GSSL HELP THREAD!!!

[dissonantstring]

audioguyII,
try avel lindberg: http://www.avellindberg.com/transformers/y23_range_specs.htm
or parts express might have them (they carry avel lindberg too, but you can get them direct).
regards,
grant

 

[Greg]

I like these better than the Amveco from Digikey.

http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=122-605

 

[AudioguyII]

Thanks Greg,
Just ordered them...... hope this cures all my ills!

AudioguyII

 

[ioaudio]

6 hours of error tracing... found the problem, a bad `lytic...thanks for your attention...

 

[Greg]

Fantastic... was it shorted or open or leaky?

 

[BladeSG]

[quote author="BladeSG"]Now I'll ask my own question....

On the gssl pcb it's marked (in the area for pcb mounted toroid) that a 4.5VA toroid will do.

I've got the above mentioned MT2086 toroid which is a 15v-0-15v 20VA. Is it safe for me to assume that if the gssl only requires 4.5VA I'll be able to power 2 gssl's with this one toroid?

Also how might I go about calculating if a PSU pcb (in this case Keith's SSL 9K PSU pcb (thanks Neeno for the idea)) will handle 2 gssl's?

Thanks in advance

Steve[/quote]

Would it be easier/smarter to just leave the PSU sections of the gssl's intact and use 2 toroids?

Steve

 

[gyraf]

Would it be easier/smarter to just leave the PSU sections of the gssl's intact and use 2 toroids?

Yes. Feeding two bridge rectifiers from the same transformer windings can give unpredictable results.

The 4.5VA is approx. the power drain of the circuit - but this is EXCLUDING any power needed to light the meter..

Jakob E.

 

[BladeSG]

Thanks Jakob.

I was thinking of only using the one PSU pcb, one bridge and one toroid feeding 2 gssl's.

Still easier to use 2 toroids?

Steve

 

[gyraf]

Depends on your error-tracing skills. It's absolutely possible with one toroid, but potentially troublesome.

If you do this, use rectifier on only one board, and distribute unregulated DC to the other board. Maybe double reservoir capacitors to 2200/35V.

Are you building a quad compressor?

Jakob E.

 

[mathflan]

HI,

I did the trick of Replace the 100 K resistor by a 120k for correct ratio but I need to Calibrate my meter.

the meter is at his maximum when I have 5dB of compression.


DO you know How can Set it.

It's a 1mA meter, I use a 2Kresistor for the sensitivity.

Thanks

 

[Greg]

Put a trim pot in for the 2K and as you reduce the resistance you'll see that at full deflection your "dB" will go up. :thumb:

I've had to tweak this for every GSSL I've built.

 

[mathflan]

thanks greg!
it's work great!!


:grin:

I find a software called DDF3 from YMEC, there a trial full version of this.

I use it for THD trimmer, it's works great


http://www.ymec.com/products/dssf3e/index.htm

 

[BladeSG]

[quote author="gyraf"]Depends on your error-tracing skills. It's absolutely possible with one toroid, but potentially troublesome.

If you do this, use rectifier on only one board, and distribute unregulated DC to the other board. Maybe double reservoir capacitors to 2200/35V.

Are you building a quad compressor?

Jakob E.[/quote]

Thanks Jakob, I appreciate your help.

Are you building a quad compressor?

Yes, or is called a dual stereo compressor?

Anyhow (with the help of Neeno with the 4 jumpers) this is what I'm thinking might work: (I should mention in my quick hack below that the jumpers of the 7815 and 7915 are straight from input pin to output pin, I went of the 7815 part with the yellow line)

Will this work or am I dreamin'? I'm thinking it will if the 20VA toroid is enough and I'm unsure about leaving the 2 x 22uF/25V caps in the PSU section of the GSSL's PCB.

 

[Greg]

I think this looks fine for the +/-15VDC. But the GSSL also needs +/-12VDC... I don't see a PSU supplying that as well ?!?

 

[BladeSG]

[quote author="Greg"]I think this looks fine for the +/-15VDC. But the GSSL also needs +/-12VDC... I don't see a PSU supplying that as well ?!?[/quote]

I thought the same way as normal, through the 2 x 10R resistors....?

 

[Greg]

If you notice from the schematic, the 10R are being pulled pre-regulation. I think the way you have it set up 10R will be connected to the regulated +/-15VDC.

 

[BladeSG]

[quote author="Greg"]If you notice from the schematic, the 10R are being pulled pre-regulation. I think the way you have it set up 10R will be connected to the regulated +/-15VDC.[/quote]

Thanks Greg. You're right, another oversight. It's so obvious too

I suppose then it's 2 toroids, which is a shame....

 

[khstudio]

[quote author="mathflan"]HI,

I did the trick of Replace the 100 K resistor by a 120k for correct ratio but I need to Calibrate my meter.

the meter is at his maximum when I have 5dB of compression.


DO you know How can Set it.

It's a 1mA meter, I use a 2Kresistor for the sensitivity.

Thanks[/quote]

I used a 127k in that spot. 3k for the meter put me dead on on both of my units. One uses 2180's & the other 2151's. :green:

 

[ioaudio]

i think you should split the voltages before the regulators. double the filter caps (2200µ) and regulate twice, +/- 15v and +/- 12v

 

[BladeSG]

[quote author="ioaudio"]i think you should split the voltages before the regulators. double the filter caps (2200µ) and regulate twice, +/- 15v and +/- 12v[/quote]

Thanks ioaudio.

How about if I leave the LM7815 and LM7915 regs on the gssl's and use Keith's 9K PSU (remove regs from here and jumper input and output) to feed unregulated 15-0-15 DC to the 2 gssl's. So all I'd be removing from gssl pcb's would be the bridge and the 2 x 1000uF caps. There would only be one bridge on the PSU pcb.

Are you suggesting using 2200uF caps in place of the 1000uF's?

Thanks in advance.

Steve