GSSL HELP THREAD!!!

[hairyandy]

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I don't quite know where to start fault tracing. Anyone got a clue?

Yes - read this thread, looking for something similar. This help section is not meant as a online help-chat, but a place to look up fixes to various problems

I fully understand it's a long read, but there is so much great information and error-tracing information collected here. No matter how the outcome, you'll learn important things from this.

Try to go through this thread looking for answers before posting questions - that way there's a better chance someone will be happy to answer.

If you switch to "print" view (top right) you can use your browser's search function to conveniently search through all posts at once.

When you eventually solve a problem in the GSSL, please don't be shy: Post a short description of your original symptoms, what the fix was, and how you found it. This would be of tremendous value for others stumbling over the same stone..

And oh - don't worry too much: With patience and work, there is a very high success-rate on this project.

here are the most common problems and their fixes encountered by DIY builders of the GSSL compressor:

1. Voltage and Power Issues:
   • Problem: Incorrect voltages or unstable power supply readings.
   • Fix: Verify the power rails, ensuring correct voltages (+15V and -15V) are supplied. Double-check connections, especially around the power supply and regulators (GroupDIY Audio Forum) (GroupDIY Audio Forum).
2. VCA and Component Mismatches:
   • Problem: Issues due to using different VCAs (e.g., 2180 vs. 2150) and mismatched components.
   • Fix: Ensure that all VCAs and their surrounding components match the specifications. Adjust or remove certain resistors (like the 47R resistor on pin 4 of the 2180) as per the VCA type used. Confirm that both channels use identical parts to maintain balance (GroupDIY Audio Forum) (GroupDIY Audio Forum).
3. Compression Anomalies:
   • Problem: Strange compression behavior such as uneven left/right channel compression or unwanted noise during compression.
   • Fix: Check the sidechain circuit for correct component values. Troubleshoot by comparing component values and voltages between the main and Turbo boards. Replace ICs if necessary and ensure no shorts or incorrect component placements (GroupDIY Audio Forum) (GroupDIY Audio Forum).
4. Metering and Calibration Issues:
   • Problem: Incorrect or unstable meter readings.
   • Fix: Ensure proper calibration of the meters. Verify the DC voltages around the sidechain rectifier and check the integrity of the DC blocking capacitors. Properly mount and orientate the 22uF capacitor based on DC polarity at that point (GroupDIY Audio Forum).
5. Grounding and Hum Problems:
   • Problem: Hum or noise due to grounding issues.
   • Fix: Ensure that the chassis ground is properly connected to the 0V ground point on the PCB. Use a Digital Multimeter (DMM) to test connectivity and confirm grounding integrity (GroupDIY Audio Forum).
6. Operational Amplifier (Op-Amp) Issues:
   • Problem: Problems with TL074 or similar op-amps causing erratic behavior.
   • Fix: Replace faulty op-amps and verify that they are correctly oriented. Check for high-frequency oscillations using an oscilloscope and ensure proper decoupling and filtering around the op-amps (GroupDIY Audio Forum).
7. Switch and Relay Functionality:
   • Problem: Issues with bypass switches or relays not functioning correctly.
   • Fix: Ensure proper wiring and check the continuity of switches and relays. Consider using add-on PCBs for easier wiring and more reliable switch functionality (GroupDIY Audio Forum).

These are the recurring themes and solutions derived from the extensive discussions and troubleshooting in the GroupDIY forum thread for the GSSL compressor. For detailed step-by-step troubleshooting and community advice, referring directly to the forum thread can provide more specific guidance.

(courtesy of chatgpt4.o)​

Jakob E.

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Hey guys,

I just got my PCBs from Gustav last week and then the forum sh*te happened! Does anyone have the entire SSL help thread backed up? I'm not necessarily asking for it to be posted here, I'd just like to get it to have locally when I begin this project. This is my first DIY project. BTW, you guys all rock!

Thanks,

________

 

[Bauman]

So just to recall, are you guys using THAT2180LA without a problem on the SSL compressors??
I'm about to buy some and would like to know, since we don't have that good old data...

cheers!

 

[gyraf]

Attention:

This thread is an archive of possible and tried problems and solutions - NOT a help chat.

Try to go through this thread looking for answers before posting questions - that way there's a better chance someone will be happy to answer.


___________________

Hi Andy,

Welcome to the Lab, and the addicting world of DIY. You'd be hooked before you know..

We're all here (even a collection of highly estimated design engineers from well-known companies) - just ask, and we'll try to answer...

Jakob E.

Fabio: 2180LA works fine for the Clone, as does -LB

 

[ChrisA]

I'm using the 2180LB and it works fine...You should be fine if you use the LA...Are you dealing directly with THAT Corp to buy them?

If we just start another SSL help thread, it will probably grow very informative in a matter of a few days....we should just do it.

Jakob, would you care to start off the thread? would seem most appropriate...

Chris

 

[Bauman]

Thanks Chris and Jakob!

Going to get some LA fro http://www.profusionplc.com

cheers!
Fabio

 

[gyraf]

Chris,

This thread is as good as any.. let's just keep it here...

Andy - could you remove (edit) the questionmark from the thread title?

:grin:

Jakob E.

 

[keithcamilleri]

Hi guys...

I am still gathering parts for the SSL clone, and I am at a point to buy the meter, can anyone help me out?

I liked the one tha Jakob has on the site but I don't know the company who produces it, otherwise I had in mind the SIFAM AL29WF, but I cannot find the specs for the meter?

cheers

 

[gyraf]

Hi Keith,

Welcome here.

For the meter to the SSL you'll need a linear 1mA fsd type, NOT a VU-meter.

And you need one that will fit in your box. Sifam AL29 will fit in a 2U, not in a 1U box.

Sifam "Presentor" data found here: Http://www.sifam.co.uk/presentor.lasso

RS components has the Sifam linear-scale meters. The original SSL meter was a Sifam.

For 1U boxes, you'll need a different meter type, something like this:

http://www.herrong.com/CF.htm

RS components has the Kyoritsu EW-60 (order no. 143-3287 - about 34£) that should fit in a 1U box - but better check measures for yourself before buying...

Farnell also has these cheap standard types:

order no 143509 - it's 100uA, but will work with a different meter resistor (20K in stead of 2k)

Jakob E.

 

[keithcamilleri]

Hi Jakob...

I appreciate your help a lot... I am new in DIY ...but I am already hooked on it .....it is very easy to get hooked as you well said ....

regards

 

[hairyandy]

Thanks for the info on the meters Jakob. I've been wondering what to get and have been balancing the cost vs. cool factor. I think I'm now down to the Farnell #143509 or the Behringers.

On a different note, I just got a dbx 202C for my clone and I have two 2150s available to me as well. Is it OK/possible to mix different vca types in the clone? I'm assuming that since they're interchangeable it's possible but will it adversely affect the sound at all? I'm thinking that I should use the two 2150s for the inputs and the 202C for the sidechain. Would that be OK? Does anyone have an opinion about 202 vs. 215x or 218x as far as sound quality is concerned?

Thanks and sorry if these questions have been answered before...

 

[gyraf]

Andy

You can't use the 202 for the sidechain, as the 202-block option is only for the two audio-VCA's.

The 202 is simply too good to be used as a humble predictor-VCA, that noone will ever hear - so here it is 2150/80 only :grin:

And you shouldn't use one channel 202 and a second channel 2150, as even small differences can and will disturb your stereo imaging.

Save your 202 for a later project - I'm pretty sure that you will need it one day..

Jakob E.

 

[hairyandy]

Thanks again Jakob. Exactly the info I was looking for...

 

[ChrisA]

so are the dbx202 vca's more desireable than the newer 2180/2150 series thats?

I thought they were older and inferior to the new ones...

 

[ChrisA]

Hey Jakob,

would the sifam presentor meters work?

It looks like the AL19 would fit, but is it linear 1mA fsd type?

 

[gyraf]

ChrisA,

The 202's are nice stuff. The 2181's have at least as good specs. The 2150 is a low-cost solution - although with a nice sound.

The Sifam range of meters - like any meter manufacturer - can be had in all sorts of FSD values. You just order the type you like, and specify a FSD sensitivity, 1mA in this case.

Jakob E.

 

[ChrisA]

Thanks Jakob.

I think I found a store here in Los Angeles (where I am) that has the sifam presentors and just shot them an email.

I still have no meter on my first ssl and just started building 3 more, so I thought I'd better get on this.

cheers,

Chris

 

[tubejay]

Hopefully someone who's built one of the on 120v can help me sort through the power situation on the SSL. I'm getting ready to order the parts for this, but everything I've read seems to be based on 220v power. Would anyone be so kind as to tell me what I need to do differently in the power supply section to make this work properly. I'm new to this, so please forgive the basic question. Again I don't necessarily get this, but from what I've gathered, the only thing that should be different is the power Xformer...right???

Also, if you could include part numbers, like for what transformer you used, or anything that might be different from the PCB I have, which is the one from Gustav.

Thank you!

Jimbo :guinness:

 

[Ian MacGregor]

I used the Digikey part number TE62063-ND
It works great! Nice, small toroid. Just make sure you've got a nice fuse, power switch, and IEC connector and you're golden.

Ian

 

[tubejay]

[quote author="Ian MacGregor"]Just make sure you've got a nice fuse, power switch, and IEC connector and you're golden.

Ian[/quote]

Thank you for the info! Not to be a total pest, but do you have the part numbers you used for those three parts?

Thanks!!!

 

[Ian MacGregor]

Well... You can get a 5x20mm fuse anywhere, I'll give you the number of the fuse holder I used. All mouser part numbers:

Fuse Holder: 5767-345531
IEC Connector: 693-6100.3300
Lighted Switches (expensive!): 653-A165L-AGA-24D-2

Just buy a 1/3A (or so) 5x20mm fuse and you're set.


Ian