Seventh Circle Audio Preamp "Tutorial"

[Ben Johnson]

SCA modules are extremely easy to build, and I thought I'd share this time lapse video to show what is involved in putting the A12 together.

I also show the calibration procedure, which is quite easy as well.

 

[Chris_P_Critter]

HAHA! That was great Ben!

How much do these kits usually go for?

 

[cloy26]

that's awesome. I think you may have inspired me with my next purchase.

 

[Jaymz]

Looks complex as shit to me! haha

 

[TheWinterSnow]

How much do these kits usually go for?

depends on what you buy. If you don't have a chassis, psu, power cable and one pre, you can buy them all for a kit discount which depending on the preamp you chose around half off when it is all said and done. You can have the whole setup with the cheapest pre for about $400 US.

 

[No More Beers]

do they ship worldwide?

 

[TheWinterSnow]

do they ship worldwide?

yes they do any their PSU accepts 85VAC to 250VAC without the need of jumpers or switching.

 

[No More Beers]

what models of preamps do they have? anyone who can solder can build one or do you need to have ohter knowledge?

 

[Loren Littlejohn]

Thinking about doing the cheapest option for all the other shit (preamp, psu, and chassis) then slowly adding on as funds arise.

Cool video!

 

[aortizjr]

what models of preamps do they have? anyone who can solder can build one or do you need to have ohter knowledge?

http://www.seventhcircleaudio.com/

Amazing what you will find on there.

You need some basic knowledge for the calibration and what parts are what. But the instructions are seriously paint-by-numbers easy. Just take your time and get good solder joints. Even the parts are laid out in order.

Best deal for great sounding pres out there IMO.

 

[Zack Uidl]

That is awesome dude!

 

[S-O]

Hmm this summer is going to be full of fun projects, this and a SLO clone. This one is more affordable too!

 

[::XeS::]

How many Watt is your solder?
I did a ts7 modification 1month ago...everything went ok but it was so hard to solder 2 parts really close..... how are the parts on this board?

 

[sprack]

>= 50W is the sweet spot for me. I usually have to set the iron for around 450 on the Weller to get clean fast blob without having to make contact too long. The JBC's at work I can run around 350 and get the same quality. Good flux and tinning makes it go much faster too.

How many Watt is your solder?
I did a ts7 modification 1month ago...everything went ok but it was so hard to solder 2 parts really close..... how are the parts on this board?

 

[Ben Johnson]

Old 60W Weller. There's no temperature control - just on or off.

Some day I'll get some better tools when I have a proper bench, and not use my laptop stand to solder on.

 

[SimonSez]

Have you tried building the N72 yet? I think I read somewhere you need more measurement tools than just a multimeter to calibrate that one.

 

[Ben Johnson]

My first two were N72s (channel 1 & 2 in the rack). You can get by with just a multimeter - they say that's "good enough" in the manual.

Or you can go the whole nine yards and use an oscilloscope. I just used a multimeter.

 

[aortizjr]

Have you tried building the N72 yet? I think I read somewhere you need more measurement tools than just a multimeter to calibrate that one.

The calibration is really only for maximum headroom and symmetric clipping. But the headroom is so high, you don't really have to worry about it. You can get a well working and excellent sounding pre with just a multimeter.

What you need is a scope and a signal generator. Takes about 5 minutes. The ones I built, the adjustment (after calibrating with the MM) was so minor that I don't think it makes that big of a difference. I mean it is the super fine tuning.

If you are that worried about it, then it might be worth finding a repair guy to help you out or let you borrow their scope and signal gen. Not worth buying them to build a set of pres, scopes are $$$.