All things G1176 - the new "repost" thread.

[mrcase]

Yes, right! I´ve labeled them now.
And the units were in bypass when I measured. Could it be that I´m driving a too hot signal into the IC?
regarding the frequency response problem with the OEP in I´m absolutely lost....

 

[gswan]

Yes, right! I´ve labeled them now.
And the units were in bypass when I measured. Could it be that I´m driving a too hot signal into the IC?

That depends on how you have the gain structure set up.
With the output turned all the way up, you need to turn up the input control so that 0dBu in gives you 0dBu out. Now you can measure the response and distortion.

 

[mrcase]

alright! I didn´t do that.  I had it setup like I would use it in a session, just bypassed.... Gonna try as soon as I´m in the studio.
One thing though, wouldn`t I be driving the output too hard then? I have massive gain on this thing!!!  ;D
thanks so much for helping!

 

[gswan]

The gain is fixed in each stage, from memory about 26dB in the first stage and about 10dB in the second stage. The inputs to each of these stages is fed from a pot, which controls the amount of signal running into each stage.
So with the output level turned up fully, you will have about 36dB of gain through the two stages. With a 0dBu signal at the input, your input control will be attenuating the input signal by 36dB to get a 0dBu signal at the output.

 

[sedit1]

Please help me  I'm still having littlebit hum in my g1176 rev#7. All the voltages are correct and the grounding is ok and the compressor is working out great. Earlier I had a nasty -35db hum but when I ordered some 1176 boards from mnats I got a separate Psu board and when I built up one and started to use it in my g1176 the hum almost disappeard.

Yesterday I tested the compressor and for my suprise the hum was totally gone just some hiss and the compressor seemd like working great but when I measured the voltages from psu they were -10v/+27v, somehow the trimmer had moved or something, but when I raised the voltages back to +30v the small hum appeard again.

Do you have any clue what might be wrong? Or should I just use the compressor with -10/+27v voltages? 

Thanks!

 

[sedit1]

Please help me  I'm still having littlebit hum in my g1176 rev#7. All the voltages are correct and the grounding is ok and the compressor is working out great. Earlier I had a nasty -35db hum but when I ordered some 1176 boards from mnats I got a separate Psu board and when I built up one and started to use it in my g1176 the hum almost disappeard.

Yesterday I tested the compressor and for my suprise the hum was totally gone just some hiss and the compressor seemd like working great but when I measured the voltages from psu they were -10v/+27v, somehow the trimmer had moved or something, but when I raised the voltages back to +30v the small hum appeard again.

Do you have any clue what might be wrong? Or should I just use the compressor with -10/+27v voltages? 

Thanks!

Ah found the problem! Two very badly soldered resistors nearby ne5532..Hum is totally gone and I'm not getting any distortion with high input material witch I had earlier..

 

[dgoszillai]

hi all ,

after long time not able to work on it i'm back to my 1176 revJ dual. i use external PSU and OEP.
as it is coming "to the end" i will have a silly question (because noob i am)  thx for help or i'll never finish this

what the hell is C*4 BOM says i have to put 0,1uF but i can't find it anywhere :S

---
edit ah ok i red on the original BOM  (C*4 on some boards)
so if i don't see any C*4 i don't have to put this anywhere
right ?
---
other question is
what switch should i by for bypass / dual and power ?
i mean (i'm super noob ok) it's 2 positon rotary switch and 2 position switch.
but i see several caracteristics SPD DPDT ... 3PDT
http://www.banzaimusic.com/Toggle-Switches/

if you can help

 

[JW]

I ordered a couple Mnats power supply boards to use in a solid state pultec w/ 2520 DOA makeup gain amp.
So, I'm looking for around +/-16 volts.

Couple questions. Does anybody have a power transformer recommendation for this application?
Is there anything else I need to change to get this p.s. to adjust down to +/-16V? (Besides adjusting the VR1 and VR2 trim resistors?)

Here's a quick link to the p.s. page: http://mnats.net/psu.html

 

[gswan]

If you are looking at +/-16V output try using any transformer with an output of 15-0-15 VAC. This should give you a variable output up to about +/-20V.

 

[dgoszillai]

guys .. could someone help at least tell me if my qestions are so noob i should quit DIY.
i 've been askin these questions a year ago and had no answers. i'll never finish that 1176

 

[sr1200]

dgoszillai,

I got really frustrated with the G1176, shelved it.  I picked up a 1176 rev D, was done in no time, the D is WAY easier to follow.

 

[dgoszillai]

ok but i'm almost done . i have the boards populated (miss 5 or 6 resistors) i have the rack and all ..
besides i'm such a noob i don't know what is G1176 i have the M.NATS 1176 RevJ (03.11.06)
do you mean everybody here is doing the revD that's why i don't get answers ?
what do you mean fustrated ? the sound or the building ?

 

[sr1200]

The G1176 (mnats rev J) and the Rev D are 2 separate things.  (same compressor, different circuitry, transformers etc)

The information about the G1176 (to me, and I'm pretty much a n00b too) was just so convoluted and rifled with contradictions from one source to another, i just gave up on it.  One source would say to put resistor value X another would say the same resistor was Y, things like, if you put the input transformer here, do this, but only if 16 other conditions are met etc. 

Was just way too over my head at the time. 

I got the Rev D board from Mnats, and was done, built, calibrated and in the studio in under a week.  (same case, and a lot of the other parts are the same as well)  different transformers.  It's just WAY more straightforward, and the actual PCBoard is really clean and easy to read/understand. There were no "optional" build designs or schematics, what you see is what you get.  The UA resissues of the 1176 are reissues of a revD (kind of.. theres a few little tweaks here and there).  But the unit is clean and works and sounds great. 

 

[bpucekov]

just follow instructions on mnat's site and everything be ok

 

[dgoszillai]

ok sr1200 ... anyway i'm not going to trash everything now .. it's almost done

thx bpucekov you'r great usless help.

 

[kepeb]

other question is
what switch should i by for bypass / dual and power ?
i mean (i'm super noob ok) it's 2 positon rotary switch and 2 position switch.
but i see several caracteristics SPD DPDT ... 3PDT
http://www.banzaimusic.com/Toggle-Switches/

if you can help

You really can get all the info from mnats site.
all the questions have pretty much already been asked and answered before more concisely in this thread. it takes time to go through but its all there.

I'm not really sure what switch you are asking about... the power switch or the bypass?
there are many options for both the power and the bypass switch, unless you explain clearly what you are trying to achieve its difficult to help.

using the standard rotary as set out on the pcb, it is just a lorlin switch for the meter/bypass select.
There are many, many options for power switches

EDIT: the ones you have linked to are probably unsuitable for either.

 

[Gege]

Hi buddys Diyers  ;D

As you can see, i have trouble with my new "monster"  :'(

I build a mako REV J with hairball enclosure and pushbuttons.
I follow the mako's  wiring guide but i have a problem.

Terrible HUM !

So start to calibrate !
Step one qbias, OdBu, sine 1k, settings ok, drop 1dB ... fine !

Step two GR Meter Tracking, -10dBu, sine 1k, setting ok ... but when i switch the attack pot to OFF i don't see any reduction in +4 VU Mode  :'(
But in GR mode when i have a reduction, if i drop attack to off the meter go back to 0dB (i miss something !)
All the buttons are ok, in the VU they work fine.

So ... not big deal go back to smaart.
Check the audio unit

coherence OK, magnitude OK ... unit is in good health


Now check the monster

WTF !

If you have some informations ....

Signed : A desperate french diy !

 

[JW]

Hey guys,
This is concerning using Mnats' power supply for +/-16V (for a solid state pultec) again. I hope it's okay if I ask  here, as it seems the most relevant place right now.

Do you guys know what I need to do to get the two rails to not interact with each other? When I adjust one to 16.0V with the trimmer, the negative rail drops to around -9.5V. When I adjust that to -16.0, then the positive rail drops down to around 9.5V.

I bypassed 1 diode on each rail beside the voltage regulators to get into the trimmers' range for this application.

Here's a quick link to the p.s. I'm using again: http://mnats.net/psu.html

 

[gswan]

They should not interact if you do it properly and not just guess at how to extend the range. Don't bypass diodes in this circuit.
Either increase the pot resistance accordingly or use the following formulae to calculate the required resistance for your voltage range.

+Vout = 1.25(1 + R3/120) + R3*100E-6
-Vout = -1.25(1 + R5/120) - R5*100E-6

 

[JW]

Thanks gswan,

What is the "E" in the equation?