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

[kepeb]

depends on time frame but catch up and be in for two 500 series eventually 

 

[mikefatom]

[...]

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Wow Pete.  That looks sweeeeeeeeeet!  Well... all your panels do really!  8)

 

[south2577]

Beautiful Pete!

I'll take 2 x panels.
Are you doing any 1 unit panels? I'd like to order everything at the one time if possible.
I'm planning 2 x 1073 500's and 2 x 1073 1U.

cheers
Ben

 

[pidah]

Very nice!
I like this color scheme,but in Neve it will be even better,surely.
Well, I'll take 2 for starters,but surely will end well past 4.

Thanx for wanting to do this,loverly project!
Cheers,
Pieter

 

[Slenderchap]

Fits and works a treat...

Colin
www.audiomaintenance.com

 

[jandoste]

Fits and works a treat...

Colin
www.audiomaintenance.com

Wowwwww ! Great job Colin!
I want it !

 

[Slenderchap]

I have also made it simpler to build by combining the opamp subcards onto the upper PCB.... there was more space than I had originally anticipated.

Colin
www.audiomaintenance.com

 

[millzners]

Beautiful, how's the rack unit coming along?

 

[sunnen1]

drool : )~

 

[tmuikku]

Jeah, looks cool and possibly doesn't sound that bad (nevere heard one), ,maybe someday

 

[millzners]

I'm wondering if the 1 RU design will allow me to put two boards in a 2 RU chassis and run both of them off the same power supply...  I'd miss out on the stellar panels that are being made for this project, but still... I wonder if the PSU design could handle that and if I'd run into more problems than it's worth...

 

[Slenderchap]

The 1U version is still waiting for the custom mains transformer.... hopefully it will turn up this week....

I am sure you could put 2 in a 2U box..... and I expect that the power supply could handle it (when I came up with the transformer spec I am sure that I made it large enough for 2 circuits in one box on the basis that lots of people will want to use it for a dual mic pre circuit).....

However, you may end up with crosstalk between the output transformers as they would be directly on top of one another.....

Colin
www.audiomaintenance.com

 

[datune]

Count me in for 2 x 500 series, including those lovely looking panels!

 

[millzners]

The 1U version is still waiting for the custom mains transformer.... hopefully it will turn up this week....

I am sure you could put 2 in a 2U box..... and I expect that the power supply could handle it (when I came up with the transformer spec I am sure that I made it large enough for 2 circuits in one box on the basis that lots of people will want to use it for a dual mic pre circuit).....

However, you may end up with crosstalk between the output transformers as they would be directly on top of one another.....

Colin
www.audiomaintenance.com

That's great news about the PSU. 

Yes the cross talk was my biggest concern...  I am hoping it may be possible to reduce considerably with some custom shielding between the two, or maybe taking them outside of the chassis.  But either way since I have a spare 2U chassis laying around it seems like a great option even with the added difficulty.

 

[dmp]

I'm interested in a pair of rack mount 1073s. Awesome project.
I'd probably use an external PSU so would not need a custom mains transformer.
How does the output trim pot work?  
And, do the mic gain / line gain switches interact? If I recall correctly, the 1073 line input gives 6 pad positions feeding into the second gain stage, which has a gain determined by the position of the third deck of the mic gain switch.  I would think it would need a dpdt switch, and from the picture it looks like you are using a spst.

 

[Slenderchap]

Luckily, I had already added spade terminals to the DC rails of the ez1073 rev2 PCB so that you can easily plug in external power on 1/4 inch spades.

The output trim is between the 2nd and 3rd stages.... currently it is set for -10dB trim... but I am sure that with a couple of resistor value changes it could go to -infinity.

On the rev2 PCB it has a DPDT switch with the gain stage 2 boost routed through the second pole so they are independent.... however that is not the case on the 500 series version (so it should really say "cal" in the lowest mic gain position)... there is actually just not enough tracking space on the 500 series to get an extra pin on the faceplate PCB (although I'll take another look at that).... it can easily be modded with a piece of wire but tracking it on the PCB is incredibly difficult (on the 1U version it was trivial).

We should get the mains transformer tomorrow so the rev 2 can be fabricated once it has been checked.

Colin
www.audiomaintenance.com

 

[millzners]

I'm interested in a pair of rack mount 1073s. Awesome project.
I'd probably use an external PSU so would not need a custom mains transformer.

Yeah I was thinking about that too, were you planning on making one or using one you already have?  I'm just curious what your approach would be, whether it's a fixed dc output, or a variable supply.

 

[dmp]

After building a psu for my 51x rack, I decided to use the same connector and pinout for preamps, so all my gear will use the same psu(s). I'm using the Amphenol connectors. So to start with I'll just use the PSU I have (connected to just 48/24/0v). I have plans to build another psu though.

 

[Soeren_DK]

Hi Colin.

Thanks for this thread. This is heaven-sent. 

Does Gustav make the 1u PCB version now as well? Did you calculate a approximately price for the 1U?

Cheere
Soren

 

[Slenderchap]

On the rev2 PCB it has a DPDT switch with the gain stage 2 boost routed through the second pole so they are independent.... however that is not the case on the 500 series version (so it should really say "cal" in the lowest mic gain position)... there is actually just not enough tracking space on the 500 series to get an extra pin on the faceplate PCB (although I'll take another look at that).... it can easily be modded with a piece of wire but tracking it on the PCB is incredibly difficult (on the 1U version it was trivial).

I have now managed to re-track the ez1073-500 so that it also has gain independance.... same as the rack version.... soon as the new PCB is checked out I'll send Gustav the newer version (luckily he hadn't actually started).

I expect to order the rev 2 of the rack version on Monday.... so it should not be too long before Gustav has that as well.

The ez1073-500 colourbook is also well under way.

Colin
www.audiomaintenance.com