GSSL HELP THREAD!!!

[ixi]

[quote author="vertiges"][quote author="ixi"]Hi guys!

I can't find how to wired bypass switch for ssl on Purushas case (6 polls switch, bypass + led )
Long time ago find i one picture, now i can't fined it !
ixi[/quote]

Are you talking about this one ? :

eD)))[/quote]

NO, another one!
thx any way

 

[Nele]

Hi,

Finally I'm able to do some measurements on my mac and what I had already seen on my mixing desk is now being confirmed by this graph. I have about a 6db difference between the left and right channel. Any idea where to look? A wrong resistor in one of the opamp feedback-loops might be the case, but I haven't been able to spot one.

Thanks,
Corneel

 

[vertiges]

Hi Nele,

a) You should check, re-check, and re-recheck all the components values in the audio path.

b) It will sound silly, but are you totally sure about the way you made the measurements ? Did you pass through a mixer or you were directly connected in your sound card ?

c) On mine GSSL, I replaced the two 27k by two 50k trimmers because I had a "offset" of 0.6 dB.
It's strange you have exactly 6dB. :roll:

eD

 

[gyraf]

6dB is almost always a problem in balancing - you may have lost one output phase..

 

[emx]

I'm just curious if anyone here has tried this? I know with 2181 vca's you have to do the distortion trimming, what I'm curious about is if anyone has deliberately tried adding a pot in conjunction with a correct distortion trim(say a dual pot to each side) for adjustable distortion when needed. I'm wondering if so just how much could be added to munge things up and which direction it would need to go(added resistance or less resistance than where the distortion trims are set)? Then again maybe this is only capable of something very, very subtle, I don't know.

 

[vertiges]

[quote author="emx"]I'm just curious if anyone here has tried this? I know with 2181 vca's you have to do the distortion trimming, what I'm curious about is if anyone has deliberately tried adding a pot in conjunction with a correct distortion trim(say a dual pot to each side) for adjustable distortion when needed. I'm wondering if so just how much could be added to munge things up and which direction it would need to go(added resistance or less resistance than where the distortion trims are set)? Then again maybe this is only capable of something very, very subtle, I don't know.[/quote]

Hi,

1) I think Purusha did that on one of its GSSL. But I'm maybe wrong... :green:

2) You can't use a dual pot because :

Imagine you use a 1 turn trimmer : for example, on the left side you will have top put the trim at "eleven o' clock" and on the right side at 4 o'clock for getting your two (Left & Right) "less distortion positions".

3) Once you have found your less distortion point, the distortion will increase before and after this point. And it's really a "point". If I remember correctely, I used 5 turns trimmers and It was very difficult to put them in the right positions because of the shaking of my hands.

4) It's very subtle. On a full and complexes mixes, it's simple I just can't hear it. I have got the impression the sound becomes a little bit harsher, but it's maybe an impression because I know I turn the screwdriver...
With the less distortion positions of the trimmers I get 0.0025 % of THD. With the worst positions : 0.01 % which it's still very good.

5) Honestly, I'm not sure it will be very usefull to control the distortion trimmer from the front panel. :wink:

6) Have you got access to a distortion meter ? If you are on PC and you have a decent sound card you could make some tests with RMAA http://audio.rightmark.org/index_new.shtml and hear by yourself.


My 2c,

eD)))

 

[emx]

My plan (if I could get this to work) would be to use the on board pots to adjust the distortion specs to as close to 0 as I could then clip one end of the pot and add another dual pot with one side connected to one vca and another side to the one left, unless i found out that lowered resistance distorted better then I would figure out a way to use the dual pot to decrease the resistance(I have this figured out in my head but can't describe it well enough).

 

[vertiges]

[quote author="emx"]My plan (if I could get this to work) would be to use the on board pots to adjust the distortion specs to as close to 0 as I could then clip one end of the pot and add another dual pot with one side connected to one vca and another side to the one left, unless i found out that lowered resistance distorted better then I would figure out a way to use the dual pot to decrease the resistance(I have this figured out in my head but can't describe it well enough).[/quote]

You will never get the two trimmers to react exactely the same way.
According to me, it's a "lot of troubles" for something very very very subtle... :wink:

In the worst case scenario, we're talking about 0,01 % of THD here...
If you could get around 1% or more, maybe it would be interesting in some way (maybe not) but you'll never reach that amount of distortion by playing with the trimmer of a 2181.

You should made some listening tests before buying additional pots and making additional holes in your front panel.

My 2c,

eD)))

 

[emx]

I see, Maybe I should be looking into a different idea for the distortion.

 

[vertiges]

But you know... this compressor sounds very good even without distortion !!! :green:


eD))) :wink:

 

[cannikin]

[quote author="gyraf"]
The easiest and most quiet will be a toroid power transformer - you'll need 2x15V or 2x18V secondary at some 10-20VA. Then you'll have a couple of watts or so for meter illumination without annoying the important parts.

Jakob E.[/quote]

Ok I have read 53 pages of this thread, I think I have found my answer but I want to confirm:

I can USE a 18-0-18 transformer WITHOUT having to change any values in the PSU section. I have two TE62064-ND Digikey LINK

Thanks all...

 

[[silent:arts]]

[quote author="cannikin"]I can USE a 18-0-18 transformer WITHOUT having to change any values in the PSU section.[/quote]
you can use them with no problem, but you may want to heatsink the regulators.

 

[vertiges]

[quote author="cannikin"]

I can USE a 18-0-18 transformer WITHOUT having to change any values in the PSU section. I have two TE62064-ND [/quote]

Hi,

Yes you can. There are a lot of people who build the GSSL with a 2x18V.
The regulators can accept a supply voltage up to 30 volts. If they get too hot, just use some heatsinks.

eD))

 

[vertiges]

[silent:arts] we answered in the same time... but you've been faster ! :green:

eD

 

[cannikin]

You guys Rock (as always)!! :thumb: :thumb:

 

[ixi]

Please for help :?

i finisht my first GSSL and now have one big problem :sad:
Compressor not work - not compresst !!!
I read this topic but i can't find what i do now.
When go sound true the compressor, is't sound good, without distortion, brums and .... but R ch. it's 2 times louder that L ch. :shock:
On control board work just makeup gain.

Any idea :roll:

 

[vertiges]

[quote author="ixi"]Please for help :?

i finisht my first GSSL and now have one big problem :sad:
Compressor not work - not compresst !!!
I read this topic but i can't find what i do now.
When go sound true the compressor, is't sound good, without distortion, brums and .... but R ch. it's 2 times louder that L ch. :shock:
On control board work just makeup gain.

Any idea :roll:[/quote]

I lost my previous answer... strange...

ixi,

Do you mean you don't have any compression AND the sound is not good ?

Did you use any external sidechain board ?

Could you post some pics ? Could you give us the voltages you get at the rails + the ICs.

But first, you should check and re-check for shorts, bad solder or colder joints, wrong component values, etc.

And, the subjet of "no compression problem" have been troubleshooted a lot of times in this thread... You should have found a lot of infos or very useful procedures to help you by reading this thread.

Regards,

eD

 

[ixi]

[quote author="vertiges"][quote author="ixi"]Please for help :?

i finisht my first GSSL and now have one big problem :sad:
Compressor not work - not compresst !!!
I read this topic but i can't find what i do now.
When go sound true the compressor, is't sound good, without distortion, brums and .... but R ch. it's 2 times louder that L ch. :shock:
On control board work just makeup gain.

Any idea :roll:[/quote]

I lost my previous answer... strange...

ixi,

Do you mean you don't have any compression AND the sound is not good ?

Did you use any external sidechain board ?

Could you post some pics ? Could you give us the voltages you get at the rails + the ICs.

But first, you should check and re-check for shorts, bad solder or colder joints, wrong component values, etc.

And, the subjet of "no compression problem" have been troubleshooted a lot of times in this thread... You should have found a lot of infos or very useful procedures to help you by reading this thread.

Regards,

eD[/quote]

Hi, thxfor answare.

compressor not work, it's thesame, when i connect 1+8 pin on stage of That chip.
i check and re-check 10 times
I don't any external sidechain board for now

Ok, i make foto and post here with voltages

 

[ixi]

delete

 

[vertiges]

[quote author="ixi"][quote author="vertiges"][quote author="ixi"]Please for help :?

i finisht my first GSSL and now have one big problem :sad:
Compressor not work - not compresst !!!
I read this topic but i can't find what i do now.
When go sound true the compressor, is't sound good, without distortion, brums and .... but R ch. it's 2 times louder that L ch. :shock:
On control board work just makeup gain.

Any idea :roll:[/quote]

I lost my previous answer... strange...

ixi,

Do you mean you don't have any compression AND the sound is not good ?

Did you use any external sidechain board ?

Could you post some pics ? Could you give us the voltages you get at the rails + the ICs.

But first, you should check and re-check for shorts, bad solder or colder joints, wrong component values, etc.

And, the subjet of "no compression problem" have been troubleshooted a lot of times in this thread... You should have found a lot of infos or very useful procedures to help you by reading this thread.

Regards,

eD[/quote]

Hi, thxfor answare.

compressor not work, it's thesame, when i connect 1+7 pin on stage of That chip.
i check and re-check 10 times
I don't any external sidechain board for now

Ok, i make foto and post here with voltages [/quote]

Ixi,

Could you delete this post ? (the one with 1+7)

You know you still can edit your post even after posted it, don't you ?

eD