Woohoo, first step down the DIY path

[Dean Roddey]

So I just completed my first step down the DIY path, which I'm kind of taking with a vengence here lately. I guess it started with my big fridge sized iso cab. I managed not to kill myself, though I did injure myself a few times.

So I decided then to sell off all my store bought hardware and go DIY on the electronics side. Everything is sold now, and I've got lots of parts ordered. I'm waiting on the transformers from Sowter to start my LA-2A build. I've got everything else. In the meantime, I'm working on my Seventh Circle Audio stuff. I got the API and Neve pre-amps, and the DI board.

I just finished the DI board and tested it out and it works fine. It was a couple evenings of work, but a lot f that was just feeling my way along. The others will go more quickly since I know what I'm doing now.

It's quite a feeling of accomplishment. Or at the very least it's a feeling of Non-Failurement. I guess I have some Norwegian bachelor farmer stock in my and hate to brag on myself.

For anyone thinking of doing it but a little scared to step up, it's not that hard. Particularly the Seventh Circle stuff. It all comes as a kit so you don't have to order parts. And it has good instructions. You do need to have a little soldering skill and some rudamentery understanding of electronics, but nothing that you could get with a week of watching Youtube videos for an hour or two a night. I'd done nothing more complex before than a Bitmo Trio mod on an Epi Valve Jr. which isn't very complex at all.

If you've never soldered any before you definitely need to practice. Soldering on a PCB board isn't hard but you need to get the flow down. You wouldn't want to have this be your first soldering experiment. But you can buy some blank PCB board and some connector wire and stick it through like a component and practice on that until you get it down. Basically just touch the tip of the iron to the component lead and the pad on the board, give it a couple seconds to heat up, then touch the solder right there where it is touching the lead. Just a little drop. It'll wick right down into the hole and make a perfect little fill.

Since I'd done a little soldering I just started with the real thing. My first four or five were not great at all but serviceable. The next ten or so got better as I went. By the end of the DI board I was doing them like a pro. So it's not a terribly hard skill to master.

The next step up for me is the LA-2A. The design is from Drip Electronics. It's a little more in-depth than the SCA stuff, since you have to order your own parts, but he provides a list with links to the actual web site pages for each part. You can buy nice pre-fab cases if you don't want to make your own. The instructions are very well done, so they won't be hard to follow if you have some basic skills.

I'm going to start on the LA-2A after the two SCA pre-amps. That'll be really nice to get that guy going. And the money saved is huge. A store bought one of course is $3K. I'm going to have about $800 in this one, and had I been a little more hip I could have gotten that down a bit as well, more like $725 perhaps.

Drip also has some other nice projects, the Telefunken V72 pre, the REDD 47 pre, and now the 175b vari-mu compressor. I definitely will take on some of those as well when I can afford it. But after the LA-2A comes an 1176. This one will be the hardest for me, since it has the least amount of hand holding. There is a parts list. But there's no really nice step by step set of instructions. So I'm saving it for last, after I've gotten my confidence up.

But it's also a huge cost saver. It's not expensive at all, costing probably no more than $500 if you aren'tgoing to buy a fancy case. I'm going to put it into one side of a case and later add another for a stereo one.

Some of it won't look pretty, since I'm opting out of buying the nice pre-fab cases in order to save bucks. But it'll be good where it counts, and you can always get the nice case if you want. And I could also move it to a nicer case later if I want.

Anyway, I'm rambling. But this is quite an exciting adventure, and quite a money saving one as well. I was always an electronics geek as a kid but drifted away from it towards the software side of things. So it's kind of fun to get back in a bit. And to get some killer gear isn't so bad either. I figure if I had to store buy just these few bits I'm building in this first round it would cost about $8K or so. And I'm spending about $2.4K. And of course some of that cost is one time stuff to pick up some tools that I needed, which will serve me in various other projects moving forward.

[MMski]

Check this website out! La2a Compressor - Pro Audio DIY Equipment - DIY Vintage Teletronix La2a Compressor

Lots of great information and pictures of the La-2a.

[Dean Roddey]

I didn't feel quite confident enough to do a point to point wiring one like that yet. If I ever do another I may do that. But for the first one, I felt a lot more comfortable with the Drip one.

[Dean Roddey]

Whew... I got about 75% through the Neve pre-amp tonight. I should be able to finish that guy up easily tomorrow. It has some pretty meaty input and output transformers, so it should definitely have that fat Neve transformer sound I would think. I'm guessing it'll be a quite nice replacement for the Great River (one of the things sold to finance the DIY binge) for a third of the price. I'm betting that the Amer. Jazz through the DI into the Neve pre-amp into the LA-2A is going to be Creamy Bass Love. We'll see.

So once I finish the Neve tomorrow, it's either on to the API pre-amp or the LA-2A. There was a missing set of heat sinks so I can't finish the API unless the replacements arrive tomorrow. If not, then it'll be tuesday before I see them. So I'll start on the LA-2A. I just wanted to get one pre-amp done and known working before the old pre-amps get shipped out tuesday.

[Dean Roddey]

And paaasheww, finished the Neve and it tested out well and the adjustment phase was right on the money. So I'm taking a moment to enjoy the afterglow before I go turn it on and give it a try. I love the smell of solder in the morning. It reminds me.... of, of victory.

[Dean Roddey]

And of course I got cocky and put it in and closed up the enclosure and racked it, only to find out that there was a problem :-) So I had to pull it all back out again. Never close it up until you've tested it out all the way! It was a trivial problem and easily fixed and I could have saved myself a fair amount of time and effort.

But anyway, it works now. I tried the Jazz through the DI and into the Neve. It sounded quite nice. With three impedance settings on the DI to chose from I can get from thin to thick from the active pickups on the bass. Cranking the input gain on the Neve sounds really nice.

That's all I did for now. I went on to the API pre-amp since I had the enclosure back open again. I want to get these guys done, and the SCA stuff racked, so that I'm back to a working studio again. Then I can go a bit slower on the LA-2A, where I'm sure I'm going to have to ask more questions and take more care. I got a good ways into the API tonight and will finish it tomorrow and get those puppies racked and hopefully do a little recording and see how they sound.

There are some tedious bits on the Neve and API ones. Definitely starting with the DI board is a good plan, since it's far simpler. There was some quite tedious stuff on the Neve wrt to the input transformer and wiring it up. But it's all doable if you are careful and measure many times and solder once.

I was looking at the LA-2A board and, in comparison, that's going to be like Fred Flintstone stuff. The SCA stuff has lots of small parts, closely spaced. So you have to be really careful with the soldering sometimes. The LA-2 is a huge board with everything really spread out widely, and not that many parts. So, in that respect it's going to be far easier.

One stupid thing on my part is that I didn't realize that the resistors, which come in a little ladder type thing between two strips of tape, were already in order in that ladder, so that you can just pull them off (measuring to verify you have the right thing of course), and put them in. On the first two I'd just pull them all out and would spend a good bit of time just looking through them for the right color patterns. Doh! This time I figured it out and the resistors went a lot faster.

[Dean Roddey]

OK, the API pre-amp is done. All three boards (DI, Neve, API) are tested and the enclosure is closed up. So I just need to rack it and patch it in and phase 1 is done. Then it's on to the LA-2A.

Whew... That was a bit o' work but very satisfying in the end. I'm not going to stop now though. I want to get the LA-2A done first. I want to use my kitchen table for actual eating again.

[memphisindie]

You are hauling ass on this. man, I wish I could get stuff done that fast.
Congrats on the finished stuff!

[Tinfly]

Nice work Dean -

Keep posting your successes - it's inspiring me to do a SCA project this
summer or perhaps fall. Looking forward to hearing about the LA-2A as well.

[Dean Roddey]

I got it racked up and patched up. I improved the patchbay this time around, using more normalled slots, so that a lot fewer patch cords are needed for the common scenarios. Amazingly it all worked perfectly the first time. I also get my little Mopho synth hooked up and MIDI'd up and patched in. So now I can just keep that guy hooked up and drive it from any MIDI source easily. So I'm looking forward to playing with that some. Makes me want to do a Rush type tune.

I played around a bit tonight with recording some accoustic, so that I could test the new mic (AT4047) and the pre-amps. Other than room and my accoustic sounding horrible it went well :-) Too bad SCA doesn't have a Big Sweet Room kit. Though, to be fair, I've not spent nearly enough time yet really just relentlessly moving around the room to see if I can find some good spots. I did some more tonight and made some progress, but I need to spend way more time on that.

I did notice, and I'm not sure why, that I'm picking up a lot less room noise when cranked enough to get a good level than when using the old Great River/P-1 and Pearlman. Unfortunately, it's hard to say why that is because I went from those to these. So too many variables have changed to say whether it's the mic or the pre-amps that made the difference. And the 4047 this is the first time using it so I don't know its ins and outs yet. I generally used the Pearlman in cardiod mode as well, so it's not because of a different pattern.

Anyway, that's spilt milk under the bridge. No use crying over camels of a different stripe and all that. Time to move forward. So tomorrow it's on to Le LA-2A. But at least now I can also get back to recording some as well, and learning the new bits.

[Dean Roddey]

Well the LA-2A is taking shape. Other than about 4 missing or wrong parts that I'll have to go get, I've got all the resistors and capacitors in place. Definitely there's more cypherin' required before taking each new step, because it's not so much a step by step recipe like the SCA stuff. But so far, so good. In terms of soldering technique, it barely requires any. The solder pads are huge and except for a couple cases always a long way away from each other. All the parts are pretty large, with the smallest resistors being half watt, and just a couple smallish capacitors. Mostly everything is very large and easy to work wtih.

[Dean Roddey]

And, other than a few missing pieces I need to pick up tomorrow because I flubbed the bill of materials when ordering, here is the LA-2A board all in one day:

So, tomorrow I pull out the case parts, cut the holds for the XLR connectors and meter, drill holes for the switches and knobs, and for the power transformer mounting and grounding lugs, and the mounting holes for the PCB card. Then it's just put the case together and hook up the case bits to the board.

So I may actually finish this puppy tomorrow, which would be pretty cool. Other the capacitor uncertainty, this one was pretty easy compared to the SCA stuff, in terms of actually assembly. A good bit more complicated in terms of parts selection and being sure you are putting the right stuff in the right places.

I also included the SCA Neve board for comparison. Definitely a very different sort of challenge. One is easy to assumble but you have to do a lot more work figuruing how how to do it. The other is considerably harder to assemble but the steps are laid out like a recipe.

[Dean Roddey]

Oh well, I couldn't find one of my missing parts locally, so I had to order it. So I won't be able to finish the LA-2A for a few days. I'll get the case prepped and ready to go in the meantime, so that I'll just need to stick in the missing bits and hook up the wires and then I can fire it up (hopefully not to explode and kill me and everyone nearby.)

[memphisindie]

I feel your angst.
Boy do I keep a lot of parts around "just in case" now.

[Dean Roddey]

Anyone have any good ideas for cutting IEC power inlet holes? I can just do it the hard way, but is there any sort of specialized punch for that? I've not seen one.

[iangomes]

hauling ass indeed! jesus, my drip la2a took months and months! nice work man! i hope I can get that kind of ass kicking going in my diy stuff!

[Dean Roddey]

Well, to be fair it took like 3 weeks to get all the parts in, with the Sowter trannies taking the longest. I waited until everything was 'in the bag' before I started. Well, I thought everything was in the bag but I keep finding out I missed this or that, so that has delayed things a bit. But I think I have everything now but the power lamp. I need to find a 6.3v power lamp. I couldn't find one locally and failed to noticed I'd failed to notice I hadn't ordered it when I made my mouser order for the missing capacitors.

So I'll have to go back retroactively and put that in.

I got my hairballaudio.com 1176 Rev D stuff in today. So that's most of the less obvious stuff. I need to order a case and the other bits now so that I can get started on that next week. That one looks to be reasonably straightforward (famous last words perhaps.)

[memphisindie]

I've found that the "written list" is indispensable when compiling, ordering, and checking a shipment, check off what was ordered, check it when it gets in.
Doesn't stop me from missing something from time to time.

[iangomes]

I'm just about to start my mnats rev d! and just finished my la-2a! we can be friends!

[Dean Roddey]

I may pick your brain a bit on that one :-) I got my hairball kit, and just ordered the board and will be ordering the other bits this week.

[Dean Roddey]

Well, so far so good. The LA-2A seems to be working correctly. The meter isn't working right. It works ok on the output side, but I get nothing on the GR side. I've tried the zero adjust pot both ways and it doesn't budge. So something is awry there, but I'm not sure what. And I need to figure out how to be able to get the backlight to work. It's a 12V and all I have available is 6.3VAC I think.

It also doesn't have enough oomph to drive a +4 input to a manly signal level (above -18dBFS'ish) without getting some quite noticeable grunge going. Changing the converters to -10 works fine. It can drive that easily without output distortion (though I can still drive the inputs and get some grunge on it, which is nice.) I'm not sure if this is because I got something wrong or if that's just the nature of the beast with the LA-2A.

So, anyway, another triumph of the human spirit against the tyranny of the machine. If I can get the meter going, I'll be happy. It looks pretty rough. But, in the end, I kind of like it. It has a pre-vintaged, war surplus sort of vibe going on.

[iangomes]

lol, that's funny. My GR was working and my output wasn't! turns out i wired the switch wrong for both.
Mine seems to have a tonne of gain, but not clean gain. I'll clip +4 at like the 30 mark on the gain (it's got so much drive on it!).
I need to fix a couple of hums on it as well... (and some noise... still sounds good though). I'd say double check your meter connections with a ohm meter.

[memphisindie]

Sometimes hum and hiss can be caused by flux and metal dust crossing connections, get a dental pick from the hardware store and clean between connections. Especially those little tight ones.

[Dean Roddey]

The problem, after a huge debugging session in which I just assumed was my DIY fault, turned out to be the patch bay! There was an issue with unreliability of phantom power through the patch bay. So sometimes it was getting a weak signal to the mic, sometimes none at all. It worked perrfectly fine before with the lunchbox, so it was the last thing I suspected, so I went through this brutal session to figure out what I'd done wrong. When the signal was weak, it worked but the output was much reduced, and was noisy.

Sigh... Oh well, at least I know what it is. I have to have the pre-amp inputs patchable so that I can patch the DI into them. So I'm probably going to just buy a separate little 2 channel phantom power box. I only have two mic inputs and I can't afford another rack space for a separate XLR bay just for two mic inputs.

When I go straight into the pre-amps, the pre-amps are super quiet and have huge gain. So, a lesson learned...

[iangomes]

haha, just realized you're the guy on the drip forum!

[Dean Roddey]

Yep, dats me. I wish he would be more active on his forums. I've e-mailed him about this and explained the importance of his active participation if he wants to build an involved community there, and hopefully also make some bucks. I'd make the same argument about the Seventh Circle guy as well. They don't seem to understand the importance of being active on their fora. As busy as I am, I'm on my company's forum all the time, answering questions quickly, and our community is growing all the time and very involved, and that makes all the difference.

So, anyway, I did some recording thorugh the LA-2A last night. It sounded good, but it didn't seem like I was getting much compression. I had to go by ear since the meter isn't correctly working yet. But it didn't sound like much. Then it hit me this morning that I'd probably turned the limiter reaction and stereo adjust trims the wrong direction. And sure enough I had. I cranked them correctly in the other direction and now it's doing the kind of compression I'd expect.

It's very quiet and, as others have mentioned, has stupid gain, way more than you could ever use. I just did my first bouncing test (with SONAR) out through it and back in and that worked, though with some SONAR anomolies I need to investigate. I may make use of that gain sometimes I guess by using less at the mic, to pick up less room noise, then push it up after compression on the way in, since the gain seems to be very quiet and noise free within the reasonable range of converter input levels I'd ever use.

So I'm happy now at the end of phase two. The pre-amps are sounding righteous, powerful and quiet, and the LA-2A is now working as it should. So next it's the 1176 for me as well. I need to order the case and electronics. I've got everything else.

What case are you using? Though I swore after this one that I'd buy a pre-done case next time, maybe I'll try it again, with lessons learned. But if there's a good case, or even just case front, that someone's done, I'd seriously consider it.

[Dean Roddey]

So I was looking out to the next step after the 1176, and that was going to be the Gyraf SSL bus comp clone. But, after looking at it, Chameleon Labs has basically implemented that design already, in a nice case, with some of the extras that would have probably ended up costing me $400 to $450 to do. With their introductory rebate the cost is only $600. So it just wasn't worth the sweat and toil in that case and I just bought the Chameleon Labs box.

When you are talking about $800 vs. $3000 or $500 vs. $2500, that's an easy choice to DIY. But for a $150, it ain't worth it.

[iangomes]

I suppose so, butcha don't have the satisfaction of building it yourself!

[NorseHorse]

Originally Posted by iangomes

I suppose so, butcha don't have the satisfaction of building it yourself!

I still support adoption!

[Dean Roddey]

Originally Posted by iangomes

I'm just about to start my mnats rev d! and just finished my la-2a! we can be friends!

Did you did the push button variety or the rotary variety? I got the hairball kit, which has the pushbuttons. But making the slots for those is going to be a joke I know already. So the rotary version would be easier to do. But I can't find anyone who has the 4-pole, three position rotary switch, which would replace one of the push button sets.

Either that or I buy a pre-fab case that someone has done, which will add considerably to the cost probably.