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Project Specific Discussions => Dynamic Processors => Topic started by: Neeno on July 10, 2009, 05:22:03 PM

Title: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: Neeno on July 10, 2009, 05:22:03 PM
Hi guys.
I'm looking for a readable version of the 1176 rev A schematic.
I can't read the value of R11.
An high resolution interior shot would be ok too.

If you own an original rev A (not AB or B) please send me an email.
I'm trying to solve the plosives problems with all ratio buttons in.

Thanks in advance.
Title: Re: Looking for: 1176 rev A schematic or high res internal shots.
Post by: EmRR on July 10, 2009, 05:34:57 PM
Is the rev A repro schematic of no help?   I see the exhaustive UREI manual download is illegible on that value.
Title: Re: Looking for: 1176 rev A schematic or high res internal shots.
Post by: Neeno on July 10, 2009, 05:39:16 PM
Hi Doug,
yes, the repro is referred to a different schematic.

Title: Re: Looking for: 1176 rev A schematic or high res internal shots.
Post by: Rob Flinn on July 10, 2009, 07:30:27 PM
neeno I'm with you we need to work this out.   Do you get the pumping thing on all in mode ??
Title: Re: Looking for: 1176 rev A schematic or high res internal shots.
Post by: edanderson on July 11, 2009, 01:00:55 AM
i don't understand the connection between the all buttons in mode and R11, which is attached to Q2 (the first signal FET in the preamp)?  R11/R12 is a bit fuzzy but i would say it looks like 10k/1k in the original and 9.1k/2.2k in the rev A.  this is a pretty minor tweak and doubtful the cause of your issue.  i'd rather look at R18 and R22 or anything having to do with the sidechain when all the ratio resistors are all bypassed.

ed

Title: Re: Looking for: 1176 rev A schematic or high res internal shots.
Post by: Neeno on July 11, 2009, 06:33:47 AM
Hi Ed !
Thanks for your reply !
You're right, R11 and R12 wouldn't solve the plosives problem.
What I'm doing now, is following the Rev A schematic.
I still have to compare the sidechains of the original and the rev A, but it looks like they didn't modified anything there.
The major differences I found are in the preamp section and the ratio board resistors.
Probably stuffing the board following the rev A schematic would solve the problem.

Do you have more readable rev A schematic ?
Thanks for your help.
Title: Re: Looking for: 1176 rev A schematic or high res internal shots.
Post by: Neeno on July 11, 2009, 08:34:38 AM
neeno I'm with you we need to work this out.   Do you get the pumping thing on all in mode ??

Hi Rob ! Thank you.
Well, I don't have any problem with the brit mode.
But that's because I'm testing the rev A board inside a rev D I already built.
Try to use the values shown on the JBL rev A schematic for the ratio board, I'm 99% sure it will fix the problem.

Report back what you find out !

Now I'm trying to figure our all the parts that have been changed from the original 1176 to the rev A.
It's referred to the schematics, so it would be great if someone with a real rev A can help up sort this thing out.

The bright side of the story is that probably Mnat's rev A could be stuffed in 2 ways, isn't this just great ?  :)

Cheers,

Title: Re: Looking for: 1176 rev A schematic or high res internal shots.
Post by: Rob Flinn on July 11, 2009, 08:40:13 AM
Neeno.

I used the ratio board values that are supplied with the pcbs the Hairball supply.  They are different from the rev D values, in accordance with the diagram the Mako supplies.  If you are using the rev D values then both scenarios have been tried ??

I keep thinking that backing off the gain in the side chain might be useful maybe decreasing the value of R46 ???
Title: Re: Looking for: 1176 rev A schematic or high res internal shots.
Post by: Neeno on July 11, 2009, 08:48:12 AM
I think that the original 1176 has a lower threshold compared to the rev A.
As you can see, the preamp stage of the rev A has an higher feedback resistor.
If I'm not wrong that means less gain from the preamp stage then less signal in the sidechain.

The rev D ratio board is similar to the rev A. But different from the original 1176 (Mnats version)
In fact in the original 1176 the signal from the output pot goes straight to the meter board, when in the rev A or D there is a resistor in between.

That's why I think following the rev A schemo should help solve the problem.
But as far as I can see there is more stuff to change for a clone of a rev A.
Mako did a great work btw, but there is still something I don't understand.

Please Mako, chime in !
Title: Re: Looking for: 1176 rev A schematic or high res internal shots.
Post by: orangerec on July 11, 2009, 11:59:59 PM
Neeno, I replied to your email. Thanks for attempting a fix. I've been using my RevA for months and I love it. I don't use nuke mode much but if I need to, I use my G1176 or a Distressor.

Cheers,

Tony
Title: Re: Looking for: 1176 rev A schematic or high res internal shots.
Post by: Neeno on July 12, 2009, 06:51:24 AM
Thank you for your reply Tony.

Now, as promised I post the comparison I did between the "Original 1176", "Rev A" and "Mnats Rev A"
Check out the attachment.

I still have to compare the ratio board resistor.
I'll do that and update the list later.
If anyone would like to check if all the values are ok, it would be just great.
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: Rob Flinn on July 12, 2009, 10:17:23 AM
Neeno,

Could you clarify exactly which diagram relates to which ?   

original diagram = the first diagram in manual which they only made about 125 of ??

Rev "A" value = 2nd diagram in manual serial numbers 125-216 ??

Is Mnats values from the diagram at Waltzing Bear ?
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: Neeno on July 12, 2009, 10:32:30 AM
Hi Rob !
Well, the original 1176 is the first diagram in JBL pdf.
They did just 24. Serial from 101 to 125

The rev A is the second diagram "Titled Rev A" is what I call Rev A.

As you can see, the Blue Stripe diagram on Waltzingbear refers to the "original 1176" wich is not the "Rev A" and this is what Mako used (with some slight modifications).

Probably what we've built now is the first version of the 1176.

Hope it helps.
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: Rob Flinn on July 12, 2009, 12:47:48 PM
I've been comparing the diagrams & noticed that on the original R46 is 22k & on rev A it's 8k2,c ompared to Mnats 47k.   It strikes me that tese values would reduce the gain of the s/c amp significantly !
Title: INTERIOR SHOT OF MY 1968 Bluestripe 1176 #1
Post by: zmix on July 12, 2009, 02:25:47 PM
Here is an interior shot of my 1968 Bluestripe...
Title: INTERIOR SHOT OF MY 1968 Bluestripe 1176 #2
Post by: zmix on July 12, 2009, 02:26:51 PM
And another... :)
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: Neeno on July 12, 2009, 02:42:30 PM
Chuck !
Thank you very very much for the pictures.
Is that a rev A ? Or is it the original version ?
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: zmix on July 12, 2009, 02:46:08 PM
Chuck !
Thank you very very much for the pictures.
Is that a rev A ? Or is it the original version ?

Well, it is from 1968 or 1969 so it's as close to the original series as I have ever seen, plus it has the original all-black input and output knobs..!
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: Neeno on July 13, 2009, 08:21:40 AM
Thank you very much Chuck !
Do you have the original manual of the blue stripe ?
I'm looking for a schematic a bit more readable than the one supplied by the JBL manual.
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: Rob Flinn on July 13, 2009, 12:28:05 PM
I've been comparing the diagrams & noticed that on the original R46 is 22k & on rev A it's 8k2,c ompared to Mnats 47k.   It strikes me that tese values would reduce the gain of the s/c amp significantly !

I just swapped out R46 for the 8k2 that is used in the REV A version.  It makes quite a difference to the operating range.   If using the 47k or 22K in the other versions it goes from nothing to -20db GR at about 10 o'clock input pots rotation.   With an 8K2 in this position -20db happens at about 12 o'clock on the input control.  The threshold point stays the same.

Basically it's more controllable.
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: Neeno on July 13, 2009, 02:28:55 PM
Hi Rob !
That means you still have the plosives problem.
Try this:

Remove the 130k resistor from your ratio board and put a 68K instead.
If you used Hairball's ratio board, remove the jumper and put a 47k instead.

Let me know if this solves the problem.

I've been comparing the diagrams & noticed that on the original R46 is 22k & on rev A it's 8k2,c ompared to Mnats 47k.   It strikes me that tese values would reduce the gain of the s/c amp significantly !

I just swapped out R46 for the 8k2 that is used in the REV A version.  It makes quite a difference to the operating range.   If using the 47k or 22K in the other versions it goes from nothing to -20db GR at about 10 o'clock input pots rotation.   With an 8K2 in this position -20db happens at about 12 o'clock on the input control.  The threshold point stays the same.

Basically it's more controllable.
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: mnats on July 13, 2009, 05:07:11 PM
Neeno, I got your PM asking me to look at this thread, but I'm not sure if I understand what you would like me to contribute.

The boards I designed were made to encourage the DIY of the 1176 with the FET in the pre and line amp. The values I ended up with are an amalgam of the various schematics that are circulating on the 'net but there is no suggestion that I am trying to prevent anyone from using other values or say that the ones I ended up with are "best". I have always been ambivalent about putting component values on boards as there is obviously some ambiguity about some of the components in a design as old as this one - though the R46 value that Rob found was obviously a mistake!

According to the JBL document serials 101-216 are all Revision A. The circuit is very similar between the earlier serial numbers and later ones and each should require only the smallest of modifications to implement. Since the rarest ones seem to be the most coveted I decided to base the audio path on the earlier schematic.

If the Rev A worked just like the Rev D in the all buttons mode would mean that they were more similar than not and to me defeats that would the purpose of offering a Rev A. If you want the all buttons mode sound that we know, build a Rev D. The Rev A does other things well as some have already discovered.

Hope that clears a few things up. I'm happy to see that you are experimenting with your build and sharing it here. That's the DIY spirit!
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: Neeno on July 13, 2009, 05:42:41 PM
Thank you very much Mako !
I did some confusion.
Today I checked the UAUDIO website and they state that the FIRST 1176 was called 1176A wich means rev A.
That sound strange, but probably it was the first revision after the first prototype.
After the first 24 pieces Mr.Putnam revised it and they built the AB version (which in the JBL document is called Rev A), this is what I understand looking at the serial number logs.

Now, I tried to populate another board following the JBL REV A schematic (which in reality should be the REV AB) and that solved the brit mode behaviour. No plosives and no unexpected distortion.

Thank you again to give us the rev A board !
The layout is just great to experiment, and well, I'm really learning something this time !

Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: Neeno on July 13, 2009, 05:48:13 PM
I just checked, but on the rev A schematic I see 47k, on the original 1176 is 22k but I can't find where you got the 8.2k value.
The sidechain used by Mako is more similar to the sidechain used on the Rev D, but I think that it doesn't make much difference.
As you can see the 10k resistor connected to the Q Biad trim pot was implemented only from rev B and it is not present in the original nor rev A schematic.

I've been comparing the diagrams & noticed that on the original R46 is 22k & on rev A it's 8k2,c ompared to Mnats 47k.   It strikes me that tese values would reduce the gain of the s/c amp significantly !

I just swapped out R46 for the 8k2 that is used in the REV A version.  It makes quite a difference to the operating range.   If using the 47k or 22K in the other versions it goes from nothing to -20db GR at about 10 o'clock input pots rotation.   With an 8K2 in this position -20db happens at about 12 o'clock on the input control.  The threshold point stays the same.

Basically it's more controllable.
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: Rob Flinn on July 13, 2009, 06:47:39 PM
Hmmmmm,

Maybe I should use my reading glasses more often !!   Anyway it much more controllable with an 8k2 ;-)

I'll try you mods tomorrow.

I just checked, but on the rev A schematic I see 47k, on the original 1176 is 22k but I can't find where you got the 8.2k value.
The sidechain used by Mako is more similar to the sidechain used on the Rev D, but I think that it doesn't make much difference.
As you can see the 10k resistor connected to the Q Biad trim pot was implemented only from rev B and it is not present in the original nor rev A schematic.

I've been comparing the diagrams & noticed that on the original R46 is 22k & on rev A it's 8k2,c ompared to Mnats 47k.   It strikes me that tese values would reduce the gain of the s/c amp significantly !

I just swapped out R46 for the 8k2 that is used in the REV A version.  It makes quite a difference to the operating range.   If using the 47k or 22K in the other versions it goes from nothing to -20db GR at about 10 o'clock input pots rotation.   With an 8K2 in this position -20db happens at about 12 o'clock on the input control.  The threshold point stays the same.

Basically it's more controllable.
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: edanderson on July 14, 2009, 07:29:31 AM
rob, i think you may have mixed up the values for R46 (47k or 22k) and R48 (8.2k). 

ed
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: martthie_08 on July 14, 2009, 08:40:44 AM
here some more inside photos of a blue stripe 1176:

(http://www.martenthielges.com/diy/image/1176A/bbec_3.JPG)

(http://www.martenthielges.com/diy/image/1176A/c68a_3.JPG)

(http://www.martenthielges.com/diy/image/1176A/c138_3.JPG)

these have been completely recapped, it seems...
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: Rob Flinn on July 14, 2009, 08:42:59 AM
rob, i think you may have mixed up the values for R46 (47k or 22k) and R48 (8.2k). 

ed

Ed, i think your right !!

I just performed the mods that Neeno documented, but haven't listened to them yet.  However, certainly in conjunction with swapping R46 to a 22k they soften the action of the blue stripe very significantly, when I test  them with an ac millivolt meter & scope on the bench.

I will do some audio tests later this afternoon.
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: Rob Flinn on July 14, 2009, 01:58:28 PM
Having had a brief play with it, that seems to sort the problem out a bit, & makes the i/p control not as fierce.

I'm not convinced that the problem has completely gone though.   When used on all buttons in, you still have to be very gentle with the input & attack controls to eliminate the initial click when the compression kicks in.   

So in a nutshell I'm not sure if that has completely eliminated the problem.  What do you think Neeno ?
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: Neeno on July 14, 2009, 02:47:52 PM
Hey Rob !
Good news !
Well, actually I have mine built like a rev AB.
I did more than the mod on the ratio board.
Tomorrow I'll make a list of all the parts values I've used.

Pick a sample groove from your collection, squash it in brit mode and record the results.
Send me the unprocessed sample, tell me the setting you've used and I'll do the same and report back.
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: Rob Flinn on July 15, 2009, 01:06:19 PM
I took the modded Blue Stripe to a friends studio this afternoon, where we had a bit more of a play with it, & the general opinion was that it worked very well in all different ratio combinations on voice & drums.  We didn't notice any popping etc
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: Neeno on July 15, 2009, 04:23:03 PM
Great !
If anyone is interested I'll post the list with the values of the Rev AB.
It should be more stable than the rev A.
The values are what I was able to read from the fuzzy schematic and are not checked.

I'm still looking for someone with a real Rev AB to compare them, please.

Cheers


I took the modded Blue Stripe to a friends studio this afternoon, where we had a bit more of a play with it, & the general opinion was that it worked very well in all different ratio combinations on voice & drums.  We didn't notice any popping etc
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: Rob Flinn on July 15, 2009, 05:11:28 PM
Would be interested to see the AB mods you have performed.

Have you tried it yourself ?    Does it stop the meter action from being sloppy ?
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: Neeno on July 16, 2009, 04:15:31 AM
What do you mean with "Sloppy" ???
What I've learned is that with the discrete meter circuit, you must use a real ANSI VU-Meter.
Sifams works great and they are faster compared to the original UA meters I have here.
Probably the fastest of the bunch I have here are the good old Triplett.

Would be interested to see the AB mods you have performed.

Have you tried it yourself ?    Does it stop the meter action from being sloppy ?

Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: Rob Flinn on July 16, 2009, 06:58:13 AM
By sloppy I mean they have overshoot.  i.e if you switch from say +4 to GR the meter bounces around the zero mark before it settles. I'm using modutec meters.
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: cannikin on July 16, 2009, 06:19:41 PM
Great !
If anyone is interested I'll post the list with the values of the Rev AB.
Cheers

Neeno, please post your findings,  I have been watching this thread because I'm about to build two RevA
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: Stagefright13 on July 17, 2009, 02:14:50 AM
Well been using Mako's original rev A for a long time now. It's on 4 CD's now. Never had a need to change it. I'm really really picky on sound. And it is working for me. Not much worried about the all buttons in. I don't even use that on my rev D's. I guess that sound would be cool here and there as an effect.

I am actually afraid to change it cause it is working so well. For me it would be like upgrading protools in the middle of a gig lol!

Thanks Mako my stuff is running daily! ;)

John
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: Rob Flinn on July 17, 2009, 09:44:10 AM
John I don't use "all in" mode much, but the mods make the input control less of an on/off switch, & give you smooth control.  So in my opinion they are worthwhile to do.
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: Stagefright13 on July 17, 2009, 09:49:18 PM
Thanks Rob I may try that. Right now I have promised myself to finish my dual rev D. Just needs a wiring job and Cal. Been so busy but I could really use it lol. It's SO close.

John
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: ilfungo on July 19, 2009, 06:20:21 AM
sorry  but I am a beginner...


the mod are:

1  - R46=47K or 22K instead 8.2k

Ratio board:

2 - 68k instead 130

3 - 47k instead the jumper

is it correct?

Thanks
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: Rob Flinn on July 19, 2009, 07:29:06 AM
R46 (47k) is now 22k
130k  is now 68k
jumper is now 47k
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: ilfungo on July 20, 2009, 08:08:14 PM
Thanks
I have changed the 3 resistors
and the unit it's more controllable...
In nuke mode must be more light with input and attach pot...

I have used attack pot with off switch
from hairball connection but I don't understand pad 22 where is connected,
is connected to the ground?
Ciao :)
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: SaMpLeGoD on July 21, 2009, 05:44:55 PM
Thanks
I have changed the 3 resistors
and the unit it's more controllable...
In nuke mode must be more light with input and attach pot...

I have used attack pot with off switch
from hairball connection but I don't understand pad 22 where is connected,
is connected to the ground?
Ciao :)

Look at Here (http://www.groupdiy.com/index.php?topic=20058.1080) is there some conversation about the wiring...
Hope it helps...
Cheers,

Eddie :)
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: ilfungo on August 03, 2009, 08:50:23 AM
Thanks Eddie!!! ;)
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: ethervalve on August 17, 2009, 02:01:33 PM
Hi all,
I'm in the same boat as Stagefright13 (I already finished my pair of blue strips and love 'em). I have no interest in the slam mode, i am intrigued by the r46 mod. i would prefer if the threshold were higher (particularly for 1:4), but would this resister swap mean that i would have to completely re-calibrate? I had some difficulties calibrating and i would prefer not to go down that road again for a while.
thanks in advance for any insight.
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: Stagefright13 on August 18, 2009, 02:23:53 AM
Well I have 3 Mono Rev D's and a stereo one, And 1 rev A. And don't use nuke on any of them LOL. You can really slam a track with the rev A or D. They are both so fast already. But both sound different. So glad I have both. But if ya want to use Nuke the best way is with parallel compression. Otherwise it is just an effect like a guitar pedal kinda.

And I was in Brooklyn last week and they had 2 1176's but no rev A's so could not try the nuke on one.

So glad people are working on this tho. I will consider messing with mine when it get's cold out and I have time. :)

But realistically it works fine just as it is. Actually more than fine. The albums are in stores LOL!

I'm sticking with Mako's original setup using the JBL Pro schematic. And probably less noise due to Mako's ground plane setup on his board.

John
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: Rob Flinn on August 18, 2009, 05:41:03 AM
Hi all,
I'm in the same boat as Stagefright13 (I already finished my pair of blue strips and love 'em). I have no interest in the slam mode, i am intrigued by the r46 mod. i would prefer if the threshold were higher (particularly for 1:4), but would this resister swap mean that i would have to completely re-calibrate? I had some difficulties calibrating and i would prefer not to go down that road again for a while.
thanks in advance for any insight.

This doesn't require recalibrating, all it does is lower the gain of the sidechain amp.
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: ethervalve on August 29, 2009, 06:12:22 PM
Thanks for the great investigative work Rob!
I performed the mod and it works great. I no longer have to trim down signals for a more manageable threshold. I'd recommend the 22k resistor for r46 for anyone out there building a blue stripe.
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: Rob Flinn on August 29, 2009, 07:37:18 PM
ethervalve

I'm glad it worked for you.   The mod definitely makes the blue stripe more controllable.
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: Neeno on January 09, 2010, 06:11:14 PM
Ok guys, after comparing the various schematics (original 1176, rev A and Mako's rev A) I came across a bunch of values that should be the ones used on the real Blue Stripe. Of course those have not been checked with a real unit, so, please if you own an original rev A Blue Stripe check the values and report back !!!

I did this as an experiment, you don't need to change anything if you followed Mako's BOM, in fact his revision sounds really good as it is !
And well, Mako, thank you very much for the rev A !!!! A great board, an easy build, just lovely !

I've got the values comparing the Rev A schematic to the one used by Mako (Original 1176) which are the ones between parenthesis.

R6 = 2.2M (560k)
R7 = 2.2M (560k)
C6 = REMOVE (33pF across R16)
C6a = ADD 68pF across R7)
R11 = 9.1k suggested by Ed Anderson (10k)
R12 = 2.2k (1k)
R16 = 100k (47k)
R17 = 4.7k (8.2k)
C9 = 6.8uF (47uF)
R30 = 150k (120k)
C11 = 10pF (47pF)
Rx14 = REMOVE (820k)
Cx6 = JUMPER (6.8uF)
R76 = 10k (8.2k)
R54 = 1.2k (470r)
C27 = 0.012uF (0.022uF)

Ratio Board
=======

R22 = 47k (56k)
R19 = 68k (130k) NOTE: If you're using the great Hairball PCBs R19 is marked as R8 on the documentation
R78 = 47k (NOT PRESENT) NOTE: R78 is marked as R10 on Hairball PCBs
R64 = 2.2k (1.2k)

LINE AMP MOD
=========
This mod adds a resistor (3.9k) in series with a capacitor (1000pF) and it should be connected from the (-) of C9 to the junction of WHTRED - R32. Take a look at the picture.

(http://www.studio21.ch/diy/1176%20Rev%20A%20Line%20Amp%20mod.jpg)





Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: mata_haze on January 09, 2010, 06:30:41 PM
well done NENO!
thank you very much for this precious info!


Best,
Mattia.
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: Biasrocks on January 09, 2010, 07:38:38 PM
Interesting...

I've been doing some research here as well.

I've got the values comparing the Rev A schematic to the one used by Mako (Original 1176) which are the ones between parenthesis.

Some additional notes that I found.

There's two versions of the limiter using the 2 FET pre-amp.

Serial #101-125, original version, no revisions labeled on the schematic and
Serial # 125-216 which is labeled REV A on the schematic and appears to be
the version which you are pulling your changes from.

Mako implemented the pre-amp as detailed in the unlabeled, original schematic and
I'm assuming that the guys at Universal found this pre-amp to be slightly unruly and
made the changes in the REV A version of the limiter.

The Gain Control Amplifier is modeled after the REV D version of the limiter and
I have found detailed some changes there as well as some changes to the ATTACK
pot values.

Perhaps we should pool the info at this point to get to a true REV A version.

Mark
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: Neeno on January 09, 2010, 07:46:09 PM
Great work Mark !
Please post the XLS file !
If you don't have a hosting service, send it to me by email and I'll publish it.
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: la-2a on January 17, 2010, 08:31:11 AM
Hi, I just remembered that I had some original schematics laying around here
from the time I got my 2 used Bluestripes in 1982. BTW I STILL HAVE THEM .
javascript:void(0);
Here some informations about the pushbotton resistor values.

Effective serial No.125 subsequent  Date: 2/20/67 -R 10743

R21=56k ,R20=56K , R19=68K ,R78=47K , R61=470 ,R62=470 , R63=1.5K R64 =2.2K
R58=120 ,R22=47K

Effective Serial No.217 subsequent  Date: 6/20/1967 -R 10743 (present circuit Serial 293)

R21=56K, R20=56k , R19=68K, R78=56K , R61=470, R62=560, R63=1.5K R64=1.5K
R58=150 , R22=47K

Hope this helps:.!! I´ll make some highres pictures next days and post them here.

cheers

Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: Biasrocks on January 17, 2010, 11:59:47 AM
Here some informations about the pushbotton resistor values.

Hope this helps:.!! I´ll make some highres pictures next days and post them here.

cheers



Awesome,

Are these ratio values from your copy of the schematic, or your actual units?

If you could also include some pics of the mainboard to verify against that would be a big help.

Mark
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: Neeno on January 17, 2010, 01:44:18 PM
Great job La-2a...
And it's also great that you still have the original schematics, and well, of course the real units.
So you own an original 1176 and a rev A.

You're the one that can really help us getting a real rev A clone.
Now, it would be just great to have some high resolution pictures and if possible also a good scan of the schematics, since the ones we all own are almost unreadable at some spots.

Thank you for your help in advance.
I think we're all looking forward to hearing from you.

Cheers
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: zmix on January 17, 2010, 03:09:38 PM
...
Now, it would be just great to have some high resolution pictures...

Page one of this very thread has some pretty clear photos of the internals of my original bluestripe, someone could check these resistor values against the various schematics...   ;)  :

EDIT:  Here is what I think the resistor values are:

Top left  rear  row: 1k, 560k, 1M, 22k, 6k8
2nd left rear row: 27k,  2.2M,  68k,  82Ω
3rd left center row: 3.9M, 2.2M, 270Ω, 1k8 , 910


Front left center clusters:
row 1: 3k9, 1k5, 680Ω
row 2: 10k (vertical) , 1k5,  1k (R44) , 4k7,
row 3,4:   1k5, 8k2,  2M7 (R74)

RIght top row: 82k, 1M2, 8k2, 560Ω
Right center row: 2M7, 10k, 150k
Bottom right row:  2M7, 1k5, 27k, 18Ω
(http://www.groupdiy.com/index.php?action=dlattach;topic=34502.0;attach=765;image)
 
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: Neeno on January 17, 2010, 03:55:37 PM
Hi zmix !
Thank you for the pictures, I tried to track the pcb from the circuit, but it is pretty difficult.
In fact the pcb traces aren't really visibile, and the perspective doesn't help really.

If only I could have a chance to have a bluestripe for a day or two I'll do it of course.

In any case thank you very much for posting them, since we could easily identify almost all the caps and some of the resistors.
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: Biasrocks on January 17, 2010, 04:49:50 PM
...
Now, it would be just great to have some high resolution pictures...

Page one of this very thread has some pretty clear photos of the internals of my original bluestripe, someone could check these resistor values against the various schematics...   ;)  

Thanks for those!

I did check your photo's against the schemo. It turns out that yours is a REV B which doesn't have the dual FET pre-amp.

The info, we're looking for pertains to the earlier versions with serials under #216. A truly rare beast, but it looks like we might be getting closer.  8)

Mark
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: zmix on January 17, 2010, 05:03:11 PM
...
Now, it would be just great to have some high resolution pictures...

Page one of this very thread has some pretty clear photos of the internals of my original bluestripe, someone could check these resistor values against the various schematics...   ;)  

Thanks for those!

I did check your photo's against the schemo. It turns out that yours is a REV B which doesn't have the dual FET pre-amp.

The info, we're looking for pertains to the earlier versions with serials under #216. A truly rare beast, but it looks like we might be getting closer.  8)

Mark

I am aware that mine is a rev B, but Are you sure that the Rev B didn't have the dual FET? My schemo shows it, and  q4 is socketed, as are the other FETs....
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: Biasrocks on January 17, 2010, 05:30:48 PM
I am aware that mine is a rev B, but Are you sure that the Rev B didn't have the dual FET? My schemo shows it, and  q4 is socketed, as are the other FETs....

Hi Chuck

I'm not sure which schematic you're referencing.

REV B as noted in the 1176 docs from the JBL site shows this note for 1176 "B".

"Two transistor input amplifier"

The REV B schematic shows this as well.

Mark
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: la-2a on January 18, 2010, 11:21:45 AM
Hi, I uploaded the scans.  1176_125 is serial 125,  1176_293 serial 293.

here the link : http://yfrog.com/dy11761251jx

Hope I could help and all is O.K. Pictures will follow soon when I am back in the studio :)

I was just thinking about recapping the units. What would you guys do.?? Keep it original.??

cheers
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: Biasrocks on January 18, 2010, 11:36:09 AM
Hi, I uploaded the scans.  1176_125 is serial 125,  1176_293 serial 293.

here the link : http://yfrog.com/dy11761251jx

Hope I could help and all is O.K. Pictures will follow soon when I am back in the studio :)

I was just thinking about recapping the units. What would you guys do.?? Keep it original.??

cheers

Thanks for those!

You should definitely recap it, you need only do the electrolytics and tantalum capacitors.

Everything else, leave as is.

Mark
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: la-2a on January 18, 2010, 11:47:36 AM
Hi, here the pictures of one of the units .Serial 293 labeled B-Version. The other one is
is older and has no LN modification. It should be the real A-Version.

Cheers
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: la-2a on January 18, 2010, 11:48:56 AM
another one SN:293 -B
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: la-2a on January 18, 2010, 11:50:24 AM
ONCE MORE :)
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: barclaycon on January 18, 2010, 12:53:19 PM
la-2a
Thanks for the schematic scans - some of the clearest I've seen.

When you get chance can you do some pictures of your 125 unit, like the ones you've done for the 293.

They would be extremely useful.

Thanks again.
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: ChrioN on January 19, 2010, 09:41:56 AM
This thread confuses me  ;D
I hope someone makes all the hard work for the rest of us.  :D
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: la-2a on January 19, 2010, 05:03:12 PM
Hi here  we go, here are the pictures of my Bluestripe Serial Nr. 142 ....sorry not 125 like It was written on the schematics , but not that far away: And it is  an original REV A.! :) .

I  will make some postings now here because of better resolution.

cheers
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: la-2a on January 19, 2010, 05:04:23 PM
next one
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: la-2a on January 19, 2010, 05:05:55 PM
the pushbottons
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: la-2a on January 19, 2010, 05:08:16 PM
and the serial..........

I hope I could help again ........this forum gave me so much.....

thank you .
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: Rob Flinn on January 19, 2010, 06:05:30 PM
LA2a thanks for that..   You're pics are very useful.   

Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: Rob Flinn on January 19, 2010, 06:25:11 PM
From what I can see so far it seems to have all the resistor values of the Rev "A" diagram.

By the way most of the blue electrolytics on the board look a little past their sell by date.  Have you tried testing them with an esr meter ?
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: la-2a on January 19, 2010, 07:25:13 PM
From what I can see so far it seems to have all the resistor values of the Rev "A" diagram.

By the way most of the blue electrolytics on the board look a little past their sell by date.  Have you tried testing them with an esr meter ?

You will not believe it. I checked them some time ago with my Tenma LCR Meter and the values were inside the tolerance.
Compared to my REV A Clone it has not that open end, but I love them how they are.
But your´re right. I got to recap the units soon  ;). I just don´t know where to buy that big sized
PSU Caps  :D

cheers

Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: Rob Flinn on January 19, 2010, 07:35:34 PM
From what I can see so far it seems to have all the resistor values of the Rev "A" diagram.

By the way most of the blue electrolytics on the board look a little past their sell by date.  Have you tried testing them with an esr meter ?

You will not believe it. I checked them some time ago with my Tenma LCR Meter and the values were inside the tolerance.
Compared to my REV A Clone it has not that open end, but I love them how they are.
But your´re right. I got to recap the units soon  ;). I just don´t know where to buy that big sized
PSU Caps  :D

cheers


D

Does your Tenma LCR meter test ESR (equivelent series resistance)?  That is really the property that is important.  Many caps can spec near to the correct capacitance value but their ESR is out of spec.  TMostly I notice that the smaller values are most problematic.  You may find that the larger PSU caps are ok.


Also how did you populate you blue stripe clone, which diagram did you use ?? DOes it sound like your originals ??
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: la-2a on January 19, 2010, 08:30:02 PM

[/quote]
Also how did you populate you blue stripe clone, which diagram did you use ?? DOes it sound like your originals ??
[/quote]

I used  the complete Hairball Kit inclusive  Altran C-3837-1 and EA-5002 transformers, mnats  rev A board, the orange drop 1mf caps.

Resistor values pushbutton now: 180R,470,470,1.5K ,10M, 56K, 56K, 68K. (130K changed to 68K)
R46 = 22K.
The reason why I went to this threat was, that I was not satisfied with the threshold and the ratios.
So I went to compare the pushbutton values and to make some changes.  (I already work on that. :) )

Than I remembered that I got that schematics somewhere and finally I posted them here and made the pictures to come closer to the real one. But who knows maybe they were new the same like my clone. :)
What I can for sure say is that we are very very  close to the real ones.
Sure there is a difference but I think I cannot seriously compare them until I have not recapped the old units. Now my clone has more top end and smooth . The originals act a bit more harder.......they are more pumping with slow attack and release values.
Finally I can say that in a couple of days when all work is done. :) I will post the results.

Does somebody know where I can get those big PSU caps .?? :)

cheers
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: barclaycon on January 19, 2010, 08:53:33 PM
Thanks very much for the pictures la-2a.
Very useful and much appreciated.
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: Biasrocks on January 20, 2010, 12:19:19 AM
Thanks for the pictures La2a, very cool.

Any chance you could take a picture of the Attack and Release pots?

Mark
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: Neeno on January 20, 2010, 03:16:19 AM
Hi La-2a !
Great pictures, thank you so much !

You can source the caps from http://www.banzaimusic.com/Electrolytics/ or www.tubetown.de
I've got some Sprague Atom will fit.

Thank you very much again !
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: la-2a on January 24, 2010, 08:03:50 PM
Thanks for the pictures La2a, very cool.

Any chance you could take a picture of the Attack and Release pots?

Mark


here the pictures

cheers
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: la-2a on January 24, 2010, 08:04:55 PM
another view :)

cheers
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: kazper on December 12, 2010, 12:41:14 AM
Anyone have the better scan of the schematics, the link is broken. If you can send them to the group emails that would be great!

Another interesting thing is the missing RC network off the attack time control.

Kaz
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: ilfungo on December 12, 2010, 08:15:06 AM
Hi guys
know if there is a layout of the original 1176?
I'd like to build one with PCBs as the original
Thanks
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: kazper on December 12, 2010, 11:31:53 AM
Hi guys
know if there is a layout of the original 1176?
I'd like to build one with PCBs as the original
Thanks

I'm not up on the newer revision A Pcb's, but Mnats A version is basically what your after.

The original A version 1.0 PCB layout was done to the first 1176 schematic, read his post in this thread. His newer boards have slight revisions to get you to A.

Kaz
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: haima on December 12, 2010, 08:04:13 PM
Anyone have the better scan of the schematics, the link is broken. If you can send them to the group emails that would be great!

+1
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: mnats on December 13, 2010, 04:51:03 AM
I stitched together la-2a's scans while working on the V1.2.5 boards: http://mnats.net/files/1176_125.pdf

I've linked the document from my Rev A page (http://mnats.net/1176_revision_a.html) as well.
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: outoftune on December 04, 2012, 09:41:47 PM
finally getting around to this. want to be sure the 'jumper' everyone is refering to is Cx6...and the mod is to replace it with a 47k? Ive already swapped r46 to a 22k and the 130k on the ratio to 68k.
Title: Re: 1176 Plosives: looking for Rev A schematic or high res internal shots
Post by: martthie_08 on April 18, 2015, 03:19:45 PM
Quote
finally getting around to this. want to be sure the 'jumper' everyone is refering to is Cx6...and the mod is to replace it with a 47k? Ive already swapped r46 to a 22k and the 130k on the ratio to 68k.

this probably comes two years late, but if you look at the schematic you will note that Cx6 is not present, so just jumper this (with a bare wire or 0Ω resistor, not 47kΩ).
On the V1.1 boards, Cx6 has already been omitted...


Ok guys, after comparing the various schematics (original 1176, rev A and Mako's rev A) I came across a bunch of values that should be the ones used on the real Blue Stripe. Of course those have not been checked with a real unit, so, please if you own an original rev A Blue Stripe check the values and report back !!!

I did this as an experiment, you don't need to change anything if you followed Mako's BOM, in fact his revision sounds really good as it is !
And well, Mako, thank you very much for the rev A !!!! A great board, an easy build, just lovely !

I've got the values comparing the Rev A schematic to the one used by Mako (Original 1176) which are the ones between parenthesis.

R6 = 2.2M (560k)
R7 = 2.2M (560k)
C6 = REMOVE (33pF across R16)
C6a = ADD 68pF across R7)
R11 = 9.1k suggested by Ed Anderson (10k)
R12 = 2.2k (1k)
R16 = 100k (47k)
R17 = 4.7k (8.2k)
C9 = 6.8uF (47uF)
R30 = 150k (120k)
C11 = 10pF (47pF)
Rx14 = REMOVE (820k)
Cx6 = JUMPER (6.8uF)
R76 = 10k (8.2k)
R54 = 1.2k (470r)
C27 = 0.012uF (0.022uF)

Ratio Board
=======

R22 = 47k (56k)
R19 = 68k (130k) NOTE: If you're using the great Hairball PCBs R19 is marked as R8 on the documentation
R78 = 47k (NOT PRESENT) NOTE: R78 is marked as R10 on Hairball PCBs
R64 = 2.2k (1.2k)

LINE AMP MOD
=========
This mod adds a resistor (3.9k) in series with a capacitor (1000pF) and it should be connected from the (-) of C9 to the junction of WHTRED - R32. Take a look at the picture.

(http://www.studio21.ch/diy/1176%20Rev%20A%20Line%20Amp%20mod.jpg)

sorry to revive this over two year old thread, but in case someone stumbles over it:

the above collected information comes in very handy for anyone wanting to mod their V1 Rev A boards (V1.1 31.01.09 in my case) to the current V1.2.5 schematic values that are what you get when you currently order a board from mnats.

There is one minor mistake in the above information:

R76 = 10k (8.2k)

this should be

R76 = 18k (8.2k)

thanks for all the hard work everybody has put into this project!

EDIT: one more addition to this list, on the ratio  board,
R1 (R58 on schematic) = 120 (180)