Feeler: an "Eee-Zzz" christmas present...ez1073 and ez1073-500

[chipss36]

I would like to help but am 1000 miles from home , offshore and working right now, but everything you need to know is in the color book,  a layout for 120 and 220 vac , if your still stuck there are plenty of pics in this thread, I am very fond of mogami console cable for shielded wire, makes for a very neat clean wire runs, but there is so little wiring needed for this kit, an old mic cable would work  in a pinch,
Get it running , you'll be amazed, just a killer pre/eq.

 

[Slenderchap]

You need to use screened cable for the XLR connections... for the mains I would probably just find an old length of mains flex (0.5 - 1.0 sq mm) and strip the 3 wires out of it... that way you have the correct colours.

Colin
www.audiomaintenance.com

 

[dacapitan]

Thanks for the replies guys - appreciate it, I used shielded balanced Microphone cable, and I cut up an old power cord I had laying around.

I apologize for the n00b questions, but this is my first build,

I have everything good to go except for a power switch, I know this is a simple question but could some one please give me a part number for a power switch, Ive searched all the posts and come up with nothing, Ive searched mouser and I understand it should probably be 240V+ 5A+ but when it comes to ON-OFF / (ON)-(OFF) / (ON)-OFF SPST/SPDT etc Im lost. Is there a part number you could please give me? Or an explanation. Thanks again

(The colour book does not mention any thing about any of the questions I have raised)

 

[rob_gould]

The best option is a double pole single throw switch so that both live and neutral lines are disconnected when the switch is off.

You also need to ensure that the switch is rated for mains voltage.  Not all of them are.

The hardest bit is finding one you like the look of that fits your project...

All these will work :

http://uk.farnell.com/marquardt/1552-3102/switch-dpst-16a-250v-black-i-o/dp/7892527

http://uk.farnell.com/arcolectric-switches/c1350xbaaa/rocker-switch-dpst-black-red-i/dp/273247

http://uk.farnell.com/marquardt/1935-3112/rocker-switch-lamp-dp-100/dp/7892489

http://uk.farnell.com/lorlin/rms1130/rotary-switch-dpst-pcb-terminal/dp/1360551

etc

 

[dacapitan]

The best option is a double pole single throw switch so that both live and neutral lines are disconnected when the switch is off.

You also need to ensure that the switch is rated for mains voltage.  Not all of them are.

The hardest bit is finding one you like the look of that fits your project...

All these will work :

http://uk.farnell.com/marquardt/1552-3102/switch-dpst-16a-250v-black-i-o/dp/7892527

http://uk.farnell.com/arcolectric-switches/c1350xbaaa/rocker-switch-dpst-black-red-i/dp/273247

http://uk.farnell.com/marquardt/1935-3112/rocker-switch-lamp-dp-100/dp/7892489

http://uk.farnell.com/lorlin/rms1130/rotary-switch-dpst-pcb-terminal/dp/1360551

etc

Thanks Rob - That explains the DPST

2 Questions:

1. From what I understand the Voltage Rating will need to be 250VAC or more (EU) and 1A or more to be suitable for mains voltage, is that correct?

2. I'm still not sure what the difference between ON-OFF / (ON)-(OFF) / (ON)-OFF / ON-(OFF) is?

Regarding style, I need a Toggle Switch as Dans Case has a hole with which the switch needs to fit through. (Im sure with the two questions above answered I will be well on my way to power switch purchasing for this and the next couple of projects)

 

[rob_gould]

1 - it depends on the project.  Yes - 1A should usually be enough, and it is in the case of this project.

2 - I'm not sure about what the brackets indicate there either.  Where did you read that?

 

[dacapitan]

1 - it depends on the project.  Yes - 1A should usually be enough, and it is in the case of this project.

2 - I'm not sure about what the brackets indicate there either.  Where did you read that?

Great, thanks! that clears that question up for me, I understand some other projects may require a higher amp rating but I think 5A is a safe bet generally speaking.

The brackets are indicated on the mouser site - If you select the "switch function" menu you will see the options presented there.

http://uk.mouser.com/Electromechanical/Switches/Toggle-Switches/_/N-5g2j?Keyword=Electromechanical+Switches+Toggle+Switches&FS=True

Farnell Also has these available options under "Switch Operation"

http://uk.farnell.com/toggle_toggle

 

[jona]

hi all,

i finished my first ez1073 a few weeks ago and everything worked great.. until yesterday. as soon as i engage eq i do not have output signal anymore. if i disengage eq again, there is output signal again. i measured the output between hot and cold with all gain controls at zero, eq bypass, and 1k sine 0,775V at line input. meter shows 0,558V. if i measure between hot and ground meter shows ca. 0,136V, between ground and cold  ca. 0,417V. thats not normal as well, isn't it ? can somebody help me troubleshooting ?

thanks..

 

[JW]

Hey folks,

I saw Colin has the full kits back in stock again. I don't have any experience with ordering these. Are people in the U.S. generally being charged customs? Trying to factor that into the cost.

 

[sr1200]

As long as you dont get stuffed shipped by TNT. lol. 

 

[JW]

Hmmm

Can you explain that? I'm asking about customs fees. Bad experience w/ TNT? I don't think that's how Colin sends them. Maybe I'm wrong though.

 

[sr1200]

Let's put it this way, TNT has been reported to the DA in my area for numerous fraudulent activities surrounding "duties" and import "fees".  There's a reason that TNT has an F grade with the BBB.

 

[dandeurloo]

TNT tried sending some of that crazy stuff on me as well.  I just didn't pay it.  It's like they are fishing for suckers to give them free money.  I maybe would have paid it if it was 30 bucks but not 250!

 

[jona]

if disengage eq and dial all gain controls to zero and put a 1k sine in the line input and adjust output level of the sine generator that my DMM reads 0,778V between hot and cold at line in. (if i measure between scn and hot or scn and cold get approximately 0,389V. thats how it should be so far). when i now measure the output of my EZ1073 between hot and cold i get 0,590V and between scn and cold 0,389V / scn and hot 0,191V. where are the 0,200V gone ?
i replaced the output tranny, but it´s the same with both output transformers.
if i measure between yellow and brown (input VTB1847) meter shows 0,348V. if i multiply this with 1,7 get ca. 0,590V and this is what i read between hot and cold on the output. i think there must be a very easy answer to my question, but i don´t get it.
it would be very cool if someone could help me with this.. i really want to understand this.

 

[dacapitan]

Well guys, this was my first project ever..... and it works!!

powered the unit up today, the first good sign was the red LED lit up, tested the terminals and R26 all readings were as per the colour book, adjusted the trims correctly and now it is working in my studio.... wow!?

Thanks so much to everyone for putting up with my n00b questions, at least now they are available for others who may come along and search for the same questions.

And most of all thanks to Colin, who has provided us with this superb project....

Just 1 question, when the EQ section is engaged and the High Pass Filter is set to off, then no audio passes through, if the High Pass is set to 50> then the signal becomes audible - is it supposed to be like this?

 

[Slenderchap]

..... when i now measure the output of my EZ1073 between hot and cold i get 0,590V and between scn and cold 0,389V / scn and hot 0,191V. where are the 0,200V gone ?

You cannot measure between a floating transformer terminal and ground.... you will only get a sensible reading between the transformer terminals (unless one end of the transformer winding is attached to a fixed voltage (eg ground))....

... when the EQ section is engaged and the High Pass Filter is set to off, then no audio passes through, if the High Pass is set to 50> then the signal becomes audible - is it supposed to be like this?

No.... there is something wrong.... if it is set to "off" you should get full bandwidth signal.

Next projects (Pultecs) are easier than this.... just built an ezP-1A in 1 hour and 51 minutes from a blank PCB to a fully finished unit.

Colin
www.audiomaintenance.com

 

[dacapitan]

No.... there is something wrong.... if it is set to "off" you should get full bandwidth signal.

Next projects (Pultecs) are easier than this.... just built an ezP-1A in 1 hour and 51 minutes from a blank PCB to a fully finished unit.

Colin
www.audiomaintenance.com

Do you have any clues as to what it may be? I mean, everything else seems to be fine except this? Possibly the pin in the rotary switch placed incorrectly? - I think I may have called it - I have 6 Turns on my High Pass, I think there should only be 4?

** Problem solved! - I had turned the High Pass Switch when inserting the pins because it was giving trouble when trying to insert them - My gosh, what a task it was to get the pins out!  So it was switching to the incorrect positions, Plugged it back in and the unit is working 100%

Looking forward to the Pultecs!

 

[Slenderchap]

Getting the pins out of the Greyhill's can be a struggle..... but you can use a magnetised screwdriver to encourage them to pop out as they are made from steel...

Colin
www.audiomaintenance.com

 

[guitar4444]

Hi EZ1073 builders,

I have built 6 x EZ1073 and all have a small problem with hum. I've spoken to Colin a little about this but wanted to get some other thoughts as I'm sure Colin is also very busy.
If I plug it into my system (fireface 800) and then apply 6db input gain and 6 db output gain and turn my headphones up full I can hear hum when the EQ is engaged. It is not there with the EQ out. Also the line in has a much smaller amount of hum but more than the mic in. The mic amp on it's own is totally clean.
I was wondering if anyone can confirm that this is "normal" for these preamps.
I have been meticulously over the circuit board on at least one of the units and can find absolutely nothing wrong and all functions seem to work properly and all the units are the same with regard to hum and performance. Also I have the transformers off the board at the back of the case and a mains filter installed
The amount of hum is not loud enough to be a problem in general use though if recording something with a wide dynamic range or if allowing a lot of headroom and the possibility of compression later it could be a problem. It would definitely be better if it wasn't there.
Also if anyone else has this same hum or has tried running from an external or different power supply has it helped?

cheers  Greg

 

[guitar4444]

Hi Again,

Ok I've done some measurements.  I've just realized that the RME digicheck software has a convenient noise measuring function. So not as bad as I thought.
So the figures I get are into the line in set at +4 mic level +15 (input not shorted, no mic connected) output trim on full level. When the EQ is engaged all switches are off and gains set to zero.
EQ out  =  -99.7db  (RMS +3  20hz -20khz)
EQ in  =  -92.6    (RMS +3  20hz -20khz)

so about 7.1 db more noise. It sounds like mostly hum.

cheers  Greg