[BUILD] 1176LN Rev D DIY

[carnitas]

yes, 2n3708 will work fine.  the issue was that folks were having a hard time finding 2n3707s with an HFE over 250.  all my 2n3708s averaged between 350 and 450. 

as far as an updated BOM, i don't know about that, but the first post has a link to Kato's parts list for folks who live in the states.  That's the parts list i used and all of it has checked out fine.....with the exception of the 6 position rotary switch (no ability to implement the "all button mode" as far as i can tell).  But i'm replacing those switches with the alpha switches on Mnats rotary switch wiring page. 

Its all here in these pages.  Even when i could swear that it wasn't here, i'd find it a few minutes (or hours, or days) later.  This thread addresses most of the issues i've encountered with my build and has given the info to troubleshoot.  In many cases, information i initially glanced over became very valuable later. i.e.  wire the output transformers correctly or witness the untimely demise of R32. 

it will take some time but its worth it.  before this build, i couldn't tell AC from my a$$hole.

 

[Echo North]

I'm going to start selling transistors at my store.

I'll have match pairs of 2n5457's starting this Wednesday.

In the next 2 weeks I'll be selling 2N3708's and 2n5088's with high enough HFE's and within 5% of each other.

Hopefully that will provide another option.

Mike

 

[carnitas]

cool, mike.

 

[carnitas]

mattia, i rewired the output of one of my channels (from the EA 5002) and in an extremely cursory test found it made no impact on the sonics of the comp.  there was slightly more noise when the blue wire was connected to the hot pin and the red to the cold, but that could easily have just been a bum joint somewhere or that some wires need to be moved or something.  This test was only done with vocals, so i'll check it out on some other souces with different frequency curves to see if there are any losses on either side of the spectrum.  in any case, i don't have any oscillation in either of the channels. 

interesting experiment.  Mike i noticed that you were the one who was pretty explicit about the wiring of the OT a page or so ago, any comment on this? 

regards, jj

 

[Echo North]

Looking at the schematic:

Blue goes to output labeled as "X" or "+/-" on the back plate
Red goes to output labeled as "Y" or "Common" on the back plate

I always assumed since "common" is usually negative that would be the cold.

I could be wrong though.  Wouldn't switching red/blue flip the phase?

Mike

 

[carnitas]

Blue goes to output labeled as "X" or "+/-" on the back plate
Red goes to output labeled as "Y" or "Common" on the back plate
I always assumed since "common" is usually negative that would be the cold.
I could be wrong though.  Wouldn't switching red/blue flip the phase?

well, that's what i wondered as well.  and it may have.  but i have yet to hear it affect anything in the real world.  If the polarity were reversed i suppose i would expect a notable difference in the frequency curve. I personally haven't experienced this (again, just with a 4 minute, very unscientific test).  But it sounds like i would have drawn the same conclusion from the schematic were i to have seen it. sort of puzzling.

by the by Mike, would you happen to have a copy of the scheme that you could share or is it already buried in this thread somewhere and i missed it. 

 

[Echo North]

Nice collection here:
http://www.waltzingbear.com/Schematics/Urei.html

Mike

 

[carnitas]

aha!  i see it now.  i didn't follow the traces back through the schematic when i looked at it last and so just (semi-arbitrarily) assigned values to "X" and "Y" by the usual color coding (red=hot, blue=cold).  still though...its strange that it hasn't appeared to make much difference.  does anybody else have this experience? 

i don't mind being exposed for the novice that i actually am.

jj

 

[mata_haze]

does anybody else have this experience?

no...I haven't noticed any difference...

Mattia.

 

[crisotop]

Regarding stepped T-Attenuators again:

I just cross checked NYDave's drawing with the calculator at http://www.microwaves101.com/encyclopedia/calcattenuator.cfm and the values don't quite match? Can anyone explain which formula is correct, or what the difference between the two is?

Some quick example values for z0 = 600R
2dB Atten: R1=155.36 R2=2,317.27
4dB Atten: R1=350.94 R2=1,025.83

Thanks
Christoph

 

[keefaz]

For the R2 equivalent in NYD circuit, you have to add all resistor values from the db atten pin to gnd
(resistors are in serie)

 

[crisotop]

Damn, how stupid am I  - thanks keefaz!

christoph

 

[luis]

I´m using a pushbutton Purusha case,  but the Sifam bezel does not fit on the extra pannel (the one used to hold the buttons).
The Sifam i´m using is the AL29WF wich fits perfect in the front pannel, but not in the extra one.

Did any of you had this problem. If not, Maybe my case is defectiv!

Thank you

 

[Stagefright13]

It SHOULD fit... Put the bezel on the meter first and wiggle it in as an assembly. May a bit of a snug fit. Just use some care.

John

 

[ewald]

There is a step by step guide for this about 2/3 down Mako's J page:
http://www.geocities.com/m_natsume/1176-wiring-pushbutton.html

The only difference is to remember when he says "solder 22/Grn/Blk to the meter board" it will be the attack pot switch for you.

Mike

HI guys,

Firstly I want to thank all the contributers to this tread/project, I sallute your selfless divulgence of time and knowledge...wich i directly attribute the success of my now fully functioning revD to!

One thing still stumping me though. I used the spdt switch for the attack controll and wired it according to the hairball instructions. I.e common to 22(main) ; CCW(off) to BLK and CW to GRN on ratio board. Now, BLK on the ratio board connects to ground, wich allows GR to be disabled on the attack switch CCW(off) position, BUT on the ratio pcb board (also indicated on ratio board schematic)  the 4:1 switch connects the 4:1 ratio circuit to the BLK pad, automatically shorting the 4:1 ratio circuit to ground when selected. This was confirmed in the compressor's behavior i.e the 4:1 ratio selector acting as GR disable switch. I remedied this by removing the ground connection from BLK on the ratio board-obviously also removing GR disable functionality from CCW on attack pot.

Can anyone confirm this OR that i'm missing something?

 

[luis]

It SHOULD fit... Put the bezel on the meter first and wiggle it in as an assembly. May a bit of a snug fit. Just use some care.

John

Thank you, but it won´t work. I will have to cut a little of the inside pannel.
Just tought that you guys may had the same problem

 

[pantsonfire]

Howdy,

Does anyone have Mouser or Digikey part numbers handy for a 3 pin header and shorting plug like Mnats suggests using for removing R44 from the circuit during the Discrete Meter Circuit Calibration? They're not listed in his BOM or Kato's (though mostly everything else is, so I'm not complaining).

Many thanks,
Chris.

 

[Skylar]

Mouser or Digi-Key PNs


3-pin header 0.100" spacing
22-28-4030


shorting jumpers
STC02SYAN

 

[pantsonfire]

Thanks so much Skylar! It was the spacing that I was unsure about. Thanks also for all of your other helpful input in this thread.

Best,
Chris.

 

[Echo North]

One thing still stumping me though. I used the spdt switch for the attack controll and wired it according to the hairball instructions. I.e common to 22(main) ; CCW(off) to BLK and CW to GRN on ratio board. Now, BLK on the ratio board connects to ground, wich allows GR to be disabled on the attack switch CCW(off) position, BUT on the ratio pcb board (also indicated on ratio board schematic)  the 4:1 switch connects the 4:1 ratio circuit to the BLK pad, automatically shorting the 4:1 ratio circuit to ground when selected. This was confirmed in the compressor's behavior i.e the 4:1 ratio selector acting as GR disable switch. I remedied this by removing the ground connection from BLK on the ratio board-obviously also removing GR disable functionality from CCW on attack pot.

Can anyone confirm this OR that i'm missing something?

Something is not right here, unfortunately I'm too tired to think straight.  BLK should conect to the 47K resistor on the ratio board.

Have a look at it again and walk through the Mnats wiring guide again.  Let me know if you still have the issue and I'll crack mine open and see what's going on.

Mike