GSSL HELP THREAD!!!

[JRE Productions]

Ok question: What happens if I use a 10k threshold pot instead of 50k? I thought I read on Jacobs site it was ok, but now I can not find it.

I am not getting very much compression. All buttons seem to work as they should. I used THAT 2180 and left out the trim pots, the 68, 1m 10K and change the 3k9 to 5k1.

Help!

Thanks,
Joe

 

[JRE Productions]

WOW! Ok so I am answering my own questions and have once again learned alot.

I had a originally used a 10K pot in the threshold. I thought I read that you could use anything between 10K and 50k. But I guess I was wrong. I was getting very little compression. So I replaced the threshold pot with a 25k I had laying around. Now the compression is what I expected. Connected to my insert point on my consoles main outs with music around 0db, the threshold now kicks in at about 3 o'clock on knob. The meter appears to read right, though I have not calculated the actual amounts of compression.

I still have a 10k in the makeup gain position. I guess I will at least change this to a 25K pot too (I have one), to see if it makes any difference in output. But at this point it seems to work excellent as is.

Maybe I should leave well enough alone! :thumb:

Thank you for the project, and also thank you for not answering my questions right away! As this made me go back again and again until I found my problems.

Joe

 

[tommypiper]

Jacob, et al,

I have some BA15532 ICs, will these work in the NE5532 positions?


Matt,

Thanks for the suggestions. I think the components are OK, since nothing else died except the chip that burned up. I have some THAT replacements now, and the above 5532s. In any case, yes, I think it would be helpful if we could teleconference and compare readings on our boards again.


Greg,

Thanks for the corrections and suggestions. Cannot find any solder bridges or shorts.

 

[gyraf]

I have some BA15532 ICs, will these work in the NE5532 positions?

That will depend on if they are ment to be compatible with the 5532's - try locating data sheets and compare.

WOW! Ok so I am answering my own questions and have once again learned alot.

:thumb: :green:

 

[tommypiper]

Jacob, et al;

Can you tell me please how the bypass switch contacts should be jumpered to engage compression, please? Is it "on" and "com" -- or "off" and "com" as previously mentioned in this thread?

I've been asking this for some time now.... :? Tak.

 

[JRE Productions]

I wired a single pull double throw. When I have the switch engaged to compress, it is using the ON wire. So com and On is the ones I think you need.

Hope that helps.

Joe

 

[gyraf]

..yup..

 

[Oli Q]

Just finished my SSL board, checked all the voltages on the ICs and they were fine so I connected the ICs and powered up- all I got was a loud hum.

Then I noticed I had left out one of the jumper wires next to the left VCA. I connected this, powered up again and one of the 5534s exploded! Both the regulators also got so hot they melted their connections.

I was very careful to check all the solder joints and link wires for shorts and continuity, but as I'm quite new to this I don't really know what to do next, can anyone help?

 

[JRE Productions]

Make sure you have the right regulators in the right spots. (neg vs positive regulators.) and make sure they are in the right orientaition (direction). The regs gettting hot probably means a short somewhere else. So also check to make sure the opamps and VCA's are in the right direction too. A few are turned a different direction. Then last but not least, I would check to make sure the caps are in the right orientation too. Make sure the postive leg is in the square pad or where it is marked + on the silk screen.

J

 

[Oli Q]

Cheers, Ill check those out =).

 

[Oli Q]

Well I'm not entiorely sure what made the difference but I replaced a few parts in the power supply and it's working now =). Still a bit more hum than I expected... but I'll work through the fixes listed above and see....

Thanks very much for the help =).

 

[gyraf]

:thumb:

 

[JRE Productions]

Good news :thumb:


Jacob......see I did learn something from you after all! Check and recheck components and soldering. Check orientation of IC's, regultors and Caps. Now I too can help someone! LOL


Good Day Chaps!

Joe

 

[bluezplaya]

I am working on my SSL right now to finish this thing up and start using it. I have been busy on my Green Pre's and have had it on the backburner for a while now. It has been wired up for testing but is now racked in it's case.

My problem is that it passes audio (right now I am listening to Dark Side of the Moon through the unit into Pro Tools) It is a clean signal passing through. However, there are some issues:

-Meter adjusts with only the makeup gain and it is a constant signal. The meter does not jump, only moves from left to right as I turn the knob left to right

-None of the other knobs work

-The right channel is slightly louder than the left channel (I A/B'd the left and right I/O's)

-No LED whatsoever

The bypass switch was working (I could turn the meter on and off) but I double checked the parts layout and missed wiring a jumper on the control PCB next to the 750k resistor. It is now soldered in place and the bypass switch seems to not affect the meter either way.

That's right. It sounds like a case of the DIY blues.

Can anyone help in any of these matters or shoot some thread hyperlinks? Thanks in advance for this help!

Adam
:sam:

 

[gyraf]

-Meter adjusts with only the makeup gain and it is a constant signal. The meter does not jump, only moves from left to right as I turn the knob left to right

As always: check and recheck everything - in this case, specially the wireing between the PCB's (are they reversed?). Follow the schematic - check connections between pcb's for continuity and shorts.

Jakob E.

 

[tommypiper]

Update on my saga. Finally got compression to work -- whopee. I have no idea what the problem was, suddenly today it just started working. The last thing I tried -- I swapped all the THAT chips and it worked! However, putting back in the old THAT chips, and it still works. :?

My question is now about the meter resistor. I am confused about the comments in this thread. Some people are saying 2k resistor, some are saying 127k resistor or 100k resistor... what's going on? :sad:

I have tried a 2k resistor per the Layout instructions and it makes my 1mA meter peg full to the right at any comression setting. I tried a 21k and then the meter barely moves.

So, where are people using 100k resistors? What am I missing?

The schematic shows 330 Ohm resistor... Where does that resistor go?

Where on the schematic is the 2k resistor which is shown in the Layout?

I'm totally confused here. Thanks for any help.

 

[suprughetto]

what kind of meter you have?

 

[gyraf]

My question is now about the meter resistor. I am confused about the comments in this thread. Some people are saying 2k resistor, some are saying 127k resistor or 100k resistor... what's going on?

That's two completely different things! Re-read the related info please!

I have tried a 2k resistor per the Layout instructions and it makes my 1mA meter peg full to the right at any comression setting. I tried a 21k and then the meter barely moves.

2K to 21K resistor change should result in a 1:10 meter behaviour change. If not, please make sure you change the right one!

Are you sure you have a 1mA meter, and not a 100uA? The 2K meter resistor is kinda universally right for 20dB fullscale on a 1mA meter. If you've got a 100uA meter, try soldering a 330 Ohm resistor across it's terminals - that should get you in the right area.

Jakob E.

 

[Luny Tune]

I just finished yet another GSSL and I can tell you what I did there.

First of all, since your meter is a 1mA one it should actually work just fine with the 2K resistor in place and nothing else, and it should give you an indication of -20 dB at full scale deflection.
For -10 dB at full scale deflection, replace the 2K resistor with a 1K resistor.

Now, you should actually be fine with the meter you have and as described above but for future reference and in case someone else is using other meters, they can find the solution here:

The meter in my newest GSSL is a 100uA one and that won't work just as it is. The solution is very very simple though. (Jakob Erland took me through it all on our danish diy site almost step by step so it's nothing I came up with. I'm just passing it on. :grin: ) What you do in that case is simply to put a trimpot in parallel with the meter. Solder it directly on to the terminals on the meter.

Now, the thing to mind here is that this resistor works opposite of the 2K resistor om the main board. That 2K resistor is in series with the meter. Increasing it's value will make the meter deflect less and decreasing it's value will of course make the meter deflect more. The recommendation for that resistor is to leave it at it's specified 2K if at all possible and, if replacing it, to not leave in a resistor with a value less than 1K. Keep in mind that we have to take care to give other components good working conditions as well. A value less than 1K will start to add more load to the opamp than it'll like. What you will gain from lowering the value of the 2K is that you can then use a 2-3mA meter instead. Jakob mentioned that you could make a 5mA meter work but if you want to push the boundries you should at least know more about what you're doing than I do. :wink:
Here let's leave the 2K resistor in place and focus on the other solution where meters on 1mA or less is used.

For my 100uA Jakob suggested that a 680 Ohm (appr.) resistor in parallel with the meter would give me a -10 dB reading at full scale deflection whereas appr. 330 Ohm would give me a -20 dB reading. To be able to adjust it perfectly I soldered a trimpot across the meter. A 1K trimmer would be perfect but I only had 5K pots around so that's what I used and it worked ok.

The way I adjusted it was to use my consoles meters to measure in- and outputs with. The comp was inserted on two channels and the meter on those channels represented the inputs and then I used the Master Output meters to represent the comps output. This means you must have unity gain through the channels and to the master to begin with.
Then I...:

- adjusted the trimpot VERY ROUGHLY to where I'd think that it's value would be appr. 680 Ohm.

- chose 10:1 ratio.

- set threshold at a suitable level, which means high enough to not let the comp be triggered by very low input and yet low enough to let the comp be triggered at a level that's not too high. Using console meters means that measurements are most accurate at around 0 dB.

- fed a 1 KHz sine into the input at a suitable low level where it stayed below the comps threshold

- made sure there was unity gain through the unit.

- turned up the input level (NOT lowering threshold on the comp!) and found the exact spot where there's 6 dB less output than input level.

- adjusted the trimmer so that the meter reads 6 dB gainreduction.

- checked different input levels and that the difference between the input and output level always matched what the meter on the comp said. (Mine was correct at once but you may need a little fine tuning.)

That's it! You're done and you can trust your meter. :razz:

 

[tommypiper]

[quote author="gyraf"]

My question is now about the meter resistor. I am confused about the comments in this thread. Some people are saying 2k resistor, some are saying 127k resistor or 100k resistor... what's going on?

That's two completely different things! Re-read the related info please!

I have tried a 2k resistor per the Layout instructions and it makes my 1mA meter peg full to the right at any comression setting. I tried a 21k and then the meter barely moves.

2K to 21K resistor change should result in a 1:10 meter behaviour change. If not, please make sure you change the right one!

Are you sure you have a 1mA meter, and not a 100uA? The 2K meter resistor is kinda universally right for 20dB fullscale on a 1mA meter. If you've got a 100uA meter, try soldering a 330 Ohm resistor across it's terminals - that should get you in the right area.

Jakob E.[/quote]

Yes, I'm sure it's a 1mA meter, thanks. In fact I have tried three different meters from three different manufacturers and they are showing the same readings.

(The scale on two of them reads "milliamperes 0 to 1")

As I said, the 2K resistor completely pins the meters to the right.

Where is the 330 resistor (next to the meter on the schematic) located on the layout, please?

Is that the one that people are using a 2K?

If not, where -- on the schematic -- is the 2K resistor located -- the 2K meter resistor which is shown in the Layout?

Yes, I am sure I am referring to the correct 2K resistor as shown in the Layout. (It is indicated with **) Where is it on the schematic, please?

(Why was this project made without part numbers? It is very confusing.)

Where is the related info you are referring to, please? I don't see it on the Layout or schematics. I have reread this help thread several times.

Do I need to change the 100K resistor? Where is that resistor?! Where is it located on the schematic?

Where is it located on the layout?

Is there something else that could be causing my meters to pin?

Is it this 100 K resistor people are mentioning?

(I don't believe my problem is fine tuning or calibrating. I'm not getting anything close to normal meter readings with the suggested 2K resistor.)

I'm totally confused. Thanks.

(BTW, I hesitare to mention this as it may complicate the discussion, but it may also be a clue. The compression is extremely aggressive and difficult to control and on program material. It's either squashing the signal or hardly touching it. I can't seem to get it to work within a musical range. Is this normal behavior for this unit? Or is it another problem I'm having? Thanks.)