Is the Alesis 3630 compressor really that bad? Teardown of "the worst compressor ever made"

[@jimrogers7425]

Large scale manufacturers (like Alesis, etc.) design products with a final price point in mind. They then call for an initial design from engineering that will be appropriate for that particular piece and price. After this, the design is reviewed along with manufacturing costs (which include labor costs, benefits [if any], company overhead [including local taxes], etc.) and any adjustments to the final design will be made at this point. Pricing is often arrived at with some kind of formula, which can range from 3 x parts + labor, or 4 times parts + labor, or some variation of that) and projected into the future with the possibility of keeping the price the same over longer stretches of time. One reason for the single-sided PCBs is that they significantly reduce the overall manufacturing cost and the jumpers were more than likely machine inserted as opposed to hand added later. At that time there were plenty of quad op amps that could have been a better choice for fidelity, but again, overall costs governed the part selection process. The fact that this uses a DBX VCA and detector chip set already makes it more than reasonable as a piece of gear. Apparently when this first came out Mick Guzauski, world-class mixing engineer, was reported to LOVE the 3630 and used it a lot on his mixes... so there ya go! As you can see from the above, this is why small-scale manufacturers like you have an upper hand advantage in many instances. The larger manufacturers are making products that will hopefully have a LONG product lifespan while smaller scale manufacturers can make a set of products that will be purchased by a smaller segment of the market and still make a profit.

[@kensmechanicalaffair]

That's was oddly thorough.

[@Hermiel]

My first compressor ever, circa ~1994! Bought it the year after high school, I think. I will *never forget* the excitement I felt the first time I patched it in and ran a drum mix through it (from my Fostex A-8 playing through an ART Phantom 1608 mixer) and naively dialed in way too much squash. It was mind-meltingly awesome. It was that... THAT SOUND!! 🤯🤩 And such was my introduction to compression with arguably the worst compressor of all time. Anyway, I still have it right here in a drawer so I pulled it out to check the back panel and found that the level-set switch is correctly labeled: +4dBu and -10dBV. You might have a collector's edition on your hands! Now that mine is out I think I'll patch it into my desktop mixer and use it for gaming. ;)

[@JohnnyRock]

I think they moved production to Taiwan and probably fixed this error by then? Check the back of your unit, does it say made in Taiwan?

[@Hermiel]

@@JohnnyRock Mine says "Made in China".

[@JohnnyRock]

@@Hermiel I don't know the exact timeline, perhaps it was earlier, but the one in this video and the one I have are American made. Not sure what year they moved production.

[@JohnnyRock]

@@Hermiel There are 3 versions that I know of, Taiwan, China, and USA. I was under the impression Taiwan came after USA, but I could be wrong!

[@Hermiel]

@@JohnnyRockThe circuits are so sparse, I wonder if there is a substantial difference between the US and Chinese units.

[@Brainbox97]

I think its prevalence came from the french electronic scene, a lot of french house artists in the 90's and 2000's used them. Most famously it's claimed that daft punk used it across discovery. I've seen producers like Lifelike use it across the mix-bus to purposefully make it pump.

[@lavenderllamamusic]

before discovery, they used it for homework and definitely during their Alive 1997 tour as well. They had two of them

[@AlexKenis]

Aaaaaaah 3630... I remember when frigging everyone was using those, especially bass players back when all the 'cool kids' were gigging with rackmount gear. It was never actually 'good', but having a sidechain and a zillion controls was just mind blowing for the price back then. I wouldn't run music through it, but I'd use one in a minute on the mix buss for something like a live group podcast. If you're looking for a 'diamond in the rough' from that era at 3630 prices, Symetrix 425 are surprisingly good at the DBX-VCA vibe

[@Theineluctable_SOME_CANT]

Good comment.

[@NullStaticVoid]

Symetrix made a lot of good stuff. I think they are often overlooked.

[@peterbigblock]

I still have one of the 3630s I bought after college for use with my Mackie 1604 and Fostex R8. It was a really cool bedroom setup for the time. A reel of 456 or 499 and we got very reasonable demos and rough mixes done. And, yes, SM57s can be used for vocals, drum kits, guitar and bass amps.

[@dannydaniel8975]

Hell, even your obsolete analog setup still sounds better than the icy cold sound of protools, logic and cubase...

[@thefeet]

yep! i also owned a Fostex R8 withe the MTC-1 midi controller for sync to an old 486 back in the day using Greg Hendershot's "Cakewalk" (DOS then windows version)... b4 it went "Sonar"(bleh)... nice to see folks here who know what they are talking about

[@radicalfreq]

Tear down videos are one of my favorite from DIY:RE!

[@Theineluctable_SOME_CANT]

You may be interested in my Old home-made 6 channel x 50 W rms 2U 19" rack mount high fidelity power amp... On my channel here on YT... Not for long.

[@markdayneowalla]

I bought one of these back in...1992 or some such. I bought it for all the reasons you mentioned. What it could do and what it cost for a poor boy like me. I still use it, but now it's in my entertainment center to compress TV audio for commercials and movies, both of which have annoyingly large dynamic range.

[@PetersonGoodwyn]

That's a great use for it!

[@monkeyxx]

"Harrowing" is a perfect descriptor of the experience of taking one of these apart. Those pots will snap off in a mexico city minute. The switches aren't made of much either. I put some 1,000 uF reservoir caps in mine and they literally exploded, they weren't backwards, I still don't know why. I think I even had Burr Brown op amps in there for a little while. My best use for this thing was fuzz bass. On mix bus, it's too dark, it just kind of swallows your top end and all your transients. It was a fun project, but ultimately, of all things, the Behringer MDX-2100 Composer was a higher quality product after some little upgrades. Probably designed to compete with the Alesis.

[@tacomancini]

What upgrades?

[@peterbrandt7911]

Thanks for the insides. We never had an Alesis, but it reminds me of my dbx 166, which is still in my rack. Featurewise it's basically the same, although the 166 board seems almost packed in comparison.

[@jon42689]

Unbalanced is pretty standard, usually this is equipment you'd use with an insert cable which is unbalanced. It breaks TRS into a common-send-return setup. Lack of balanced I/O doesn't make it less "pro", considering even if it was balanced internally, simply using it inserted would unbalance it due to a TS connector shorting ring and sleeve.

[@nickwallette6201]

You're also generally not running 100 ft of cable from a channel insert into the processing rack, so as long as your interconnects have a reasonable shield, you're gonna be fine.

[@els1f]

Ummmm... If you push an already relatively hot signal into channel A, crank that thing into channel B, then use the side-chain to control the level of A into B it makes some incredible distortion sounds. There are few things that alter sound that are TOTALLY useless. I always thought it was basically a rack mount guitar pedal. True it's not that great of a studio compressor, though. 😁

[@shardsrecordingstudio-matt2247]

I'm definitely trying this! Might circuit bend it or something too

[@bestsplash89]

Sounds promising! Could you explain "use the side-chain to control the level of A into B"?

[@TheREAPERBlog]

I had one and couldn't get it to do anything interesting. I think you've got your shutter speed wrong which is causing the jitter and motion blur. For 24fps you want it at 1/50.

[@PetersonGoodwyn]

Thank you! I was wondering how to fix that. I'm hopeless w cameras

[@JohnSummerford]

Really enjoying these teardowns, thanks. Any chance of going over an API 312 preamp (or clone) ?

[@PetersonGoodwyn]

That's the plan!

[@dale116dot7]

Besides crappy grounding on a single sided PCB, the biggest problem is the LM339 comparator in the control voltage part of the side chain. It is being used as an op-amp. Never use an op-amp as a comparator. Never use a comparator as an op-amp. It will add crap and noise. Balanced is nicer so you can use it either in line with a preamp or as an insert, but in an insert on most lower cost mixing boards it doesn’t matter, only when you get to the higher end mixing consoles do you get balanced inserts.

[@DMKahn]

Great video. You explained this so well for an “electronics noob” such as myself. Always wondered how a VCA differed to a FET and OPTO. That would be a cool video explaining how those 3 provide compression. Oh yeah and Vari Mu too! Cheers

[@DDPAV]

That brings back some memories- had a small commercial studio in the 90's and had two 3630's in my rack. The two things I remember most was one channel was always on the snare at mix and they never broke (hard to believe). Really like the teardown vids!

[@thefeet]

Why the FUCK would you compress a SNARE? EVER??? omg /falls over ... so the drummer could just stare off into space dreaming of dynamics and say "they coulda hired an rx-5"

[@Bruce147]

I have had two of these recently and they have both failed in a similar fashion. The green lights stay lit on the left channel with no input, and the noise gate lights are red, showing no output. Now, even with nothing plugged in, the lights are on. They worked well for a while, then each one started making odd noises and the display failed. I use one as a stereo limiter with my multi-keyboard rig in a band, so I don't get overly loud when my exuberance takes over. I am now using a DBX 166xl and so far, it works just fine. I think it is interesting that the display PCB had more IC's, and maybe was a higher priority, and possibly more costly, than the audio part of the Alesis 3630. People listen with their eyes, not their ears? I kind of miss that display.

[@nickwallette6201]

Nah. The ICs on the metering board are probably just comparators, which are similar to op-amps, but usually dirt cheap since they don't exactly need to be hi-fi. The metering serves two purposes: 1) Having both in/out AND gain-reduction metering is nicer than having to pick one, and it costs very little to do. It isn't essential -- you can just listen, after all -- but when you have a rack full of these, being able to glance at the meters to get a sense of what your gain staging looks like is quite helpful. Also good for newbies or weekend sound guys to learn how the controls affect the signal. 2) It looks neat. Let's not pretend that ANY of us are beyond a little eye candy, given the choice. Show me one engineer that has never sat back and looked at the dancing LEDs in their effects rack and felt that sense of pride in their gear, and I'll show you a filthy liar.

[@DaveHuizing]

There are some awesome mods for this compressor. What makes this compressor from average to great, but still no SSL. But that's what makes DIY stuff exciting

[@ET2carbon]

Describe them and link please

[@lolKbgTgm6621what]

I've seen that same silly plastic switch-extender on some rack gear from both Yamaha and Korg, so I doubt it was custom-molded for Alesis. And nobody had to hand-wire those jumpers, nor is their purpose to bring traces to the top board - they're acting like road overpasses, allowing traces to continue in a E/W or N/S manner without interfering with the traces running N/S or E/W, respectively. So yeah, they bring traces to the top board, but that's just means to the end of their actual purpose. You still see them in modern-day mass-produced kit. A via would be used when the purpose is actually to bring traces to the top (or bottom) of a double-sided board.

[@monkeyxx]

well, I mean, you're not wrong, but somebody or some "thing" had to place and solder them. I think petersen was just keeping it quick and to the point.

[@bankal1442]

I love your vids man, just stumbled across your channel two days ago, Im a total noob and these teardown vids are soooo useful I love those !!! thanks :D

[@acdnrg]

Had a good laugh at the finance vs engineers angle :D because that´s exactly what still happens today in the large corporation I work for. Dilbert vibes. That said, it´s amazing how you throw in little pieces of knowledge left and right of focus. In fact, I learned more about compressor circuit types and their characteristics in 30 mins (watching two of your videos) than I got from hours of talking to "pro shop" sellers and years dwelling in forums. Great insights, well presented - please continue to provide these valuable lessons.

[@oscarordiano2112]

This compressor is what it is but, no one ever mentions how the light meter adds noise artifacts to an audio signal when the illuminated bar collapses. I wonder if a diode somewhere with a cap or two might reduce those ticks for each LED as the meter collapses… great vid btw.

[@kisho2679]

is the audio quality of the RNC half sized compressor better?

[@tonyspada2744]

Mine hums and just touching the outer casing it sounds ungrounded!!! Any ideas how ground this thing? Would help if not I'll trash it. Any ideas would be appreciated

[@NullStaticVoid]

I've heard about people modding these to sound better. Which I can understand the thinking of. They were cheap to begin with, then later on Alesis was blowing them out for $99 and I even saw $79 a few times. So it's not uncommon to pick one up for $50 USD. And as you point out, it's all through hole and single sided PCB. However it's limited by the 9VAC power. So it is never going to have the headroom that a 12v or 18v design does. Which would be fine if it had a nice crunch or thwack to it. But it just sounds kind of hazy and slow. I had one for a few years in the early 90's when I was getting started in audio engineering. It worked okay on sound reinforcement duties. But had zero character. I later got a better DBX unit to replace it. I have to say, the biggest let down for me was the +4 operation, but not balanced. In SR you always want to be balanced. CMR is armor for your signal and if you allow a chink in your armor, someone will be operating a funky shortwave transceiver near your PA that day. Honestly I'd rather have one of the downmarket DBX units or even a Peavey than this. It's a classic example of plenty of knobs and lights with so called 'features' tacked on, but it really doesn't do the job. Like a lot of Alesis stuff! PS. I actually like the old Alesis Microseries stuff. Microlimiter, Microverb etc.

[@davegraham716]

Amazing channel!! You should do another on Alesis other 2 superior (& gar less known about) compressors from around that same Era. (I mean insanely unkown about, & far superior to the 3630) the 3632 & the quite incredible CLX-440 (has 2 channels of simultaneous stereo compression & expansion) with a look ahead feature, not only a peak or RMS switch like the 3630 has (which os itself still today a very rare feature on any compressor) but a knob that let's you blend between the 2!, pf course a parallel compression blend knob (which blows my mind that that's only recently become a standard feature in hardware comps), also in addition to having 2 sets of stereo ins & outs its also got a Sidechain input fir the Comp + another Key input for the Expander + a Direct (uncompressed) output (all 3 per stereo channel!). All of those are unfortunately phono with no XLRs (but hey at least they weren't like Roland in that Era going all RCA's!). There's a few more great features as well.

[@mikeh7434]

Nice vid.. Any idea what I can try to remove a mild humming that mine developed a few yrs back? I tried new cables but it didn't help. I put it aside and got a Dbx but I love the look of it.. thx

[@oldtimefreedom]

this was a simple but powerful tool for live sound... in the 90's....

[@PetersonGoodwyn]

Indeed, it hasn't aged very well

[@shardsrecordingstudio-matt2247]

Tried it when I was a kid learning, tried it now that I'm a full time big kid engineer and it still just small-i-fies stuff. Definitely want to believe it can do something helpful but would much rather do clean compression itb and use my 1176 on the way in on key tracks. Definitely wanna try it as a distortion box though!

[@project-95]

The hatred of the 3630 has become a meme. The 3630 is listed in Rob Playfords studio gear used on Goldie's Timeless album. www.soundonsound.com/people/rob-playford-producing-goldie

[@WurstPeterl]

I have one somewhere and it’s great for brutal sidechaining.

[@Linksimpson]

Do a video on the Blackmer gain cell that made this possible ...

[@PetersonGoodwyn]

I just ordered a bunch of old 202s! We'll see what comes of it

[@richardjamesmusictech6838]

“For a closing thought...this thing is a piece of crap” bahahaha!

[@topa1798]

I'm pretty sure plugin can beat this,i have this crap😅

[@thefeet]

Whatever. I used this thing to make $$$ for more than a decade (live performance rig)...eeeeek... wrong.. NOT a piece of crap. Very reliable, quiet in-line and did it's job just fine.... MORE than "fine"

[@nickwallette6201]

I bought one recently, mostly out of curiosity. Haven't used it yet other than a quick test. I find it funny how preconceived notions color subjective analysis, though. Depending on who you ask, it's either the worst compressor ever made, or a silver bullet. I'm willing to bet the truth is somewhere within the acres of space between. I also find it silly how much effort some people have put into modifying this unit to be "better." Uhm... why? Are there not warehouses of compressors, new and old, new and used, large and small, that already do "clean" and "unassuming" just fine? If you're going to use _this_ particular model, why not use it for what makes it unique? And if you don't like what makes it unique, then why use it at all? Ya aren't short on options... IMO (and again, from the dubious perspective of someone who has not spent significant time with this unit), the things I see worth modifying are: Lifting the regulators off the PCB, giving them their own heat sinks (to avoid discoloration and damage to the PCB, and even eventual failure of the regulators themselves); Replacing the PSU capacitors for good measure, since they're upwards of 20 to 30 years old now; And if the background noise is troublesome, MAYBE swap out an op-amp for one with lower noise. Beyond reliability improvements, you really have to question whether you're not better off with a different compressor before going to extremes like fitting in different VCA ICs or changing passives. (Unless tweaking is just your zen, in which case, you do you.)

[@maxcarter970]

Thanks for the easy to comprehend explanation. Great stuff. I remember these from when I was playing bass in a band in the 90s. Even at that tender age I knew it sounded like crap :)

[@toxyl3915]

you should rip out the crappy gate, cleans out the sound quite a bit. also the newer revisions sound quite a bit better than the first release.

[@diegocastro5114]

i have one. thanks for the demo!

[@stringsnare]

Did you go to engineering school? I would love to learn how to make and design the stuff you sell it is totally fascinating

[@alextotheroh8071]

Very insightful, great idea for a video

[@PetersonGoodwyn]

Thank you!

[@BadChizzle]

Ok... now... could you mod one channel to do some changes that might make it better? Pretty open in there. Hmmmmmm... ? Say... change out some cheap components? Many opamps have the same pin outs. Better caps? Some adjustment trimmers included inside? Ha ha I know it’s not worth it. Just throwing it out there. I’ve been enjoying your break down videos. Thanks man!

[@PetersonGoodwyn]

I've tried it! In fact we used to sell a mod kit. You can clean it up a lot with better chips and especially capacitors

[@BadChizzle]

DIY Recording Equipment Cool! I’m just glad my suggestion made some kind of sense to you, to be honest. So... the main trouble in the stock circuit, aside from the unbalanced system is noise or unnatural/harsh response? Like super obvious clamping or what? Thanks for your response, by the way! Chuk

[@toxyl3915]

@@BadChizzle the noisiness is what annoyed me, I ripped out the gates and it became a lot better.

[@BadChizzle]

Tox Yl Thank you! Haven’t owned one, so I’m not sure what the problems are. Have seen them for sale used, though.

[@BadChizzle]

Tox Yl But, ya know... that’s a shame, cuz a good gate can be so useful! Ya know... if you have a noisy mic or whatever. Or a buzzing amp. Too bad.

[@thefeet]

Don;t you DARE call the 3060 a "piece of crap".. that thing was in my rig through the 90's to the late 20-teens... as an absolute reliable comp/limiter for a front-of-house live rig. Pffft.. piece of crap? Maybe your special "30-year-younger" ears can pick apart stuff on KZbin but damn bro... /SLAP! The 3060 was AWESOME to have in a rack! If you had two or THREE of 'em? yeah... dual mono at that price! again... if you had 3 of em you just NOW have 6x comps for SIX instruments you are mixing LIVE... yeah... /slap! PFFT! Kids these days!!!

[@TheNickmeeks1]

So interestingly just dug out my 3630 and it would appear, at least on my one they realise their mistake and have the in out level -10dBV/+4dBU. So you’re it’s rare-er?! Lol. But anyway I think it is well known that this is a “piece of crap”. But what I’m wondering (with my total lack of expertise) is it in regards to the compressor just been some input gain and attenuation with a VCA in the middle, what makes it crap. Is it just a bad IC? The unbalance ins and outs? Low voltage? I see a lot of people say taking the gate out of the circuit helps, what if you took the limiter out too? Could you just add some input/output transformers to balance it? What separates this from, let’s say the king of bus compressors, the SSL G Buss comp. What has that compressor got that the finance department at Alesis didn’t think was necessary. I guess the question is what would you need to add takeaway or swap to make this ‘Pro’. And can it be done On the cheap.

[@dandrehn]

These videos are great! thanks!

[@PetersonGoodwyn]

Thanks!

[@sundogaudio851]

I heard there was a DBX mod for these and that they are similar to a dbx unit, can you comment?

[@PetersonGoodwyn]

Yes they're very similar in that they are feed-forward, VCA compressors with an RMS detector.

[@joeblack007forever]

Nice video!!! Thanks a lot! :)

[@searchiemusic]

5:58 wait til you see what they do in mixing consoles

[@saintjames7387]

gearslutz says its bad so it must be.

[@lucasc5622]

anything that doesnt cost an arm and a leg is bad according to gearsluts

[@jredmusic1164]

these videos are awesome

[@alphasnk]

Great video! If you want to see the craziest switch cap ever, check out the yamaha a3000, it'll make you smile :)

[@davidmohr1920]

I got mine 20 years ago I think I will retire it :-)

[@taylorsharp5928]

Looks like they just took a couple $15 chinese guitar pedals and put it in a rack case.

[@PetersonGoodwyn]

Haha that's about right

[@modulblok-e3168]

Any good ?? I have just a inbuld viritual digital gimmick sidechain on my plastik sonicware liven bass and beats 😂👆🏻

[@rocketsauce5067]

It's nickname is dirty six thirty.

[@jargero8203]

It cant possibly be anywhere near as bad as the framerate in these videos

[@PetersonGoodwyn]

Cruel, but fair

[@FrankNobelMusic]

👌🙏

[@kiosko33hz]

If you refer to the original 3630, all you haters are right. Now, modify the right components and you own a one of a kind compressor. But yeah, they don't teach you this in engineering schools do they?

[@Not-Only-Reaper-Tutorials]

bachelite for PCB. No-go. Cheapy-plastiky connectors. Cheap trimmers. No-go device

[@lucasc5622]

clearly you are not the target audience. this is fine for most people.

[@Theineluctable_SOME_CANT]

Very Naive guy doing the review. Obviously no bench tech... The CA1080, LM13600. OTA... Also the NE 571 COMPANDOR.

[@Theineluctable_SOME_CANT]

@@PetersonGoodwyn hi dude. I'm unable to easily comply. I'd need to write a small book. No, I'm not kidding. I used to repair, modify and also design audio equipment. It's like you're asking a brain surgeon: "Hey, mister, what are you doing? " Electronics Engineering is very involved, man. Look into the development of the Operational Transconductance Amplifier if you have STRONG knowledge of transistor theory and have some experience with audio equipment repair. DBX was an early professional pioneer of the hardware compressor expandor. From your video I can see that you don't really understand anything about what you're looking at. You ripped the cover off a magic black box. ✌

[@champ1114]

@@Theineluctable_SOME_CANT okay burner account

[@Theineluctable_SOME_CANT]

@@champ1114 well yeah it's a "burner account". My previous channel got burnt alright! Thanks KZbin. . .