GSSL HELP THREAD!!!

[Barforama]

[quote author="DESOL"]
I think i had this problem..turned out to be a ground issue. lol :roll:[/quote]

Could you please specify where you had a grounding issue? :wink:

 

[tubemonkey35]

Using THAT 2180LA's after removing the two 10k's, 68R and 1M from each of the two VCA's, do I still need remove or not connect pin 4 of the 2180LA's in this section?

I also left out the trimmers.

For the Sidechain using the 2180LA, do I need to change the 100k resistors to 127k and remove both 47R resistors? Do I need to disconnect pin 4 on this 2180LA as well?

Should I replace all three 3k9 resistors associated with the 2180LA's with 5k1 reistors?

 

[tubemonkey35]

Anyone?

 

[JRE Productions]

Nope. Look at the schematic and then ask again. Once you remove the above parts, is there still a path to pin 4?

I fell into this same trap. It was easier to ask then to just look. Turns out it was easy to look than it was to ask.

I used the same VCA's.

 

[tubemonkey35]

Fair enough, I thought so.... but wanted validation.

What is the issue with the side chain, it seems the consensus is to use a 127k instead of the 100k for the 2180LA. The only think I'm not sure on from reading, is what to do with 47R to pin 4 in the sidechain; to leave it or not is the question?

 

[JRE Productions]

Look in this post. There is a link to a table with the items to removed. Only remove those items and make the changes it shows.

http://www.groupdiy.com/FORUM/viewtopic.php?t=14701&highlight=&sid=b7ca09177874726bbb70bb1efb112d3f

 

[Barforama]

[quote author="Barforama"]Hi NG

We have just finished a weekend SSL-building-get-together. A total of 6 clones were constructed. Two of the units was working right away. We were able to trouble shoot on two of the others and make them work properly. Leftover are two units. The one I have here is semi-working. One channel is working just fine, the other is outputting 5-6dB less than supposed.
My first thoughts told me that the error would be in the output or VCA-circuit of the less hot channel, but I cannot find any errors in those areas. I have checked solderings extensively, orientation of OP-amps and condensors and finally I have checked all resistors in the same areas.
I have read most of this Meta-thread and it is frequently suggested that there might be a short around pins 1-2-3 in the 5532 of the faulty channel, but there's not. Any suggestions?[/quote]

Anyone?

I have been staring myself blind on this board for, i think 3-4 hours by now. Everything is as it is supposed to be....except the result. I think the next move will be using it as a mono-compressor

 

[gyraf]

Check the levels right before the resistors to the VCA inputs. This tells you wether the problem is at input or output circuit.

Then check levels on the output of the first-half 5532 after the VCA's

Last, check that both + and - outputs are running! Easy to loose 6dB here..

If all else fails, stop by here in our studio some day - we should be able to get it fixed quite quickly..

Jakob E.

 

[byoung]

I would like to use EAO switches (or something similar to the Smart C1 buttons......any ideas?) on my clone for the power and the bypass switch. Does anyboday know which part# to use for each application and where the best place to buy them from is in the US?

 

[gyraf]

byoung,

This has been discussed on several occations before. Re-read this thread, or try a search.

Jakob E.

 

[tommypiper]

I'm almost there.

What are the normal voltages for the ratios and where?

My ratio is crazy - I get whacky results which make no sense, sometimes negative output for increased input. Ratios bear no relation to what they are supposed to be. Ratios change dramatically with release settings. Also, the fastest release setting distorts terribly.

Please, please, any ideas, places to check? (I've read this thread front to back over three times - it took like 12 hours over days. I have not seen this problem like this before.)

 

[gyraf]

Seems like there's a serious mess-up somewhere..? Have you checked that the board interconnection wireing is sequenced right, i.e. no swapping of places?

Recheck +12V and -12V lines on the control board!

Recheck that switches are "end-stopped" correctly!

Recheck all components, values, and soldering, mainly on the control board.

Jakob E.

 

[tommypiper]

Thanks. Yes, voltages on control board, values, wiring, switches, everything is fine. I removed some resistors to double check them when I couldn't confirm their values from the stripes, but they were fine. I've triple checked everything. I've swapped in different VCAs. It's not happy. Ratio is not working. I don't know what to do.

Are there control voltages I can check at various places? What would they be?

 

[desol]

[quote author="Barforama"][quote author="DESOL"]
I think i had this problem..turned out to be a ground issue. lol :roll:[/quote]

Could you please specify where you had a grounding issue? :wink:[/quote]

The problem...was that i hadn't grounded the input on one side...i searched for the problem for two weeks...burnt a few opamps AND a vca...stayed up till all hours of the night...cursed DIY and the board...almost threw it in the garbage. This was my first electronics project.... Anyways....one day...i noticed my right side input(i think?) wasn't grounded to the common ground for that side. OMG.

:shock: ......:grin:

It was an awesome moment. I swear. lol

Make sure your soldering is really good on all your wiring...wiggle the wires around...keep looking...you'll find the problem...

Hope that helps.

 

[gyraf]

Desol, :razz: :thumb:

Tommy,

Use the schematic for reference - all should be pretty clear..

I think we have a signal-tracing post somewhere earlier in this thread.

Jakob E.

 

[dustbro]

I'm very new at this whole thing and need help confirming a cap's value in the VCA section that seems to be unmarked. Looking at the PCB between the 1K* and the 1K resistor is a cap. I followed the lines on the schematic and it took me to a 100p. Did I do that correctly? The right side has a slight marking that may resemble a .1 so I'm confused.

 

[gyraf]

Dust,

Another topic that has been discussed many times before. Use a 100nF, but it isn't important really.

Jakob E.

 

[dustbro]

[quote author="gyraf"]Dust,

Another topic that has been discussed many times before.[/quote]
My bad... after reading 64 pages of this thread, I assumed no one else questioned this. sorry.

 

[Aaron Wiles]

tommypiper and Aaron Wiles:

I've been very busy with some Engineering jobs lately, so I haven't been checking lately. But I'd like to clear up a few things just for clarity since I read a little bit of bad info in your posts.
1. Measure AC across center tap and green, then center tap and blue... they should be close. AC across green anc blue will be twice that.
2. The rectifier does not convert positive to negative, it converts the AC from toroid to raw unfiltered DC.
3. Aaron, you said you were getting about -24VDC at the input of the 7915... this is perfect. This -24VDC is regulated and filtered down to -15VDC. I'd suspect something "downstream" is shorted, which might be causing the regs to get nice and toasty, and perhaps even the toroid.

Ohm out the negative rail (with regulator installed)... what are you measuring?

My apologies for just getting back to this. Been slammed.

OK, here's some voltages: From the transformer secondaries (Green wire: 19.2vac; Blue Wire: 39.46vac; Red/Brown together: 29.25vac)

I'm assuming the center tap is the Red/Brown? if so, I am reading 18.69vac & 18.70vac with the Green & Blue secondaries across the center tap. So that is close.

The Bridge Rectifier is not converting to DC. I am still getting AC voltage off the rectifier (the + reads 28.48vac).

Also, without the voltage regulators attached, I am reading 28.7 to 28.5 vac on all the ground rails (it's coming from the Red/Brown of the transformer). Should this even be connected to the board?

When I connect the 7815, I'm ok. Getting +14.79vdc
When I connect only the 7915, I'm getting +9.1vdc (I should be getting a negative reading).

Edit: I just double checked a few things. When I ONLY have the 7815 attached, all voltages appear to be ok, including the +/- dc voltages coming from the bridge rectifier. Yes, I said DCV. When I plug ONLY the 7915 in, I get AC voltage from the rectifier it appears. And getting all the readings I mentioned above. When both regulators are plugged in, the transformer instantly gets hot and burns up.

I'm just now diving back into the project to try and get it going, but I'm stumped.

Thanks for the help.

 

[Greg]

I think you've done a very good job as to finding the source of your problem. I'd suspect there's a short somewhere on the -15VDC rail. Ohm out the negative rail and see if you have a short. In general, I ohm out every rail before I power anything up. Powering up with shorts can potentially damage components.