GSSL HELP THREAD!!!

[Jonkan]

Ok, thanks!

If i have any caps at home that will fit i might try it. If not, i wont. Im not too worried about it, just curious.

/J

 

[tree]

Hi;
my rail voltages are a tad on the highside.... 18.57 and -19.13
the 12 v rails too were high - around 15.
somehow while checking these and others i managed to pop a 750 ma fuse too!
Anyone have thoughts on how best to trace down the culprit AND NOT do this again?


scott

 

[gyraf]

[quote author="tree"]Hi;
my rail voltages are a tad on the highside.... 18.57 and -19.13
the 12 v rails too were high - around 15.
[/quote]

As mentioned a couple of times earlier, you need to install the IC's before measuring voltages, as the regulators needs a bit of load to function.

Are you measuring without ic's installed?

Jakob E.

 

[tree]

Thanks, Jakob.

Yes, i've read about this here before, but this seems very odd to me...
Measured both ways. Chips in, chips out. Tripple checked power supply section for bad joints, component orientation...all look good - identical to my 4 other much loved GSSLs.

Now my DMM reads 50VAC across green and blue secondaries of xformer
(amveco 62063) 25VAC between ct and either blue or green and this reading doesn't seem to change when plugged into the card measuring after the rectifier, smoothing caps (1000uf, 50V) - same. Now center of card 15 rails read 24dc,
12v rails nearly 17. Blew a second fuse (1a) along the way.

Wondering if xformer was defective cooking rectifier, regs etc?
Also second guessing the DMM itself a bit.
Quite a mess, huh?

 

[buschfsu]

i have a question about my toroidal. i have a 22V amveco that i could use for this project and save some $$$. Can the regulators handle 22v or can i drop the voltage somehow before the regs?

this threads pretty crowded. i just verified the datasheets max voltages so i guess ill go with that unless someone wants to chime it??? :grin:

thanks

 

[crisotop]

Has anyone an idea about my meter behaviour?

thanks
cri

 

[gyraf]

Wrongly marked meter?

 

[crisotop]

could be, but i built two ssls, and both behave in the same way? But I probably shouldn't be worried as long as it works as it should.

thanks
christoph

 

[crisotop]

One of my two builded units rolls off the highs on the right channel. Starting at 1k, I'm losing about 4dB until 20k? Any spots that I could easily check? Also S/N is about 18dB worse on the same channel?

thanks in advance,
christoph

 

[gyraf]

Check value of compensation capacitors (the ones from opamp output to -inputs)

Jakob E.

 

[crisotop]

Thanks Jakob, I used them, and they're identical for both 5532 (at least the writing on them is identical). I'm pretty sure, I haven't misplaced any components. But will double check everything.

thanks again
christoph

 

[crisotop]

there seems to be a bit of a problem with the measuring tool - will check back later...

thanks
cri

 

[Jonkan]

My Ultimate Gssl is up and running. I am having a strange issue that i was hoping someone would have a clue on how to solve or atleast explain.

There seems to be some distorsion (very subtle) in the sound when the unit is in bypass.

I measured the unit in bypass with RMAA and everything was reported as expected, except for one thing.

The THD value seemed a bit high, which seems to respond well to what my ears were telling me. I got a figure in RMAA at about 0.017%

Now here comes the strange part. When the unit is not bypassed the THD value is lowered to 0.0079% !!

Very strange !!!

I had the makeupgain at 0dB, the threshold at max. The makeupgain is switched out when in bypass.

I can definately live with this flaw since i dont see that ill be switching the unit to bypass very much, but it still bugs me somewhat.

Anyone else that has experienced similar issued?
Thanks,
Jonas

 

[gyraf]

I'm not familiar with how the ultimate version is wired - could it be dirt in the sidechain due to wireing? Is this real THD or is it THD+noise? If real THD, then audio may be interfering with sidechain in bypass - if noise, then check what remains in sidechain signal when bypassed..

Jakob E.

 

[vertiges]

Jonas,

0.017 % in bypass ? :shock: That wouldn't bother me !
0.0079 % is very good !

I'm just curious : what monitoring system do you use ?
What VCAs did you use for your unit ?

Congrats ! :thumb:

eD)))

 

[Jonkan]

Jakob, what do you mean by dirt? Bad soldering or "dirt" in the actual electric signal? Perhaps i should recheck the wiring to the bypass switch.

audio may be interfering with sidechain in bypass

How could that happen? Im not sure i understand what you mean by this. Can you elaborate?

If you want to read up on the wiring heres everything explained: http://www.groupdiy.com/index.php?topic=18017&postdays=0&postorder=asc&start=135

Vertiges: Im using old Jbl 4406 monitors modified with charge coupled crossovers through an BLA modded motu traveller for DA conversion. The charge coupled network is supposed to eliminate crossover distorsion and phase anomalies in the speakers, and the DA is really clean, so i can hear very tiny differences in soundquality very easy with this chain.
The VCAs are 2180LA. And since there are two of them differentially connected for each side of the audio the distorsion in them should in theory be a bit less.

Im not too worried about the values themselves, but im very curious why the values differs so much between bypassed and not bypassed.

/J

 

[Vito Janeiro]

Hello everyone and thanks for the nice forum.

I have a chance to compare the GSSL to original SSL 4000 console master compressor (G+) and I just have to wonder how it´s possible that the clone sounded so good but even punchier than the SSL compressor!

Nice job Jakob and everybody who have participated to the developing process, to the clone and the original!

Only thing I´d like to modify is the makeup gain, I´d like to be able also reduce the volume when compressor is active. Any idea how to do it?

Wbr,

Vito

 

[Grooveteer]

Hi all,

I'm trying to troubleshoot my GSSL. One channel is working fine, the other distorts really bad. I have tried swapping VCAs and 5532s and 5534s but that didn't make a difference so I suppose those are OK.

This happens also in bypass, by the way.

The 5534 (VCA section of the board) and VCA get pretty warm on the channel that works OK but do not get warm on the bad channel. Are they supposed to get warm?

Thanks!

Cheers,

G

 

[stitch-o]

[quote author="Vito Janeiro"]Only thing I´d like to modify is the makeup gain, I´d like to be able also reduce the volume when compressor is active. Any idea how to do it?

[/quote]

Are you looking to increase the decrease? There is a fair bit of down volume on mine as it is.

I've been contemplating an altogether new amp circuit for makeup gain stage? based on a 990 opamp maybe?

 

[Vito Janeiro]

Decreasing. There is plenty of makeup-gain available.

I need it to trim the parallel bus level after the automation for example...