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

[jandoste]

Hi,
I try to understand how I can make the "Link" wires connections?
any idea?
Thanks,

 

[Purup]

Hi,
I try to understand how I can make the "Link" wires connections?
any idea?
Thanks,

You connect the "Link" of each board to the toggle switch named "Link", so this connection is enabled/disabled when you toggle the switch. Do not connect shield "S" to the toggle switch, and don't connect the shield of the two cable to one another at the toggle switch end (this way you will not get a ground loop).
Hope you understand my description.

Mikkel.

 

[ruckus328]

Like this:

 

[jandoste]

Thanks Guys,

 

[jandoste]

Hi Mike,
I got a problem with power xformer, it's too hot(
- I tied gry to vio for input Connection,
- Apply to BLU and BRN
- S1S = Black
- S2F = org
- 0 V = yel+ red

I'm wrong?
Thanks,

 

[Davo]

Thanks Mike!

Great, the calibrations are definitely helpful.

I haven't been able to completely eliminate the 60hz... but it's so low that it won't be any problem at all.... I'd be inclined to have an
external supply next time round.  

Jandoste... try floating your centertap (org+red)  I grounded mine first time round... cause I'm so used to making +/- supplies.... and my voltages just
weren't adding up

cheers,
dave

 

[ruckus328]

I'm wrong?

Yes, very  

Let us hope there's nothing fried, probably not.  You don't have your secondaries wired correctly, they should be wired in series - schematic shows what to do, but......

FOR THE VPT36-690 TRIAD TRANSFORMERS ONLY:

Secondaries should be as follows:

Red & Orange Tied Together
S1S (Secondary 1 Start) -  Black Wire
S2F (Secondary 2 Finish) - Yellow Wire
0V - TO CHASSIS STAR GROUND

 

[jandoste]

I'm wrong?

Yes, very  

Let us hope there's nothing fried, probably not.  You don't have your secondaries wired correctly, they should be wired in series - schematic shows what to do, but......

FOR THE VPT36-690 TRIAD TRANSFORMERS ONLY:

Secondaries should be as follows:

Red & Orange Tied Together
S1S (Secondary 1 Start) -  Black Wire
S2F (Secondary 2 Finish) - Yellow Wire
0V - TO CHASSIS STAR GROUND

Oupppps( I see I'm very wrong...
Now everything is working
Thanks Sir!

 

[jandoste]

D-O-N-E !!! Awesome!
and I'm so H-A-P-P-Y !
Thanks Mike,

Ps: I'll take some picture! Asap!

 

[lsskmki]

Finished mine.

I was surprised it only took three days to build it (from bare boards to a finished compressor).
I'm very happy with the sound and the way it responds to audio. Can't complain about a thing.  ;D

Thanks to Michael (ruckus328) for a great project and for sourcing parts. It wouldn't have been such fast project to build if it hadn't been well designed! 


I'll probably replace the knobs with a different type later, but as of now the unit looks like this.

 

[jandoste]

Finished mine.

I was surprised it only took three days to build it (from bare boards to a finished compressor).
I'm very happy with the sound and the way it responds to audio. Can't complain about a thing.  ;D

Thanks to Michael (ruckus328) for a great project and for sourcing parts. It wouldn't have been such fast project to build if it hadn't been well designed! 


I'll probably replace the knobs with a different type later, but as of now the unit looks like this.

Cool! vintage ! and good work !

 

[AlbertoM]

Hi!, my boards are nearly finished but I still have to get the box, knbos, xlrs...and I have a question regarding vu-meters.

The holes on Mike's front pannel are made for the hb-8037s. I've found a sifam dealer near and I'm trying to find what model of meter fits, but I belive that the data sheet downloadable from sifam website is wrong about the dimensions specified for the cutout of ALxxW and ALxxWF models. Does anyone know which model should I buy?

Thanks

 

[dtrax]

So, I got everything wired up, and now I'm at the point of wiring the power transformer/power inlet/front panel switch. Admittedly, I'm a bit over my head with this, so I need someone to hold my hand for this part. For a bit of info, here's where I'm at:

POWER XFMR OUTPUT
red/orange wired together for series.
black to S1S
yellow to S2F
0V to star ground

POWER XFMR INPUT
grey/violet jumpered together for series
Brown???
Blue???

For the power inlet, would Blue go to Line and Brown to Neutral? Would I then wire Earth to star ground?

Like I said, I'm certainly in over my head, but it's been fun and educational so far. I'd just rather not be electrocuted after all the time invested so far... ;-) Please let me know if you need more info from me. Thanks guys!

 

[Davo]

You've got it almost all correct... for the xformer primaries (for 110v) tie gray and brown together and tie blue and violet.

This is how I do it:
Tie the gray/brown to IEC neutral
Tie IEC hot to power switch
Tie the other half of the power switch to blue/violet
IEC ground goes to star ground

Since the switch is in the middle of the front panel, I ran it with a shielded wire.... I used belden star quad (24g), two conductors tied together to the switch, two returning..... with the doubling up of the conductors, it becomes the equivalent of 18g wire... works a treat.

cheers,
dave

 

[ruckus328]

Yes, Davo has explained it, for 115V mains the transformer should be wired in series, for 230V it is wired in Parallel.  The secondary side is wired for + and 0V, there is no center tap or negative rail in this design.  Please note the colors he is referring to are for an Triad transformers only that were provided with the kits.  Other brand of transformers will have different colors.

I always recommend to run the Line from the mains to the power switch and break the signal there like Davo has said.  Running the neutral to the power switch would work of course, but then there's always live mains voltage inside the unit. 

I've also seen people run the secondaries of the transformer to the power switch, which I would NEVER recommend.

Also, again you must use at least 18 gauge wire for the mains connection.  Doubling up like Davo has done will work too, however if you have the choice I would always opt to use a single wire.  Just playing devil's advocate, if you double up the wires using 24 gauge and one of those wires somehow breaks free, then all the current will be forced through the single 24 gauge, potentially a fire hazard.  If you use a single 18 Gauge wire and it were to break free, then the unit simply just wouldn't work is all.

 

[ruckus328]

Finished mine.

I was surprised it only took three days to build it (from bare boards to a finished compressor).
I'm very happy with the sound and the way it responds to audio. Can't complain about a thing.  ;D

Thanks to Michael (ruckus328) for a great project and for sourcing parts. It wouldn't have been such fast project to build if it hadn't been well designed! 


I'll probably replace the knobs with a different type later, but as of now the unit looks like this.

Thanks, this makes me smile.  Glad to hear it went well, unit looks great.

 

[ruckus328]

Hi!, my boards are nearly finished but I still have to get the box, knbos, xlrs...and I have a question regarding vu-meters.

The holes on Mike's front pannel are made for the hb-8037s. I've found a sifam dealer near and I'm trying to find what model of meter fits, but I belive that the data sheet downloadable from sifam website is wrong about the dimensions specified for the cutout of ALxxW and ALxxWF models. Does anyone know which model should I buy?

Thanks

Alberto, I don't have any experience with the sifam meters so I can't help much here, maybe someone else can chime in.  I believe the dimensions of the 8037 are a pretty classic form factor, so would think there has to be a sifam that will fit.  Have you asked Mike at hairball?  Maybe he'll know.

 

[Echo North]

Hi!, my boards are nearly finished but I still have to get the box, knbos, xlrs...and I have a question regarding vu-meters.

The holes on Mike's front pannel are made for the hb-8037s. I've found a sifam dealer near and I'm trying to find what model of meter fits, but I belive that the data sheet downloadable from sifam website is wrong about the dimensions specified for the cutout of ALxxW and ALxxWF models. Does anyone know which model should I buy?

Thanks

You want an AL-29WF sir.

 

[dtrax]

Davo/Mike:

Thanks so much for the help. I'm alllllmost there, just one more question regarding the power switch. Would I wire Line to the top position, blue/violet to middle, and then the ground/shield to the bottom position? Then I wire shield to Earth on power inlet as well?

Bare with me guys, I've built my share of kits but it was always more of a "solder by numbers" affair (ex: Seventh Circle Preamps).

 

[Marcocet]

Davo/Mike:

Thanks so much for the help. I'm alllllmost there, just one more question regarding the power switch. Would I wire Line to the top position, blue/violet to middle, and then the ground/shield to the bottom position? Then I wire shield to Earth on power inlet as well?

Bare with me guys, I've built my share of kits but it was always more of a "solder by numbers" affair (ex: Seventh Circle Preamps).

No worries man. It's even simpler than that. Just wire the IEC jack positive to one side of the switch, and the blue and violet power transformer lines to the center. That way when the switch is in one position they will be connected, and in the other position the power transformer will be connected to nothing.

If you did what you suggested and wired the third point to ground, then when you switched it off the power transformer would go to ground. That wouldn't cause a problem, but it's certainly not necessary. If however you put the blue/violet on the top and the IEC hot in the middle, then when you switched off hot would be connected directly to ground! You'd blow a fuse every time you shut it off. Assuming you had a proper fuse in line. If not you'd blow something further up the chain (prob the circuit breaker).

Yes you want to wire the IEC ground connector to the chassis. Then make sure that all the sides of you chassis are connected to ground with a continuity tester. I had to scrape some paint off of all the screw holes holding the chassis together for the sides to make contact.



I finished the build today. Wiring was a breeze. Thanks so much for putting this together! After some fussing with the switches the only problem I'm having is that channel two is WAY hotter than channel one. The reduction is metering the same (or at least very similar) level so I've got to assume that the problem is in the output amplifier section near Test Point 1. I'll start pouring through it on Wednesday when i get a minute. It sounds great so far!