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Soundcraft Ghost modifications

Discussion in 'Pro Audio Equipment' started by erockerboy, Aug 14, 2001.

  1. erockerboy

    erockerboy Member

    Hi gang,

    We recently replaced an old Mackie 8-bus with a Soundcraft Ghost in our little MIDI room. While the Ghost sounds noticeably better to everyone and feels much more like a 'real' console, there has been a super-annoying HUM on the 2-mix bus that we cannot get rid of. Mind you, this is after driving a grounding rod outside, bringing in an Equitech balanced power unit, and converting the entire room's wiring to a centralized patchbay with a star-grounding scheme.

    My local mad-scientist tech guy has made a couple of suggestions. One, he wants to take a stab at re-capping the master section of the console, substantially upping all the cap values... which he claims will not only help the console sound better, but will improve hum rejection across the board. Two, he wants to bring in a souped-up power supply to replace the existing PSU, cuz those bigger caps are gonna ask for more juice. Plus, the original PSU is designed to run on U.K. power, i.e. 50Hz, and my tech theorizes that its hum rejection at the USA standard 60Hz may not be what it should. On top of which, giving *any* console a stiffer current source can only help... right?

    We were briefly considering re-chipping this thing as well, but all the IC's are soldered right to the PCB. Bummer.

    Anyway, point being: has anyone out there performed any mods along these lines to a Ghost? Any thoughts, cautions, advice??? Love to hear from ya.

    TIA,

    -e
     
  2. We have the Ghost 32 LE. We installed Drax automation by Optifile who BTW is now out of business.

    It has always been a very quite board. We asked aroung about mods and the feed back we got was leave it like it is. All ours is used for is monitoring during tracking (we use all outboard pre's and some EQ) and mixdown. One thing that I do at mixdown is use send/out in the mix insert to go to 2 trk, by-passing the master fader which has a little noise. The other thing and I feel stupid telling it was we had all the effect returns comming back in thru the tape returns in 25-32 for eq, pan, auto. and they were very noisy. After a while it was like "DUH!!" bring them back thru line in, no more noise!

    I would however like to mod the mix bus if possible, I think it would help but I don't know if it's practicle. If you find out any thing let me know.

    Soundcraft service is in Nashville and we have a tech manual with all the drawings if you need any.

    Good luck and keep me informed!
     
  3. If you would like to add a producers talk back w/remote, wired or wireless with monitor dim to your board check this out:
    qtiav.com/
     
  4. erockerboy

    erockerboy Member

    The other thing and I feel stupid telling it was we had all the effect returns comming back in thru the tape returns in 25-32 for eq, pan, auto. and they were very noisy. After a while it was like "DUH!!" bring them back thru line in, no more noise!

    Hey David-- are you saying that the signal path via line input is substantially quieter than the tape returns?? Or am I missing something?

    Hope it ain't so, cuz I am pretty much maxed out on inputs with my 32-frame Ghost, and I NEED all those tape returns.... but if the tape path is somehow inferior to the channel path, I may hafta rethink my strategy. I haven't noticed a big difference, myself (...yet...).

    BTW, I noticed you had the Ghost LE version, without the integral mute automation. Any idea whether the LE is quieter than the full-bore MIDI/auto version of this board (which I have)? I am getting some weird EFI/RFI-sounding hash on this board, which seems contrary to all the comments from other users (including you) about how quiet this console is. Just wondering if the LE vs. regular version might have something to do with it... ???
     
  5. E,

    Sorry for the confusion. No, the tape returns are not noisy when patched to the balanced tape outputs or with balanced outboard inserted in between (you do have ALL your I/O on balanced patchbays, don't you ;) ) so you are fine using them as is.

    Our problem was we were returning effects processors (-10db) into the tape returns (+4db) and the gain structures were introducing noise.

    We have never had any problem with RFI. You would think SoundCraft would shield the mute/transport computer in your board sufficiently as not to be a problem, but who knows...

    Start from ground zero and work your way up. Disconnect all the I/O except the monitors and turn the CR level up and listen. If it's clean, start adding I/O to see if it is a particular piece of gear, or if just starts accumulating as you add I/O (which would indicate a possible grounding problem).

    Best of luck to you. Keep the faith.
     
  6. Start from ground zero and work your way up. Disconnect all the O except the monitors and turn the CR level up and listen. If it's clean, start adding O to see if it is a particular piece of gear, or if just starts accumulating as you add O (which would indicate a possible grounding problem).

    You may want to look at the power supply. I hear the Ghost has an upgraded PS from the earlier models. I'm sure someone with a clue will be along any minute.

    Steve
     
  7. anonymous

    anonymous Guests

    I have heard it is possible to 'supercharge' the power suplies on these desks, something about the voltage on the 'rails' Anyhow, WAY above MY head...I suggest a search on rec.audio.pro newsgroup and a candid 'come on man, spill the beans' call to the UK engineering dept of Soundcraft UK, they are nice guys (especialy for English techs!) - grill them on the subject, well worth the 10 cents a minuit call! IMHO.

    Good luck,

    Jules
     
  8. erockerboy

    erockerboy Member

    Start from ground zero and work your way up. Disconnect all the I/O except the monitors and turn the CR level up and listen. If it's clean, start adding I/O to see if it is a particular piece of gear, or if just starts accumulating as you add I/O (which would indicate a possible grounding problem).

    Yup. Wanna hear the freaky part? This thing hums like a contented grandma when there is NOTHING ELSE connected. With all cables pulled, all inputs muted, nothing else in the room powered up, listening thru a pair of headphones plugged directly into the console... there is a friggin' 60Hz monstrosity coming down the 2-mix. Not screamin' loud, but definitely unacceptable.

    And the plot thickens. This console is replacing a Mackie 8-bus that was DEAD QUIET in the identical setup. I thought for sure I had some kind of crazy grounding problem until I brought the Mackie back into the room and set it up side by side with the Ghost to see what was what. Nothing plugged in, all inputs muted... sure enough: Mackie = dead silent, Ghost = HUMMMMM.

    During these last few weeks we have been pullin' our hair out. Running isolated grounds, driving a big-ass copper ground spike, buying Equitech 'balanced power' units, meticulously star-grounding the patchbays... NOTHING has made a difference. Hence the move to hotrod the hell out of the console PSU, and potentially do some internal recapping.

    The more research I do on this, however, the less confident I am that the Ghost is worth spending this kind of time, effort and money on. While it's definitely a significant step up over the Mackie, the Ghost is still a price-point console. Had a long chat with the guys over at Audio Upgrades the other day, and they basically told me the Ghost wasn't worth working on from their standpoint. What to do, what to do. I have half a mind to just buy something else, but 1) I cannot fit a large-frame analog console into this space (it's a tiny little MIDI room for goshsakes) and 2) seems like I gotta spend a LOT more money to get anything that is a major step up over the Ghost, sonically speaking.
     
  9. erockerboy

    erockerboy Member

    I have heard it is possible to 'supercharge' the power suplies on these desks, something about the voltage on the 'rails'

    Yeah, my tech geek wants to build a new PSU from the ground up, and design it to drive a couple volts hotter on the audio rails. Plus he wants to triple the current capacity on it. Yummy. Can only help, right?

    Believe me, I have searched high and low for other info. Google Search has turned up surprisingly little. If anyone else on rec.audio.pro has had success with Ghost mods like these, they are stonily silent on the subject.

    I spoze calling Soundcraft UK would be the next step. Looks like I'll be setting my alarm for a few hours earlier tomorrow morning. :)
     
  10. Tymish

    Tymish Guest

    Um..just in case. A friend of mine bought a used Soundcraft Spirit 32x8 Auto. When he first pugged it in he was getting a pretty bad hum. I came over and asked him if it was set for 110/60 Hz. Well, the psu was set for 50Hz! Amazing the thing worked at all! Double check the switch settings for power input. They weren't totally obvious in this unit.
     
  11. audiowkstation

    audiowkstation Active Member

    For what it is worth...Have you checked the headphone jack??

    I was using a ghost and the headphone jack nut was loose causing problems...then it fell through...because someone did not full tighten it :) and then it caused more problems...

    Hope you get the hum fixed...
     
  12. Aaron-Carey

    Aaron-Carey Active Member

    My ghost will make occasional hash noise. AND my front mount headphone jack also fell thru!!!
    It was WAY noisier before they sent us the new style power supplies too. Also the mix b bus is just noisy! nothing plugged in and it will hiss. But aside from that, laugh all you want but this board has great mic pre's and super kickass EQ that I would gladly have a rack of.
     
  13. audiowkstation

    audiowkstation Active Member

    Oh God!! What a laugh I had when you said your headphone jack fell through too!!!

    Sorry...but laughs are rare sometimes...but that was a good one...They do fall through!!
     
  14. Be careful "super-charging" the rails. The Ghost uses NE5532's and TL072's throughout. While the NE5532's will handle +/- 20VDC, the TL072's are only rated +/- 18 VDC max. At the +/- 17VDC that the board is configured for you are already just within the tolerance of the parts. Making the supply stiffer, reducing ripple, and increasing the current capacity is another matter and I would expect diminishing returns after a point. As Fletcher says, YMMV...
     
  15. Aaron-Carey

    Aaron-Carey Active Member

    That was the mod I heard about. Running the console from batteries. Way less ground noise supposedly, and no ripple. How would you set that up ? and would there really be less chance of grounding problems ?
     
  16. Originally posted by Aaron Carey:
    laugh all you want but this board has great mic pre's and super kickass EQ that I would gladly have a rack of.

    Aaron, you need to get out more. Those mic pre's and eq's suck the big one my friend. You might as well drape a green plastic garbage bag over the tracks.

    Try a LANG PEQ-2 if your looking for a taste of what EQ can be or an API 560 Graphic or how about some Neve and API mic pre's. Hell, call up Fletcher and get him to send you a Great River NV two banger.

    Oh my ^#$%ing God, you don't know how much you're going to laugh at your statement in a few years once you've been exposed to the good stuff.

    Of course YMMV. <bg>
     
  17. Originally posted by Aaron Carey:
    That was the mod I heard about. Running the console from batteries. Way less ground noise supposedly, and no ripple. How would you set that up ? and would there really be less chance of grounding problems ?

    What do you do when the batteries die in the middle of a session? <bg>
     
  18. Aaron-Carey

    Aaron-Carey Active Member

    Originally posted by mp@soundtechrecording.com:


    Oh my ^#$%ing God, you don't know how much you're going to laugh at your statement in a few years once you've been exposed to the good stuff.

    Of course YMMV. <bg>



    Just so you know, I used to run Vintage Recorders, in phoenix. We had custom tridents, trident TSM, Neve Kelso, Neve 51 series, Neve 8108, SSL E, Studer A827's, Ampex master muncher, SONY Dash, and mitsu Pro-Digi, a matched quartet of M-49's, Telefunkens, C-12's the whole lot. My new place has focusrite mic pre's among others.

    I dont dispute that these ghost mic pre's are not the best but for distorted guitar especially, I will always find myself using them.

    The E-Q's on the other hand, I gotta take issue, they really are nice! no joke! I would in a heartbeat buy a set of rackmounted ones to carry around. Laugh all you want.

    After using the SSL, the noise of this ghost bugs me, but i mix mostly in software now, so its not really an issue, except when I have to use the summing buses, which i have given up on.
     
  19. I take issue as well! The ghost is no way a Neve/SSL, but it don't SUCK. :cool:
     
  20. erockerboy

    erockerboy Member

    Fookin' fook fook.

    Well, U guyz are gonna love this. My Ghost is now on its belly here at the lab, and we have made some startling discoveries. Fellow Ghost owners, listen and ponder.

    Again: with the console powered up, all inputs disconnected, all channels muted, master fader up -- HUM CITY on the 2-bus.

    Well, we started taking this thing apart. We disconnected the headphone amp, and lo and behold the hum floor dropped noticeably.

    Then we disconnected the CPU assembly, and the hum floor dropped AGAIN.

    Then we started going over the caps in the master section, and a couple of 'em were clearly fried. (This is without even LOOKING at the rest of the console for now.)

    What gives, guys? This board ain't that old... 4-5 years or so, tops. I could not BELIEVE the improvement in the hum floor with the headphone amp and computer disconnected. Not to mention the bad caps we've already found. Aaargh!!! Is this normal?

    Frankly, I can live without the wimpy built-in headphone jack anyways, and I will probably never use the console computer for anything. MIDI mutes? Don't need it. And my DP rig has the SMPTE reader/generator thing covered. So the only thing I lose without the console CPU is the mute groups.

    But it is pretty disturbing that this board sounds sooo much better with all that stuff offline. The burning question is, does my unit just need a bit o' spit and polish to bring it back to factory spec? Or is this an actual design flaw? Ya gotta wonder what the guys at Soundcraft were thinking. The console CPU is encased in what looks like a lead "hum shield" coffin, and all the internal ribbon connectors elsewhere in the console are littered with shielding as well. Why would Soundcraft put such heroic hum shielding around the CPU, unless they KNEW it was a potentially lethal hazard to the noise floor? Yeah, yeah, what do I expect from a "price-point" console... but I swear, my trusty Mackie never had issues like THIS.

    If I'd known I was gonna be looking at these headaches, I woulda thought twice -- more than twice -- before "upgrading" from the old Mackie.

    Well, back to the belly of the beast I guess. Type atcha later.....

    -e
     

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