Studio Console-homework

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Sonic

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Aug 17, 2006
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58
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RUSSIA/Cherepovets
Prologue (or why I need it).
Since the distant 80s, when we played our own music with friends and there was a rather noisy and unpretentious 12-channel Soviet mixer "Electronics PM-01" in our rehearsal room, I wanted to get a cleaner sound. But then there was no great experience either in electronics or in the principles of mixing sound. In those years, I collected only guitars and pedals for them.
In the 90s, I got sick with the idea of creating my own studio, but there was no room for a studio, nor the possibility of purchasing equipment (in our country there was quite a large inflation+ default of 1998).
By 2006, when I was already working as an on-air technician at a TV channel, I began to study the technical part of studio equipment (including, thanks to this forum, when it still had the name prodigy-pro), while simultaneously developing condenser microphones/capsules.
In the summer of 2007, when left to work at a local theater as a leading engineer and sound engineer, more closely engaged in mixing sound at performances and concerts there. Then I became more clearly aware of what functions I needed from the console. At the same time, I purchased three Soviet 16-channel studio consoles "Electronics PM-03". I improved the sound part, changed the Soviet OpAmps to NE5534\5532 and OP275. I added the number of AUX up to 8 and the number of subgroups up to 12 (thanks to the merger of all three consoles, where there were 4 subgroups in each). Mic preamps were assembled according to the Shiklai scheme and on SSM2019\INA217. EQ there were standard, 4-band, according to the classic scheme of Soundcraft 200\400\800 mixers. I wanted more functionality from EQ than I had.
2015-10-01 19-10-54.jpg2015-10-01 19-11-07.jpg2015-10-01 19-11-25.jpgSoviet upgraded consoles. The room was recently allocated from the theater for a studio and workshop, so it is not yet properly equipped here.

So, after that, the idea of building a console from scratch began to mature in my head. The project began to be implemented with the development of circuits and PCBs in February 2019. The first prototypes of the boards were ready by August 2019.
Since there is a lot of work during the theater season, the project is not progressing very quickly. I have been on vacation since June 28, so something should move (I'm already finishing with switching the master section).
So, the pictures:
The first PCBs. I did it with the help of a negative photoresist on film. I stroked the PCBs on the laminator. The process of copper etching took place in a solution of citric acid. Tinning of copper is chemical:
IMG_20190628_093953.jpgIMG_20190628_171937.jpgIMG_20190629_101850.jpgIMG_20190720_115807.jpg
PCBs in the series:
IMG_20190726_171911.jpgIMG_20190726_175408.jpgIMG_20190823_080625.jpg
Box with Connectors from China:
IMG_20190622_115426.jpgIMG_20190622_115439.jpg
Production of bands for modules:
IMG_20200909_230612.jpgIMG_20200909_230621.jpgIMG_20200909_230633.jpgIMG_20200909_230647.jpgIMG_20200909_230753.jpg
 
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groselicain

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Feb 9, 2009
Messages
181
Location
Tennessee
Now that I have more of your history, I have so much more appreciation for everything you're doing. Thank you for sharing this with us! I look forward to reading and learning more about what you've done.
 

Sonic

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Joined
Aug 17, 2006
Messages
58
Location
RUSSIA/Cherepovets

groselicain, boji

thanks for feedback! I will post pictures of last year, there are some. Then I will make fresh ones, in the process of construction, and spread them out.

It became interesting to me that in the West (Europe and America), many more people are interested in mixing music through analog consoles than in Russia, although it is more expensive commercially. It is already difficult to find threads on our music and technical forums dedicated not only to the construction, but also to the modernization of analog consoles. The current threads relate mainly to either digital consoles or ITB mixing. Although, even 7-10 years ago there were interesting threads.

I don't want to think that I have already passed into the category of dinosaurs. ))) I'm not even 50 yet, but I'm already around that.

So, I continue:​

Production of panels for modules:
IMG_20200302_164158.jpgIMG_20200302_164245.jpgIMG_20200322_143504.jpgIMG_20200322_143512.jpg
Birch side panels:
IMG_20200725_170052.jpg
Somewhere I lost pictures of alder armrests.
 
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Sonic

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Joined
Aug 17, 2006
Messages
58
Location
RUSSIA/Cherepovets

abbey road denfer

, thanks!
I found the lost pictures-fitting armrests:
IMG_20200830_135539.jpgIMG_20200830_135553.jpg
The modules are ready for installation:
IMG_20200626_164542.jpgIMG_20200626_164614.jpgIMG_20200626_164647.jpgIMG_20200626_164729.jpgIMG_20200626_164748.jpgIMG_20200626_165044.jpgIMG_20200626_165313.jpgIMG_20200626_165458.jpgIMG_20200626_165514.jpgIMG_20200626_165528.jpg
wow, all that etching. you must have the patience of a saint. truly outstanding work!

grid_stopper

, thanks! There is still a lot of work, but there is no way back.
What is currently in my studio / workshop:
IMG_20210628_152050_обработано.jpg
It remains to put the PSU connectors and you can put the modules for testing (this is the master section):
IMG_20210628_150015.jpgIMG_20210628_150234.jpg
 
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PermO

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Joined
Mar 16, 2011
Messages
359
Location
Hilversum, Netherlands
Well... actually this is the only topic with lots of pics that does not freak out my PC.

Most posts with multiple pictures attached result in a blank screen for me for some reason.

This is fine ! thanks !
 

Sonic

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Joined
Aug 17, 2006
Messages
58
Location
RUSSIA/Cherepovets
Good afternoon and evening! These hot days were not in vain - I was engaged in launching and configuring the master section. There were minor problems, but everything went better than I thought. ) Several images:
I collected headphone amplifiers according to the scheme from the network. They work in class A. They turned out to be too hot, so had to reduce the quiescent current, because can't put decent radiators in the limited space of the modules:
IMG_20210711_130458.jpgIMG_20210711_131824.jpg
The sequence of installing modules with their verification:
IMG_20210707_151617.jpgIMG_20210710_173142.jpgIMG_20210711_131754.jpgIMG_20210711_134517.jpg
I collected the output buffers according to the PEQ Orban 622 scheme. I wanted to listen to how much this buffer colors the sound. In principle, I am satisfied with the result:
IMG_20210711_134649.jpgORBAN 622.jpg
The signal was supplied from the MAIN outputs of the black mixer, sequentially to the MAIN and AUXes of this mixer through resistors on the DB25 connector. Everything works fine, including sending the AFL to the monitor lines:
IMG_20210711_134917.jpgIMG_20210711_135013.jpgIMG_20210711_135055.jpgIMG_20210711_140537.jpgIMG_20210711_140658.jpg
You may find it superfluous, but I added Inserts to all AUXes.

Today I started to unsolder the switching of motherboards of the subgroup section.
 

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Sonic

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Joined
Aug 17, 2006
Messages
58
Location
RUSSIA/Cherepovets
Greetings! Some technical information about my project. Headphone amplifier Circuit:
stereo-headphone-amplifier-schematic.jpg
Emitter resistors at 100 ohms were replaced with 220 ohms, to reduce the quiescent current at a supply voltage of +-18 V.

The summing cascade on MAIN, AUXes and subgroups was applied according to the scheme of the Crest Audio V12 console. Only I applied it not in the differential \ balance inclusion, but in the inverse. To do this, had to exclude one resistor from the circuit:
Mix_Buffer_Crest V12.png
This cascade, as well as the cascade from D&R (Orion, Avalon, Octagon):
Mix_Buffer_D&R_Orion.png
I tried it earlier on that black mixer from the picture. The V12 variant sounds more neutral\transparent and holds the load better than the D&R variant. D&R gives a more noticeable sound color-a little matte.

Output stage diagram from Orban 622:
Orban 622b_OUT.png
I applied it without output transformers, at the outputs of MAIN, AUX and subgroups, in pseudo-balanced mode.

EQ collected according to the scheme from an old German magazine, reprinted in our magazine:
ParaEQ.jpg
only the values of the resistors were reduced proportionally and the capacitors were recalculated for four bands. And I added the shelf\bell switches for LF and HF.
 
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cyrano

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Sep 6, 2010
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1,166
Location
Europe
My god, what a task.

Really like that headphone amp. Saved the schematic for later...
 

Sonic

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Joined
Aug 17, 2006
Messages
58
Location
RUSSIA/Cherepovets

cyrano

this amplifier has good sound detail. I think that you will not regret if you collect it. It works equally well with both the DT770 pro (250 ohms) and isodynamic (36 ohms).

ruffrecords

yes, a lot of switching from wires is not quite good, but I chose this option for ease of maintenance and likely modernization in the future. In this case, it is not necessary to disable the channels entirely, but it is enough to unscrew and get only the necessary module. There was a danger of increased noise because of this, but testing shows a fairly quiet operation. When I also assemble the input channel module, I will be able to throw off audio examples of the console's operation. Thank you for your opinion! I am interested in any recommendations.

 
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