All things G1176 - the new "repost" thread.

[Harpo]

In my place it's hard to find 1K1 1W resistor, can I use 1K2 or 1K instead, is it gonna be tragic?

With R89 220R, R87 1K2 instead of 1K1 will drop supply voltage by 0.4V, 1K0 will rise supply voltage by 0.4V. You could use a 1K in series with 100R instead for a closer to 30VDC supply rail.

c23 what value? on layout it 10uf on schetmics it's 6.8uf 35V? what should i use?

With supply rail +/-about 30VDC, I'd up this caps voltage rating and use a 10uF/50V or 10uF/63V.

c30 c31 c33 are 6.8uf 35v (near NE5532), are those tantalum or electrolitycs?

6u8/35V or 10u/35V electrolytics.

 

[Olegarich]

HArpo thank a lot!

 

[Greg S.]

Does someone have HighRes Pics of the MNATS rev F/J 1176 PCB or the layout?

Want to change my LL 5402 at the out for an OEP a262a2e.
Same for the In.

I got the 1176 V/K Boards from Gustav

THX

 

[JW]

Hey folks,
I've had my G1176 for a long time, and have been using it a lot. Sounds great, but I don't think it's as fast as it should be (attack), or as fast as I remember 1176's.

It can't catch the transient on snare for example, even when at the fastest attack setting.

Where should I look to increase the speed?

 

[gswan]

Maybe you should measure the attack time first, so you know what it really is and confirm that there aren't any problems with your unit before attempting modifications.

 

[JW]

thanks,

I did a search of this thread, but I can't find the info. How exactly would I measure the attack?

 

[gswan]

Simple. Just use a periodic tone burst of a 1kHz sine wave at a known input level and then switch on the GR and observe the output waveform (the burst envelope) wrt the input waveform. The amount of time between the start of the burst and the start of GR is the attack time. You need to do this with release set to minimum and allow enough time between bursts to allow the gain to restore between bursts.

 

[Olegarich]

Hey Folks!

I've finished assembling G1176 on Mnats Board. Couple questions:
My power transformer gives 22.8 V not 24 is it ok? I noticed that all the transistor voltages drop a bit from specs on gyraf schematics, is it ok?

I have problem with Vu meter, it just doesn't correspond. Can you please explain a bit how meter circuit works, where should i fing volts and where it's about current. Thanks a lot.

 

[Olegarich]

Does anybody had problems with unit when after voltage regulator it gives 28 volts?

 

[Olegarich]

I hope somebody gonna still check this thread( I have compression, input output atack and realease everything seems to be working well expert meter. it's doesnt give anything, just like if it turned off. No moves. checked with other meter, same stuff. If compression is working then it's something in the meter circuit? If Gr control section gives  signal for the q1 and same for the q10, and compression is working then it's something with tlo71 area am I correct at this?

 

[Greg S.]

First, check the meter with a 0dB Signal alone!
second
there is a 3k6 R at the GR Board for getting +4dB "normalisation",
you might bridge for 0dB, but depends at your meter data!

good luck

 

[Olegarich]

To check meter for 0 db is just taking directly from input with 0.775volt? I did that and it reads. Is it might be problem with tl071?

 

[gswan]

Does your meter have an internal bridge?
If not then it won't show anything, even measuring the output level. You'll have to construct a bridge using some schottky diodes.

 

[Olegarich]

gswan could you please tell me how to find out if meter has it. I ccant find any data sheet of it.  What do i have to get from tlo71? Do i have to see voltages on scope after q10? after all thank you a lot for help!!!

 

[gswan]

gswan could you please tell me how to find out if meter has it. I ccant find any data sheet of it.  What do i have to get from tlo71? Do i have to see voltages on scope after q10? after all thank you a lot for help!!!

Firstly have a look at the meter face. Usually, in very fine print, at the bottom left or right there will be an indication of the meter 'class' (ie FS accuracy) and a diode symbol if the meter has an internal bridge.

Alternatively try driving the meter directly with a 775mV 1kHz sine wave. If it shows deflection to 0VU then it has an internal bridge. If not, then it is a DC meter and needs an external bridge to show AC.

 

[Olegarich]

i tried to drive it with 1 khz wave with 775 mvolt and yeah was corresponding. im not sure if it showed me 0 il check tomorow but defenitely it correspondents. any others ideas what to check?
thanks

 

[gswan]

If the meter responds OK with an AC input then it does not need an external rectifier.
It should be working in your unit when the metering is switched to +4 or +8 positions.
If so, then it is only the GR metering section that needs checking.

 

[Olegarich]

gswan meter coresponds now in 4db mode. but when i turn to gr its not even at zero. i found that if i crank in and out fully there is a little movement. do i have to see ac volt near tlm071? and there resistance beetweb q1 D and S but not same in q10 is there might be bad transistor? im still not sure if gr is ok. i have everything siting well before fdh333 but dont know how to check next. any thoughts?

 

[gswan]

I'm assuming you have calibrated the GR fet bias. If not then you should do this before anything else.
If your GR metering calibration is failing then start at the beginning of the GR metering circuit. Is the GR metering FET inserted correctly? Check components around this section, there aren't many.

 

[Olegarich]

No i haven't calibrated but i did that now. I changed q10 and TL071 and i've  got Gr on metering. Not sure what caused problem, but defenitely one of this parts was out of work. Now it's left calibration with atack pot. Thank a lot man!