GSSL Finished - Sounds bad :-(

I have just finished my SSL and it really does not sound that great :? Everything seems to work fine, the meter shows GR and all the knobs seems to work.

When I get over a gain reduction of 2 I get light distortion and the more I turn the threshold and get GR of 5-7 the sound becomes very faint and distorted - full throttle on makeup cannot counterbalance the lost in level. I worked 3 hours yesterday trying to find bad resistors, bad values, bad soldering, going over the wires to the XLR pins but nothing :sad:

I have recorded a short snag of drums in our studio - I have not processed the 6 tracks in any way (just mixed levels) so it's raw material. It's a 16 sec. 24bit/44kHz bounced to a stereo wav-file (4,3MB) and I would really like for some of you to run the drums through your SSL and post the result in lets say a high quality mp3 file (320kbit) so I have something to compare with. I don't know if it's me who don't know how to adjust the SSL (only used to digital comps :roll: ) or there is something wrong with it or I just dislike the sound of it?

Drums

Got your drums, be back in awile with the results. :grin:

Well I've worked a bit more with the SSL and I found out that it is very sensetive on the controls but no matter what I do the signal gets too hot/distorts when the GR gets beyond 2dB on the meter (maybe it's the meter that's no working right??)

Is it easy for you to get the SSL too hot/distorting??


I'm really not impressed with the SSL at the moment maybe I have to work some more with the unit on different sources!!

no no there is something definately wrong with your unit. i have 4 of them and they are tight and smooth. if you are getting any distortion then there is something wrong. I would suggest starting at the inputs and look over the traces and part values.

Look for some cold solder points around the switches, I had some bad solder points on 2 of the switches which resulted in bad distortion. they looked fine at first but just heating the iron and alittle solder fixed it for me. I'm no expert but maybe thats what you have.

I can assure you the GSSL sounds great, I've got some nice comps (1176ln, decca, ward beck, altec) and this one sounds just as good.

I would have to say check your release switch. If it is not set to five positions, and you are on the sixth, your audio will distort. I think Jacob said something about this in a thread:

http://www.groupdiy.com/index.php?topic=331

If it is happening on all settings then this may not be the cause, but check it out. Mine had this problem.

Vetsen

[quote author="Vetsen"] If it is not set to five positions, and you are on the sixth, your audio will distort.
[/quote]

yes, and this is a good thing ! :razz: :razz: :razz:

Gustav

yes, and this is a good thing !

Click to expand...

Yeah distortion is a great coverup for bad singers. :twisted:

Ok Thanks to bubba_b for your effort!!

I have made some measurement on my SSL and I don't think they look all that great :?


Can someone tell me where I measure the points "A" , "B"....... and so on and the correct measurements here??

Thanks!!

I have made more measurements :roll:

On the right/left audio inputs I have 14,82V on pin 6 on both 5534's but I have no voltage on both legs of the two 22µ electrolyts (to sidechain) nor the the two 47k resistors and pin 1 on the sidechain VCA

Could it be two bad 22µ electrolyts to the sidechain or what do you think??

bumb

Hi Hulk

If you have 14.82V DC on pin 6 of 5534 it is something really wrong because those pins are the audio outs and the dc should be very low, in the milivolt range. You measured this voltage between pin 6 and ground?

My sugestion is to take out all the chips from the sockets (I hope you used sockets for all your ICs) and leave only the two 5534 input receivers in the PCB. Power up and do the measurements at pin 7 (close to +15V) pin 4 (close to -15V) pin 6 (close to 0V)
After you do this test we can go further.

chrissugar

Hey chrissugar

I'll get right on it and post my results!!

Thanks a lot!!!

I measured at the wrong pin on the 5534's

It's like you said:

5534:
Pin 4: -15.10V
pin 6: 0V
Pin 7: 14.89V

So they are ok right?

But I still cannot measure any voltage on the two 22µ electrolyts(to sidechain) nor the two 47k resostors(to sidechain) and no voltage on pin 1 on the sidechain VCA?

Ok Hulk, next step

You do not have to have any DC voltage (only some DC in the milivolt range) across the 22micro. Also no DC at pin 1 of the sidechain VCA.

Leave the 5534 input receivers in the sockets.
Now put back only the 5532 output driver opamps and measure at pin8 +15V, pin4 -15V, pin1 and pin 7 on each chip 0V.

If everything is ok the next step is to fizically bypass the VCAs (not with the bypass switch) and verify if the audio signal will pass the opamps undistorted. I already described this in another thread to J.Hall, so I will copy and paste what I said there:
"Pull out the 2180 from the socket and make a bypass from pin 1 to pin 8 of the VCA. It should pass audio.
The bypass link will connect the output of the balanced input receiver to the input of the rebalancing output circuit."

BE CAREFUL TO NOT MAKE SOME SHORTS while you do these tests.

chrissugar

I soldered all the 5532 and 5534 directly onto the PCB that was before I read that it's best to use sockets (but the VCA's, TL072 and TL074 are with sockets:roll but the output 5532's show the voltages that you said!

Can I still try to bypass the VCA's and is it all 3 VCA's that needs to be bypassed??

I don't know if it is clear that I'm talking about bypassing only the VCAs from the two audio channels, NOT the one from the sidechain.

chrissugar

If you have the VCAs soldered, do not do the bypass procedure because it can destroy the chips, only if you can extract them from sockets.

chrissugar

I can extract the VCA's but not the 5532 and 5534's!

Can I fire it up then with pin 1+8 connected on both audio VCA's ?? should the sidechain VCA stay in it's socket while tring this out??


Thanks for your help!!

Ok , I'm back.

Ch1 - extract VCA, link pin1 to pin 8
Ch2 - extract VCA, link pin1 to pin 8
sidechain - extract VCA, do not link anything

Power up and listen to audio if it pass undistorted from in to out.

chrissugar