All things G1176 - the new "repost" thread.

[Kingston]

I have lundahl transformers, should i go for the 2:1?

How much gain do you need? 1:2 "upside down" will give you more gain, 2:1 less (too lazy to calculate exactly how much). With Lundahl quality, there's not going to be any difference in sound or frequency response. No impedance concerns here, the 1176 class A/B version at least will drive anything.

I would say, test it 2:1 first in your studio/patchbay/DAW configuration, and see if you need more. 1176 has a lot of gain, way too much for plain line amp usage.

Or, maybe you really like the way this amp sounds like. maybe you'd like to use it as a preamp of sorts? Then 1:2 output will suit you better.

choices, choices.

 

[alexc]

For the output, I like the 1:2.

I find that the output knob is at about 1 o'clock most of the time when I have around 15dB GR,
going to my converters.

What a box! Just tonight I had my session bass player mate going thru it from the modded
Chineve 1081. I thought it might not work so well with bass, but I was *wrong*.

Awesome stuff. And on the clean-ish guitar,  just amazing. And acoustic guitar.
So glassy and spongy with incredible feather touch.

Makes me sound a lot better than I thought I was.

Now for a few revD boxes!



Thanks Jakob, MNats!

 

[mokkinger]

hmm, ok.

i will try the input 1:2 and 2:1 as well, and decide. the output i will put in 1:2, and see if thats fine, if its too much i can easily switch it.

has anybody built a unit with a switch on the backside from transformer-input to "normal" balanced input - can i just put a DPDT-switch on the + pole? would love to use both versions, without having to switch cables, just switch a knob...

thank you all for helping!
mark

 

[Biasrocks]

My recently completed version includes a Neve/Marinar 31267 configured 10k:2k5, which is a 4:1 ratio.

On inital testing with pre-recorded tracks, I have found it to work satisfactorily,  but I will need to test it in a session situation to be sure.

Curious, if anyone else has tried a 31267 front end.

Mark

 

[mokkinger]

Hi Guys,

I´ve got one more question regarding the Slam/Nuke mode:
Do i understand it right on jacobs page that I can´t do the Muke/slam mode with the 6-pole 2 way lorlin switch? Or is there any trick how to modify the lorlin switch to work in Nuke/slam-mode?

I don´t want to change the lorlin switch to an open alpha if i don´t really have to, but i did not find any hint on how to modify the lorlin... right now i have the lorlin set to 5 positions, but the all-position just puts the comp in bypass mode...

 

[crisotop]

http://www.geocities.com/m_natsume/1176_slam_mode_rotary.html

hth, christoph

 

[mokkinger]

Thanks, but I knew this one already. thats why I asked if this Mod is also possible with a Lorlin Switch...
like the one listed in the BOM, which I already soldered in the Ratio PCB...   ??? ???

could I maybe use a relay to switch to the Slam Mode? so i dont have to drill another hole in the front for a switch...

 

[Biasrocks]

Thanks, but I knew this one already. thats why I asked if this Mod is also possible with a Lorlin Switch...
like the one listed in the BOM, which I already soldered in the Ratio PCB...   ??? ???

could I maybe use a relay to switch to the Slam Mode? so i dont have to drill another hole in the front for a switch...

You need a double pole / double throw switch for Nuke mode, so you can't do it with the single deck Lorlin without adding a relay as suggested or DPDT toggle switch in the front panel.

Mark

 

[crisotop]

Get the suggested ~4$ Alpha, desolder your Lorlin and you're good to go. Mako wouldn't post the Alpha slam-mod if it could easily be done with a Lorlin. Adding a relay is at least as much effort as just swapping the switches.

cheers
cri

 

[JoleFIN]

Also, if I've got the correct voltage readings on the BD139 and BD140 could they still possibly be inserted in correctly?

Did you check the layout of these transistors? They may be just the other way around, which causes the R36 to get smoked (that's what I did 2 days ago, I had BD135+136 just the wrong way around in their own insert holes.. don't ask me why I didn't trust the layout graphic on the PCB, I was measuring the transistors with a meter first and understood the meter wrong (don't ask about this either )).


It seems that my transistors are still OK, this time I measured them with the "diode measurement" part of my cheap multimeter. Could it still be possible that ie. Q6 is fried although it's working just as it should be, according to the meter? I had it soldered off and tested.

My problem(?) is that I get 37VDC / 80VAC on the VU-lamp pins, and this doesn't sound correct for a 12V lamp. Another thing that concerns me is that one of the pins on TL071 (not inserted to it's socket yet) is getting 24VDC / 51.6VAC. Can anyone sort something out of this?

 

[gswan]

My problem(?) is that I get 37VDC / 80VAC on the VU-lamp pins, and this doesn't sound correct for a 12V lamp. Another thing that concerns me is that one of the pins on TL071 (not inserted to it's socket yet) is getting 24VDC / 51.6VAC. Can anyone sort something out of this?

Are you really saying you have both AC and DC on these pins? Do you really have 80VAC + 37VDC on your lamps?
I'd suggest that you aren't taking your measurements correctly.

 

[JoleFIN]

I had - cable attached to the ground pin under the out trafo, and + cable on the VU-lamp pin. For some reason I get a scary 80.6VAC and 37.3VDC.

Is the voltage at TL071 socket OK? 24DC sounds good but rough 52vac sounds crazy.

Concerning the measuring points (-10.2V and +29.2V) at Mnat's page it seems the PSU side is OK.

 

[gswan]

Try hooking the -ve cable of your DVM to the PSU GND. Your measurments are all wrong. There would be much smoke if what you measured actually existed there.

 

[guitarguy12387]

Alright guys... i need some troubleshooting help. I built two G1176's a few months ago. They were working great! But i turned on one today (i hadn't used it in probably two months) and i had no low frequency response. It sounded like a high pass filter at about 2khz or so. I just pulled the top off and all looks ok. That is, all the connections look good, no shorts or disconnections that i can see. Nothing looks burned out or anything like that. Anybody have any ideas where i should look to find the issues?

Thanks in advance.

FYI, these are MNats Rev. J boards with lundahls.

 

[mokkinger]

do you have sidechain boards in your SSL? or the turbo board?
if yes you could take these out and check if it sounds right, so you can maybe isolate the problem...

just a quick thought..

hth,
mark

and, by the way, this should be in the GSSL thread, right?

 

[guitarguy12387]

Oops! That was supposed to read 'G1176' not GSSL haha. I'll fix it.

 

[mokkinger]

ok, then forget what i said about sidechain and turbo board

cheers,
mark

 

[JoleFIN]

Try hooking the -ve cable of your DVM to the PSU GND. Your measurments are all wrong. There would be much smoke if what you measured actually existed there.

Is there something wrong with the AC measuring side of my multimeter? The ground pin naturally is the same lead as the PSU 0 (tried this point too in case there's a cut somewhere), and according to the meter, I get something like
63.6VAC
12VAC
81.6VAC
on the pins of 7824. The DC voltages of the pins in same order are
29.2VDC (this is OK as it should state 30V by Natsume's instructions)
5.8VDC (is OK?)
37VDC (this is the one that connects to the VU-lamp pins and sounds nutty since the lamp will be 12V).

I don't have the IC TL071 installed yet. Also I haven't done any wiring yet, so no pots etc. installed in the circuit. But I don't think these have anything to do with the situation, right?

 

[gswan]

The DC voltages are about right. If you connect your 12V lamp across 37VDC is with emit a bright flash and vapourise. I doubt this is the effect you are looking for. Use a couple of 24V lamps in series (one for each meter) and you should be OK.

If your meter is reading those AC values then it's probably stuffed. I doubt that there is and AC at all, given that the loading is probably very light on the rectified and filtered output. Unless, of course, you forgot to put in the electrolytic capacitors after the bridge ...

 

[JoleFIN]

Hmm ok.. This is a mono unit and I ordered the Hairball Audio's VU kit with the 2 x 5V led set (thought it was correct for this one (Mnats Rev J) without any hassle). That's why I was/am concerned about the high DC for the 'VU lamp', but this should be still OK..? This would mean I can go about connecting a few more leds to make the VU meter shine :>

Yeh the ecaps and everything else is stuffed on the PCB, except for the stuff in balanced input circuit since I'm using the input trafo, and also except for the mod parts (C* C*1 etc). Maybe I'll wait for the rest of the stuff (case + VU) to arrive so I'll get to do the wiring and see what's up then. Still just concerned if the BC107s are ok (haven't measured them off-pcb separately after the burning of R36 due to wrong-way-around connected Q8 and Q9) ... Think I'll desolder them each for a check meanwhile.