All things G1176 - the new "repost" thread.

[radiance]

OK, for the relay's it worked, but the LED's are not working this way.
They are 2,1 V and 20 mA LED's (well it sais If nom.=20mA, I don't know what that means)

They don't even light up with no resistor in series. Are they drawing to much currend?

Also, they DO light up when connected to a wall wart power supply set to 9V. This is a regulated power supply and it is rated 1000 mA (12 VA) max.

What is it with the 1176 lamp out power that it will not light my LED's?

 

[radiance]

OK, I found it. I'm working on a stereo version of the 1176 and I have two toroit power trannies. I also have a relay bypass and to power the relay's I use both lamp out's from the two boards to even the load. To power the LED's I took power from one off the lamp outs, well, thats what I thought I did (it's a birds nest in there). What I actually did was take the ground from one lamp out and the +V from the other one. Since I had not properly grounded the unit yet I had two separate grounds and that was the reason the LED's where not lighting up.
It was really confusing to get 37 V on the multimeter and no response from the LED's..

 

[dukasound]

Hi
Too I have two question:
What transformer (wattage) to use for Dual?
I have Sifam 19WF with his festoon 12V lamp.
How to got voltage for this lamp. I mean best way.
Thanks Duka

 

[gyraf]

Duka,

Read the thread. Do some calculations. All the needed info is already there.

Jakob E.

 

[dukasound]

[quote author="gyraf"]Duka,

Read the thread. Do some calculations. All the needed info is already there.

Jakob E.[/quote]
Hi
I read the thread!!!!
Yes, I read the thread :grin:

We teach from clever and from expert.
I make some math. If I wrong tell me.
My lamps are 12V - 0,1A. E.g. if I want to wire lamps in series I need to drop from 37 to 24V. Current stay same 0,1A. 37V-24=13V. Than 13V/0,1A=130ohm (next 150ohm). And on the end 13Vx0,1A=1,3W (2W).

If I want to use two lamps in parallel. I must drop to 12V.
Does current is 0,2A ?first dillema :?
If is it 0,2A I find 125ohm - 5W.

Also about transformer, I find a different value. I know I cant make mistake to use bigger. I find for single 2x25V 500mA. Is it 25VA or 12,5VA. In fact I must use doubled current for dual.
Thanks
Duka

 

[gyraf]

:thumb: Well done..!

 

[dukasound]

[quote author="gyraf"]:thumb: Well done..![/quote]
What about transformer :sad:

 

[gyraf]

2x25V 500mA is - straight forward - (2x) 25V/500mA, that is 2x25x0.5 =25VA

 

[dukasound]

[quote author="gyraf"]2x25V 500mA is - straight forward - (2x) 25V/500mA, that is 2x25x0.5 =25VA[/quote]
Thanks :thumb:
Is it enought 50VA for Dual?
Duka

 

[keninverse]

Hi guys,
first time poster...I'm in process of building a 2 x 1176 and I have all the parts amassed with the exception of the AL29 VU. I have several AL39s that I pulled some time ago but I was wondering can you use these larger meters without modifying the meter driver? Will I just see a slightly slower response on the meter if i leave the circuit stock?


ken

 

[kdawg]

I have a Sifam w/24V Festoon Lamp @ .125 A... now I see what's going on above tapping the Lamp Power w/resistor, but can I just tap after the 24V Regulator or is that a bad idea? Thanks

-kdawg

 

[gyraf]

Ken,

If your AL39 are true VU-meters, they should work fine as-is. Look at and compare the data sheets for these.

Kdaw,

It's NOT a 24V regulator, it's a 30V regulator. Yes, it uses a 7824, but it is offset to +30.

Don't load the +30V line more than it already is - better use the unstabilized DC (or the AC) with suitable dropping resistors.. See previous pages for the calculation.

Jakob E.

 

[keninverse]

Thanks Jakob,
Looking at the datasheet, the only difference I see b/w the AL29 and AL39 is rise time (~0.01s).


ken

 

[radiance]

In my 1176 I have used polyester caps for C1, C10, C17, C5 and C27.
Will I hear any difference when I change these for say Wima polypropylene cap's ? I mean is it worth it?

 

[gyraf]

no

 

[kdawg]

I decided to build an MNAT version of the 1176 and it went together smoothly. I ducked, then flipped the power switch. No flames or flying capacitors. I even have all the voltages OK off of Gyraf's schematic. The meter even zeros on GR. BUT - R87 (the 1 Watt 1K1 resistor in the power supply) gets VERY warm, like I can't leave my finger on it for more than a second.

I thought it was my meter lamp drawing, but its disconnected and I still have the problem.

Where should I start? Too much current draw from something... no obvious shorts. 30 volt rail is solid. 7824 doesn't get too hot. Thanks

-kdawg

 

[gyraf]

the 1W resistor will get hot. That's why it's 1W after all :grin:

If you're unsure about the dissipated power over the resistor, simply measure voltage across it and calculate...

Jakob E.

 

[lumpylipton]

Hi Jakob and gang,

I've nearly got my first 1176 working, but I need some help. All my transistor voltages look good, it works great at a line amp (signal passes through and input and output pots increase/decrease gain), but it seems it's not compressing, and I can't get the VU in GR mode to go near 0, it's way short of that regardless of where the trims are set (it moves, just not nearly far enough). I have replaced the FETS and the TL071 with no change at all, and I know my meter is a real VU (it works as expected in displaying output and is a NOS Dyson).

In previous posts in this thread, Jakob made mention of points 21 and 19 and DC voltages. My DC voltages at those points are different as expected(the diodes are conducting) and they do change with Q-bias changing. However, the DC voltages do not change at all when changing the input level. As I understood the thread, they should right?

More info: I have signal traced through, and I see signal at the gate of Q1, but not at the gate of Q10.

Any clues would be be much appreciated. Thanks.

Warren

 

[gyraf]

More info: I have signal traced through, and I see signal at the gate of Q1, but not at the gate of Q10.

Q1 has a bit of audio on it's gate to compensate for distortion. Q10 isn't in audio, so here we don't care.

What is interesting is if what kind of DC you have on the gates.

Try tracing ac signal through the sidechain amplifiers and diodes, and check that DC alters with signal level.

And as usually, check for right components, shorts, and such..

Jakob E.

 

[Hulk]

I'm going to build a G1176

Can I use this PSU for the G1176???? :guinness: :guinness: