bruno2000

Dual Mid 1084 Clone Project
« on: August 24, 2010, 10:20:14 AM »
I’ve always wanted a rack of 1084s, but they are really expensive!  So I decided to build my own.  Since I was building my own, I wanted more EQ control, and some more frequencies, especially in the bottom end region, so there are two mid band sections.  On the lower mid band selector, I added a Carnhill HPF inductor and the appropriate caps to enable peaking at some additional lower frequencies.  I left out the LPF entirely since in practice, I hardly ever used it.  

A am also a big fan of the 1073, so I  made the “Hi Q” switch position to match the “Q” of the 1073 (a little sharper than the 1084), getting the best of both worlds.

The rack is a Dumpster Prize (green, huh?), and the faceplates are custom 2"x7" from FPE.  The transformers, inductors, and switches came from Colin at Audio Maintenance.
Best,
Bruno2000



« Last Edit: February 17, 2011, 09:29:56 AM by bruno2000 »


okgb

Re: Dual Mid 1084 Clone Project
« Reply #1 on: August 24, 2010, 10:31:17 AM »
nice work all around
but it's not greener than me [ envy ! ]
GKB Audio / Greg Boboski

briomusic

Re: Dual Mid 1084 Clone Project
« Reply #2 on: August 24, 2010, 10:39:47 AM »
 :o :o
great project and kudos for seeing this through all on your own!
at first I thought "how does he fit all the switches in" but then I saw it's not actually 500/51x format. ::)
i am not sure if you are planning to release pcb files, or indeed do a run of pcbs (I am sure interest would be there, especially as a mic pre seems to be included as well), but one thing I would really like to know is the value of the "Q resistor" that you used to achieve a 1073-like bandwidth. I believe it's R51 (7k5) in the original schematic, on the PPEQN it's R17 with a choice of 2k7 or 6k8 (or anything in between).

that's quite a lot of iron colin had to send over the atlantic!

Ptownkid

Re: Dual Mid 1084 Clone Project
« Reply #3 on: August 24, 2010, 10:50:18 AM »
wowsers....things like this are starting to motivate me to get on it this winter...but I also have a huge boat restoration project in the works so I may only get a handful of unit finished. Where the time goes I don't know.

Really, really, nice work bruno!

Re: Dual Mid 1084 Clone Project
« Reply #4 on: August 24, 2010, 10:52:04 AM »
that is real nice man! wish I had a couple of those!

Re: Dual Mid 1084 Clone Project
« Reply #5 on: August 24, 2010, 11:04:32 AM »
omg. That's a gorgeous frontend.

Good for you!

mylesgm

Re: Dual Mid 1084 Clone Project
« Reply #6 on: August 24, 2010, 11:15:47 AM »
very sweet...
Check my work at www.mylesmumford.com

bruno2000

Re: Dual Mid 1084 Clone Project
« Reply #7 on: August 24, 2010, 11:51:30 AM »
:o :o
great project and kudos for seeing this through all on your own!
at first I thought "how does he fit all the switches in" but then I saw it's not actually 500/51x format. ::)
i am not sure if you are planning to release pcb files, or indeed do a run of pcbs (I am sure interest would be there, especially as a mic pre seems to be included as well), but one thing I would really like to know is the value of the "Q resistor" that you used to achieve a 1073-like bandwidth. I believe it's R51 (7k5) in the original schematic, on the PPEQN it's R17 with a choice of 2k7 or 6k8 (or anything in between).

that's quite a lot of iron colin had to send over the atlantic!

And quite a lot of shipping money going to FedEx!!!!
In the BA211 board circuit used in the 1073 (with no "P" terminal) the resistor setting the "Q" (from the coil "starts" to terminal E) is 2k7 ohms.  In the BA211a board circuit used in the 1084 (with the P terminal), that resistor is 6k8 (6k81).  In the 1084 the resistor switched in parallel with the 6k8 resistor when you select "Hi Q" is 7k5 ohms.  What I did was change the 7k5 ohm resistor to a 4k42 so that the resulting resistance was about 2k7 (2k68) ohms.  I checked all of the curves with "real" 1073s and 1084s and they were spot on.
Hope this answers the question!!!
Best,
Bruno2000

ultra-alex

Re: Dual Mid 1084 Clone Project
« Reply #8 on: August 24, 2010, 04:44:34 PM »
awesome!

baadc0de

Re: Dual Mid 1084 Clone Project
« Reply #9 on: August 24, 2010, 04:54:11 PM »
Ummm... speechless! You nailed exactly what I wanted (only with an extra mid section no less). A small format 1084 with a micpre and phantom power. Wow!


Re: Dual Mid 1084 Clone Project
« Reply #10 on: August 24, 2010, 05:04:00 PM »
so this just happened out loud when i saw these pics... i'll do my best to translate into stylized type:

ho-leeeeeeeee sh*t.

no joke.  pardon my "french."
There's nothing like the right tool for the job.
And -usually- that's what I end up using...
..nothing like the right tool for the job!

Soeren_DK

Re: Dual Mid 1084 Clone Project
« Reply #11 on: August 24, 2010, 06:19:01 PM »
Waoooooouuuuuwwww

Holy macaroni

and the crowed goes: "P-C-B", "P-C-B", "P-C-B", "P-C-B", "P-C-P", "P-C-P", "P-C-P"

Cheers
Søren
Quote from: idylldon
...it works like a champ and is as quiet as a mouse pissing on a cotton ball.

http://www.soundcloud.com/doctorsclub

Joechris

Re: Dual Mid 1084 Clone Project
« Reply #12 on: August 24, 2010, 06:38:42 PM »
Outstanding!!
1000 of hours must have been spend on this project.
musicians vary +/-9dB depending on mood, drugs, and line-voltage. (PRR)

California Road

Re: Dual Mid 1084 Clone Project
« Reply #13 on: August 24, 2010, 06:49:57 PM »
That is a serious front end!  I would love to hear these in action. 

deuc224

Re: Dual Mid 1084 Clone Project
« Reply #14 on: August 24, 2010, 11:55:28 PM »
Since no one has the balls to just come out and ask, i will. Are you gonna do a run for us primative people :'( look at my tears

darnell

Re: Dual Mid 1084 Clone Project
« Reply #15 on: August 25, 2010, 02:20:59 AM »
Since no one has the balls to just come out and ask, i will. Are you gonna do a run for us primative people :'( look at my tears

Seriously, this project looks too clean to not put to the presses!!!!!

d.
_______________________

Daryl Rabidoux
Radar Recording Studio
http://theradarstudio.com/

bpucekov

Re: Dual Mid 1084 Clone Project
« Reply #16 on: August 25, 2010, 04:11:16 AM »
WooooooW

evilcat

Re: Dual Mid 1084 Clone Project
« Reply #17 on: August 25, 2010, 05:08:11 AM »
Me too ! me too ! me too !!! I want one, no, two, no, eight !!!!

SIXTYNINER

Re: Dual Mid 1084 Clone Project
« Reply #18 on: August 25, 2010, 05:26:02 AM »
 :o  compliments !!!
really nice "porn" eq project !
 8)
>>" 1 Picture say what billions words cannot "<< - >>"SMD Kill the DIY STAR"<<
Why in the  forum  if no share

zayance

Re: Dual Mid 1084 Clone Project
« Reply #19 on: August 25, 2010, 07:01:13 AM »
Ouch.... heart my eyes  :)


 

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