[BUILD] 1176 Rev A - Back to the beginning...

[muffy1975]

Hey team,

here's another picture. Will only let me file one at a time?

Regular John, glad your a fan of team Zissou. Are you a paid intern or a member of the team? If so you will need a glock.

XOX

 

[muffy1975]

Oh yeah,

and team....I used carbon resistors all over  the pre amp and line amp. i think this may have made a difference? In the GR section and meter section they are half metal types and half carbon types.

2n3707's in these areas had an hFe of around 230 hFe and the GR control area had 4 3707's with hFe of over 280hFe.

2n5088's in the meter driver were around 450hFe.

Can people hear a difference using orange sprague 1uf caps? What is the benefit? Shall I get some? They are not cheap are they!!

here's the picture of the meter section with the 2n5088 thangs.

XOX

 

[emrr]

at the schematic says 1/2 W because that's all that was available back in the day?

They are 1/2 W because in manufacturing for the mass market with carbon resistors back then, one would be guaranteed a lower noise floor and fewer complaints by using larger wattage resistors.  There's tons of old professional tube gear built with 1W-2W resistors where 1/4 W would be acceptable from a power perspective alone.   Much of it still relatively low noise after 50 years.   Wouldn't be true to the same degree, if built with 1/4 W.   Today, it's not the same issue it once was.  

 

[kazper]

Can people hear a difference using orange sprague 1uf caps? What is the benefit? Shall I get some? They are not cheap are they!!

715 series
Http://www.smallbearelec.com/Categories.bok?category=Capacitors%2C+Sprague+715+Series%2C+Orange+Drop
716 series
Http://www.smallbearelec.com/Categories.bok?category=Capacitor%2C+Sprague+716+Series%2C+Orange+Drop

Most people rant about the 716, and they cost about the same.

Kaz

 

[phatmateo]

I'm going to try using 2n5088's in just the meter section today.  I'm using 3708's everywhere else.  Does anyone know where to find 3707's in the USA with a hfe >=250?  Mouser seems to not carry any that do. 

 

[Rob Flinn]

Does anyone know where to find 3707's in the USA with a hfe >=250?  Mouser seems to not carry any that do. 

I seem to remember getting mine from ebay at quite a reasonable cost, all with high Hfe.

 

[Matthew Jacobs]

at the schematic says 1/2 W because that's all that was available back in the day?

They are 1/2 W because in manufacturing for the mass market with carbon resistors back then, one would be guaranteed a lower noise floor and fewer complaints by using larger wattage resistors.  There's tons of old professional tube gear built with 1W-2W resistors where 1/4 W would be acceptable from a power perspective alone.   Much of it still relatively low noise after 50 years.   Wouldn't be true to the same degree, if built with 1/4 W.   Today, it's not the same issue it once was.  

Cool, Thanks for explaining that. So basically we can use 1/4W metal film resistors as they are more reliable, but if using carbon comp it's better to go with 1/2W?

As the Rev A is a special beast, is it best to go with carbon comp to keep that "original sound"?

J

 

[Ryanp010]

Please put me down for 20- 1176 rev A blue stripe boards. 9/13/09

Thanks

Ryan
Austin TX

 

[emrr]

So basically we can use 1/4W metal film resistors as they are more reliable, but if using carbon comp it's better to go with 1/2W?

As the Rev A is a special beast, is it best to go with carbon comp to keep that "original sound"?

Today's carbon comp is probably a whole lot better.  I'd personally err on the safe side and use 1/2 W of any type, if it fits.  It's as much a longevity issue as anything. 

 

[barclaycon]

phatmateo wrote:

I'm going to try using 2n5088's in just the meter section today.  I'm using 3708's everywhere else.  Does anyone know where to find 3707's in the USA with a hfe >=250?  Mouser seems to not carry any that do.

I found that the 2N5088's were a bit quieter than 2N3707 types and if you get the G version they all have a higher Hfe than 250.

I was going to build a few of the Blue Stripe units but have decided just to stick with one for the time being. So I've got a lot of parts left over. A set of mnats boards, the pots (except for the input pot), hard to get resistors, and all the semiconductors (except for the matched FET's).
I'll probably put them on Black Market later on Monday.

Whilst I'm here, I can highly recommend Hairball Audio for all of the transformers, matched FET's, switches, VU meter and bits. Excellent stuff. Mike does a complete kit of all those parts (including the input attenuator). Very worthwhile.

 

[regularjohn]

+1 on Hairball!

Mike's a great guy, who's really easy to work with.  Great product, great company!

 

[phatmateo]

ok, so I switched the 3708's in the meter section to 5088's and I was able to read 0.00v dc across tp10 and 11.  Now, when I go to the Gain Reduction Meter Tracking calibration, I cant get the meter to see a drop in db when I engage/disengage the gain reduction.  I should be feeding it 1kHz @ .244v RMS(-10db), correct?  It shows no change whatsoever when its on/off.  Anyone else have a problem like this?  Should I replace R44 with a higher value than 5k?  Someone had suggested this, but I'm not sure if this is whats causing my problem

 

[Echo North]

You want to input a 1kHz 0db signal.

-------------
Input = "24" mid rotation
Output = "24" mid rotation
Attack = full CW
Release = full CW
Compression ratio = 20:1
Meter mode = "GR"

Apply a signal (1 KHz, 0db).

Set output control for 0db as read on an external meter.

Set attack full CCW (off position). Set input control for +10db as read on an external
meter.

Turn the attack control OFF (CCW) and readjust the output level control for "0" if
necessary.

Repeat 7 & 8 until the output drops 10dB whenever the attack control is turned ON.
-------------

I think your problem is that your test signal is too weak to engage GR.

Mike

 

[phatmateo]

Thanks for the quick response Mike   I think I got it all calibrated.  The signal was definitely too low and I see a drop in 10db on an external meter now when the GR is engaged.  The JBL 1176LN manual confused me on that part of calibration, so I appreciate the help!  I'll be ordering a Rev D kit from you soon since I have this project out of the way now

 

[muffy1975]

Team,

I'm noticing that when my rev a is in bypass there is slight rounding of the top end by comparison to the original signal. Is this normal? There is also a slight low mid bump. Is this the sound of the unit?

What's the vibe on WIMA 100V caps for the 1uf and 0.15 uf and the 0.22uf positions in the pre and line amp? At the moment I have normal polyester metal foil caps there?

I notice the UA gear uses Wima caps. Are there particular ranges that sound good? Will they sound as good as the orange drops in this rev a model?

I'm thinking 100v Wima caps for the above values! What's the vibe?

Thanks team

Michael

 

[stereokillah]

hello ,

like Ilfungo my r32 burn , i checked is good value 39 r, but when i disconnect the 5002 transformer , all seems fine. Ilfungo said it is a bad connection batween the pcb and transformer , but i have checked the pdf and follow it, perhaps i do the same little error , that's why i ask you some help to know the good wiring method for the hairball transfomer 5002 please.

start from the corner of pcb

Brown
Withe/BLack
White/Red
Black
Grey
Violet

And finaly orange connected with the yellow.

Is it right

 

[Echo North]

Are you sure you have V2 boards?

If you purchased your boards a while ago you may have V1 boards which have a different wiring.

It should say the date or version on the PCB.

Mike

 

[stereokillah]

that's right Mike  i 've the version1.1
date 31/01/09

without seclection mode otpions

 

[Echo North]

that's right i 've the version1.1

There you go.

MNATS has the V1 PDF on his website.

Although I thought V2's started in 2008.

Mike

 

[stereokillah]

yes i got it already and it's like i said .