GSSL HELP THREAD!!!

[djfatum]

me wondering Systems with 3 manufacturers I have a strange voltage and high on tl074 TL072

 

[djfatum]

after cutting the jumper between SC and vca and int out appears correct sound, after re-shorting jumper is getting no sound clean and quiet 

 

[Harpo]

I have a problem with ssl

...or other circuits/parts that are connected to the GSSL supply (probably rev.#12)...

.. and starts blinking LED

blinking red power-on LED, indicating that at least the 78L12 can not deliver the current demand of onboard and maybe additionally connected load when thermal self protection mode shuts the regulator down until this vreg cooled down enough to try again.
From the movie, the blue meter backlight (with unidentified incandescent lamp(s) or LED(s) inside, supplied from whatever voltage rail) and a yellow LED on the SSC-filterboard wasn't steady on as well. We have no idea of how you have connected parts or PCBs, what type of power transformer you are using and how you have connected this transformer for your whatever it might be local mains voltage.

 

[Greg S.]

Looks like some problems with the voltage regulators, maybe also a latchup problem with the 7815 regulator.

Which kind of brand do you use for your 7815? TS branded regulators don't seem to work properly, I have switched to Fairchild to solve the problem.

I got this Problem too, I changed to 7815 from ST Microelectronics, now it's fine.
you may get 'em at Segor.de
(I'm not getting money for this    )

 

[djfatum]

whether the problem may be that I used at http://expataudio.myshopify.com/products/gssl-crc-pcb the start of the voltage then I-15v and +10 v after disconnecting the voltage CRC have +15 and-15V I have ssl ver 11 plus SC https://pcbgrinder.com/index.php?route=product/product&path=59_73&product_id=55

 

[ptron]

well slowly but surely im getting back on the horse!!! good to be back

i have another quickie...
the trimpot from the main GSSL pcb, on the revision 11 it says % as well.. i was going to place the regular 50k trimpot there but now im quite unsure!
i got 10k trimpots with Serpent Audio`s VCA`s i wonder if these are right ?

thanks a lot!

 

[djfatum]

Fix  bad 78L12  8)

 

[salomonander]

hey
i do have a question regarding 27k resistors right next to the main vcas. should these be 15k when using original 202c vcas?

also the left 47r resistor right above the sidechain vca is labeled % on my pcb. what goes there (im using THAT 2150A)?

there are a few more parts labeled with % next to the main vcas. looks like two trimmers and two resistors. what goes there when using 202c vcas?

thanks a lot!

 

[ptron]

hello!! just wondering still about this trimpot.. so i came with more information

the vca`s are 4x2181B, so just wondering if this 10k trimpot that came with the vca boards is ok? havent seen 10k placed there in all the thread and ive gone back quite a long way!!!

thanks a lot

 

[Harpo]

ptron, anything in range 10K...50K will work and the trimmers 30V^2/10000=0.09W min.power rating needed should be sufficient for the usual suspects.

 

[ptron]

thanks a LOT(yet again) harpo! im really sorry to post such basic questions, but dont know where else to turn !!  expect some pictures soon!!!!!
onwards and upwards now!

all the best from mexico

 

[Che_Guitarra]

Is there an existing project shopping cart for the Turbo and Sidechain PCBs at Mouser?

I'm happy to pick it out myself otherwise... but there always seems to be one component I forget to order  :-[

 

[Che_Guitarra]

I can't find a Mouser BOM for the SSC so i'm putting one together now.  If anyone is interested in a one-click SSC shopping cart i'm happy to make it publicly available.



One thing I need help with - op amps are new territory for me.  Can I please get a confirm that this op-amp is a direct replacement for the NE5532N required for the super sidechain:

http://au.mouser.com/ProductDetail/Texas-Instruments/OPA2604AP/?qs=%2fha2pyFadujphIjBwZ7zs7HXQ9ozgoeUMGlLsbiu%2fXplpferO4HxzRN80IHTiwLZ

Or should I just buy some cheaper Philips NE5532N's that I can source off Ebay?

 

[ptron]

I can't find a Mouser BOM for the SSC so i'm putting one together now.  If anyone is interested in a one-click SSC shopping cart i'm happy to make it publicly available.



One thing I need help with - op amps are new territory for me.  Can I please get a confirm that this op-amp is a direct replacement for the NE5532N required for the super sidechain:

http://au.mouser.com/ProductDetail/Texas-Instruments/OPA2604AP/?qs=%2fha2pyFadujphIjBwZ7zs7HXQ9ozgoeUMGlLsbiu%2fXplpferO4HxzRN80IHTiwLZ

Or should I just buy some cheaper Philips NE5532N's that I can source off Ebay?

im almost sure u got to place some caps or resistors or both differently... or maybe u dont need some resistor where before with ne5532 u needed?
i use these ones i believe!! (http://mx.mouser.com/Search/ProductDetail.aspx?R=NE5532APvirtualkey59500000virtualkey595-NE5532AP) but now im also doubtful about them!!!
i hope they r alright!!

best!

 

[frazzman]

Hi guys,

I've built a lot of the earlier revision GSSLs, but now I have a rev 11 board and I wanted to make use of the HPF filter option.

I wanted to implement a rotary switch which switches between 3 different cap values giving 3 different sidechain HPF freq's. This will be done using a 2x6 rotary switch, set to 4 positions with pos 1 as bypass, pos 2 as 80hz, pos 3 as 160hz and pos 4 as 300hz.
Will the attached diagram work in reality?

Second question - I understand the resistors marked "%" can be omitted for pre-trimmed VCAs, do the positions need to be jumpered or can they be left out entirely?

Thanks for your help.

 

[Greg S.]

the % Placeholder: no need to be jupered!

 

[frazzman]

Thanks Greg.

Looks like my switch for switchable HPF cap will work fine. This looks like a pretty quick and easy way to implement an SC HPF. I haven't finished building the rev 11 circuit but I wired up the switch and measured capacitance at each position and it was all good. I left out the 40hz position for now...
The math fails me when it comes to calculating the required value, Gyraf or Harpo or other mathematically-ept members able to provide required cap value for 40hz HPF ? Much appreciated

 

[Gustav]

Thanks Greg.

Looks like my switch for switchable HPF cap will work fine. This looks like a pretty quick and easy way to implement an SC HPF. I haven't finished building the rev 11 circuit but I wired up the switch and measured capacitance at each position and it was all good. I left out the 40hz position for now...
The math fails me when it comes to calculating the required value, Gyraf or Harpo or other mathematically-ept members able to provide required cap value for 40hz HPF ? Much appreciated

I am not smart enough to determine the impedance at the HPF point, but I think Jakob said to expect 10K.

You can use this calculator to find the corner frequency.

Looks like 400nF should give you 40Hz, but empirical testing never hurts

http://www.sengpielaudio.com/calculator-RCpad.htm

Gustav

 

[mitsos]

Speaking of the HPF, I've been wanting to implement a simple passive one on an older GSSL board I have, and now I see there is one on the new PCBs, I understand how it works, but I have a question. If the schematic is more or less like the old GSSL, it looks like the HPF is after the sidechain VCA, whereas the old "super SC" circuits were put in prior to the VCA I think.  I like how the new way is simple and I'm hoping the end result is the same since it's before rectification?  Can anyone confirm?

thanks!

 

[berkleystudios]

Well I have waited for a while to post to try and figure out my issue on my own but alas I need some help.

My GSSL setup: rev #7 with 2180 vcas, switchable turbo, and crc. have also taken out the 100p caps on the output as I was reading that is a common mod.


The issue: While feeding the GSSL with a 1k sine wave the output is over 6 db difference between the left and right, when I raise the output gain, the the db  difference remains the same no matter the setting.


What I have done: Originally I had LM 4562s on the output but only one channel would change when the output gain was the same, when no gain was applied they output was the same level. I swapped out the LM 4562s for 5532s and the issue is now what I have written above.


is there a resister I can swap out with a trimmer to make the output even?