this. Thank You.

Miska

 

[gyraf]

Hi Miska,

Use your ohm-meter to find out switch function, and read the schematic (comparing with the pcb's) to find correct wireing.

Jakob E.