Build Your Own Dual LA-2A Optical Compressor [Silent:Arts]

What's better than a Teletronix LA-2A? TWO of 'em that's what! In this video we cover the Silent Arts Dual LA-2A - a PCB based build found over on the GroupDIY forum.
We'll talk about how optical compressors work, take a look at the controls, cover my build notes and dive into the calibration procedure. We'll even listen to some examples of the D-LA2A in action as we work our way through the most detailed Silent Arts Dual LA-2A video on the web!
We'll also take a close look at all the upgrades available if you need your LA-2A to be the absolute best in class. This build will blow any modern production Universal Audio LA-2A out of the water!
0:00 - Intro
3:22 - Bass Demo
4:20 - Controls
6:04 - Vocals Demo (Chinese Eric Free Download Here: / chinese-eric )
7:13 - Build Guide
7:32 - BOM
8:05 - DIY Racked Case
8:30 - Heater Wiring
8:44 - Kenetek T4B Opto Attenuator
9:31 - Crimp Tool
9:48 - Hairball Audio VU Meters
10:51 - Zener Diode
11:06 - Elma Stepped Pots
11:54 - Toroidal Power Transformer
12:24 - Tubes (12ax7, 12BH7 and 6AQ5)
12:51 - Sowter Input and Output Transformers
13:16 - Arco Caps
14:24 - R125 and R225 Trim Pot
14:35 - Electric Guitar Demo
15:48 - Calibration
16:09 - Zero Adjust
16:18 - Gain Reduction and Level Calibration (R125)
17:08 - Limiter Response
17:36 - Stereo Balance Adjust
18:23 - Final Thoughts
Group DIY D-LA2A Support Thread: groupdiy.com/threads/d-la2a-s...
Build of Materials: www.dropbox.com/s/2xky62b30cc...
Kenetek: @gearslut4020 www.kenetek.com
Silent Arts: www.51xaudio.com/
DIY Racked: www.diy-racked.com/
Hairball Audio: @HairballAudio www.hairballaudio.com/
Sowter: www.sowter.co.uk/

[@djbrettb]

One of the best DIY audio videos I've ever watched, thank you for clearly explaining everything.

[@shoetiquemusic]

I really appreciate that Bret! Let me know if you have any questions should you decide to build your own! I've been watching the pilot episode of Graffiti Rock on your channel. This show is phenomenal! kzbin.info/www/bejne/l6iVnYOHm7mLeJo

[@PhillRS]

WOW! It's a Really cool video and gear you presented to us. Thanks for showing us the ins and outs.

[@shoetiquemusic]

My pleasure Phillipi! There's plenty more interesting gear to come!

[@jimmypenrose1401]

Great video. Not my particular preference to doing a DIY though. I'm much more into the idea of an actual, complete kit, rather than a circuit board and BOM; where you need to go on a scavenger hunt and chase down all the other components yourself - pretty much every build I've tried that way turned out to be an old maid - so I just won't do them anymore. Aside from CAPI, AML and Hairball there just aren't that many people offering kits like that anymore. Seems to me that Group DIY was a much more interesting place about 10 to 15 years ago; things there really atrophied about 10 years ago in the mid-teens. I really miss the Analog Allstars 500 series Pultec clone: one of my favorite all time builds ever; it's a wonderful walk through Wima's product line! Unfortunately there just isn't much of interest on the White Market page anymore (it used to be multiple pages). Most of the people there selling kits over the years either went on to sell assembled gear only like Serpent Audio, or quit the business altogether. It's a real shame - I think most of the best analog gear I own was built from kits, not purchased retail.

[@shoetiquemusic]

Hey Jimmy! Thanks for checking out the video. I agree that the options for fully assembled kits can be limiting - especially for full size rack gear. In addition to what you mentioned above, kits are also offered by Sound Skulptor, DIY Recording Equipment and Yann Lu Audio. You should check those out! Don Classics offers kits that are 'near complete' - they provide a link to a Mouser cart which contains the necessary parts. I think kit making is super time consuming and I imagine that the profit margin is razor thin. Having put together several non kit builds I can see how much of a pain it is to gather all the parts in one place!

[@roommother3398]

Interesting never heard of a stereo LA2A before cool idea. Speaking of cool that song was super duper cool! Followed your SoundCloud looking forward to checking out more tunes tomorrow. Thanks and take care!

[@shoetiquemusic]

Thanks for checking out the SoundCloud RoomMother! Its tough to get people to make the extra click. The demo for 'Chop' on your SoundCloud is sounding tight! soundcloud.com/user-379749116/chop-rough-demo

[@amonterrosomusic]

Great video man

[@shoetiquemusic]

Glad you like it Antonio! I hope you build your own!!

[@highergrounds8018]

"Streets ahead!" Pierce Hawthorne would be proud!

[@shoetiquemusic]

Higher gets it! Everyone else is streets behind!

[@brunoromiti7708]

great presentation and awesomely presented buiid! never doing that, to be honest, but i'm happy for you!

[@shoetiquemusic]

There's nothing wrong with browsing - thanks for checking it out Bruno!

[@ShawnThuris]

The shoeman uploads after midnight for the real ones

[@shoetiquemusic]

I do it because I like you Shawn.

[@ShawnThuris]

@@shoetiquemusic Okay, now I will definitely watch the video

[@dignflykites]

Nice piece of gear you got there and nice 'write up' on the details.

[@shoetiquemusic]

Thanks Leg3ndary!

[@ThePurusha]

Awesome!

[@shoetiquemusic]

Thanks for watching Tat!

[@DarkTrapStudio]

Awesome video thanks !

[@shoetiquemusic]

Thanks Dark Trap! It’s a great build - you should take a crack at it!

[@FernandoOliveiraESouza]

Thank you!

[@shoetiquemusic]

Thanks for checking it out Fernando!

[@magnusstrenweden9097]

Nice video, neatly sums up most if not all details worth noting when building this. I've had my pcb/trafo in storage for years, gotta build it up at some point. Got most of the cheap parts, but trafo's and optical cells are a substantial expense :S Have a D-AOC that's just missing a front panel that has been prioritized, but rack units are staring to gett sparse in the studio... Keep up the good work and all the best from a fellow Gdiy'er :=)

[@shoetiquemusic]

Hi Magnus! That Dual AOC looks pretty neat! My understanding is this project started as an LA2A build by analag that evolved into a unique optical compressor. Did you get your PCB from silent arts? It looks like they might have stopped producing/selling that one. Do you plan on making your own front panel or having one screen printed? Here is a link to the DIYRE wiki for those who are interested in reading more about the Dual AOC: wiki.diyrecordingequipment.com/projects/d-aoc/

[@brian_c_909]

Wow what a great build! I also watched your 1176 build. Both are very nice. I have a question though. Did you patch things up with your dad? Thanks.

[@shoetiquemusic]

Thanks Brian, I appreciate the kind words! Things with my dad were going great until he started gambling again.

[@Terribleguitarist89]

As a diy nerd and audio nerd this channel is gold. Curious if there are any good DIY Pultec kits out there.

[@shoetiquemusic]

I appreciate that TG! The only place I know of making Pultec kits is Audio Maintenance Limited: www.audiomaintenance.com/acatalog/aml-17-022_extended_info.html . They have an EQP-1 and MEQ-5 Kit. The EQ-1 in my videos was built using a Drip Electronics board. You have to source all of the parts yourself. Greg at Drip sometimes has prebuilt shopping carts for Mouser or Digikey that can make the process easier. I'm not sure if you can still get these - you could try emailing them. www.dripelectronics.com/feature The MEQ-5 at the bottom of my rack is a point to point built using a wiring diagram and chassis from analogvibes. If you go this route don't get caught up in being a purist. Substituting some of the parts for modern production items will make this a lot more enjoyable and have minimal impact on the performance of the unit. These are still available for sale. They also have an EQ-1 chassis. analogvibes.com/

[@Terribleguitarist89]

@@shoetiquemusic awesome! I remember digging around a few years back and found a website that had schematics and a rough material list but a lot of it boiled down to "figure it out on your own". I've also been an amateur radio operator for about 20 years, so building my own stuff has always been almost as fun as playing to me haha

[@shoetiquemusic]

@@Terribleguitarist89 It's funny you say that! I'm actually getting into amateur radio over the last few months. I just got my Technician license and am now studying for my General! What types of things have you built for amateur radio? I've been toying with building something and documenting it on the channel!

[@Terribleguitarist89]

@@shoetiquemusic I'm an extra and a VE through the Anchorage VEC and ARRL actually haha I've mainly dabbled in tiny QRP radio kits like the old rockmite and such, there are a ton of CW transmitters out there that mainly lean on 2N2222 transistors. If you can snag some older copies of the ARRL magazines or books you can find a bunch of tube based builds too. I've noticed over the past 20 years those resources have drifted from building stuff to buying new gear from the big name companies unfortunately. In all fairness, my main rig is an ICOM 7200 I use almost entirely for digital hf so I can't rant too much about that haha I also lucked out as a teen to be in a club with some OG Motorola engineers who took me under their wings to teach me about homebrewing stuff. A few were guitars as well and built my first tweed champ clone with one.

[@zpsznh113]

Great video; I would love to put together something like this, but I have no idea how! Do you have any recommendations for some starter projects for someone with absolutely no experience with making audio gear?

[@shoetiquemusic]

Hell ya Zach! If you're looking for a place to hone your soldering skills I would start with a guitar pedal. Aion Fx has some nice kits that are well documented and won't break the bank. Once you can get through a couple pedals you could try something more advanced like a 500 series unit from Sound Skulptor. Alternatively you could try a nice FET compressor from Hairball Audio. These projects provide nice build guides and take away a lot of the guess work. Then, when you're feeling bold you could try tackling something like the DLA-2A! Let me know if you need help deciding on a starter soldering iron or any other basic info. I'm always happy to help get someone into the hobby!

[@DaftyBoi412]

Nice build dude! I'm building one of these atm. I'm just waiting on my custom case to come through so I can finish off wiring it up. Pretty much everything else is in place! I have a couple of question (as I can't get onto the GDIY forums, as my account keeps getting banned every time I sign up as they require you to pay to join, or they IP ban you within 24 hours for good!). Firstly What is that funky high tech looking ground connector you have connecting the PCB channel ground to chassis ground star wire? I want that, it looks super bomber! xD Secondly, with the pots, or in your case the stepped switches, are you using 3 core sheilded wire, and if so, are you tieing the sheild into the the grounded pin of the pot at the board side? If not, how do you have it set up? I would experiment with the grounding, but I'm running low on moplex pins, and will only have 8 left if I change out the pot wires, and I still may want make other alterations down the line. Thanks dude.

[@shoetiquemusic]

Hey Dafty Boy! Regarding the PCB ground: Are you talking about this item? www.digikey.com/en/products/detail/keystone-electronics/4907/255324 It's called a quick disconnect. I used three of these total. There is another next to each relay. It legit took me a half hour to figure out what I had put there - too many receipts for this project! For the the gain and peak reduction wiring I actually used some left over microphone cable (2 core shielded). Not sure if this is the best approach but the noise floor on my unit is very low. The shield is connected to the slot for ground in the pcb side molex connector. The bottom of this document shows how to wire the pots: cdn.imagearchive.com/groupdiy/internal_data/attachments/2/2755-6fbb80788a67cf70e2cd1ec50ecc6cbe.data?response-expires=Mon%2C%2022%20Apr%202024%2012%3A18%3A52%20GMT&response-content-type=application%2Fpdf&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=I3UPHPWOPY63ZMOGLZFM%2F20240415%2Fnyc3%2Fs3%2Faws4_request&X-Amz-Date=20240415T121852Z&X-Amz-SignedHeaders=host&X-Amz-Expires=604800&X-Amz-Signature=74fa380f41db637cb1b4e5ecebf1ed76f8839002df4812a3d28a0e032b6972ae GDIY has made some changes that have had a negative impact on registration, access to the white market and usability. You could try using the contact page - hopefully someone will reach back out to you and help sort things out! If that doesn't work realgearonline.com is a great alternative. Happy to answer more questions or clarify if anything above isn't clear! Let me know once you get it up and running!

[@DaftyBoi412]

@@shoetiquemusic Thanks a bunch dude, I think I have that grond wirering diagram I just wasn't sure if I could get away using the sheilding (which is how I also have it set up atm too). Glad I can just leave it as is. And yes that quick disconnect bit is exactly what I was after! It really makes that groun connection look super clean. I tried contacting gdiy with a second account, but they banned the account i used to contact them within the hour from me signing up and sending a help reqest. I've given up trying now as I have to open a vpn to even try and sign up as it's an IP ban, not just an accout ban! Thanks for the time and help! Volker is already probably sick of me, so I try not to ask him if I can help it and figure it out on my own haha.

[@bonzology322]

really great job, subbed you, i went to DIY racked and i cant find the case for this project? I'm with you as 2 is better than 1 lol

[@shoetiquemusic]

Appreciate that sub Bonzology! Reach out to DIY Racked directly using their contact page. This one's on the secret menu. Let me know if you run into any trouble!

[@realiam1am]

does the diy case come with all the buttons and everything already on it?

[@shoetiquemusic]

Hi iAM1AM! The case only includes the screen print. There are pre drilled holes for all the controls/VU Meters on the front and the hook ups in back. You need to source the knobs, switches and VU meters yourself. The knobs, switches and potentiometers are from Mouser. The VU meters are from Hairball Audio.

[@MusicSasho]

Hey guys I need to upgreat my Stam LA2A, which IN/OUT tranformers should I buy?

[@shoetiquemusic]

Hi Sasho! What don’t you like about the transformers? If you’re looking for a drop in replacement I would recommend taking some pictures of each transformer and starting a thread at realgearonline or groupdiy. Let me know once you post and I’ll take a look!

[@-______-______-]

Hi great vid. Total cost for the build?

[@shoetiquemusic]

This one cost me roughly $2,000 USD with all the upgrades!

[@-______-______-]

@@shoetiquemusic not bad for a double!

[@ernieg]

Can I just purchase yours 😊

[@shoetiquemusic]

Sorry Ernie, no can do! Too much blood and sweat into this one!

[@ernieg]

@@shoetiquemusic I had to try 🤷‍♂️

[@mrsyd258]

interesting

[@shoetiquemusic]

I'm glad it caught your attention!

[@theprogrammerrolandmc3039]

sales marketing gone wrong can i sell you some streaming revenue

[@shoetiquemusic]

Only if it’s free programmer!

[@DaveChips]

20 seconds in... i hate you... i hate how right you are xD

[@shoetiquemusic]

Hi Dave! It's my job to be right - that's why i get paid $0/hr to make these videos! Let me know if you decide to build one. I'd be happy to answer any questions you have along the way.

[@DaveChips]

@@shoetiquemusic Appriciate all the good will, but I can't now. 😭 + I heavily suck at soldering, so I'd imagine it would take me more then 6months to complete it 😅

[@shoetiquemusic]

@@DaveChips Try starting with a smaller project and working your way up! I believe in you Dave!

[@DaveChips]

@@shoetiquemusic I'm going thru a house buying proces, so hopefully when all of that is finished, and I have also checked few diy midi controller kits just to get the soldering skill. As up until this point, I was maybe soldering, a cable, connector, resistor... Once every 6 months. And this will be first time doing something from scratch, and I'm not gonna lie. It kinda scares me 😅