Slow Blow pre?

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I`m also finishing the La2 and the sloblo would be my next project, I`m really interested in do it as my first p2p project :)

Would be great have a "certified" schematic/layout... :roll:

Synthi
 
Sorry Kubi, but what's the point of sending me on a search when you know all the links are dead?
I am just as irritated as you if someone asks a question when there's obviously a wealth of information available via a simple site search.
But this is not the case this time.

Incidentally, I had already done that search and as I mentioned, found nothing, hence my post.
 
YEAAHHH. I am back...
Hi to all of you. Synthi i send you some files. Sysmofit links are dead.
Slowblow pre is akiller pre. Try it before you cry for it... :grin:

Fotis
 
Since I know diddly-squat about transformers and their correct usage, could someone tell me about the suitability of this transformer (of which I own a few) as the input tranny for this preamp.

This transformer is so high inductance that you could try it as a 150:4k5 input at the slow blow preamp. Knowing tamura transformers, I say it will work great, at least... But probably not permalloy core, so expect color if used with low level mics.
 
Fotis,

You are the reason I want to make this pre! I read your "orgasmic" description and now must make one (or 2).

Is it possible to post the files on your site or send me them and I will post on mine.

If others want, I can post all documents so that we all have the same files and can discuss them.

Thanks

Jim
 
Cool, Fotis is back. Fotis, it would be nice if you could bring the links to your PSU schems back to life (this thread:
http://www.groupdiy.com/index.php?topic=10751&postdays=0&postorder=asc&start=0 )
I think it would be extremly helpful for future SlowBblo builders; I took those files as an inspiration for my Slowblo-PSU. Where did you end with the tubes? All 5687? Or "classic" with ECC82/5687? I have it running "classic", like it so far.
Now we only need Jazzy to post his version of the signal part (the "asymptot"). I have the file, but I would like to have the permission of Jazzy to post it (or better he posts it).
For those who think about doing this pre on a PCB: the 5687 is a very hot tube, I wonder if a PCB could stand the heat (but I am not very experienced with that).
Toff :sam:
 
This is starting to gather momentum! I think that "orgasmic" description is luring us in!

But do we have a definitive set of schematics?

Like I said before I have a bunch of documents. I could furnish the space on the web to have a central location for everything. How does that sound?

I can send whoever wants my email address in a private message.

Let me know.

jim
 
I'm not in Montreal this weekend but I'll try and set something up with all that I have and post the url. I am staying at a hotel and they have high speed so maybe I can do it from here.

Thing is we need to get everyone elses documents and then decide on the newest and most valid ones.

jim
 
Don't worry about shematics-infos. I have everything you need and i have build all versions. The double srppp the 2x5687 and the last one that jazzy tried,too with the 12sn7 and 5687. I promish to help everyone, just have a litle patience because i am always busy...
cheers
fotis
 
OK Lets start. :thumb:

The classic (first version) shematic is here : http://www.qsl.net/sv3eao/preamp.jpg and http://www.qsl.net/sv3eao/powersupply.jpg


The second version is here : http://www.qsl.net/sv3eao/slowblow2.jpg

My project contains 2 channels. One channel is the classic slowblow and the other is like the slowblow 2 but with 5687 at the first stage instead of 12sn7. The psu is redesigned by me and is here : http://www.qsl.net/sv3eao/psu.gif

Some pics from my project are here:

http://www.qsl.net/sv3eao/Micpre/123_2353.jpg
http://www.qsl.net/sv3eao/Micpre/123_2367.jpg
http://www.qsl.net/sv3eao/Micpre/123_2371.jpg
http://www.qsl.net/sv3eao/Micpre/123_2380.jpg
http://www.qsl.net/sv3eao/Micpre/123_2397.jpg
http://www.qsl.net/sv3eao/Micpre/124_2440.jpg

My regards
fotis
 
[quote author="FotisGR"]



My project contains 2 channels. One channel is the classic slowblow and the other is like the slowblow 2 but with 5687 at the first stage instead of 12sn7.[/quote]

So which one do you prefer?
Thank you for posting this...and yes, very very very nice job!
 
thanks for the links Fotis! :sam:

It would be neat to find a transformer with all three voltages needed in the PSU. I read from an old thread someone suggested the TRA200 from this company:
http://die-wuestens.de/

sec 230V 0,12A ; 20V 0.12A; 6,3V 4A.

And then use a voltage doubler for 48V and running the heaters on 6V. Is there any disadvantages with running heaters on 6V instead?

Another option is to have a transformer custom-made, but it?s pretty expensive I guess..
 
I have for sale some quality toroid trafos and chokes for this project if someone wants to buy.

The trafos are multivoltage (250VAC , 50VAC and 13VAC) 150VA enough for 10 channels psu and the chokes are 10H/150mA - 65Ohm.
These are that i use on the pictures of my project.
The prices are 45Euros for main trafo and 25Euros for each choke.
If i can remember from Jazzy's order the delivery cost was about 10Euros (from Greece to France).

I will come back later...
fotis
 
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