GSSL add-on help thread

[audiophreak]

Hello,
    I seem to remember either on Gyrafs DIY page or the GSSL help thread here that the 12v was a reference voltage and not to use it for power on LEDs or meter illumination and such ....
  I've built several of these, although it's been years , I think I used the 15v for those things...
  worth looking in to ...

 

[salomonander]

thanks,
i just found a scetch by igor for running his relay board. i attached it.  the only thing that worries me - at these points i have +-18v not +-15v.
my relays are 12v. will they be able to take the 18v? sorry for the noob question...


ps: this is embarassing.... my clicking was due to the fact that i had not ground connected to the main board argh.
connected it and the click is gone. but the 12v point seems to be wrong still. the leds dim and my +15v rail drops about 3v when i engage the relays.

 

[audiophreak]

maybe try an appropriate dropping resistor to get  +12v 

 

[Potato Cakes]

thanks,
i just found a scetch by igor for running his relay board. i attached it.  the only thing that worries me - at these points i have +-18v not +-15v.
my relays are 12v. will they be able to take the 18v? sorry for the noob question...


ps: this is embarassing.... my clicking was due to the fact that i had not ground connected to the main board argh.
connected it and the click is gone. but the 12v point seems to be wrong still. the leds dim and my +15v rail drops about 3v when i engage the relays.

How many LEDs are you using and for what? I had to separate where I was pulling the power for the LED's I was using for my pushbuttons as they would dim when engaged when coming off a single source.

Thanks!

Paul

 

[salomonander]

thanks guys,
i run my main power led off the switch pcb and my bypass led off the ssc board. right now my main +15v rail drops whenever i engage the bypass (so no bypass) to about 12,5v.

 

[salomonander]

maybe it would be best to split the transformer outputs to a second little psu like this?

 

[salomonander]

darn it im lost. i tried implementing the attached voltage regulator. but no matter where i connect it to (right after rectifier +18v or elsewhere to a +15v point), my +15v rail drops to about 12v. i take ground off the star ground....

connecting my relay board to +15v -15v drags the supply voltage down to 8v on both rails

 

[audiophreak]

What's the PT secondaries amperage rated ?

 

[salomonander]

What's the PT secondaries amperage rated ?

thanks,
its @25VA - let me know if thats too little. and if so, to what rating. cheers!


ps: still having that rectifier on the main board although using the crc mod. could that be an issue?

tried around some more.... no improvement. no matter what combinations i try. i ran my relay board off +-15v from ssc, i ran it off the +-18v after my rectifier. also tried creating a seperate 12v with 7812 off the +18v from the rectifier. but i always get voltage drops whenever i engage the relays. the voltage drop depends on how many relays i have on my board.
when i run it from either +-15v or +-18v both the + and - rails drop. when i built my little 7812 board only the + rail dropped.

any suggestions are welcome - im just a noob.

 

[Harpo]

... maybe the psu isnt strong enough (i run main board, turbo, 2x ssc, crc plus 4x 12v relays)? ...
... its @25VA ...

Your 25VA transformer with maybe series connected 2x 15VAC secondaries or a  center tapped 30VAC secondary winding, connecting to a bridge rectifier, so form factor 1.8, will deliver (25VA/30V)/1.8=0.46A DC.
For your 4 secret type relays, FI Mouser https://www.mouser.de/Electromechanical/Relays/_/N-5g31?P=1y95lh1Z1z0x3ub lists 391 different pcb mounting types with 12VDC coil voltage.
You are operating these 12VDC coils with 15 VDC, so 15VDC/12VDC=factor 1.25 consumption on top.
From row 'coil current' of this list, these might consume 2.9 ... 41.7 mA per relay, so worst case you need 4 x 41.7mA x 1.25 = 231 mA only for operating your 4 relays.
Add the current demand of the gssl, the turbo, the sidechainfilterboards and optical gimmics on top, your 25VA whatever type transformer, delivering up to 460mA, seems to be the bottleneck. Without a lot of further information, nobody could seriously tell you the transformers VA-rating needed. Good luck.

 

[salomonander]

Your 25VA transformer with maybe series connected 2x 15VAC secondaries or a  center tapped 30VAC secondary winding, connecting to a bridge rectifier, so form factor 1.8, will deliver (25VA/30V)/1.8=0.46A DC.
For your 4 secret type relays, FI Mouser https://www.mouser.de/Electromechanical/Relays/_/N-5g31?P=1y95lh1Z1z0x3ub lists 391 different pcb mounting types with 12VDC coil voltage.
You are operating these 12VDC coils with 15 VDC, so 15VDC/12VDC=factor 1.25 consumption on top.
From row 'coil current' of this list, these might consume 2.9 ... 41.7 mA per relay, so worst case you need 4 x 41.7mA x 1.25 = 231 mA only for operating your 4 relays.
Add the current demand of the gssl, the turbo, the sidechainfilterboards and optical gimmics on top, your 25VA whatever type transformer, delivering up to 460mA, seems to be the bottleneck. Without a lot of further information, nobody could seriously tell you the transformers VA-rating needed. Good luck.

thanks Harpo,
looks like i need another xformer. problem is... im a darn noob im honestly too dumb to figure out what is needed exactly. do you think i can get away with a 2x18v 50VA 1,39A transformer? i could still fit that in the case, its at the surplus down the road and doesnt break the bank..... should be twice the power right? thanks a lot!

ps: im using omron g5v-2 12v relays (40mA). and 15v DOA opamps

 

[Harpo]

..do you think i can get away with a 2x18v 50VA 1,39A transformer?

Maybe. How would I know. Up to now you only uncovered the use of 4 G5V-2 12V type relais on a bypass pcb and a maybe 2x18VAC 25VA transformer. A single illuminated switch might draw more current than the complete GSSL without. Compared to LEDs (these will need a current limiting resistor), incandescent lightbulbs are powerhogs .

ps: im using omron g5v-2 12v relays (40mA). and 15v DOA opamps

From datasheet, the G5V-2 12V come with 288R coil resistance. From Ohm's law, 12V/288R=0.041666...=41.7mA.
If you had selected the high sensivity type G5V-2-H1 12V instead, these would lighten the current demand per relais to 12.5mA at rated voltage. You still operate these at 125%, but the 12VDC part will withstand a 180% overvoltage according to datasheet.
Whatever your 15V DOA might be, current demand is mainly defined by connected load to your DOA. Depending on DOA used, assume idle/supply current in range 20...40mA per DOA. Icc of bipolar opamps assume in range 10...20mA, FET opamps a lot less. Read the parts datasheet in order to know the current demand without load and add up connected load to this part by applying Ohm's law.

 

[salomonander]

Maybe. How would I know. Up to now you only uncovered the use of 4 G5V-2 12V type relais on a bypass pcb and a maybe 2x18VAC 25VA transformer. A single illuminated switch might draw more current than the complete GSSL without. Compared to LEDs (these will need a current limiting resistor), incandescent lightbulbs are powerhogs .
From datasheet, the G5V-2 12V come with 288R coil resistance. From Ohm's law, 12V/288R=0.041666...=41.7mA.
If you had selected the high sensivity type G5V-2-H1 12V instead, these would lighten the current demand per relais to 12.5mA at rated voltage. You still operate these at 125%, but the 12VDC part will withstand a 180% overvoltage according to datasheet.
Whatever your 15V DOA might be, current demand is mainly defined by connected load to your DOA. Depending on DOA used, assume idle/supply current in range 20...40mA per DOA. Icc of bipolar opamps assume in range 10...20mA, FET opamps a lot less. Read the parts datasheet in order to know the current demand without load and add up connected load to this part by applying Ohm's law.

thanks Harpo,
ill try to do the math. my switches use leds no bulbs. i use capi gar1731 opamps - cant find any specs on them. but they should be close to api opamps i guess.

 

[salomonander]

all seems well with the 50VA transformer so far. i can even run the relays off the 12v point on the main board without issues. no more rail drops and no more clicks. thanks guys - i really appreciate your help!

ok more testing. all is fine except a little volume drop most likely due to the cavendish. im not getting unity gain. i did remove the two 15k resistors on the output ics. i read in the cavendish thread that some people replaced the 27k resistors feeding into the vcas (im using 202c). guess ill have to try that.

 

[Potato Cakes]

The Cavendish has spots for trimmers on the output. This would allow you to get unity gain.

Thanks!

Paul

 

[salomonander]

The Cavendish has spots for trimmers on the output. This would allow you to get unity gain.

Thanks!

Paul

thanks Paul,
yes i know. i have a 5k resistor in there and a 5k trimmer. but even with the trimmer cranked, im missing some db. guess i should try to swap in the ics again to see if this happens on the in or the output.

 

[Potato Cakes]

Also change your feedback resistors to your 202c's as you mentioned to get more gain there then trim with your Cavendish. Or you can change the feedback resistor on the output of the Cavendish with the 5k trimmer. Several ways you can go about getting a little more gain.

Thanks!

Paul

 

[salomonander]

Also change your feedback resistors to your 202c's as you mentioned to get more gain there then trim with your Cavendish. Or you can change the feedback resistor on the output of the Cavendish with the 5k trimmer. Several ways you can go about getting a little more gain.

Thanks!

Paul

cheers Paul,
ill give this a shot tomorrow - too late now. ill let you know. thanks as usual

 

[Rochey]

Sorry for the spam, but I feel that anyone trying to Design In the Cavendish board needs to be aware of our new docs for it.
Just a wee update on the documentation: https://groupdiy.com/index.php?topic=70128.msg914772#msg914772

 

[weiss]

Hello guys,

i got a working SSL compressor clone but as soon as i add the SC HPF board by steffen/greg into the circuit problems occur:

1. when the output is turned hard CW suddenly the signal gets completely distorted and sounds like bit crushed (none of the usual distortion or overdrive one would expect)

2. the threshold/compression sensitivity is totally off.. the compressor reacts to very low signals and completely goes crazy. It does't compress the peaks, but it seems more random. Sometimes it's compressing so hard, i can't hear anything anymore even when makeup gain is fully CW. is the IC damaged? what could i have possibly done wrong? wiring issue?

i used this wiring scheme.

My question is, do i actually need this pcb? or could i just use a rotary with some caps attached to achieve the same effect?
like here: http://snw.lonningdal.no/gssl/gssl_local_HPF_compackt.png

i would be really happy about any input that helps me solve this issue!

thank you
Ansgar