Summing Mixer

[Consul]

the dug,

Wow, that is about as simple as it can get. I just might have to try making one of those some day.

Do you like how it sounds versus mixing "in the box?"

 

[Consul]

Cool! Thank you!

 

[daArry]

nice1 again rf :thumb:

 

[mathtracks]

cool rf!!
thanks :guinness: :guinness:

 

[Guest]

Marik, can you explain to a dunce how you pan between the grids of your mixer? I understand the anode/cathode paralleling for summing OK but I am loosing focus on the grids.

 

[Marik]

[quote author="thomasholley"]Marik, can you explain to a dunce how you pan between the grids of your mixer? I understand the anode/cathode paralleling for summing OK but I am loosing focus on the grids.[/quote]

I guess I lost focus myself
Since I don't need any intermittent pan points (only mid-->R, mid-->L, or mid--> both L and R) I made a switch, which connects grids of the mid channel to the signal. When I need mid-->L, the signal gets on the grid of the first half of the tube (which anode and cathode are connected to the L), and grid of the second half (which anode and cathode connected to the R) is grounded. When I need mid--> R, the signal comes to the second half of the mid channel tube grid, and first half grid is grounded. For mid-->both L and R, both grids of the mid channel are paralleled. Of course, if you need continiuos pan you could easily put a pot between grids.
And of course, you can make as many channels as you want.

Does it sound more clear, or do you want me to draw schematics?

 

[henk]

I read some interresting stuff here about a Crest V12 , i also would like to know were i can download the schematic?

Further there is a nice symbuss reciever in ETI febuari 1987 made by Mr Barry Porter.

Is it possible too put things on a server somewhere , soo everybody can see this?

 

[mathtracks]

here is my idea of what is happening in that magic dangerous box.
simplified of course but maybe a start?

http://www.lunarrecording.com/Summing.pdf

 

[Guest]

That is very clear now Marik. Thanks. Of course I would always like schematics when it is not too much trouble.

 

[daArry]

ye, i was aiming to use those INA chips in a line mixer config, but have external (or hot swappable in this modular case) gain stages for makeup...ic, discreet etc...whatcharek?

I posted sum pics of a test brd i done in a thread a while bak, im now redesigning the brds for standard eurocard sizes to fit those VERO rack modules

 

[ijr]

Been at this point halfyear ago.
http://img.photobucket.com/albums/v436/IJR/mx1_2.jpg
http://img.photobucket.com/albums/v436/IJR/mx1_4.jpg
http://img.photobucket.com/albums/v436/IJR/mx1_1.jpg
http://img.photobucket.com/albums/v436/IJR/mx1_3.jpg

 

[mathtracks]

simplified block diagram version.
http://www.lunarrecording.com/Summing.pdf


o.k. here is the first schematic
can someone help me figure out a few things on this.

the gain of this mixer should be 0 right?

1-What value should the resistors be in the feedback loop on the OP134's?

2-What value should the resistors be on the output of the OP134's(10K)?

3-Coupling caps before the input to DRV134(probably)?

4-Best place to put master attenuator?

let's spark this monster to life!

http://www.lunarrecording.com/SummingMixer.pdf

 

[Marik]

[quote author="ijr"]Been at this point halfyear ago.
[/quote]

Wow! Igor, do I see Ero--these big blue tubular polypropilenes? :shock: :shock: :shock:
Ha! I used to get them on Tahana Merkazit a'yashana in Tel Aviv in one of the stores--only one guy used to
have them then. Never saw those in US. Cool! Almost made me cry :twisted:
:guinness: :guinness: :guinness: :guinness: :guinness:

 

[NewYorkDave]

That's a really nice piece of work, Igor.

 

[daArry]

ijr, that looks superb! can we see some ckts?? :thumb:

 

[ijr]

Anything new in this design...ina2137/opa2604;
all dual 10k pots (pan is lin., others log); I used some freakin' Frakos
here... one thing, btw: master bus is passive and going to trafo's
primary, then tube makeup...freakin' Telefufkens and Toshiba's pulled
from Tektronix new-old scopes-Technion stuff))
Main goal of passive buss running into good trafo is mix WIDTH.
It is 3-d instead of 2-d best active bus based on discrete opamps.
aux2 and 1 are usual v-gnd opa2604 based summing buses...
Unit on photo working more than halfyear in one nice studio,
and they seems VERY happy...
If there's people interested in this mixer, I can came up with
whole docs and pcb's for sale. In small qty's, front pannels maybe too.
BTW, this is my design, then, no annoying people like.... :evil:
who can cut this thing with IP shit ) and I have no problems if some people will buy pcb's and sell these mixers
BTW, now I'm working on this:
http://img.photobucket.com/albums/v436/IJR/big_channel_1.jpg
(photo is not up-to-date- now it is working channel).

 

[ijr]

Marik, ata mitkaven be-Siman Tov Electr.?...
They have some stuff... but these blue caps (10m/63v)are not Ero, they are Japanese metal-film...also, more freakin' stuff here is 10u400v Sprague's (white big ones) and passive bus trafo's (hard to see them, they at right side of tube board), some Nikon Kohden Japanese stuff, 10H pri,
1:4, 7hz-70kHz @-10 db, 20hz 0.5% dist. @+2db at pri, all this with very nice sqw. resp. (allmost no overshoot if properly loaded).
These trafos killed pair of Jehnsens by sound in same ckt)

 

[mich]

igor, you are the man! :thumb:

met lishmoa et hamixer haze....betaj nishma sof haderech!

 

[daArry]

i have trouble keeping up but it all sounds good am i understanding right that your runnin multiple busses? like aux chans seperate from regular input chans? a block diagram would be tasty :>

 

[ijr]

Lo pahot mi sof'a'derh, ahi)