SA-3A (LA-3A Clone) Support Thread

[jwhmca]

Anybody have a estimate for the parts cost for a mono unit?

 

[Austee]

Hey all,

I've emailed Serpent Audio a couple times about grabbing a duple of these boards before they disappear for good. I'm sure he's a busy guy with plenty of projects but until he emails me back do any of you know are there a few left? I know on the website it says discontinued and last order will be in August and such. I was wondering if that was 2013 or not until 2014?

Thanks for any info.

Also, There seem to be no face plates ;eft. Do any of you have the FPE file so I can just build/customize my own?

Austee

 

[Brotastic]

http://www.studioelectronics.biz/sunshop/index.php?l=product_detail&p=1167

Does anyone know if I could use this for the power transformer for the SA3A stereo build?

 

[mrdarwin]

About bridge rectifier...
w08g is for 1.5A 800v
w04g is for 1.5A 400v

so if I have only a w04g, it's enough for a stereo unit no?

 

[GregNey]

Hello, I am about 97% done with this bad boy and am a little unclear how to wire up the stereo link switch... I saw the note to only connect the shield on one board.. but am unsure how to rig it all up. Any help is greatly appreciated.

Thank you, Greg

 

[mulletchuck]

http://groupdiy.com/index.php?topic=42541.20 it's on page2 of this thread

 

[GregNey]

Much appreciated. I did a search of the thread for the words "link" and "stereo" and nothing came up. I didn't realize that the search limits the results to 30.

Thank you, Greg

 

[jason baliban]

Hey Guys,

What is the first time startup procedure/calibration for this guy?  I just finished the build!

jB

 

[jason baliban]

All finished! A great project and an amazing sound!

jB

 

[GregNey]

I just finished mine as well... Primary channel is working like a charm w/the first few tests I've thrown at it. Super quiet too, even though it's closer to the torroid.

Secondary channel (left in case as I'm looking at it is not working. Since the primary channel is working, I started testing a few points with a little signal probe in both locations. I quickly found that the signal dies in the CM2511 X-former. I'm getting a beep at pins 1 and 4 and nothing at pin 5. You guys seen anything like that before? Yes, transformer is properly spaced off the case. I'm about to pull it all apart to check everything, but wanted to report my findings.

 

[GregNey]

Well, the good news is I fixed it... and it sounds great! The bad news is that I pulled a CM-2511 + PCB from an 1108 clone and wired that in (the terminals made it very easy)... so the 2511 that I initially used was dead  :'(. Any idea why that would be?? I am 100% sure that the transformer was completely isolated from the PCB- There was no continuity between anything.

 

[sage]

Hello there

i am building 2 more SA-3A and since on my first build the Audio LOG potentiometers 100k are Alpha as indicated by the BOM and these pots are way too sensitive I was wondering if there is a better part that could be used - I am not sure if the Alphas are the problem but they seem to react to fast to GAIN control - just a minimal touch and the level increases dramatically …

Any suggestions?

Sage

 

[North]

Yeah I noticed that too. They almost act like reverse audio where most of the gain is up front.

 

[sage]

is there a solution to this? if not in the pots maybe elsewhere in the circuit ? this is my only complaint in a otherwise PERFECT machine!!!

Sage

 

[North]

Could try a different manufacturer part such as a PEC. Not nearly as smooth to turn though. The audio log is definitely the way to go with the slow climb up front, just don't know why its acting like a reverse log. Yeah I love this compressor, Ruckus you rock!!

 

[sage]

I was talking to Gary Mannon who is the head tech at the glorious Henson's studios and he is my guru when it comes to finalizing these projects… he doesn't think it would be the actual brand  problem for the pot sensibility, he thinks could be something before the pot, this would be an interesting topic to throw out there to ALL who have done this build and figure out if in the circuit itself there might be an issue somewhere - I don't recall ever the LA3As to have this sensibility issue - basically I get a TON of gain between 1 and 2 and it increases so drastically by the touch it is a real challenge to get the right and left channel to be even….

SO  I AM CALLIN FOR  ANYONE OUT THERE WHO DONE THIS BUILD AND HAS SOME KNOWLEDGE LET'S SHED SOME LIGHT ON THIS AND SEE IF WE CAN IMPROVE IT !

Sage

 

[rainton]

I've built an SA3A too  a while back - no problem here - everything works as it should and expected from an LA3A  ???

 

[North]

If you have normal gain range Rainton, then there may be something going on as I also have major gain level between 1 and 2. The thing is, correct me if I'm wrong -I'm not looking at the schematic but the pot is an attenuator and not a pot performing gain staging so all it is doing is turning down a seemingly hot signal and though very unevenly which is why it sounds like the pot. If you have your lid off (mine's unavailable at this time) you could measure the pot and see if the resistance rise is greater in the front end than the rear or vice versa.

 

[MarsonAudio]

Hello there,
Sage and I are building 2 stereo SA-3As, they must've been two of the very last before they got discontinued. We successfully built a stereo unit last year as well, so when I opened that up to check out the wiring, I noticed that this new version has 2 more switches per unit labeled 600R/load. I couldn't find anything online about it.

Do you have suggestion about the functioning and wiring?

Thanx,

Marson

 

[rob61]

Nice. I had to drill out my own, now they are already drilled/labeled for you on the panel. Its for the "optional" 600 ohm load for the output transformers. There is a place on each board to either wire in a 600 ohm resistor. Now, you have have front panel switchable, so wire the resistor with the switch to give you front panel selection.