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Conference napalm::guitar

Title:GUITARnotes - Where Every Note has Emotion
Notice:Discussion of the finer stringed instruments
Moderator:KDX200::COOPER
Created:Thu Aug 14 1986
Last Modified:Fri Jun 06 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:3280
Total number of notes:61432

159.0. "Sholtz SR&D Power Soak" by RICKS::CALCAGNI () Wed Feb 04 1987 20:50

    Anybody know anything about em?  I heard one of the reasons an amp
    will scream at high volume is due to core saturation in the output
    transformer.  Does the power soak get this effect at reduced volume?
    
    /rick
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159.1Bona Fide ToasterBIZET::LOWRYNuke the SmurfsWed Feb 04 1987 21:199
    The power soak goes between your amp and your speakers.  It converts
    watts into heat, thus reducing the volume coming out of the speaker.
    So you can crank your amp and get nice distortion without shaking
    the fondation.
    
    When you overdrive a tube amp, you get really nice distortion. 
    That is why Marshall and Mesa Boogie and most guitar amp makers
    have vacuum tubes in their amps.  Transistors don't distort when
    you feed them too much power.  They usually smoke.
159.2Power Soak - Eh...FLOWER::JASNIEWSKIThu Feb 05 1987 11:2034
    
    	The so called "power soaks" are a waste of time - that's probably
    why you see so many for sale in the want ad...The "singing" quality
    of a guitar amp comes from several different attributes all working
    together in a precise, uncanny manner. I'll list them here -
    
    	1. Sonic regeneration, due to the air vibrations effecting the
    	guitar strings.
    
    	2. Another regeneration path, this time to the grid and plate
    	elements in the tubes. This is the only advantage a "tube amp"
    	has over a properly designed solid state model.
    
    	3. The "alignment" of the clipping points of each amplification
    	stage in a given amp. That's why a Mesa Boogie has THREE volumes.
    
    	4. The "transfer function" of the entire amplifier - including
    	the speaker - is optimised to pass even harmonics.
    
    	5. Sonic feedback to the reverb unit, if used, can augment a
    	sustained note.
    
    	As I've mentioned somewhere before, the guitar itself has a
    	lot to do with getting those "singing" leads. Try a Gibson.
    
    	The Power Soak was Mr Sholtz's first product, in an attempt
    	to get "that sound" in a managable form. Why bother roasting
    	the Sh** out of your amp, losing a few of the reasons you do
    	get "that sound" anyway?  Tom has come up with *much better*
    	schemes since; my advice would be to capitolize on his research
    	and just get the latest RockMan!
    
    	JJJ
    
159.3RICKS::CALCAGNIThu Feb 05 1987 12:049
    Thanks for your very detailed analysis.  I've tried Rockmen and
    they're definitely NOT the sound I'm talking about.  "Edge" on a
    Rockman is still way too distorted.  A compressor gets sustain,
    but no "bite".  The only way I've found so far to get it is to
    crank the volume knob.  (ie, I've heard 6 watt amps "scream" but
    at a very comfortable db level).  It would be nice to be able to
    do this at different volumes without having a dozen amplifiers.
    
    /rick
159.4Get a Boogie or a RockmanDREGS::BLICKSTEINDaveThu Feb 05 1987 12:1015
    If I recall correctly, a lot of amp manufacturers have said that
    you void your amp's warrantee if you use a power soak with it.
    Apparently it's possible that they may do some damage to the amp.
    
    Of course if you got a Boogie, you wouldn't have any need for a
    power soak.  You can get a killer lead sound at almost inaudible
    volumes.  When I lived in an apartment, I used to turn the boogie
    way down (so as not to disturb my neighbors) and then mike it and
    run it through some headphones at full blast.    First time I tried
    that, I set it up, put on the phones, put on the guitar, and hit a 
    power chord.  I immediately whipped off the phones cause I could've
    have sworn that the whole world had heard it, and maybe I forgot
    to turn the volume down.
    
    	db
159.5Main Pain GainERASER::BUCKLEYThu Feb 05 1987 12:146
    Re .2:
    Joe, Marshalls have three stage gain also, its just that the first
    two are governed by one volume control.
    I've got a power soak..great for those old Marshall without the
    master volumes, but i don't need it anymore...anyone want one?
    WJB 
159.6ZZZZZzzzzzzzzzapHAMSTR::PELKEYLoco boy makes goodThu Feb 05 1987 15:237
    	WARNING:
    
    	I know a repair tech out of westminister.  Hes had more DOA
    heads come in due to that power soak.  His professional
    advice was to stay away from them.  

    
159.7If it blows more than three times, its sold! ERASER::BUCKLEYThu Feb 05 1987 16:424
    My opinion...if an amp can't be run balls-to-the-wall without blowing
    up...what good is it??            
    Now, I had these Music Mans....
    WJB
159.8HAMSTR::PELKEYLoco boy makes goodThu Feb 05 1987 17:076
    If it can't run balls-to-the-walls, it aint a guitar amp.
    
    I used a music man once, for about 5 minutes....
    
    rp
    
159.9BTW, it sounded great tooERASER::BUCKLEYThu Feb 05 1987 18:578
    What I mean by that statement is...if you have to baby your equipment
    cuz it might fail you...its not very good now is it?? I had a 50WT
    music man head that was all tube an sounded a lot like a marshall...
    I ran that thing full tilt for three years and never had a single
    failure...and never had to replace the tubes either...that's what
    I call a good amp (others may call it luck, however)
    
    WJB
159.10MTBLUE::BOTTOM_DAVIDFri Feb 06 1987 11:459
    I second the fear about the power soak, a friend of mine is a repari
    tech and he said the power soak will kill your amp if you use it
    long enough, no question. The reason is that tube amps require that
    the impedance be well matched, and the power soak is a comprimise
    in impedance matching, as you change power levels to the speakers
    the impedance changes as well....even Scholz had trouble with  his,
    blowing up all but once of their amps at one of Boston's early shows.
    
    dave (who also has a music man with good reliablity and fair sound)
159.11DONJON::CROWLEYMon Feb 09 1987 16:4514
    
    
    I'm not sure about other Boogie models, but mine has a fourth stage
    built in it called limit.  This is pretty much the same idea as
    the power soak.  You can crank up both preamps, and the master
    volume up to 10.  Now you've got incredible distortion, but enough
    volume to rip the head off an elephant.  Thats where the limit comes
    in.  It acts like a power soak, so you can get that distortion
    at an almost inaudible level.  How about you, db?  I never really
    got a chance to check out your Boogie at the jam... Do the other
    models have Limit in them??  (BTW I got my cover back. :^) )
    
    ralph
    
159.12Mesa Boogie - the ART in TechnologyDREGS::BLICKSTEINDaveMon Feb 09 1987 19:3242
    re: .11
    
    First, I'm VERY glad you got your cover back.  That whole thing
    was a bummer.  Glad it worked out ok.
    
    I believe that the limit feature is only present in the "Calibre"
    or "Son of Boogie" models (Boogie seems to use these names
    interchangably for that model line).
    
    The Mark III series have something that sorta accomplishes the same
    goal of great sound at low volumes, but in a different way.  There's
    some thing that they do that causes the first two power tubes to be run
    at 15 watts each.  They refer to this feature as "SimulClas".
    
    The Mark III's chunky and distortion sounds are definitely an
    improvement over the Mark II's.   The Boogie singing lead sound
    is even "cleaner" than in the II's, although I think the II's are
    better for clean sounds.  Mine is a Mark IIB, which I bought new in
    1980.
    
    I didn't get a chance to check out your amp either.  I was originally
    planning to use your amp as a second amp for stereo delay but decided
    that would cause too many problems with the PA.  (I shoulda used
    it as mono anyway as it might have improved the monitoring problems I had.)

    My Boogie is currently having problems.  It seems to have all the
    classic problems of bad 6L6C's (unwanted compression, signal clipping,
    noise) but replacing the 6L6C's hasn't got rid of the problem.
    I've made some experiments replacing the preamp tubes, but I only
    have the two replacement tubes that came with the amp.  The guys
    at Boogie said that if they were stored with the amp for that long,
    their not likely to be much better than the tubes that were actually
    being used (because they were subject to the same vibration) so
    I'm going to just replace all the preamp tubes (the Boogie guys
    have said that's NOT a good idea, but haven't offered any other
    suggestion other than to send the amp back to Petaluma, CA).
    
    It's a bummer because the thing just doesn't have that "singing
    lead" anymore.
    
    	db
    	db
159.13Not to get off the subject, but....DONJON::CROWLEYTue Feb 10 1987 11:2312
    
    
    re .12
    
    Why do you think they told you not to replace all the preamp tubes??
    I haven't replaced them in my Boogie yet, only the power tubes,
    but I HAD done this several times in my Marshall and didn't find
    any problems.  I guess I better take those extra preamp tubes out
    of the little clips on the back of the amp huh?
    
    ralph
    
159.14Preamp tubes tend to be flakey I guessDREGS::BLICKSTEINDaveTue Feb 10 1987 11:5621
    re: .13
    
    They said that as a general rule, you don't replace preamp tubes
    unless you know they are bad, and the symptoms of my amps don't
    aren't typical of bad preamp tubes.
    
    They said that when a preamp tube goes, it GOES.  That is, the amp
    starts failing in a big way (lots of noise, awful sound, etc.)
    Although I don't quite remember why, they said the reason you don't
    replace preamp tubes is that it's more likely to introduce new problems
    than fix old ones.   Perhaps it's that preamp tubes have a high
    failure rate, but when they work they work a long time.
    
    I don't see what the big deal is.  I'll just number the tubes I
    take out according to their slots, and then put the new ones in.
    If it fixes it, fine, if not, I just put them back.  Only real hassle
    is that in order to get at the preamp tubes, you have to take the
    speaker out (dumb design, and I've passed that comment onto them).
    That's a pain.
    
    	db
159.15I hope this helps!MOSAIC::BUSENBARKTue Feb 10 1987 12:4329
	Replace preamp tubes? Very unlikely I 've very rarely replaced preamp 
tubes in any of the amps I've had including a 70's vintage Mark I. However 
if the amp has reverb,graphic eq you might want to try to do some simple
troubleshooting like eliminate playing it with reverb and then without
the graphic eq? If that doesn't eliminate the problem find a friend who
owns a scope and follow your input until you see it clipping if it is 
distortion or if it is noise(like hissing)a flaky cap which is harder to 
find. It really sounds like three separate problems. 
	I have replaced reverb springs in a fender which were creating unwanted
distortion or the transducer in the springs ,but this is very unlikely.
	Heres a diagram which shows you the different stages of a Boogie
which might help. It's pretty accurate except for terminology maybe?
    Like the people at Mesa said when a preamp tube goes you really hear it!

Tubes V1             V3b        V3a/V4 V2
In   Preamp          Lead Drive Reverb Effects  Eq Circuit 
     Tube(Volume 1)  Tube       Tubes  Ret/Send Transistors  
>----[]--------------[]---------[]-----[]----------[]---->


      V5     
      Driver Power Impedeance matching  Out
      Tube   Tubes Transformer
 ------[]-----[]----[]---------------Speaker 


						Good Luck!

						    Rick