Input transformers on GSSL??

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Lowfreq

Well-known member
Joined
May 28, 2005
Messages
574
Location
Christchurch, New Zealand
I'm messing round with my gssl and I want to experiment with some input transformers.

Attached is where I tried patching into the circuit from the transformer, but I ended up getting a very weak dull signal.
ssl_xfmr.jpg

Is the first 5534 unbalancing the signal? or doing more?
Gyraf website said:
Input signals are de-balanced by a couple of NE5534’s, who in turn are driving the VCA in current mode via 27K resistors
If I can't skip the 5534 I can't really see the transformer being much use.

I found this thread, but the links to the schematics are gone.
http://www.groupdiy.com/index.php?topic=8174.0

Anyone done this?
 
You still must use the buffer (NE5534) before the VCA even with an input transformer.

Lowfreq said:
If I can't skip the 5534 I can't really see the transformer being much use.

Indeed. The only technically valid reason for using an input transformer here would be galvanic isolation. A less technical reason would be if you need "more color". Both valid, if maybe expensive excuses.

But many people have done it anyway, for output as well. Here's one of the related topics: http://www.groupdiy.com/index.php?topic=8174.0

For less colored and better performing input, just use a modern opamp, say LME49710 or OPA627. By the way, those 100n caps bypassing the input electrolytics are completely unnecessary. Modern elcos perform well enough (or better) without this hack.
 
Yeah, I've been reading some of your posts about the 100nf caps, and I'll try some different opamps.
I put some opa2604's on the ouput. The difference was minimal at best.

When I insert my gssl on the inserts on my pro tools, it seems to do something subtle on the top end. Kinda smeary, maybe it's a transient thing.
 
Kingston said:
Lowfreq said:
If I can't skip the 5534 I can't really see the transformer being much use.

Indeed. The only technically valid reason for using an input transformer here would be galvanic isolation.

Another reason might be that you don't need both 22uF & 100nF caps on the input.

here the pic from the original post...

SSLJensen_in_outputmod-1.jpg
 
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