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Thread: Modifying a Ampeg SVT3 PRO

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    Modifying a Ampeg SVT3 PRO

    Hi there,
    Just wanted to share this for other Ampeg SVT3 PRO owners ...
    Here's a description to install a better heatsink, improving the mute function and adding a soft start.
    Things that should normally built in from factory ... unfortunately, they're often not.
    Attached Files Attached Files

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    Last edited by Stoffie1974; 12-08-2010 at 08:20 PM.

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    Lifetime Member Enzo's Avatar
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    Hi Stoffie, welcome to the forum.

    This is a very nice article you have written here. May I suggest you add a brief description in your post. That will allow people to know what it is before downloading the large file, and also your description will make it easier for the search function to find it.

    Good work.

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    Education is what you're left with after you have forgotten what you have learned.

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    Old Timer J M Fahey's Avatar
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    Hi Stoffie, excellent work.
    *Very* useful, and can be applied not only to SVT Pros but to many other amps as well.
    Congratulations.
    PS: I was always dismayed at the marginal dissipation available on those amps and their brothers, specially compared to the early SS Ampegs and their *huge* heatsinks.
    Adding real fins at the factory (what you did), costs very little.
    Besides, these amps are not cheap !!!!!!!!!!!!!!!!
    Oh well !!! The Corporate greed !!!

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    Noodle of Reality Steve Conner's Avatar
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    Excellent work. I can't believe how small the original heatsink was.

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    "Enzo, I see that you replied parasitic oscillations. Is that a hypothesis? Or is that your amazing metal band I should check out?"

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    Thanx guys ... I realy enjoyed modifying them, and Enzo, i will add a brief description, just didn't thought of it.
    I'm not a tube tech, but i'm learning (slowly).
    One of my hobby's is buying defective amps on Ebay, fix them and selling them back, and it's true Steve, many "commercial" amps have too small heatsinks
    I did the same mod to a Warwick Pro Tube IV, same kind of heatsink and here it DID blow the very expensive MOSFET's !! But at that time i didn't make a manual for it.
    I have some pictures though if you're interested ...
    BTW, i live in Belgium, here the SVT3 PRO costs 1200€, i bought my first one on Ebay in America ... NEW ... for HALF the price ... delivered @ my front door !! (still can't believe it)
    This was a risk, because you have to pay first and then you wait ... and hope it will arrive one day. Also the voltage had to be adapted, but hey, i had the schematics from ... you know.
    you'll hear from me soon.
    Grtz

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    Last edited by Stoffie1974; 12-08-2010 at 08:25 PM.

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    Old Timer J M Fahey's Avatar
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    ¿Wallon ou Flamand?

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    AAhhh, vous parlez francais?
    d'Origine un Wallon ... habitant chez les flamands depuis mes 2 ans. Vous avez demenage vers le soleil ?
    Ici il fait -5 et tout est blanc... and i hate it !!

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    Old Timer J M Fahey's Avatar
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    Bien sûr.
    Buenos Aires est un pot-pourri d'immigrants, principalement Européens.
    Mon grand-père était Irlandais, ma grand-mère Française, touts les autres Espagnols.
    Même ça, Celtes partout.
    Récemment j'ai vu ce filme (je ne me souviens le nom) du gars Français qui *doit* vivre chez les Flamands, très amusant.
    ¿Peut être "Bienvenue chez les chtis."?
    Salut.
    On continue en Anglais pour les amis.

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    Lifetime Member Enzo's Avatar
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    우리는 당신이 말하고 있는 무슨과 파악할 것이다

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    Education is what you're left with after you have forgotten what you have learned.

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    Old Timer J M Fahey's Avatar
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    On continue en Anglais pour les amis.
    means:
    "Let's go on in English for our Friends' sake"

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    Lifetime Member Enzo's Avatar
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    And the Korean says , "we can figure out what you are saying."

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    Education is what you're left with after you have forgotten what you have learned.

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    Old Timer J M Fahey's Avatar
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    Well, I can "figure" what Korean, Chinese and mainly Japanese texts say, thanks to my son Alberto, who speaks and reads/writes fluent Japanese.
    Thanks God, Japanese Kanji symbols come straight from Chinese and usually mean the same or very close, and Korean are not *that* far away.
    It's useful specially when reading Japanese esoteric audio pages (which can be *somehow* Google translated) and scanned datasheets, which definitely can not be translated, being pure images, with no text.
    My next Language will be Chinese, for obvious reasons , although I don't want to get into it before fully perfecting my Portuguese, which I'm now using everyday for commercial and technical purposes.
    Learning never ends (Thanks God).

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    Hello,

    I'm replacing the .47 ohm 5W ceramic resistors in the power section and I've found the replacements do not have the "feet" on them that keeps the bulk of the resistor off of the heat sink. While looking for some input on if I should lay them flat on the heat sink or elevate them above, I ran into this thread for the heat sink mod. Problem is, it will not load. Is this link still active or are there any issues with the download noticed from other users?

    Thanks,

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    Hi Jammer56,
    I tried to download my uploaded PDF and it indeed doesn't work!
    I found this threat onthis forum though : http://music-electronics-forum.com/t32799/
    It's about exactly this problem, you're not the only one!

    Strangely i cannot add the PDf again, or to this reply...
    Send me an email and i will mail it back to you.
    stoffie@pandora.be

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    Supporting Member Jazz P Bass's Avatar
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    The forum's file for old posts will not let you reload the file Unless you change the size of the file.
    I recommend Cute Pdf or BullZip to rewrite the pdf file.

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