Pictures of my first DIY - Seventh Circle A12 A*P*I* clone

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Category 5

Well-known member
Joined
Jul 24, 2004
Messages
698
Location
Palm Beach, FL
I used the stock conemag input tranny, profile output tranny and a 2520 pulled from a 1973 console...running at +/- 17.4v as per Tim's recommendation. The power supply is the seventh circle ps02 which is 27 volts...the regulators are on the preamp.

I have not heard a better sounding preamp....

www.pbase.com/image/33139147.jpg


www.pbase.com/image/33139146.jpg


www.pbase.com/image/33139148.jpg


Whaddya think?

Shane
 
Hey nice work Shane!

Looks great...what else are you going to fill that chassis with?

Also where did you get the 2520 - ebay?

Cheers Tom

PS looking forward to hearing some tracks with it over at UAD forums........
 
Whether you use Tim Ryan's A12 kit or Joe Malone's 99x or one of the Group DIY members variants .... or build up a PCB of your own ...
... this is a great project and with many options worth trying.

If you bought Tim's rack as well, then you could get some more PCB's and assemble them with other options ... however that might not be so easy to have different voltages. :shock: NO wait ... there is voltage trim on board with this one ??? yes ??

Either way the project that I call Project 2 is a must for everyone.
 
[quote author="TomWaterman"]Hey nice work Shane!

Looks great...what else are you going to fill that chassis with?

Also where did you get the 2520 - ebay?

Cheers Tom

PS looking forward to hearing some tracks with it over at UAD forums........[/quote]

The 2520s are from ebay. I got a pair that were both pulled from the same 1973 console. They were $100.00 each. I have seen them go for less, but they were all different and not guaranteed to be working (i.e. one Mellville, One Huntington, and one Studio products Division labeling, untested).

There are frequently line cards on ebay that go for about $75 to $100 and contain a 2520 and the original output transformer, but the Profile 4804 is only $15 anyway and is the same thing (it's the one in Tim's kit).

There are a lot of API boards available and many great schematics, etc. but you can't beat the SCA chassis and power supply combo. If you build one of the other versions you'll be left with the task of drilling chassis holes and mounting the power supply...not to mention isolating the modules from power supply noise.

The SCA kit makes easy work of all that and assures a noiseless pre...not to mention that power supply can handle up to 8 modules (which can even be mixed and natched between the API, Neve, and Jensesn Twin servo).

I'll be building one more API, then two Neves, and two Jensens. By that time the C33 discrete preamp card should be ready to top off all 8 slots.

Then i guess I'll move on to an 1176 or something. The Green Pre looks awfully fun too.

Shane

P.S> Kev, all the SCA preamps have the voltage regulators on board so you just daisy chain the power leads for up to 8 modules and you're set. That's another reason the SCA kits are good. I imagine these are going to be pretty popular. The A12 sounds amazing!
 
cool cool!!
Tim´s boards are very well done... btw, do you like the Cinemag sound ? :) I do.


cheers!
Fabio
 
Thanks for posting Cat 5,

your name makes me wonder what that hurricane is doing. I must check. Anyway, what other pre amps are you comparing the sound of your 7th circle to?
 
[quote author="Bauman"]cool cool!!
Tim´s boards are very well done... btw, do you like the Cinemag sound ? :) I do.


cheers!
Fabio[/quote]

I have not tried the Jensen or Lundahl so I can't comment on them, but the Cinemag sounds fantastic to me. I think it is a different part number than the one that was discussed here a while ago. All in all the kit just sounds perfect to me the way it is, so i trust Tim Ryan did most of the lab-work and came to this conclusion based on how close it sounds to the original 312.

Tims boards ARE done very well. This is my first audio DIY, but I have built plenty of other circuit kits and never come accross a board as nice. Usually the stuff I've built has tin leads, rough edges, and feels flimsy.

Orson,

I am comparing to my modded Presonus MP20 (Jensen/AD797 mod), AMEK 9098 EQ, the DBX 586 tube, and of course the standard Mackie. David Kakon from the UAD forum sent me some samples recorderd with his SCA N72, A12, and J99 along with a Buzz MA2.2 and the SCA pres were better soundign than the buzz IMO (just more exciting, although the buzz is great in its' own right). I especially liked the J99 but after I buy the kit, the op amps, and opt for the output tranny I will have invested almost $700 for a single channel's worth of parts. I'll do it, but not next!

Shane
 
I heard Digi-Key sells that exact same Chassis. If I have the tools to punch something like that, couldn't I save a nice chunk of money by buying the same chassis from Digi-Key? If anyone knows the model # of the Chassis, could you please tell me? Thanks and your kit looks awesome..I'm just trying to find a way to create 8 sca channels and be able to afford it..got the time to build it too.
 
[quote author="dejacky"]I heard Digi-Key sells that exact same Chassis. If I have the tools to punch something like that, couldn't I save a nice chunk of money by buying the same chassis from Digi-Key? If anyone knows the model # of the Chassis, could you please tell me? Thanks and your kit looks awesome..I'm just trying to find a way to create 8 sca channels and be able to afford it..got the time to build it too.[/quote]

If you buy the chassis with the power supply and at least one kit he will discount the chassis by 50% so you are only paying $150. Believe me, by the time you get a chassis, paint it, drill it, and apply graphics you'll be kicking yourself for no getting a complete one.

I was going to build my own chassis since my dad is a machinist, but by the time we bought and formed the materials, and had them powder coated like the SCA chassis the time and money invested would have been silly.

I am glad I got the sca chassis, not only because the work is done and it looks great, but also because everything fits together tight like legos.

I am still loving this kit, at the same time looking for a decent EQ kit of medium or less difficulty.

Shane
 
$150 discount? :grin: . Me feels it's time to purchase my SCA rack sooner :cool: . Do you think I can get any more discount if I buy the following at the same time?:

N72 preamps (4)
J99 preamps (2)
A12 preamps (2)
PS02 p.supply (1)
CH01 Chassis (1)

I'd be buying everything in kit form to keep costs as low as possible.
 
Whoa, I didn't know about that discount either... does it say that on the site somewhere, or do you have ask about it? I guess I might be able to get something together a lot sooner than expected.
 
The discount is calculated automatically by the shopping cart when you add a power supply, case, and one module.

The minimal kit doesn't make sense either (i mean the preamp) since you'll save maybe $20 at best and the transformers and connecter have a lead time of 4-6 weeks.

I don't think there are any other discounts though.

Shane
 
Dejacky,

I thought about it and if you e-mail Tim I am sure he will do something for you if you are planning on ordering that much at once. At the very least he'll probably throw in some extras.

I really hope his kits become more popular because it will be better for us all. I don't actually think he's making too much profit per module, and he has turned down offers to carry his kits retail (prbably due to the difficulty of providing quality support).

He has a 1272 based DI due out in 3 months, and a completely new discrete pre due out after that. The more profitable his business gets, the more new and exciting kits well see...and we all know there is a shortage of high-quality COMPLETE projects out there. Most projects require sourcing parts from several different vendors, waiting for component arrivals (usually with lead times), corresponding on building directions...can be fun, but can be tiring!

Shane
 
Category,
Which pre is on the files named BOULDER? The one vocal track with the boulder pre sounds really open on the hi end. I like it.

Brandon

Thanks for the clips
 
has anyone compared their SCA A12 to a real 312? I'm very curious to hear them in comparison.
 
[quote author="frist44"]Category,
Which pre is on the files named BOULDER? The one vocal track with the boulder pre sounds really open on the hi end. I like it.

Brandon

Thanks for the clips[/quote]

That's the John Hardy Dual 990c preamp. THe SCA J99 is about the same design but uses a lundahl input tranny, and the Jensen output tranny is optional (extra!). The one in the samples has a Jensen input and output tranny.

The Mic2 is a MXL990 ($60.00 at www.jrrshop.com) and one of the best kept secrets in budget mics.

Shane
 
thanks for the audio samples! :grin: . I like how the Buzz preamp emphasized less high end "sizzle" on the vocals...seemed like it would sit well in a mix.
 
Great job!

Tim's work is really pro... and your are right, those Cinemag trafos sound amazing!

My studio partner called me a whole week to thank me, cos I left my a*p*i prototypes there to test... :razz:

enjoy!
Fabio
 

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