[BUILD] 1176 Rev F/G - new board, new transformer!

[loopermc5]

What happens when you turn the tracking adjust trimmer?
[/quote]

It moves but only up to the 7 the zero adjust does nothing at all.


By the way the new f/g boards are really cool.

 

[mnats]

What happens when you turn the tracking adjust trimmer?

It moves but only up to the 7 the zero adjust does nothing at all.

And you have checked the entire GR Meter Driver Amp section for "incorrect or faulty components, solder bridges and wiring mistakes" as posted earlier and found nothing wrong?

 

[onlymeeee]

Hi,

Just wondering if you can clarify the ratio/turns of the B11148?

As I understand, the B11148 was wired as 1:3.5 (10dB gain - US market) or 1:1 (unity gain - for export)

Personally 10dB gain seems too much so I'm looking for some info on how UREI implimented 1:1
and also whether they used a terminating resistor in this configuration.
I've never seen any documentation on it.

Obviously I'll have a go with experimenting and see what loading gets the best response,
but of course knowing what UREI did would help get a more "authentic" sound

 

[Echo North]

Hi,

Just wondering if you can clarify the ratio/turns of the B11148?

As I understand, the B11148 was wired as 1:3.5 (10dB gain - US market) or 1:1 (unity gain - for export)

Personally 10dB gain seems too much so I'm looking for some info on how UREI implimented 1:1
and also whether they used a terminating resistor in this configuration.
I've never seen any documentation on it.

Obviously I'll have a go with experimenting and see what loading gets the best response,
but of course knowing what UREI did would help get a more "authentic" sound

Here is some of the info you are looking for:

http://www.groupdiy.com/index.php?topic=28923.msg440805#msg440805

[quote author=edanderson]
the b11148 is a 1+1:3.5+3.5 ratio, with something like a 150 ohm primary impedance.  it is not gapped, so there must be a cap or some other means to block DC from flowing in the primary.
[/quote]

 

[mnats]

As I understand, the B11148 was wired as 1:3.5 (10dB gain - US market) or 1:1 (unity gain - for export)

I believe it was the 16-11148 used in the later revisions that had a third output winding for the 60 ohm output. See the Rev G schematic in the manual.

 

[onlymeeee]

Hi mnats,

That's what I thought too until I came across this post by Ed,

"revs F-H used an output transformer (B11148) that was configured
as 1:3.5 (10db gain) for the domestic market or 1:1 (unity gain) for export to europe."

That got me thinking that the B11148 too was configured in two ways.

However having reread that post, I think perhaps Ed was using "B11148" as a generic
term for three different traffos(F-H) and didn't mean the B11148 specifically. 

Mine (IC input/B11148 output) is certainly hotter than any 1176 silver face I've used. 
If I put 0.775dB in, to get 0.775dB out, the input and output are about 1/3rd up. 
Usually, I'd expect, input 1/3 up, output 2/3 up approx.
I guess if the traffo has 10dB gain, whereas the silver faces I've used are unity,
then I guess that makes sense.

 

[loopermc5]

? what kind of mistake could cause my rev f build to have a serious high end roll off? I got all the calibrations done.

Thanks Rob

 

[mnats]

? what kind of mistake could cause my rev f build to have a serious high end roll off? I got all the calibrations done.

The same ones that might have caused your previous meter problem: "incorrect or faulty components, solder bridges and wiring mistakes" (which was it?)

Get or build a signal tracer. Put a signal into the input and use the tracer to find out where the highs disappear. You can work from the output back or from the input forward - whichever you choose will be furthest from the fault Look closely at that part of the circuit.

 

[loopermc5]

(which was it?)

:-[ 4.3 ohm instead of a 4.3k in the meter section. Thanks for your answer (you most get tired of stating the obvious)  but it's nice to be able to ask and vent. I'll just keep plugging away this should be a difficult one.

 

[edanderson]

... I think perhaps Ed was using "B11148" as a generic
term for three different traffos(F-H) and didn't mean the B11148 specifically. 

no, i meant that the b11148 (same as the 16-11148) can be wired either for 1:3.5 (10db step up) or 1:1 (unity gain).  in the 1:3.5 configuration, the yellow-orange winding is in parallel with the red-brown winding.  those two windings have a 1:1 relationship.  if, as mnats suggested, you look at the rev G schem, you can see how the yellow-orange winding can be used in place of the normal output windings, giving a 1:1 output.  you could even put both on a switch and give yourself the option to switch between them.  i would not recommend using both simultaneously unless you have known loads and can be sure that both outputs will be lightly loaded.

I guess if the traffo has 10dB gain, whereas the silver faces I've used are unity, then I guess that makes sense.

yes, if you are used to "export" models wired for 1:1 output, then you will be used to turning up the output knob a bit further.  with the 10db step up, the total gain in the unit is like the rev d models where there is almost 45db of gain with both input and output knobs at max.  getting down to unity means turning the knobs down quite a bit.

ed

 

[onlymeeee]

Hi,

Thanks Ed, I hadn't realised that the B11148 and 16-11148 had the same windings and as such, the B11148 could be wired as the G schematic states.

 

[joshco]

I have a small question concerning the Transistors in this Version of the 1176. The most types which are listed in the BOM are not available in the shops around Germany. Can I take the ones listed in Gyrafs BOM as substitutes? These are BC and BD types which are better available. Sometimes pinouts are diffrent, but thats no problem as long as I don´t have to change any resistor values.

However, some tips or experiences would be very appreciated.

 

[beaversaber]

Hi all, I've been posting over in the general 1176 thread, but I figured I'd try here too.  Basically my 1176 rev f/g is passing audio, input and output gain knobs are working, but the unit is not compressing.  Here's my last post over there:

"Just replaced all the transistors q5-q9 in the line amp section to no avail.  This morning I probed around with my signal tracer thing and signal when i have GR disabled, no signal goes to the GR control section of the pcb, and when i engage it, signal is sent to the section, so it seems like that is working properly.

So at this point, the unit is passing audio, but the voltages are a bit odd in the Q5-Q9 (line amp) section of the circuit and it is not compressing.  I've replaced all caps, transistors, and double checked resistor values/looked for shorts in that section.

Not really sure where to go from here"

Any ideas? =(

 

[envelope]

"This morning I probed around with my signal tracer thing and signal when i have GR disabled, no signal goes to the GR control section of the pcb, and when i engage it, signal is sent to the section, so it seems like that is working properly.

maybe check all of your work/components in the GR section as well? Confirming that a signal is being sent to the section, may not be enough of a test to determine if that section is working properly, but it  does confirm that the switch is working.  I am nearing completion of a rev F/G as well. I hope it all works out in the end. Is this the same unit you talked about in Oct. 09?

 

[beaversaber]

"This morning I probed around with my signal tracer thing and signal when i have GR disabled, no signal goes to the GR control section of the pcb, and when i engage it, signal is sent to the section, so it seems like that is working properly.

maybe check all of your work/components in the GR section as well? Confirming that a signal is being sent to the section, may not be enough of a test to determine if that section is working properly, but it  does confirm that the switch is working.  I am nearing completion of a rev F/G as well. I hope it all works out in the end. Is this the same unit you talked about in Oct. 09?

Nope, different unit (thankfully =P) The unit i built last year works great.  It was for a friend and he uses it all the time.

I'll check the gr section

 

[beaversaber]

Although my dc bias voltages in that section (q12-q15) all checked out okay...

 

[envelope]

okay ...that is good to know....good luck with the rest....maybe you can borrow your friends (as it is the same revision) and make some electrical comparisons...

 

[beaversaber]

I would, but he's in Atlanta and I'm in Philadelphia =/

 

[envelope]

that figures....  when I get mine completed, I'll check back in, but I'm sure some of the fine folk here will help you solve this. I suppose you've already checked and double checked the parts placement, values and and wiring for the ratio board and controls, and your test set-up is sufficient to trigger/monitor the threshold/GR etc etc. sorry to ask, but without seeing your test setup and the rest of the unit, I'm no more help for the rev.F

Flyers and Thrashers eh? The Maple Leafs might surprise this year. Brian Burke has been very busy.
The Stanley Cup is in Mimico Canada right now and will be in a parade here on Friday Sept 2. more exciting than DIY

 

[beaversaber]

that figures....  when I get mine to the working point, I'll check back in, but I'm sure some of the fine folk here will help you solve this.

Flyers and Thrashers eh? The Maple Leafs might surprise this year. Brian Burke has been very busy.

Haha I'm not much of a hockey follower =P

I did get your PM though and appreciate it a lot, I'll send over some pics