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

[spneca]

Hello all,

I just finished a build, and the line input and eq works great.  I checked the power voltages and adjusted the output bias and everything was fine.  My problem is that the Mic Pre section is not passing any signal.  I did some probing and found that there is continuity between pins 2 and 3 of the mic in.  Looking around the board , I could not find any obvious short.  I did some trace cutting and the short does not appear to be near the connectors.  One thing I noticed is that all of the contacts of SW4 (the impedance switch) have continuity.  Could it be that I have a bad switch?  Could this be the cause?

Hi there, I'm by no means an expert but I can share my experience after two successful builds, since I had similar issues.
Continuity on the mic input between pins 2 and 3 is normal as these pins are connected through the mic input transformer which has a low DC resistance. I have the same on my two builds and everything is working fine. One hint if you are using a dynamic mic, make sure the phantom power is not on. The 48V switch pointing downwards is the phantom power on position, so if you are using a dynamic mic it should be pointing upwards otherwise it wont pass any signal. The labeling on the frontplates (from both Dan's) are a little bit confusing regarding this, and there is no led indicator for the 48V on/off position.
J.

Thanks for the reply.  Unfortunately, this did not solve the problem.  I used an SM57 to test, and I got the same result with the phantom power switch in both positions.  If I hit the top of the mic I can hear a very quiet impact sound, but the gain doesn't seem to affect it at all.  I tried the mic and cable on another pre to verify that they are working, and they both checked out fine.

 

[ding]

How is everyone getting their 6.35mm pots to fit the 3.23mm holes on the grey fluted neve style knobs from classicapi?

 

[haystack]

I'm not sure they are, are they? I thought they were for thin shaft pots - I may be wrong here. I am
ordering - when in stock - the blue/grey and maroon ones. You can get grey elmer knobs that are 6.23 mm which are a bit like
the marconi type.

cheers

Haystack

 

[ding]

I could swear that Aaron said something about drilling into the aluminum knobs to make the hole bigger but now I can't find the quote. Is this an option or will I just screw up some nice knobs?

 

[haystack]

Oh perhaps you can, I wondered where people were getting the fluted ones as well as the pointer 6.4mm ones.
I would like a mixture on my 1073 not all pointer ones and would also like some fluted knobs if they fit.

Hay

 

[stribor1]

I drilled the grey fluted marcconi style knobs from CAPI (I think I used a 6mm drill), no big deal just use a vice to hold them down and be careful on the depth when you drill.

However, a bigger problem is that the shafts of the pots are a little bit to short for these knobs and it's a tight fit to lock the knobs as the knobs locking screws position is too far away from the knobs edge. A managed to do it on one unit but on the other one two knobs are constantly getting loose. I'm trying to figure out how to extend the shafts for 2mm with an epoxy glue. The best solution would be to use pots with at last 2mm longer shafts if you want to use these knobs.

They sure look cool but it's a hustle to get them fixed with Collins kit.

 

[ding]

Are you using the 15mm shaft length pot?

 

[stribor1]

Are you using the 15mm shaft length pot?

Hmmm, I used the ones coming with Collins kit and although the Colorbook's BoM quotes 20mm shaft the ones that came with my kit are 15mm. Just opened the case to measure them, didn't notice this so far. The part of the shaft which is sticking out of the case is barely 8mm and this is approximately the position of the locking screw of the grey CAPI flutter knob so it's very difficult to lock the knob which this shaft length.

Are you guys getting pots with 20mm shafts with the kits you ordered?

 

[stribor1]

Are you using the 15mm shaft length pot?

Hmmm, I used the ones coming with Collins kit and although the Colorbook's BoM quotes 20mm shaft the ones that came with my kit are 15mm. Just opened the case to measure them, didn't notice this so far. The part of the shaft which is sticking out of the case is barely 8mm and this is approximately the position of the locking screw of the grey CAPI flutter knob so it's very difficult to lock the knob which this shaft length.

Are you guys getting pots with 20mm shafts with the kits you ordered?

Actually, just figured that the 20mm reference for the pots in the BoM is referring to the diameter and not the shaft length.

 

[stribor1]

Are you using the 15mm shaft length pot?

Hmmm, I used the ones coming with Collins kit and although the Colorbook's BoM quotes 20mm shaft the ones that came with my kit are 15mm. Just opened the case to measure them, didn't notice this so far. The part of the shaft which is sticking out of the case is barely 8mm and this is approximately the position of the locking screw of the grey CAPI flutter knob so it's very difficult to lock the knob which this shaft length.

Are you guys getting pots with 20mm shafts with the kits you ordered?

Actually, just figured that the 20mm reference for the pots in the BoM is referring to the diameter and not the shaft length.

This is what I'm talking about, notice how the locking screw comes to close to the shaft edge.

 

[stribor1]

One more tip of you are going to drill the grey CAPI knob, don't forget to remove the locking screws prior to drilling.

 

[delichef]

First post here, I just completed 2 of these kits. Both worked straight away and sound fantastic! Hats off to Colin/AML for making such a quality kit and to Dan of collective cases.

The last bit I need to get sorted is the knobs. I have the red/blue/gray Marconi style from CAPI, they fit and look great. The gray round knobs from CAPI were out of stock, so I've been waiting for those to finish it up...but it looks like those may not fit?

I see the Elma vintage round knobs with the plastic skirt (cae041189). Has anyone tried these or know of a source to order them from?

 

[littlesicily]

1st time post, 1st time build (ez1073)

Hello to all,

1) What are the proper fuse ratings to be used for the IEC connector?

2) Am I correct that Mic and Line transformer 8-pair of connection closest to the back (PL8, PL9) of the PCB are NOT connected to anything?
I only see traces on the underside of the PCB going to/from the PL10, PL11.

 

[ding]

1st time post, 1st time build (ez1073)

Hello to all,

1) What are the proper fuse ratings to be used for the IEC connector?

2) Am I correct that Mic and Line transformer 8-pair of connection closest to the back (PL8, PL9) of the PCB are NOT connected to anything?
I only see traces on the underside of the PCB going to/from the PL10, PL11.

1) use the search feature and search the thread. Could come in handy to know how to do that.
2) seeing as there are no audio connections on top of either transformer it would be funny of Colin to have wired those pins to anything.  ;D

Good luck

 

[littlesicily]

1st time post, 1st time build (ez1073)

Hello to all,

1) What are the proper fuse ratings to be used for the IEC connector?

2) Am I correct that Mic and Line transformer 8-pair of connection closest to the back (PL8, PL9) of the PCB are NOT connected to anything?
I only see traces on the underside of the PCB going to/from the PL10, PL11.

1) use the search feature and search the thread. Could come in handy to know how to do that.
2) seeing as there are no audio connections on top of either transformer it would be funny of Colin to have wired those pins to anything.  ;D

Good luck

Thanks Ding. Being a noob, I just wanted to be sure and not assume anything   Thanks for your reply.

 

[delichef]

Has anyone connected a fader in place of the final 10k pot (and shunt the resistor to make it a full fader)..and used the 1073 like a mixer channel?

I was thinking about running 8 channels into an Api 8200(a?). Since the 8200 doesn't support connecting a fader pack, could I just run the gain levels up on the 8200 and mix into them with the 1073 faders for volume?

 

[Beauvais]

Just got two ez1073 kits and am populating the board now. First question: The two voltage regulators touch the heat sinks without insulation, so their 'back' is connected to ground, right? Also, do I need to solder the big pins from the heat sinks? Thanks!

EDIT: OK, to answer my own question in case somebody might be unsure about the same thing. It's yes to both. 

I can say this with certainty, as both my units work flawlessly and sound great!

 

[ding]

I just finished my ez today and no smoke! I am only getting 23.8 volts. Is that sound right? Also, changing the output bias trim does nothing. I am at -300mv. Maybe the trim resistor is shot?

Edit: The output sounds very distorted so I am guessing this is normal when the output bias trim resistor is not working.

 

[ding]

Hello groupDIY comunity! I am stumped with my ez right now. Maybe someone can offer me some assistance. The preamp will not give me any output (maybe undetectably low) unless I turn the mic level grayhill switch all the way up and then I get a mountain of distortion. I am getting 28.5mv across the 1 ohm (R26) resistor and it wont change no matter how much I turn the bias trim resistor. I have replaced the 5k trim resistor just in case it was damaged. I have also replace the 2N3055 thinking that could be the problem with not joy. Some things of note: my 1R resistor is 1/4 watt and sometimes when I am measuring the current across it I blow a fuse (100mA). I looked below to see if the resistor was touching the chassis but it is not. The resistor does not look burned or smell. Any ideas where I can start to trouble shoot this? Thank you all so much. I am really looking forward to finishing this project.

 

[ding]

Okey I discovered that there's a problem with my output Bias now. I only measure 28.3 MV Dc across R26 and it doesen't change in value when turning R20 ( the output bias trimmer ). I may have damaged the semiconductor D3 with my dmm at some point could this be the problem? Edit: Wasn't the diode..

No one have any clue why the output is so low? The tech I left it to didn't leave it back for like 3 months and said he lost his wife and children and couldn't help me for a year at least. And there's no other technicians that want to help me for a fair price down here really.

/Isak

Similar problem. There has to be something I am missing here. Sillen is still no closer to figuring it out either. /headscratch/ -  :'(