[BUILD] 1176LN Rev D DIY

[jordan s]

I checked the mnats schematic and bom, neither of which specify the voltage rating of that cap. Thanks for the help.

 

[Echo North]

The original usually does but depending on the version, they can be a hard read.

http://www.waltzingbear.com/Schematics/Urei.html

 

[jordan s]

No kidding, that rev D schematic is nearly impossible to read. It doesn't seem specify a voltage rating for C1, unless it's in the notes, which I can't read. Thanks for the good resource though.

 

[Biasrocks]

There is a clearer version of all the 1176 schematics contained in the manual on the JBL Pro site.

http://www.jblproservice.com/pdf/Vintage%20JBL-UREI%20Electronics/UREI-1176LNmanual.pdf

If you look at the schematic. C1 is the first component past the gain control FET in the audio path. Since this cap is handling audio I would anticipate a 25V capacitor to do the job nicely, in fact in almost all cases for line level and below audio signals you're going to be okay with a 25V capacitor. Since this is a film cap, the abundance of 25V caps is limited (or non-existant), hence the higher voltage rating.

Mark

 

[jordan s]

Awesome, thanks for the tips guys!

 

[rrs]

Just about to build another 1176 this time a dual so using Mnats PCB for Meter and Ratio boards allong with Hairballs stereo kit and Dan's Stereo FET case which looks really cool BTW..

A few differences and just want to be sure so I am about to ask some novice type questions.

1) Hairball Meter 8027 http://hairballaudio.com/shop/product_info.php?cPath=25&products_id=59
Uses 2 LED's 5.6 to 7.6V for illumination. Can I hookup like mono versions here taking voltages straight from toroidal via 2W resistor. An what resistance range is optimal?

2) Also I am assuming the larger connectors on the back of the meter are for meter connections and smaller ones are for the illumination am I right??

3) The rotary switches for Mnats Ratio and Meter PCB's I am assuming as long as they are correctly fitting the PCB all is ok and there is no specifying hole for say pin 1. I see no indicator on PCB to align like an Op Amp would for example.

4) I will be using a fender amp style jewel illumination amp for power on indicator with 6.3V lamp. How is best to illuminate this?
This one....http://cgi.ebay.com.au/Pilot-Lamp-Holder-Suit-Fender-Mesa-Gibson-Peavey-Amps-/370490315643?pt=AU_Amplifiers&hash=item5642f1937b

Any help would be much grateful.

 

[SaMpLeGoD]

Just about to build another 1176 this time a dual so using Mnats PCB for Meter and Ratio boards allong with Hairballs stereo kit and Dan's Stereo FET case which looks really cool BTW..

A few differences and just want to be sure so I am about to ask some novice type questions.

1) Hairball Meter 8027 http://hairballaudio.com/shop/product_info.php?cPath=25&products_id=59
Uses 2 LED's 5.6 to 7.6V for illumination. Can I hookup like mono versions here taking voltages straight from toroidal via 2W resistor. An what resistance range is optimal?

2) Also I am assuming the larger connectors on the back of the meter are for meter connections and smaller ones are for the illumination am I right??

3) The rotary switches for Mnats Ratio and Meter PCB's I am assuming as long as they are correctly fitting the PCB all is ok and there is no specifying hole for say pin 1. I see no indicator on PCB to align like an Op Amp would for example.

4) I will be using a fender amp style jewel illumination amp for power on indicator with 6.3V lamp. How is best to illuminate this?
This one....http://cgi.ebay.com.au/Pilot-Lamp-Holder-Suit-Fender-Mesa-Gibson-Peavey-Amps-/370490315643?pt=AU_Amplifiers&hash=item5642f1937b

Any help would be much grateful.

For 1) and 4) I think the best is bleed current from the +30VDC point on the main PCB... add some resistors like 600 Ohm / 2W for each VU meter. For the pilot lamp, in general is 1.2W, so consume 50mA... If I'm not mistaken... if I'm right use 470 Ohm / 2W.

2) I'm not seeing the back of the VU meter right now, I builded a dual 1176LN a few time ago using this VU's, I'm not sure but I think you're right with that

3) See the photos on mntas website, they will help with that

 

[rrs]

Great thanks.

the rotary boards still have me unsure though as here http://mnats.net/1176-wiring-rotary.html
here is no mention of a correct orientation so can I assume all as long as it fits the PCB holes I will be fine. My Rotary switches are soldered to the PCB unlike the ones used by Mnats above.

Also Re lamp illumination: the 30V point on the PCB will go to the stereo link so will this interfere with that.

 

[SaMpLeGoD]

Also Re lamp illumination: the 30V point on the PCB will go to the stereo link so will this interfere with that.

No problem with that... try to divide between your 2 main boards, don't draw only in one PCB because it could interfere with your filtering part of the PSU... I forget to explain: drawing from a +VDC part of the circuit avoid the AC flickering that you get when connecting the lights directly to the power xformer. You could instead make a little psu for what you want... a bridge rectifier , couple os caps and a LM7809 could give you +9VDC stable... so, just recalculate the resistors 9V -> 6.3V and 9V -> 6V and you're done
Hope it helps
Cheers

Eddie

 

[rrs]

Thanks that seems to have done the trick.

OK calibrated Q Bias and R75 and all went well.

But have struck a problem. I have to turn up the input significantly to get any GR and the output level is way too high.

1) Checked EA5002 transformer wiring which I belive to be correct.
used this as refference.  http://www.groupdiy.com/index.php?action=dlattach;topic=20058.0;attach=616
2) Double checked all wiring connections. seem OK.
3) Input transformer right orientation and wiring.

My only thought and doubt is on the ratio board (Mnats rotary version) marked R-opt 1 Threshold. I did not populate this as I assumed it was optional to use in place of a resistor already on the PCB.

 

[mnats]

1) Checked EA5002 transformer wiring which I belive to be correct.
used this as refference.  http://www.groupdiy.com/index.php?action=dlattach;topic=20058.0;attach=616

Who drew that? While it is a very pretty drawing and much better than I could achieve, a quick glance shows that the output secondary is reversed; there may be other issues as well. Why not rely on the original schematic or my own wiring page?

 

[rrs]

I have wired up 2 mono versions previously using this and another by Skylar as a guide quite successfully (but not the rotary version). Not to be disrespectful to Mnats but I just find there diagrams to be easier to follow for me so thought I would go with a proven formula with the exact parts I am also using.

I am aware the output (blue/red) are reversed and this was explained by the person who posted this.

I also noticed another diagram floating around that originally was to use for Cinemag output transformer but someone has modified it and now shows it as the EA5002 but using Cinemag wiring guide.

Anyway wiring to pad 15 and 17 on my main PCB I have found are reversed. Could this cause the problem I have mentioned above? May be a while till i get a chance to check myself unfortunately..

I should also note both boards show the exact same problem.

 

[rrs]

OK all sorted now time to do the stereo link.

BTW this is my second rev D and also done a mono Rev A.

I really like this one with Orange drops over my previous Rev D with Wima's. Have owned Purple and a Silverface and think the Wimas take off a little of the edge the 1176 is known for.

 

[Stagefright13]

Use the small tabs on Mikes meter for led hook up. Is marked for + and -

Measure your voltage you have and go here: http://led.linear1.org/1led.wiz

I tapped the voltage after the regulator for mine.

 

[jordan s]

Just finished my Rev. D. No issues, no troubleshooting, just gold. This is my second 1176, the first was a Rev. A. Thanks to Mike from Hairball and Mnats for the awesome supplies and documentation.

 

[Adam Smith]

I'm working on a Rev D.

Mouser is listing the 1N914A Rectifier (Mouser # 512-1N914A) as Obsolete. I'm assuming I can sub out the 1N914ATR (Mouser # 512-1N914ATR), as they both have the same datasheet. Mouser seems to agree. But, I though it would be a good idea to check with you esteemed and knowledgeable folks before putting in the order.

advice is much appreciated

 

[earth tones]

I also placed an order with Mouser recently and ran into the Obsolete 1N914A part.  Three other items are backordered, with the following estimated availability dates (one of which is August!).  Did you run into this as well?

505-MKP20.15/250/5
250V .15uF 5%
WIMA Polypropylene Film Capacitors AUG 17, 2011


505-MKP20.033/250/5
250V .033uF 5%
WIMA Polypropylene Film Capacitors APR 20, 2011


505-MKP20.022/100/5
100V .022uF 5%
WIMA Polypropylene Film Capacitors MAY 11, 2011

 

[Nele]

for the 1n914 diode you can also use a 1n4148 and for the wima's just select different caps with the same value and footprint (5mm)
the 914 is in stock in a variety of versions and I guess they all work..

 

[Citrus Hill]

you can also check TAW Electronics in Burbank for the Wima caps.  They got them for my build much faster than Mouser.
Rob Mc.

 

[agauchede]

TAW is where I got mine.

Chris