All things G1176 - the new "repost" thread.

[kenrinc]

Looks like you pointed me in the right direction: I didn't finish the ratio switch! I cut that bugger out and lo and behold I put on all the lugs accept the two middle ones as well as not soldering one of the outside ones. Checked with a meter and sure enough no connection.

Of course when it rains it pours; my soldering iron just crapped out. For some reason I have to replace the tip every week or so because it oxides and no longer wants to melt solder. Anyway, I'll let you know as soon as I get this fixed.

Ken

 

[Dave-B-Brown]

I don't have a scope, found this , is this o.k to use?[/url]http://www.mitedu.freeserve.co.uk/Prac/winscope.htm

 

[MartyMart]

[quote author="kenrinc"]

Of course when it rains it pours; my soldering iron just crapped out. For some reason I have to replace the tip every week or so because it oxides and no longer wants to melt solder. Anyway, I'll let you know as soon as I get this fixed.

Ken[/quote]

Hi, sounds like a "cheap" iron , I've been using them for 4 years ( on my second one )
and on my fourth "tip" so I get a year out of them !
The tips I use on it are about 5 bucks each, so are decent quality, trick is to keep them
"tinned" with a little solder, clean 'em regularly and don't leave them "hot" when not in
use - so turn if off if you have a 30 minute break.
Plain cheap metal tips will die very quickly if abused, mine have a special coated tip that
seems to last quite well, it's pencil shaped and goes down to about 2mm at the very end.
MM.

 

[gswan]

[quote author="Dave-B-Brown"]I don't have a scope, found this , is this o.k to use?[/url]http://www.mitedu.freeserve.co.uk/Prac/winscope.htm[/quote]

I guess you could use something like that. If you are serious about doing some DIY it's worthwhile investing in a scope.

Tricky Dicky often has a neat little one, suitable for audio work, on sale for under $100. Hard to beat if you really want to do some measurements. I just checked their site. The Q1803 scope is currently only $88 and is a 10MHz single trace unit.

http://www.dse.com.au/cgi-bin/dse.storefront/4847acc40b25027c2741c0a87f9c06e8/Product/View/Q1803

 

[Dave-B-Brown]

$88,Thats awesome!! Thanks for checking that for me, Im close to giving up, your the only thing that's keeping me going.

 

[Dr nEon]

Hi !

I am building a g1176 into a 1u case , and am trying to use a very small 'el cheapo' type dc meter with an (alledgedly!) VU scale, via a germanium bridge which I have added.

If I feed .775mV ac test tone thru a 3k6 resistor , it meters around -8dB.

This is 4dB less than the required spec as stated by Jakob , and others.

What I'd like to know is : Can I simply substitute the 3k6 resistors (r51 and r59) with another value which will compensate , and put the meter at -4dB?

I've searched but couldn't find any reference to this. .If I lowered the value of the 3k6's , could this have any negative impact on the audio,seeing that the meter feed (in vu mode) is taken directly from across the audio output.

cheers

nEon.

 

[gswan]

What do you know about the meter?
What's the movement's FSD current and its impedance?
You can adjust the series resistance to compensate for the meter's different characteristics.

Any direct-connect VU meter straight across the audio will introduce distortion, since the current waveform through the diodes will be non-linear.

Use the meter in signal mode to check the signal level during mix setup, and then leave it in GR metering mode when you use the unit to avoid adding unnecessary distortion.

 

[kenrinc]

Thanks MM. It is a "cheaper" iron, lower cost Weller but it's actually pretty nice considering what I had before. My tips also are expensive ($5 or more) so my guess is I'm not treating properly :grin: I do leave it on for long periods of time even when I'm not working (cause ya never know ...) so that coupled with the fact that I do clean the tip but I do not retin it may be what it's down fall is..

Ken-

 

[kenrinc]

It Works !!!! :thumb: :green: Thanks Geoff !! You pointed me in the right direction and hung out helping me. Was quite frustrating for awhile but hey, I even learned to use an Oscope at the same time !! Problem turned out to be the ratio switch. The photos at Mnats site were a bit confusing. Not really his fault it's just difficult to tell exactly how it's wired and there is only one photo that shows the two pins I forgot to add (the two center pins). The switches aren't marked in any standard fashion so you have to go based on where the tab is on the side. Anyway, these weren't hooked up and one of the outside pins wasn't even soldered or making contact. Fixed the problem and I had it calibrated within 5 min and was tracking with it !!

Sounds absolutely f**kin wonderful. I actually wish you could raise the threshold a bit above what's shown on the chart though it's hard not to get GR at at even the lowest input setting. But that's not such a bad thing. So far I hear only one small problem, I can hear what sounds like "motor boating" and a small hum, very, very low level (input all the way down). I haven't done any internal wire routing or anything like that so that may help. Can't hear it at all when using it.

Thanks again for your help Geoff (and everyone else who's helped). Your site was very helpful! Many :guinness: :guinness: for you! I owe you one.

ken-

 

[gswan]

Good to hear it's working for you Ken.
The hum may be induced, so route the audio signal wiring as far away from the mains and transformer wiring as you can.

 

[MartyMart]

Is This Normal operation ??

Have gone back to the 1176 for proper calibration and setup, though it has
appeared to be working pretty much fine so far.
I found that when I DI a bass into it ( passive P-Bass ) that if I run the input
vol much above 12 o'clock, I get some "farty" distortion on the low E & A
notes.
The amount of comp seems about right, but fast attack release makes the
"fartyness" worse.
Having said that, at 12 o'clock input there's plenty of volume available and
it's clean way above unity - compared to bypass/GR
Comp at this setting on all ratios is between -3 and -6 dB and noticeable !

So slamming it quite hard is going to produce some distortion right ??
( could be useful and not totally unpleasant IMO )

Marty.

 

[lofi]

i would have thought so, but whats your input output xformers? i noticed a similar but i was also pushing it :grin: so not too bothered .... and it will def have a use in my line of music :green:

Iain

 

[kenrinc]

Yeah mine works similar to that. Not used to the threshold being so low but again it's useful to me. I was thinking if the threshold could be moved up just a bit further I could get a bit more transparency but I'm cool with it. I don't notice the distortion but I've not tried bass yet just vocals and acoustic guitar. Bass can be a notorious test of a compressor. Remember the old alesis 3630?

When doing FET matching which two FETs need to be matched? Was it Q1 and the 245? I know one is for the GR meter the other problably the GR amp.

Ken-

 

[lofi]

i've not got a clue where my threashold is, and to be honest, i couldnt give a shitsu!! :grin: i just listen to the sound and its sweet ...

mine was built to be used with a daw, but its also going on pre daw bass ... even thinking about making a peddle to use live

 

[MartyMart]

Input is the recommended Lundahl and output is an OEP.
I guess Di'd bass chucks out a hefty signal, a volt or so, perhaps I'm being
over cautious !
It sounds great though and is totally noise and hum free

MM.

 

[gswan]

[quote author="kenrinc"]When doing FET matching which two FETs need to be matched? Was it Q1 and the 245? I know one is for the GR meter the other problably the GR amp.
Ken-[/quote]

There are only two FETs in the circuit.
One is the compression FET (Q1) and the other is the GR FET (Q10). Their gates are both driven from the same voltage, so if they're matched then it makes calibrating the GR tracking much easier.

 

[lofi]

mines oep both ends, cant see a bass throwing it that heavey a load, but if you can get the 'distortion' nice it works soo well :grin: :grin:

 

[gswan]

Maybe not at the input side, but with 36dB of gain through the unit you may see some low frequency effects through the output transformer.

 

[kenrinc]

MM,

Are you actually DI'ing directly into the input of your 1176? No pre beforehand?

Ken

 

[lofi]

Off Topic question from me, how would i go about measuring the draw on these? i want to know the minimum amp fuse i need for the plug. but as i will need this info in the future for other projects so wondering how to go about it.

Iain