EZ1084EQ NEW BATCH COMING - SEE MY MARCH 27 COMMENT ON PAGE 38

[Bluzzi]

OK, more troubleshooting....the signal is not making it past the input transformer.  As in, I've got nice signal going into the transformer on pin 2 and 5, but all that's coming out is a loud buzz on pins 7-10 (the output pins).  I've disconnected the output pins from the screw terminals to take the rest of the circuit out, but same thing, loud buzz on pins 7 through 10.  I then verified the DC resistance of the output coils as per Carnhills specs, they both (pin 7 to 9 and pin 8 to 10) measure the correct 56 ohms.  I'm mystified, do I have a bad transformer?  Upon very close inspection, there are no pins shorted (those would also have screwed up the coil resistance anyways). 

Anything else to check or try?
Thanks,
Warren

I'll have more time next week to help you . We can do a Skype and I can see maybe what is going on. Just hang in there. Everytime someone has had a problem it has been a very simple thing. At worse you can send me the board here and I can have a close look.

You can email me.

Cheers

Jim

 

[Bluzzi]

I've got nice signal going into the transformer on pin 2 and 5, but all that's coming out is a loud buzz on pins 7-10 (the output pins).  I've disconnected the output pins from the screw terminals to take the rest of the circuit out, but same thing, loud buzz on pins 7 through 10.  I then verified the DC resistance of the output coils as per Carnhills specs, they both (pin 7 to 9 and pin 8 to 10) measure the correct 56 ohms.  I'm mystified, do I have a bad transformer? 

From reading what you've said you don't mention if pins 3 and 4 are connected together and likewise pins 8 and 9 ?

Good point. I presume following my Build guide? All points on XFR are connected.

Cheers

Jim

 

[lumpylipton]

Hi guys, thanks for staying with me on this.  I have a terminal block soldered on the PCB, and wires soldered to the input xformer.  All wires are connected as per the build guide (pins 2-10).  So, pin 3-4 are joined to make the input coils in series.  However, according to the schematic I looked at and my voltmeter confirmed, the output coils are in parallel, so pins 8 and 9 should not be connected, correct?

Still have the same thing after soldering the vias and going over connections again; good signal on the in of the input transformer, but nasty buzz on the output of the input transformer.  Jim, I may very well take you up on the skype thing, however I will have to borrow a camera from work to do that, I don't have one. 

Do you have transistor voltages so I could verify those?  That might point to me to the area of trouble.
Thanks,
Warren

 

[MatthisD]

Sorry Warren, when you said output on pins 7 and 10 I thought it was for 2:1 not 4:1 in which case pins 9 and 10 from the transformer go to 9 and 10 on the PCB which is 0v. With a test signal at the transformer input and the output pins not connected to the PCB but to your soundcard or other monitoring device will tell you whether the transformer is working as normal or not.

 

[lumpylipton]

Thanks Matthis, I just wanted to make sure.  Some good news at least, I tested the transformer as you suggested (just routed the xlr in/out directly to/from it) and all coils work fine, so we've ruled that out as a problem.  It means I've buggered up something else along the way.  I'm now going to double-check my R and C values.  This is where some sample voltages off a working unit would come in handy to narrow it down.  Thanks again for your patience and tips!  I know I'll get it working eventually, I've successfully built an LA2A, 1176, G7 pre and a zillion pedals and smaller stuff.  Usually any problems I've had are with complicated off board wiring or things like that, but this one is so easy in that regard.
Another thing that would be helpful is pdf's of the PCB layout, it's tough to follow the board and components without that.  Jim, are those available?
Warren

 

[lumpylipton]

Well, I found a big problem.  My BC184 transistors are BC184L type, which has a different pinout than the BC184C.  I do have a proper desoldering station, so I'll remove them, bend some legs, and try again.  I could not find BC184C from Digikey or Mouser, but Small Bear had them, except I didn't notice they were L type.  Where have others got them in North America?

I'm happy to have found a rather glaring issue, but not looking forward to the delicate surgery I'll have to do to all 13 of them!!  It will be all worth it if it works in the end.

 

[lumpylipton]

Well, that wasn't so bad after all and IT WORKS!!!  Thanks a lot for the great project Jim, and all the help Jim and Matthis.  I'm so happy, I'm going to have a beer, even if it is only Monday night!!  I might have 2.

THanks again.
Warren

 

[Bluzzi]

Well, that wasn't so bad after all and IT WORKS!!!  Thanks a lot for the great project Jim, and all the help Jim and Matthis.  I'm so happy, I'm going to have a beer, even if it is only Monday night!!  I might have 2.

THanks again.
Warren

Like I said it's always something silly. So glad you found it man. That is the hard part sometimes. Don't feel too bad. On my first prototype the BC184C's were all wired wrong due to a wrong library I had naively trusted. Taught me a huge lesson and I made my own from then on.

Still 100% success rate on thsi project! It's what I set out to do and so far so good.

You will have a gaz with this puppy. Enjoy!

Cheers

Jim

 

[Volume11]

Anyone have a good source in the US for the inductors and transformers? The exchange rate for the kits in the UK is just way too much. Also, up to how many units will the five fish audio psu power?

Thanks, I'm looking forward to this project

 

[Bluzzi]

Anyone have a good source in the US for the inductors and transformers? The exchange rate for the kits in the UK is just way too much. Also, up to how many units will the five fish audio psu power?

Thanks, I'm looking forward to this project

The Fivefish supply will do OK for 2 units. You could go with a larger power XFR but I think you'd stress the supply somewhat.

The problem is not exchange but shipping fees. There are other inductors but when I looked into them they cost about the same so I didn't make allowance for them in my design. Maybe things have changed now? If anyone has any ideas let me know.

The audio XFRs are Carnhill and you will not get better price than Audiomaintenance I believe. However there are starting to be alternatives to those in the U.S.. I have not tried them so I can't say what they sound like but they are supposed to be replacements. Those I'd like to get around to seeing if they are a viable alternative to the Carnhills. I forget who makes them (they are here on GroupDIY so it should not be that hard but I can't do it just now).

Cheers

Jim

 

[Volume11]

Ok, thanks for the info. I am looking at $800 for two kits... Seems a bit outrageous to me but, in the end this will be a fun project and a great piece of gear. Now it's time to sell something  :'(

 

[Volume11]

The output transformers being heavy you could get: http://hairballaudio.com/docs/1166/1166.pdf which should reduce your shipping from the UK. I can't think of too many alternatives for the input unless you would use the EA mic input with the secondary as the input as is done in another project. Leaving out the lowpass filter will save an inductor and the more expensive rotary switch.

Thanks for this info.. I actually went a few steps further into the order process with AML. Once I put my shipping info in, the vat price went down to about a third of the listed price, making the over all price $667.91. That makes me feel a little relieved. I'll check out the transformers on Mikes site as well. Thanks!

 

[3nity]

Yes hairball EA1166 are great transformers.
Im pretty stocked with those.

And if you ever need something cleaner you can go with cinemag for outputs too.
Too bad they dont do an line input.

Good l

 

[Volume11]

Hey guys I have a couple of questions before I continue my build. From my understanding, if I want to use the bypass switch on the front panel, then I need to use all three relays. Hard bypass bypasses everything while soft bypass keeps the transformers in the audio path, right? What does "In" stand for on the switch, and which bypass is labelled "Bypass" if I have the option for both on the same switch? Is the "In" option referring to the direct in? If this is the case, do I choose which bypass option I would like more, and insert those relays, and jumper the traces on the relay spot that I won't be using? By the way, I am referring to Danderlous ez1084 1u case.

Also, I am looking for a floor box style psu case that will house a five fish audio psu. Anyone have any suggestions? I would prefer aluminum, because the steel ones are a total pain to drill through.

Thanks

Chad

 

[dandeurloo]

I wonder if the PSU would fit in one of my Tube mic PSU cases.  My guess is it would.  They are steel but could be an option.

I was confused on the bypass switch as well.  I think I need to go look but I think EQ in is straight.  Hard Bypass is up and Soft bypass is down.  It makes sense once you use it and is very handy!

 

[Bluzzi]

Hi Chad,

Yes the bypass switch can be confusing when using it. If the switch is positioned and wired as per build guide you have hard bypass in the Up position and Soft bypass in the down position. The middle position (IN) is EQ engaged. So in both cases bypass takes EQ circuit out of audio path. The Hard bypass takes the signal from the XLR and sends it directly to the output XLR. It's straight wire through, so what goes in goes out. Handy when you want to hear what the circuits and XFRs are doing to the original signal.

The Soft bypass only disengages the passive EQ circuit from the audio path. What is left is the XFRs and Class A circuitry. In this mode the Gain switch is still active and you can push the signal if your heart so desires.

There are 2 relays for the Hard bypass. I used 1 on the prototype and first run but relays with that many poles are getting rare so I used 2 smaller and more common ones. If you do not want to use bypass you just hard wire following the jumper markings on the PCB. Voila! If you only one bypass you could use a simpler switch. But Chad that switch is too cool to replace! For the small cost (relatively) of the relays I would keep everything as is. You may not use them all the time but they are there for those times that you would.

I am in the middle of looking for cases myself for power supplies to recommend them. If you find something cool let me know. I'll do likewise.

Hope that helps. Happy DIY.

Cheers

Jim

Hey guys I have a couple of questions before I continue my build. From my understanding, if I want to use the bypass switch on the front panel, then I need to use all three relays. Hard bypass bypasses everything while soft bypass keeps the transformers in the audio path, right? What does "In" stand for on the switch, and which bypass is labelled "Bypass" if I have the option for both on the same switch? Is the "In" option referring to the direct in? If this is the case, do I choose which bypass option I would like more, and insert those relays, and jumper the traces on the relay spot that I won't be using? By the way, I am referring to Danderlous ez1084 1u case.

Also, I am looking for a floor box style psu case that will house a five fish audio psu. Anyone have any suggestions? I would prefer aluminum, because the steel ones are a total pain to drill through.

Thanks

Chad

 

[Volume11]

Ok awesome, that clears that up then, thanks! Dan, I have one of your cases here on hand, so I'll measure the kit when it arrives and report back. This project really is a cool one, I'm glad I took it on. Thanks for the help

Chad

Ps.. Anyone have a source for the power cable? I looked for some four conductor from redco, but I don't know which is the most suitable. I figured that id play it safe and ask you guys.

 

[Bluzzi]

Ok awesome, that clears that up then, thanks! Dan, I have one of your cases here on hand, so I'll measure the kit when it arrives and report back. This project really is a cool one, I'm glad I took it on. Thanks for the help

Chad

Ps.. Anyone have a source for the power cable? I looked for some four conductor from redco, but I don't know which is the most suitable. I figured that id play it safe and ask you guys.

Chad, for the power cable you only need 2 wires as you are carrying +24vdc and 0v from power supply. I'm using a 4 conductor XLR so as not to confuse with 3 conductor. Also if anyone was adding the mike pre they would need the +48vdc so 2 conductors would not have been sufficient. If you have any questions feel free to contact me at [email protected]

Cheers

Jim

 

[Volume11]

Hey Jim, I tried to email you but, no response. Hopefully I'm not bothering you too much. Maybe someone else can tell me if this cable (http://www.redco.com/shopexd.asp?id=656&bc=no) will be ok for power between the psu and racks? If not is there something more efficient for this project? I am not really sure as to what gauge is sufficient and if shielded or unshielded will matter in this case. I won't be using the 48v line so, I was thinking that I can run the shield to the 0v rail and one of the remaining to the 24v. I'll probably make the cable about 8ft. I hate asking such noob questions but, I like to be sure of things rather than finding out the hard way. Thanks again

 

[Bluzzi]

Hey Jim, I tried to email you but, no response. Hopefully I'm not bothering you too much. Maybe someone else can tell me if this cable (http://www.redco.com/shopexd.asp?id=656&bc=no) will be ok for power between the psu and racks? If not is there something more efficient for this project? I am not really sure as to what gauge is sufficient and if shielded or unshielded will matter in this case. I won't be using the 48v line so, I was thinking that I can run the shield to the 0v rail and one of the remaining to the 24v. I'll probably make the cable about 8ft. I hate asking such noob questions but, I like to be sure of things rather than finding out the hard way. Thanks again

Sorry, I thought I did answer you. The cable is no problem whatsoever. You could use the shield on 0v too depending on what the rest of the equipment is wired on rack. If you are not sure leave it out or just connect at source only (the shield that is).

Cheers

Jim