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The insides of my Ampeg SVP - anything wrong here? (pics included)

Discussion in 'Amps and Cabs [BG]' started by dood, Apr 1, 2005.

  1. dood


    Dec 9, 2004
    Hi Folks, in Hindsight I thought it'd be better to post my question in a seperate thread as not to confuse Tombowlus' Preamp insides thread.

    So here's the deal, below are three pics of the inside of my Ampeg SVP. for those who are willing to look inside the ones they own, or if anyone has any tech experience with these...

    Does mine look normal? (that can be said in the embarressed prepubescent talking to doctor voice LOL )

    OK, as per above, here is the inside of my SVP.

    Can anyone tell me if the inside is what should be expected?

    In the first link, I have circled the area that the other two links are homing in on. The images are rather large, so sorry if that is annoying.. (hence why I haven't pasted them directly on the board!!!)

    Full image, a bit blurred..

    First close up

    Second close up

    My main concern, on the images there is R16 & R17, top right hand corner.. whats going on here? has this been customised or is this how the Pre left the factory?? and the Electrolytics down in the Left hand corner, what is going on there!! what an abortion!!

    This Ampeg is a black faced year 2000 model.
  2. as far as i know, if this pre was blackfaced then that means it was modified, end of story. i dont think they came blackfaced from the factory

    now, looking at the inside of that, its debatable whether or not the black facer did a good job.

    and i dont think i have ever seen those big yellow blobs of gunk in an amp before... maybe someone with more SVP knowledge can chime in on this
  3. dood


    Dec 9, 2004
    Black face in as much as it doesn't have the new grey Hammerite finish, but is black with the red and blue markings, IYSWIM?

    Cheers anyway, I am a bit concerned!!
  4. Jerrold Tiers

    Jerrold Tiers

    Nov 14, 2003
    St Louis
    The wires are the old modification for reducing hum / noise, and is specific for that unit from a certain time period.

    While I would like for the mod to have been a bit cleaner, the RTV is in fact successfully holding the re-routed wires etc in position.

    ALSO....that unit appears to be EARLIER than 2000 based on part date codes. All the date codes seem to be in 1995, for visible ICs, and for the PC board. If it were made in 2000, I would expect it to have some newer date codes...ICs and PCBs don't hang around that long in general....

    The "yellow blobs" (RTV) also suggest a bit older, as that RTV material generally takes longer than that to turn color. Serial number will tell the story on date of manufacture.

    The RTV material is used in normal production to hold parts in position, as a preventive for microphonics for certain parts, and to generally "road-ready" the unit against knocks and drops, etc. The color change doesn't affect its effectiveness.

    I suppose I ought to mention that an authorized modification does not affect the warranty status of a unit........
  5. Man that thing has boogers in it!
  6. dood


    Dec 9, 2004
    Cor Cheers Jerrold! Anti hum measures eh? hmmm... mine is still a noisey beggar compared to the preamp of my SVT2pro.
    If it's any help, my serial number is BBPXM80023.
    Could you date this fella for me?

    I have meant to stick some new valves in, but haven't had the time to get round to it. On searching TB, there appears to be one or two threads that say words to the effect of 'only certain valves will reduce the hum inherent in these units'

    Ideally I'd want a set of ultra quiet valves that can give a fair amount of gain without turning to mush.

    I have been advised that Harma STR valves, Phillips NOS and Groove tube 12ax7-m are good. Am I going to see much improvement over my (now ageing) Sovteks? (I ditched the chinese valves that were in the unit when I got it.. can't say I was too impressed with them.)

    Thanks again Jerrold you information is very much appreciated.

  7. Jerrold Tiers

    Jerrold Tiers

    Nov 14, 2003
    St Louis
    Serial puts it in 2000, indeed......but something is funny there, because of the date codes. They don't agree well with the serial. I checked with QC, and they agreed about the date codes. Dunno, frankly.

    The "goop" is applied to anything which might vibrate, possibly breaking a lead etc. If you notice, all the Blue electrolytic caps in the pics, as well as any other tall parts that are not self-supporting are secured with the "goop" as well as being soldered.

    The material is a special type of "RTV" silicone which does not produce any corrosive fumes as it cures. Many similar materials produce a weak acid as they cure (basically vinegar), which does not do any good to components. However, this acid-free formulation does turn color.

    We have been using it for many years. It does cut down field failures, although it costs a little more.

    We figure the bean counters can suffer with it.....We'd rather have the unit keep working, even if that means it may have a little ugly goop in it, and we suspect you agree.
  8. dood


    Dec 9, 2004
    hhhmmm, thats very interesting! Well, I have no problems with goop in my gear, if it's there for a good reason. It seems logical. So I guess my next question is what is the likelyhood that the serial doesn't belong if something doesn't tally?

    Is there any more info I could give you?
    At the end of the day, I guess it doesn't matter if the unit *looks* ok. It has always had a mains hum problem.. i wondered if that was anything to do with the wiring seen in the pics. As before, I think some new valves could help.

    One thing I have noticed, If I use my SVT2pro, it is a quiet li'l fella, no extraneous hum, and gobs of power. but If I plu my SVP into the poweramp of my SVT, as if it were part of the SVT, the story is very different. LOTS of hiss even with the volume down, and when I crank the master vol up (on the SVP) even more hiss, but, and here's the interesting bit.. i don't get as much volume from the amp (with the same bass plugged in) as the SVT on it's own with the same settings.
    thus hinting that the SVP is rather too hissy.

    Next question, is the output of the SVP actually different to that of the SVT2pro preamp?