Spectra Sonics 101 pres - worth building?

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Ilya

Well-known member
Joined
Feb 25, 2005
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751
Location
Moscow
I've got a guy here who wants to get rid of his 2 extra Spectra Sonics 101 cards (pcbs only iirc) with original trafos (in/out, for 2 channels as well), schemes included.
I wanted to ask you guys if it's worth the mess and the money (he wants around 400$ for that) to build this stuff? I've personally no experience with these pres and no of my friends either. So any suggestions appreciated.
 
Well there is alot of tech info here about the 101's here though I'm not sure I or others have said much about their sound. I love my pair. API'ish, but smoother and not as foward in the mid range, a nice colour to have in the studio and are used all the time on anythign guitars to drums and even vocals.

RE the price, if you are saying you will get 2 x 101 cards and 4 triad trafos (2x in, 2 x out) then it is fairly fair, Ebay prices are around $350-$400 for then combined.

Cheers

Matt
 
[quote author="matta"]Well there is alot of tech info here about the 101's here...[/quote]

Matt, I've actually done a search here and all what I found was a photo and a general words about them. Nothing technicaly special though. I think I'll give it a try once again.
Thanks for the description btw!
 
Matt, do you know which trannies were used in the consoles with the 101 cards? I have one card here and don´t know what iron I should use it with.
 
[quote author="Ilya"]Matt, I've actually done a search here and all what I found was a photo and a general words about them. Nothing technicaly special though. I think I'll give it a try once again. Thanks for the description btw![/quote]

Yeah, the search is TERRIBLE in trying to find stuff, I just know because I contributed to the thread in length...

The thread is 8 pages long and called 'Racking Spectra Sonics 101' and can be found here: http://www.groupdiy.com/index.php?topic=11466

[quote author="jensenmann"]Matt, do you know which trannies were used in the consoles with the 101 cards? I have one card here and don´t know what iron I should use it with.[/quote]

Yip, SS in the USA used Triad's, the A-67j on input and the HS-66 on the output if I recall correctly, though I believe some of the European units had UTC's in place of the Triads.

Also good to note that the 101 and 110 cards are different, 101 is single ended, 110 is bipolar.

Hope that helps.

Matt
 
Back in the 70's, I built a custom console using 101 modules, which I believe were about 69 bucks a piece. I used a bunch of A67J trannies for the inputs, and you had to follow Dilly's wiring diagrams exactly as far as grounding went. The biggest problem was that we were constantly blowing output transistors. Since the outputs were normaled to a patch panel, the slightest short while they were putting out signal would make the card go dead.
I eventually made a photo of the circuit trace and made about 50 spare cards. Only about 4 bucks of parts on the whole card, and that's using Corning metal film resistors and quality caps. Some of the Fairchild transistors are hard to get today, but there are better modern ones to take their place, plus, I would use a beefier output pair.
All in all, a very clean sounding preamp of moderate gain.... if you can keep them from blowing up!

Jim
 
matta
Thanks for a link! There's TONS of info there!!!
It turned out that I typed Spectra Sonics without the space in between, so I never met that topic.

Jim
Thank you for sharing your experience. Much appreciated!
 
The 101 used +24 vdc for power, and I've been half temped over the years to make some model 110 pres which uses bi-polar supply, and make it the same size as a 990/API style DOA. That would be easy, since there really aren't that many parts. Of course, a model 101 could be made like that too. There really is a lot of wasted space on that pc board because it was meant for use in a card cage. Just a thought.

Jim
 

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