CAPI VP312 Pre Amp Complete Detailed Build Tutorial 

Hey Roy, I just wanted to say thanks so much for taking the time to make this video. I bought two VP28s and while I'm somewhat experienced with soldering I haven't done any kits as complex as these. Your system of keeping organized (which is also the method used by the guy who put together a VP28 photo guide/build thread) makes everything so much easier and less worrrisome. Obviously the parts in the 312 and VP28 aren't all the same, but just having this easy way to get started gave me a boost of confidence. I kept this video open, along with that photo guide, while I was building the first kit, and I had so much fun with it that I immediately started the next kit and built it in one sitting. Both worked perfectly the first time plugging them in. Thanks again for putting great information out there and showing that you don't need to be a rocket scientist to put these things together.

2 hours?!?! Jesus dude lol that's crazy fast now. Trust me I know how amazing they are I've owned 3 vc528's and 2vp28s. I literally want a vc528 for every channel of preamp I use. (Like 8 lol) I was terrified of building any of these things until I saw your video. I actually think I can do it now. Thanks to you.. I really appreciate it... that's a ton of work to do one of these videos. My goal is to build 4 to 8 vc528s, 2 x vp28s, 2 x vc526, 2 x lc53a and 2 lola preamp.

Just bought a couple of the VP312s and I've started the build. Great job on this video!! It's unfortunate that you have to gather several different documents from the CAPI web site to get all you need for a VP312 build, but this video sort of rolls all that into one. Much thanks. One note; the LED (at least on my Rev B board) is made to mount into the front panel, rather than just floating above the PCB. You can bend it at a right angle at about the appropriate height, and install it last by inserting it into the front panel and fishing the leads down through the PCB. Then solder from the top. Jeff outlines his technique here: capi-gear.com/catalog/images/gallery/VP26/Rev_B/3mm-LED-install-for-VP25_26_312.pdf Thanks again for putting this together!!! Terrific!

Thank you for your time and effort in this tutorial. I can actually build one now again thank you

thanks a lot mate, i've just ordered two vp28's and i think ill be able to tackle them now. its going to be my first ever build

Thanks for taking time to explain all of this. Very helpful.

THANK YOU A MILLION TIMES OVER! This is one of the most helpful videos I've ever seen. I'll definitely be referencing this during my first build. You have my most sincere appreciation, Roy!

Have to say, this was an awesome video. I'm looking to get 2 VP26's soon. This is the closest video I've found to a detailed instruction so I'm hoping I can figure the VP26's out using this video. It's a little long but I"m glad I watched everything because there was a lot of little small tips in there that seem crucial. You actually made me want the stepped versions too. Thanks man!

Thanks for sharing, man! Cheers from Argentina!

Very helpful and inspiring! Thank you so much 👍😁🤝

You could put loops of masking tape along the edge of your columns on the paper and use it to secure the leads as you organize them. That way you wouldn't have to worry about losing your sort job if you bumped the paper. Just saying that because I'm a klutz and it could happen.

You are a saint for doing this vid! Thank you so much!

Excellent video, very clear . There is one thing that I find helpful is when you are making your list of parts and putting them beside each one , I find a thin piece of masking tape to hold them down remove the chance of bumping them out of place. The LED is polarized be careful to get it right(if it don't light just unsolder it and turn it around ).

hey there Dane, Im so glad you found the video helpful. I was hesitant to do this at first because of the amount of time it takes to make one of these videos. I also had to fact check everything i said to make sure I was giving accurate information so it took awhile. I had only built one vp312 before doing the video but found that I had to pull up a few different documents and flip back and forth between several build forums and combine info, etc to get all of the details I needed to complete the 312 successfully and I thought it would be cool if all you had to do was bring this video up on your iPad or laptop and follow along as you were building. Im currently working on the vp26 video right now and should be finished in a few days as well as the gar2520 op amp, etc. Jeff and I talked about doing a series of these that he could send out to those just purchasing the kits for the first time. Thanks for the encouragement and keep an eye on my channel here for the next ones to show up. If you are thinking about building a classic api kit, you won't be disappointed. Since the vp312, I have built 5 more and now can complete them in less than 2 hours total. Crazy! Have fun man!

Great video, thank you!

Thank you Ray!!! This vid is veeeery precious to me!! (Im in France)

Fantastic video

Thank you so much!!!

thaaaaaaaaaank you!!!! Exactly what I needed. You are a hero! =)

Amazing build video! Some questions: Is the VPR and 51x referring to the type of PS or enclosure? Why would you choose a 312 over a VP28? Everything in the forums is all over the place. If it's just tone and dynamics, I understand if it's hard to describe, but it's impossible to get a straight answer from anyone. Variable or stepped is another thing that is just preference? Or is there a practical reason to choose a stepped gain?

Thks x effort-very didactic

I just built 2 of these. I did everything exactly the same and they don't work. Phantom power lights don't light up. No signal. Any suggestions? I've gone over every solder point twice now.

Hey, great job! I noticed you didn't run any tests with the preamp. Is this a necessary step? I building a VP26 and the instruction say to hook it up to a power supply before I install the opamp, but I'm not sure how to do that and there seems to be no information online. Any advice would be greatly appreciated.

the caps are measured in subdivisions of FARAD (micro(pol) nano pico(non pol)....awesome helpful video though thumbs up!

Awesome build man. Easily the most helpful tutorial I've seen since researching this stuff. It actually let's me think I can do this lol what was your experience level before you built this? Are you going to be doing any more tutorials? Specifically the capi vc528, vp28 or a Lola and any of the mic kits? Thanks again

I have the Vp312 Rev B version, the result at the end is 10.3 on my multimetre, is it a bad thing ?

RAD video!! I've been wanting to build one of these, but possibly messing it up might be worth paying an extra hundo or so to buy one already assembled. So all it takes is some careful soldering? Otherwise it's kind of "paint by numbers"?

What Hakko tips are you using? Thx for the upload

Anyone got links to the schematics or where to buy kits to build this? Also is there a regular (not 500 series) version of this same model? Thanks

Wow right on dale. Do I was looking to do a vc538 next for myself. How did you use yours as far as your signal chain and all. Just wondering how it would best be used. I have 5 vp series preamps in my rack with space for one more thing and I was thinking a 553eq or maybe that vc538. Thoughts?

Thank you Roy! Do you have any other Capi gear?

Hi. What is the size of PCB card?

The API 312 doesn't use the 150K resistor in the input, CAPI use this resitor . Anyone tried the CAPI VP312 without the 150K resistor?

This is probably a stupid question but where is the input and output of this circuit? I can't figure it out. I understand it mounts in a 500 series rack, but where does the signal come in and out?

Sorry Dane I called you dale!