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

[tommypiper]

The ez1073-500 colourbook is also well under way.

Thumbs Up, many thanks for the project.

 

[Slenderchap]

I have just ordered the rev2 PCB for the rack version..... it should be here on the 4th March...... I expect that it will be "good to go".

Colin
www.audiomaintenance.com

 

[sr1200]

woohoo ;D

 

[pidah]

Massivly Jummi!!

 

[canidoit]

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

If you switch between mic and line gain, will there be a click or any issues? Should a person turn off the unit first before switching between mic and line gain?

Any reason why you decided not to leave it all in one knob instead of two separate mic and line gain knobs?

 

[pietro_moog]

yeah, i wanna know that too.
personally i'd prefer only one knob as Gain / Line.

 

[dmp]

I think you would have to source a 16 pos switch, while this design gets by with a 12 pos Grayhill + another Grayhill for line.
My opinion is that it could be even simpler - with just the mic gain switch (12 pos) and a switch from mic to line. I built my EZ1290 preamps this way, and wired the toggle switch to flip between the mic tx and the line tx. I did a single pad that drops the line input after the Tx by 20 dB (which is all the line positions do, is switch pads), but left the mic gain engaged, so I could bring up the level that way. It works well, but Slenderchap's method will be fine also, in my opinion.

 

[Slenderchap]

If you switch between mic and line gain, will there be a click or any issues? Should a person turn off the unit first before switching between mic and line gain?
Any reason why you decided not to leave it all in one knob instead of two separate mic and line gain knobs?

The click between mic and line is no more noticable than that when changing mic gain... so I would say no issues.

Using a single gain control would be much more expensive.... a triple gang 24 position PCB mount Elma is about GBP 70..... and to fit the PCB's you have to dis-assemble it.... plus the PCB size would increase (and so cost more)..... and the cheaper hand wired version completely negates the goal of it being "ez"......

I would expect a line input device to have a gain control which is zero in the centre and +/- 20dB (or +/- 16dB) at each extremity.... like a console.... so that is why it is done that way.

Some people will only want to make it as a line level device (cheaper) so it is much more logical as +/-20dB.

Colin
www.audiomaintenance.com

 

[pietro_moog]

oks, i'm in

 

[pietro_moog]

any news on this project?

 

[NoBass]

I'm going to take one 500 for sure ! Great project. I hope the kits, full or partial, will be available soon...

 

[Slenderchap]

The 500 series is done..... just waiting for matalwork to confirm everything is OK with it all..... the faceplates are due about the 3rd March (Friday.... ish)

The rackmount rev 2 PCB is due to me on Wednesday.... should have that built and checked by next week....

Colin
www.audiomaintenance.com

 

[Sarcastic Sound]

bump... update on timeframe of availability?  ;D

 

[Slenderchap]

The 500 series version metalwork fits just fine..... been building a handful the last few days just to check the accuracy of the colourbook.... no errors but could do with a bit more detail.

We have a whole bunch of PCB's and metalwork so kits could include those..... I'll sort that out asap.

The rack version rev2 PCB came last week... just not had chance to build it yet.

I'll try to remember to do a couple of photos tomorrow of the completed 500 version.

Colin
www.audiomaintenance.com

 

[Slenderchap]

Here is a completed one.... (I've just got another 29 more to make).

Faceplate is powdercoated grey with white screenprinted text.

Colin
www.audiomaintenance.com

 

[sunnen1]

looks very very nice!!!

 

[Sarcastic Sound]

looks like the project is in tip top shape... looking forward to building many of these! 

 

[pietro_moog]

nice. i don't wanna break anybody's balls but, how is it going?

 

[Slenderchap]

The ez1073-500 is done..... just need to add a couple of items to the build instructions (mainly how to fit the faceplate)....

The second revision of the 1U rack version is done and just waiting for another mains transformer....which will be here in a few days (being wound today).... it will need a rev 3 of the PCB (I accidentally drew the library symbol for the toggle switches back to front.... so "IN" is up and "OUT" is down.... oops)......

Soon as the new mains transformer is tested, I'll test and up rev the PCB but on a short lead time.

Colin
www.audiomaintenance.com

 

[pietro_moog]

nice. thanks Colin.
i hope i can build a couple of 1Us this summer