All things G1176 - the new "repost" thread.

[Mr. Dave]

Too much heat from the xformer itself? What if I used higher voltage caps in the power supply section and had a larger ventilated case?
Dave.

 

[gyraf]

Too much heat from the xformer itself?

No, dissipated heat from the zener and the regulator. Better to stay at 30V max.

Jakob E.

 

[gevermil]

So after my recovery from the explosion and fire I am getting good input and output gain yet no compression . After page searching in this thread I read this -
" I had a similar problem of no compression in my 1176. I used sockets for the bf245a's and i found that the connection was intermittent. When i soldered these parts in it works fine. "
Is this a step I should take ?
Sorry for the lame questions
gary

 

[rbaker]

of course it's possible----but you shouldn't have a problem using sockets, just make sure they are in securely.

 

[API]

HI Jakob.

Thanks for the help above!
I was trying to do my homework, but could not find the answers i was looking for.
But now i know!

Regards,
Dennis

 

[gyraf]

:thumb:

 

[Magnus Lindberg]

[quote author="gyraf"]Brad,

Yes, I see that now.

Unfortunately I do not have a G1176 around to experiment on.

A better approach will probably be to install a 100K trimmer pot at the input to the sidechain, as a simple attenuator/voltage-divider (from the top of the output level pot at the ratio subboard) and keep the 56k as-is.

If you try this, please let us know how it turns out!

Jakob E.[/quote]

Hi

My two G1176's are in the testing stage now before going into rock action. Works great.
BUT
I also think the threshold levels are way too low...not optimal gainstructure at all. The 100k pot sounds like a brilliant idea. I looked at it, and i must say I am not completely sure of where exactly this should be installed despite Jakob's instruction.

Can anyone help?

/M

 

[gyraf]

Magnus,

Look at the schematic - find the place where signal is tapped off for use in the sidechain (around the top of the output level pot). At that spot, simply install the 100K trimmer as a voltage divider to ground, taking sidechain signal off the trimmer's wiper.

Jakob E.

 

[imo]

Yes, if looking at the schematic, you take the high side of the 100k output pot to the high side of your new trimpot, the lowside goes to ground, and the wiper(of new trimpot) goes to the sidechain, which would be into R26, the 56k. It is a really helpful modification. Also, using the 5457 fet gives you a bit more headroom
Best
Ian

 

[Magnus Lindberg]

Yeeah, it works!

Totally brilliant fix, I raised the threshold by exactly 10dB, much better.Will post pictures soon.

/m

 

[rbaker]

[quote author="Magnus Lindberg"]Yeeah, it works!

Totally brilliant fix, I raised the threshold by exactly 10dB, much better.Will post pictures soon.

/m[/quote]

That would be awesome if you could post pictures. I think I understand but my trimpot has really flimsy legs and I'm wondering how you implemented it without worrying that it would fall apart.

 

[Magnus Lindberg]

I actually used a ordinary pot and soldered cables from the ratio board to it. I just gotta find a neat way of attaching it to the bottom plate. Will post pictures tonight maybe.

 

[imo]

I wanted to expound on this, as the way i implemented it may be a bit different than others. I mounted the trimmer between the high of the 100k output pot and ground, with the wiper going to the 56k. I cut the trace between 100k out high the 56k, as well as from the 56k to the #15 input (and then rebridged the 100k output pot high to #15) This way the only input to the 56k would come from the wiper of the new trimpot and allow for control of the input signal to the sidechain. I am assuming this is the only way to do it, as wouldn't the signal simply bypass the trimmer without these changes?
Ian

 

[EEMO1]

i got a unit ready. just some finishing touches: lights.

i got a 12v light for power indication and the meter has got some bulbs (?) in it too. don't know nothing about the lights inside the meter... i can change them to leds if needed.

where would be the best place to implement these? the vu lamp on the pcb? i can manage the calculations for resistors to make it work, i just need a place to connect them with minimal interference to the circuit.

any help?

 

[rbaker]

Did you buy a sifam meter or something else? My sifam meter had 3 choices for lamps. I got a 12v. Anyway I think I remember there being 36v from the vu lamp connection, so there's enough for both. Just calculate the resitance from there, but you need to figure out the specs of the lamp in your meter.

 

[Magnus Lindberg]

[quote author="imo"]I wanted to expound on this, as the way i implemented it may be a bit different than others. I mounted the trimmer between the high of the 100k output pot and ground, with the wiper going to the 56k. I cut the trace between 100k out high the 56k, as well as from the 56k to the #15 input (and then rebridged the 100k output pot high to #15) This way the only input to the 56k would come from the wiper of the new trimpot and allow for control of the input signal to the sidechain. I am assuming this is the only way to do it, as wouldn't the signal simply bypass the trimmer without these changes?
Ian[/quote]

I just unsoldered the 56k on the out-pot side, attached the wiper to that and the top to where the 56k was...works fine for me. this way the trim is in series with the 56k.

We might be talking about the same thing but with different words, not sure.

/m

 

[imo]

Magnus,
Yes, this is how i did it as well. Makes things more usable!
Ian

 

[EEMO1]

[quote author="rbaker"]Did you buy a sifam meter or something else? My sifam meter had 3 choices for lamps. I got a 12v. Anyway I think I remember there being 36v from the vu lamp connection, so there's enough for both. Just calculate the resitance from there, but you need to figure out the specs of the lamp in your meter.[/quote]

hey thanks! i figured something like that myself, but wasn't sure about the location. the meter is not a sifam. there were 2 small bulbs in the meter, so i guess it's 3 12v lamps. should i do it in series or parallel?

 

[rbaker]

don't assume it's 12v just because mine is. Sifam sells 3 kinds, one is 24 one is 12 and one is 6?

 

[EEMO1]

no, i planned to buy new bulbs. there's 2 bulbs in series inside the meter...