jsteiger

API Vintage Console Channel For 500/51x Format VC528 ST2+
« on: October 27, 2010, 04:08:50 PM »
So I have a new module I have been working on.

Overall goal is to achieve the complete and lovely sound of a vintage API console channel without the cost of the rest of the console.

A little something different for the 500/51x format. It has grown a little since my original concept but only for the better. Overall, it is a 2 stage console channel with the vintage circuitry of my API board. The first stage is a balanced, transformerless receiver. Everything is true to the original circuit with the exception of feedback R and C. I have only tweaked the R to have unity gain thru the first stage. This entire first stage can be bypassed with shunt jumpers or simply left of the build if one desires.

Next in the block diagram comes the fader. Due to space constraints and a request from my friend Dan D., I have chosen to use a 24 position Elma with a 1K overall value. Original faders in my board were 600 ohm. The fader has 12dB of gain in hand to keep with the vintage API norm. Since the majority of the upper range gain steps are in 2dB increments, I have used a stepped Grayhill for a fader trim that is in .5dB increments.

Next in line is a 6 position stepped LP filter. This filter was not in my board. I have however implemented the same passive philosophy that they used for the HP filter that was in my board. Since it was easy, I added a switch to select 6dB or 12dB per octave for the filters.

I follow this filter stage with a 3 transistor discrete voltage follower using 5087/5088s. This buffer circuit is very reminiscence of the buffer amp found in use, 4 times in the 550a. Very handy indeed.

Next is the switchable HP filter. Again, the overall philosophy is the very same that was used in my board. I actually designed these filters around the same value shunt resistors.

Last stage is the post fader booster amp. Again, the same circuit as found in the vintage console. I have an unbalanced output signal that shows up on pin #3. This can be used to feed a future pan, aux and bus module. This output on pin #3 is VPR compliant BTW. I stuck my little Plug-In Relay PCB for a simple mute between the second DOA and the output tranny. This is also on a mute bus using the linkable DC pins #6 in a VPR rack.

The proto build is done and basically works a treat. The white PCB will go as I really do not like it. Had to try it once. All the switches are NCNR special order and all have been ordered.



















Cheers, Jeff
« Last Edit: October 30, 2010, 09:30:10 AM by jsteiger »
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Benny

Re: Vintage Console Channel For 500/51x Format VC528 ST2+
« Reply #1 on: October 27, 2010, 04:21:32 PM »
Wow. That looks killer. Great work Jeff.

Brolik

Re: Vintage Console Channel For 500/51x Format VC528 ST2+
« Reply #2 on: October 27, 2010, 05:19:17 PM »
geez. You guys are coming out with cool stuff so fast it's impossible for my measly paycheck to keep up. Look out for an order of these from me in mid 2011...  :'(

 ;)

zayance

Re: Vintage Console Channel For 500/51x Format VC528 ST2+
« Reply #3 on: October 27, 2010, 08:03:43 PM »
Super nice indeed :o

Re: Vintage Console Channel For 500/51x Format VC528 ST2+
« Reply #4 on: October 27, 2010, 08:10:07 PM »
my my, that's a beautiful build! Great looking stuff.

Next, we need a Panner/ Aux send module!

jsteiger

Re: Vintage Console Channel For 500/51x Format VC528 ST2+
« Reply #5 on: October 27, 2010, 08:36:48 PM »
Thanks guys.  :)

my my, that's a beautiful build! Great looking stuff.

Next, we need a Panner/ Aux send module!
I am torn on if I should do that or just concentrate fully on the full blown input channel for my 500 sized frame. The brawn of the circuit is exactly the same as this one.

This module was not originally designed to be an input module. It is however just that. Precisely why I ran the unbalanced signal out to pin 3. It for sure could easily drive a few sends, a pan and some subgroups.

I am trying to think many steps(modules) ahead and not cover to much of the same ground twice. The subgroup module for the console will have all the needed goodies except the pan. I suppose it would be easy enough to make the pan optional so the board could be used for either this VC528 module or the upcoming 412d.

Either way, a new and dedicated subgroup, bus motherboard is in order.

The plus for this module as an input channel is that it can be used in any 500 series rack on the planet. You just need to gain access to the pin 3 unbalanced out.

Oh, lots more work ahead for me boys!  :D

Best, Jeff
Visit the CAPI store at http://www.capi-gear.com

CAPI is not affiliated with, endorsed by, or sponsored by API.

Ptownkid

Re: Vintage Console Channel For 500/51x Format VC528 ST2+
« Reply #6 on: October 28, 2010, 08:13:29 AM »
you have some serious mental issues...keep it up!

jsteiger

Re: Vintage Console Channel For 500/51x Format VC528 ST2+
« Reply #7 on: October 28, 2010, 11:20:51 AM »
you have some serious mental issues...keep it up!
I tell you one thing Bryan, typing is a mutha with this straight jacket on.  ;D :o

Just gettin' this thing warmed up.  :)
Visit the CAPI store at http://www.capi-gear.com

CAPI is not affiliated with, endorsed by, or sponsored by API.

dandeurloo

Re: Vintage Console Channel For 500/51x Format VC528 ST2+
« Reply #8 on: October 28, 2010, 11:45:06 AM »
Another wonderful creation.  I would like to know what brand of coffee you drink in order to get some much work done!

PROFESSIONAL CHASSIS AND FRONT PANELS FOR DIY PROJECTS: WWW.COLLECTIVECASES.COM

Dan Deurloo
www.collectivecases.com
www.risendrums.com

jsteiger

Re: Vintage Console Channel For 500/51x Format VC528 ST2+
« Reply #9 on: October 29, 2010, 08:24:44 AM »
Another wonderful creation.
Thanks Dan. You were my muse for this one.  ;)  :D

Quote
I would like to know what brand of coffee you drink in order to get some much work done!
Dunkin' Donuts typically. The extra large. I am merrily a notch away from setting up a coffee IV.

BTW, I let my brother use the proto yesterday. He told me last night he is never giving it back.  :o
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CAPI is not affiliated with, endorsed by, or sponsored by API.


fazer

Re: Vintage Console Channel For 500/51x Format VC528 ST2+
« Reply #10 on: October 29, 2010, 03:48:31 PM »
Very nice work Jeff.  Has Boji seen this.  I'm sure he has but it looks like it would fit one of his needs. 

SIXTYNINER

Re: Vintage Console Channel For 500/51x Format VC528 ST2+
« Reply #11 on: October 30, 2010, 09:31:18 AM »
jeff the diy "amazing" man
nice "porn" project
>>" 1 Picture say what billions words cannot "<< - >>"SMD Kill the DIY STAR"<<
Why in the  forum  if no share

jsteiger

Re: Vintage Console Channel For 500/51x Format VC528 ST2+
« Reply #12 on: October 30, 2010, 09:34:04 AM »
Very nice work Jeff.  Has Boji seen this.  I'm sure he has but it looks like it would fit one of his needs. 
Thanks.  ;) 

I don't know if he has. I haven't heard from him in a while. IIRC, his metalwork has a fairly shallow depth where the input channels would go. My 400 series cards (which are 15/16" less deep than the 500) were still a little to deep. At one time he did talk about cutting the bottom out.

Cheers, Jeff
Visit the CAPI store at http://www.capi-gear.com

CAPI is not affiliated with, endorsed by, or sponsored by API.

Moses

Re: API Vintage Console Channel For 500/51x Format VC528 ST2+
« Reply #13 on: November 24, 2010, 07:34:40 PM »
Any more for anymore?!  ;)

Mo

jsteiger

Re: API Vintage Console Channel For 500/51x Format VC528 ST2+
« Reply #14 on: November 25, 2010, 09:32:05 AM »
Any more for anymore?!  ;)

Mo
Yes, I have made good progress. I actually received Rev A.1 boards yesterday. The main changes were just around the relay PCB and how the Mute switch works. Besides that I vetoed the white solder mask and went with blue.

The Grayhill's and Elma's are slated for mid December delivery still.

The production faceplate metal is also due to me mid December. From there they need to be polished, printed and clear coated.

I am doing a small 9pc demo run for some good friends and well respected ears in the industry. I plan to start working on those this Friday.

Anyhow, here are less words and more pics.  :D





Like a dish full of cashews on the coffee table...mmm...discrete voltage follower




Main PCB in blue with yellow. Mucho better looking than white.


I'll post some more pics as I am getting these 9 built.

Best, Jeff
Visit the CAPI store at http://www.capi-gear.com

CAPI is not affiliated with, endorsed by, or sponsored by API.

gar381

Re: API Vintage Console Channel For 500/51x Format VC528 ST2+
« Reply #15 on: November 25, 2010, 02:37:41 PM »
BEAUTIFUL !!

Love the BLUE :) :) :)

GARY
RETIRED.....  from 51yrs in Show Biz

gar2520, gar1731,garAM10,gar918 DOAs at  http://capi-gear.com/catalog/index.php?cPath=71_72
NEW Sphere section  http://gar381interests.com/gar381interests.html

dandeurloo

Re: API Vintage Console Channel For 500/51x Format VC528 ST2+
« Reply #16 on: November 25, 2010, 11:43:52 PM »
Those look great!  Can't wait to hear them!
PROFESSIONAL CHASSIS AND FRONT PANELS FOR DIY PROJECTS: WWW.COLLECTIVECASES.COM

Dan Deurloo
www.collectivecases.com
www.risendrums.com

lpkyer

Re: API Vintage Console Channel For 500/51x Format VC528 ST2+
« Reply #17 on: December 06, 2010, 10:51:02 PM »
I bet 16 of these would make an AWESOME summing mixer :)

Marcocet

Re: API Vintage Console Channel For 500/51x Format VC528 ST2+
« Reply #18 on: December 06, 2010, 11:27:07 PM »
Hey Jeff

Have you got a schem for this thing yet? Just wondering how you implemented the filters.

Thanks for all the work as always!

-marc alan

jsteiger

Re: API Vintage Console Channel For 500/51x Format VC528 ST2+
« Reply #19 on: December 07, 2010, 12:04:31 AM »
Hey Jeff

Have you got a schem for this thing yet? Just wondering how you implemented the filters.

Thanks for all the work as always!

-marc alan
It is more or less the same skiz from my console that was sent to the group email a while back. I don't have the filters all drawn out pretty but I used the same method that was used for the 3 position filter that is immediately after the normal channel fader. I just changed the original HP freq. points and separated the 1st order and 2nd order with a toggle.

Block diagram wise, I simply inserted the LP filter and follower between the fader and the HP filter.

It goes...-->Elma rotary fader-->Grayhill .5dB fader trim-->LPF
-->5087/5088 discrete follower-->HPF-->2nd stage DOA

I didn't really want to change any of the surrounding circuitry. This was the only way I could come up with to add the LPF and not change anything else.

You know me, I will draw out the schemo after everything else is all said and done. It's like eating your desert first!  ;D

BTW, all the Grayhills came in nearly 2 weeks early. Go figure.

Cheers, Jeff
Visit the CAPI store at http://www.capi-gear.com

CAPI is not affiliated with, endorsed by, or sponsored by API.


 

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