New - Vintage Console Channel For 500/51x Format VC528 ST2+

[jsteiger]

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. So, looks like all the parts will be in just before Christmas. :)

http://www.classicapi.com/catalog/images/gallery/VC528/1-VC528-ST2.gif (http://www.classicapi.com/catalog/images/gallery/VC528/1-VC528-ST2.jpg)

http://www.classicapi.com/catalog/images/gallery/VC528/2-VC528-ST2.gif (http://www.classicapi.com/catalog/images/gallery/VC528/2-VC528-ST2.jpg)

http://www.classicapi.com/catalog/images/gallery/VC528/3-VC528-ST2.gif (http://www.classicapi.com/catalog/images/gallery/VC528/3-VC528-ST2.jpg)

Cheers, Jeff

[jsteiger]

A few more pics...

http://www.classicapi.com/catalog/images/gallery/VC528/4-VC528-ST2.gif (http://www.classicapi.com/catalog/images/gallery/VC528/4-VC528-ST2.jpg)

http://www.classicapi.com/catalog/images/gallery/VC528/5-VC528-ST2.gif (http://www.classicapi.com/catalog/images/gallery/VC528/5-VC528-ST2.jpg)

http://www.classicapi.com/catalog/images/gallery/VC528/6-VC528-ST2.gif (http://www.classicapi.com/catalog/images/gallery/VC528/6-VC528-ST2.jpg)

[jsteiger]

and a few more...

http://www.classicapi.com/catalog/images/gallery/VC528/7-VC528-ST2.gif (http://www.classicapi.com/catalog/images/gallery/VC528/7-VC528-ST2.jpg)

http://www.classicapi.com/catalog/images/gallery/VC528/8-VC528-ST2.gif (http://www.classicapi.com/catalog/images/gallery/VC528/8-VC528-ST2.jpg)

http://www.classicapi.com/catalog/images/gallery/VC528/9-VC528-ST2.gif (http://www.classicapi.com/catalog/images/gallery/VC528/9-VC528-ST2.jpg)

The fader knob is 1" diameter on the proto build. Final version is 3/4" diameter. I did not have stock when I built the proto but I do now.

Best, Jeff

[pan60]

: )~
tease!

[jsteiger]

: )~
tease!Haha. Yes, I hope I gave you sonic wood! ;)

I am actually doing a small run of these in about 2-3 weeks. I have a friend in Minnesota who travels to Nashville all the time and has been really jonesing for these. Believe it or not Pan, I am planning on sending you one from this preliminary batch as well. The only drawback is that the .5dB trim switch is non-shorting. The perfect shorting versions were special order and still a ways out. This means that you must hit the mute before turning this switch or you may end up wearing pieces of you monitor drivers. :eek: Yeah, the BBM makes a loud-ass pop when switching but nobody stocks these in MBB. I will happily change the switch out when my stock comes in.

These modules are really something special. I am very happy with how they turned out. They are one of the few magic boxes out there they spritz up the electrons and leave your signal sounding a little more special coming out than it did going in. Hard to believe I know. They must be heard...that's all I can say. The filters are just a bonus.

Now, hows that for a tease? :)

Cheers, Jeff

[pan60]

i'll be watching: )~
pan

[danetate]

This is cool.

[jsteiger]

Rev A.1 and some other parts are here...

http://i276.photobucket.com/albums/kk12/jsteiger1965/VC528 Demo build/1_faceplates.gif (http://i276.photobucket.com/albums/kk12/jsteiger1965/VC528 Demo build/1_faceplates-1.jpg)

http://i276.photobucket.com/albums/kk12/jsteiger1965/VC528 Demo build/2_faceplates_close.gif (http://i276.photobucket.com/albums/kk12/jsteiger1965/VC528 Demo build/2_faceplates_close-1.jpg)

Best, Jeff

[jsteiger]

Like a dish full of cashews on the coffee table...mmm...discrete voltage follower
http://i276.photobucket.com/albums/kk12/jsteiger1965/VC528 Demo build/3_follower.gif (http://i276.photobucket.com/albums/kk12/jsteiger1965/VC528 Demo build/3_follower-1.jpg)

http://i276.photobucket.com/albums/kk12/jsteiger1965/VC528 Demo build/4_follower_close.gif (http://i276.photobucket.com/albums/kk12/jsteiger1965/VC528 Demo build/4_follower_close-1.jpg)

Main PCB in blue with yellow. Mucho better looking than white.
http://i276.photobucket.com/albums/kk12/jsteiger1965/VC528 Demo build/5_main_board-1.gif (http://i276.photobucket.com/albums/kk12/jsteiger1965/VC528 Demo build/5_main_board.jpg)

Happy Turkey Day!

Cheers, Jeff

[pan60]

sweet beans jeff :eek:

[Stephent28]

Price and expected availability???

[jsteiger]

Price and expected availability???I am putting together a final cost spreadsheet now. I will have that complete over the next few days.

Due to the faceplate run, kits will be available just after the New Year arrives. Besides faceplates, all other parts and components will be in stock before Christmas.

Best, Jeff

[ben_allison]

Can't wait til these land! :)

Will they be available in kit form?

Also... how does the filter section compare to the Purple Lilpeqr? Would you ever run a mix out through these?

I'm so absolutely thrilled with my VP-26, I cannot wait to add this module behind it! Thanks to your wizardry Jeff, my meagre HR-500 isn't going to cut it for much longer...

[jsteiger]

I am half way thru the test-build on the 2nd Rev of PCB. I started with only the 2nd stage. This was the original concept behind the VC528 ST2. The "+" version was the addition of the discrete, balanced receiver stage.

I currently have 2 resistors and 1 cap under the PCB, just around the relay PCB. I may do another Rev just to get them on top. I will have to see once I complete the receiver section and test.

http://i276.photobucket.com/albums/kk12/jsteiger1965/VC528%20Demo%20build/2_Demo_PCB_ST2_only.gif (http://i276.photobucket.com/albums/kk12/jsteiger1965/VC528%20Demo%20build/2_Demo_PCB_ST2_only-1.jpg)

Proper knobs and inserts are here. Hmmmm.......earthtones... :)
http://i276.photobucket.com/albums/kk12/jsteiger1965/VC528%20Demo%20build/3_Demo_face-1.gif (http://i276.photobucket.com/albums/kk12/jsteiger1965/VC528%20Demo%20build/3_Demo_face.jpg)

Cheers, Jeff

[Stephent28]

Wow, that color combo is really cool. Would really stand out in a 500 rack.

Waiting for the pricing and release information.

Happy Holidays everyone!

[ben_allison]

What's got two thumbs and a boner?

THIS GUY!

Act? Safe? Esplain!

[jsteiger]

Sorry for not answering this sooner. I kinda forgot. :o


Will they be available in kit form?Yes. I plan to offer 2 different kit versions and probably just the PCB's.

I will have a "Stage 2 Only Kit" which is basically the fader, fader trim, the filters, the 2nd DOA and the output 2623-1. Overall, exactly what is shown in my last post. The device you have just preceding the VC528 will be driving the fader. This is unbalanced and has an input impedance of just under 1K. Perfect if you have a trafo balanced mic pre, console insert point or eq just before it. Electronically balanced may not be too happy.

The other will be the "Full Blown Stage 2 + Kit". This is the same as above except it also includes the discrete, balanced receiver circuitry and a 2nd interstate 2623-1 trafo. Everything you need to fully stuff the mother. This will have a balanced input with an input impedance of 20K. Everything should play nicely with this plus you have another 2520 and a 2623-1. That can't be bad right?


Also... how does the filter section compare to the Purple Lilpeqr?I have not used or seen Andrew's (Jens') Lilpeqr. I am not 100% sure of the topology he is using there. The filters on my unit are simple passive 1st order and/or 2nd order High Pass or Low Pass only. You cannot boost with these. I am not positive either how he has his level control set up. My "fader" is implemented exactly the same way as in my vintage API console. I guess we can safely say, two completely different devices.


Would you ever run a mix out through these?Well, interestingly enough, one of my friends Dan D was a muse for getting this module out. He is probably a little disappointed that he has not received his 2 demo units yet. Sorry Dan! :confused: He pushed me all along for a stepped fader strictly for mastering purposes. Hence also the .5dB trim switch. Some of the frequency points were implemented from his feedback coming from some of his mastering associates. I guess the short answer is yes!

Funny enough, I think Dan will be tracking nearly everything thru these once he gets them. He has coined the module "the missing link" in all of our email correspondence.

Best Jeff

[jsteiger]

What's got two thumbs and a boner?

THIS GUY!Ha! That totally cracks me up and freaks me out a little...all at the same time! :o


Act? Safe? Esplain!Ok, here goes.

SAFE = unit is always on, no matter the position of other VC528 switch positions.

ACT = Active. Unit is active unless another VC528 that is on the same pin #6 DC bus gets flipped to MUTE. If so, this ACT unit will also mute.

MUTE = Well, uh...mute! Like mentioned above, one unit can be used to mute all VC528's that are connected to the same pin #6 bus and are set to ACT.

Pin #6 is the VPR DC link pin. Some use it to link compressors and so on. If you look at the above blue PCB pic, near the bottom left, just above the mounting nut, the 3 pin header labeled J8 can also disconnect the link to other modules. N = not connected, Y = connected.

Volker has the 51x backplane easily set up to link 2 adjacent slots or all in a rack if one wants. I don't know what the other rack manufacturers do. I would assume that they have also made this easier to do. I know the early lunchbox racks were not easy.

Cheers, Jeff

[pan60]

come on Jeff, GET-ER DONE!
:D

[jsteiger]

I just posted some pics of a pair of these guys under test here (http://www.facebook.com/album.php?aid=61393&id=100000491741713&l=9527d61924) on my Facebook page.

Cheers, Jeff

[pan60]

: )~