[BUILD] 1176LN Rev D DIY

[JoleFIN]

Okay my Q is about rev F but think it's ok here..

The BOM says 27pf ceramic capacitor, but I can't find one from my local supply and neither at Farnell (where I'm ordering most of the stuff in a bunch). Is there any substitute for this or should I order a surface mounted capacitor as in
http://fi.farnell.com/vishay-bc-components/k270j15c0gf5tl2/capacitor-27pf-50v-c0g/dp/1612200

Or more notoriously, am I missing something?

EDIT: Also, the 5M lin/log pots seem to be quite rare and it would cost an extra 30e + delivery times for Farnell to order one from the States... Any ideas where to get one in Finland/Scandinavia/Europe or does anyone have a spare?

"N00b", I hear them say...

-Jole

 

[carnitas]

sorry if i am getting off topic a little here, but i thought i'd post the wiring diagram i used to get my dual rev. d functional.  i used all the parts that are now conveniently located at Hairball audio. It proved very useful for me while i was wiring the thing up.  As Skylar graciously posted his diagram for the vers. 1 board, i thought i'd post mine (vers. 2 board) as it has the updated wiring info for the OT and rotary switch and meter boards. 

Also, in regards to the polarity of the OT wiring, my unit is wired with the blue on cold (-) and red on hot (+) and i'm not having any oscillation problems.  Matta_Haze, is your unit working at 100% now that you switched your wiring around?  it makes me wonder if i'm missing something.....   

 

[mata_haze]

Also, in regards to the polarity of the OT wiring, my unit is wired with the blue on cold (-) and red on hot (+) and i'm not having any oscillation problems.  Matta_Haze, is your unit working at 100% now that you switched your wiring around?  it makes me wonder if i'm missing something..... 

well my unit was working fine even when the wiring was BLUE Cold (-) and RED Hot (+) but I noticed it did not like to be used on a unblanced insert (I have used a simple mackie 1604 to test) and it was giving me oscillations in that situation.
it would be interesting to see if yours (as it is connected now) does the same.
if not I got it wrong and therefore there is something else I did not see.

I have built 3 units so far and they all exibhit the same problem, unitl I swapped the output trafo connections..
VERY interesting...

Best,
Mattia.

 

[carnitas]

hmmmm, that is interesting Mattia.  I'm sure i would not have ever come across that problem as, thus far, I have had no cause to use it as an unbalanced insert.  (i seriously didn't realize how much detective work was involved with this stuff.)

With your current wiring, do your units behave themselves when used as balanced links in the signal chain? Are there any audible differences?  Do the compression characteristics change? more, less aggressive? 

jj

 

[mata_haze]

(i seriously didn't realize how much detective work was involved with this stuff.)

in my case I had to use it on an insert (I do a lot of live gigs as well as studio work and therefore that's how I would use it) and that problem made it unusable.
I am not 100% convinced I nailed it down, as I haven't finished testing it, but I am quite confident.

On regards to wiring, yes it behaves as far as I could tell after a brief test.
Regarding differences in compression, no there is nothing I could hear as far as different behavior/sound, but again, Live sound (unless you have 3 hours for sound checking) is not the place where I could test a piece of kit.
it does work or it does not, move onto the next one.

I'll be working on it tonight again and I'll do some tests balanced/unbalanced in the workshop where I can have enough time to judge.
that should tell me if there is anything different between bal/unbal level and behaviour wise.

in the mean time it would be interesting if you could do the same test on yours to see if the problem arise.

Best,
Mattia.

 

[carnitas]

yes, that does sound like an interesting experiment.  i probably won't get to it for a week or so as work deadlines are quickly approaching.  i'll keep you posted when i get a chance to flip the wiring around in one of the channels. 

jj

 

[mata_haze]

yes, that does sound like an interesting experiment.  i probably won't get to it for a week or so as work deadlines are quickly approaching.  i'll keep you posted when i get a chance to flip the wiring around in one of the channels.

thanks.

Best,
Mattia.

 

[crisotop]

Hey folks,

I'm about to complete my partslist for a dual Rev D build and am wondering if it would be possible to build a stepped T-Attenuator? Page 29 of this thread has a nice drawing for a 12 pos t-pad if I'm getting this right? I'm thinking of using a 2-deck 24 pos Elma for this purpose - I just want to make sure this can be done, should make level settings in stereo mode a lot easier.

thanks in advance,
christoph

 

[Echo North]

Yes for sure it can be done.

There is a good thread somewhere, but basically it was about using the NYDave drawing from page 29.

You need a MBB switch.

Mike

 

[crisotop]

Thanks Mike, I'm going to investigate a bit more, mainly I need to figure out the needed resistor values for 21 steps...

christoph

 

[Echo North]

Check out this NYDave post:
http://www.groupdiy.com/index.php?topic=10593.msg254707#msg254707

Dave's made several great posts on the subject.

Mike

 

[pstcho]

does this version (d) sounds as good as the G1176?

thank you

 

[Echo North]

does this version (d) sounds as good as the G1176?

That's really up to you.

I think it sounds a lot better on most things.  But there are people who prefer the late F/G "silverface" models who may prefer the G1176.  It's like asking if blonds are prettier than brunettes (or redheads). 

The RevD and RevA are closer to their originals.  The attenuator, transformers and pretty much everything between is like the real original circuit.  The G1176 is a little different, it was designed when there was not really access to a lot of stuff that has become available in the past year.  If 600ohm T pads with the unique tapers used in the 1176, UTC O-12 clones and output transformers with tertiary feedback winding were readily available back when the G1176 was designed, it may very well have been based on the D.  However, since those parts were expensive or hard to find at the time, it was designed as a F/G type(ish) with standard available components.

The original 1176 never used OEP or Lundahl transformers like the ones used in the G1176...but that isn't necessarily a bad thing.

It's all about personal taste.

Sorry for the non answer

Mike

 

[pstcho]

no it's exactly what i would like to have

thank you very mutch

 

[crisotop]

Check out this NYDave post:
http://www.groupdiy.com/index.php?topic=10593.msg254707#msg254707

Dave's made several great posts on the subject.

Mike

Mike, this was most helpful - I'll post back here, once I've done my homework...

thanks a lot!
christoph

 

[gary o]

I have a Transistor question........Im in Uk having trouble finding 2n3391 & 2n3707 for my Rev D ....I can get one or the other if I pay extra delivery costs its working out very expensive

Ive done some searches but have ended up more confused ......

Questions is what could I use instead of  2N3391 & 2N3707 ?...... & is it that simple ?

I read in my searches BC107 instead of 2n3391 ?

I read Q7 to Q10 2n5088 as in Purple machine.....instead of 2n3707.....but would that mean other 2n3707 could be replaced with 2n5088 within the circuit ?

Im having similar problems with a Rev A Im currently building too....

I try not to ask these qestions dont like to clog up these long threads I do searches but its difficult and threads long answers sometimes hard to find correct answers....I wonder if there are alternative transistors if we could list them in the BOM

Thanks ....

 

[RedNoise]

Hi Gary , I found 2N3707 @ Evilbay...
Hope this help!

 

[carnitas]

gary, i think a lot of folks were having trouble getting the proper HFE from the 2n3707 transitors.  I've substituted 2n3708 for all of mine and have had no problems.  there's a lot of talk about it pretty early in this thread.  FYI

 

[Skylar]

gary, i think a lot of folks were having trouble getting the proper HFE from the 2n3707 transitors.  I've substituted 2n3708 for all of mine and have had no problems.  there's a lot of talk about it pretty early in this thread.  FYI

Yes, what he said!

 

[gary o]

Thanks for replys
Found 2n3055 nice n cheap 3p each at Farnell
Found Ebay seller thanks rednoise... ebay have 2n3391 quite expensive if are not gonna work & have 2n3708 cheap & you guys say will work ?
Re earlyer discussion in thread ...il have to read thru the lot then thanks...I do think it would be good to add some info to the BOM Im sure others will come along asking same questions as me...

Thanks for all help il post what i buy & where from & how if it all works as to help others