Conference napalm::guitar

    	As an aside, it occurs to me that if someone had a Rockman,
    and a good Boom box (with line input jacks) they could patch the
    rockman into the boom box and away they go. Boom boxes are available
    in high power configuration (Ghetto blasters), and could conceivably
    offer better sound quality than a Pignose (I own a Pignose, and
    while it is a good little practice amp, the power is limited, and
    the cabinet has the tendency to rattle) or other available amps.
    Many boom boxes will run off of AC, dry cell batteries, or an auto
    cigarette lighter. One other plus, is the potential of setting up
    a stereo field with the right effects pedals (battery powered, of
    course).
    
    Granted, if you didn't own either the rockman or the boom box, it
    could be an expensive proposition to buy both, but the boom box
    is not limited to this purpose. Let's face it, virtually everyone
    can use a good boom box if they don't already own one. A boom box
    would also allow you to record youself while you are playing. Granted
    it wouldn't give you studio quality recordings, but it would still
    be handy for some purposes.
                               
	Just a thought
    
    	Mark Jacques
        
    

    
    Re: .1
    
    I hope you have a big suitcase if you buy the Peavey!!!!!!
    
    I think all except the Pignose will be too large for the average
    suitcase.
    
    For Mouses, try EU Wurlitzers they sell them by the truckload in
    the summertime.  Expensive though.
    
    The Peavey Solo is sold as a mini-PA, they also make a KB-15 for
    keyboards, and the Companion 15 (which you know of) for guitar.
    All three share the same cabinet, power amp, speaker, etc. just
    the preamps vary from unit to unit.
    
    Fender used to sell a Sidekick 10 which was a small amp that could
    run on batteries, but I believe it is discontinued.  

    

    re: .1
    
    > As an aside, it occurs to me that if someone had a Rockman,
    > and a good Boom box (with line input jacks) they could patch the
    > rockman into the boom box and away they go.
    
    I thought of this, Mark, and I think it's a real good suggestion.
    My main reason for not considering it right now is the cost. It
    would, however, give a lot of flexibility. Maybe I should look into
    the Rockmans more.
    
    - Ram

    Working in Manhattan I get to hear alot of street musicians and
    the Mouse is the clear favorite of those who are any good.  (The
    range available in the subways any evening rush is amazing -- from
    "why doesn't that guy just beg" to "why doesn't that guy have a
    record contract".)  The mouse sounds awfully good and seems to support
    a range of styles and guitars without alot of outboard signal stuff.
    
    - Evan
    

One reason *not* to use a boom box as your amplifier is that its
speakers are made to reproduce recordings having highly compressed
dynamic range.  Your guitar's dynamic range is not so compressed
and might push the speakers past their reasonable operating limits.
Also, highly fuzzed signals can really beat on speakers that are not
designed to accomodate such nastiness.  In a nutshell, instrument
speakers are industrial strength, boom box speakers are (usually)
consumer strength.

    I took a look at some of these yesterday and here are the results:
    
    1. Pignose - As I said before, it's extremely limited by having
    only one tone, and no headphone output.
    
    2. Rockman + boombox - Besides the expense, this is also limited
    because the Rockman doesn't have tone controls, and as mentioned,
    you could easily blow speakers. Also, too much stuff to hook up.

    3. Mouse - I saw marketing stuff on two version: the original Mouse,
    and the Maxi (or was it Miti?) Mouse. The original Mouse has two
    inputs and two volume controls. The only tone control is a switch
    on one of the inputs that "contours" the eq specifically for guitar.
    The Maxi Mouse has a tone control, which I think has seperate high
    and low settings, and can be selected for either of the channels.
    They said it could be used to prevent feedback on a mike, or adjust
    the tone for a guitar. The Maxi Mouse is somewhat more powerful
    than the Mouse - they claim it can hold it's own against 25-40 watt
    amps. Problem is the price: Maxi, $300 list, $255 retail; Mouse,
    $250 list, $189 retail. That's more than I want to spend for a practice
    amp.

    4. Peavey Companion 15 - I was pretty impressed with this. Only one
    input channel, with pre and post gain, low and high tone controls.
    Also switches for "thick" (raunch) and "distortion" (whine). With
    this combination of controls and the stuff on my guitar I could
    get a wide variety of sounds out of it. It has something like a
    6" speaker, and can run off batteries or a 12v power supply. It's
    fairly light, and could fit into a suitcase (although you wouldn't
    have much room left for clothes in a small suitcase). It has a
    headphone jack on the front panel, but no line out. I saw it at
    Daddy's for $89, plus $19.95 for the power supply. I wish they had
    added another input channel, but for the money it beats anything
    else I've seen.
    
    5. One other alternative - the Pocket Rocket (or something like
    that). A very small module mounted on a jack that just plugs into
    your guitar and provides a headphone output. I was thinking that
    if you combined this with a distortion box you could have a fairly
    cheap and highly portable thing for practicing with headphones.
    But then again, maybe it would be better to just get a Rockman Soloist.

    - Ram

    I tried a Pocket Rocket.  I was very enthusiastic after seeing the
    ads and reading a favorable review in Guitar Player.  Then I tried
    it; didn't like it at all.  Sounded tinny, even without the crappy
    edge/distortion.  The response from the proprieter of the music store
    to my negative comments was "whad'ya expect for 60 bucks?".  Your
    milage may vary.
    
    /rick

    I have a boss headphone amp that I like alot for travel practicing.
    It's something like an HA-5?
    
    dave

    Maybe I'm missing something.
    
    If a Rockman's standard output goes to headphones without any problems,
    why would sending the signal to a boombox cause a problem?  Is the
    signal from a Rockman "hotter" than the signal from say a CD player?
    
    We'e not talking about sending a signal from a Boogie or Marshall
    preamp, or does that matter?
    
    Kevin
     

    Rockman's are heavily compressed as well...I'm not sure that it's
    a big problem
    
    dbii

    I have a Fender Sidekick 10, which someone mentioned.  It requires
    12v input and I've run it many times using a car lighter adapter.
    It's got a nice tone, price around $100.  Perhaps you could find
    a used one?  I made the adapter myself using parts from Rat Shack.
    
    Greg

    I've got a Washburn SX12 .... I think about 12 watts?... 6" spkr.
    This amp cool (for $100).  It's got gain, master, overdrive, bass
    treble, middle,  direct line out, and headphone.  I was using this
    a week ago at a jam and people couldn't believe the sound.  I was
    playing w/ 1 other gtr, bass, drums, keyboards.  .... good stuff
    for the money!   sorta like an oversize lunch box.
    
    /paul
    

    
    
    I've got a Rockman X100 which I plug into a pair of amplified speakers.
    They were designed for use with Walkmen or portable CD players,
    but they really sound good. The nice thing is you don't loose the
    stereo effects of the Rockman. I don't think you have to worry about
    blowing speakers, the output from the headphone jacks is made for
    speakers (headphones), and the other output jack is a line level
    output designed to run to a mixer or recorder. It's really a nice
    little unit. I'm still not sure how they did it, but the line level
    output is also an input to the rockman preamp. You can plug the
    output of a Walkman or anything else into it and it mixes it with
    your guitar. I think it was worth every cent.
    
                                                       Mikey Z.
    

                                           
    	You can build an portable amp giving *excellent* results yourself,
    by using car stereo components and a 12 Volt battery from a motorcycle.
    Most "power boosters", graphic or plain, have 20W per channel. These
    draw an average current of 5 amps (peaks are higher) so you could
    get two hours of full tilt playing from a 10AH battery! Using less
    power, you might get six hours or something. By building it yourself,
    you can incorporate a battery charger for an overnight recharge...
    
    	There is an array of car speakers and amplifiers to choose from.
    Some of the power booster amps, like one model from RS, have "CD"
    line level inputs, originally intended to play portable CD players
    in the car. You can use it to amplify you rockman or other "headphone"
    guitar preamp. Battery's are available from Sears, a motorcycle
    shop, or a electronics supply shop for alarm systems, which use
    these "Yuasa" sealed 12V 4AH batterys. Sears also has the sealed
    type lead/acid batterys for motorcycles.
    
    	I'd envision a 4 speaker unit using 6" drivers, connected normally
    to the power booster's LF-RF - LR-RR outputs, with the "fader" set
    dead center. I'd get a sealed, 10 AH battery and arrange a charging
    circuit for it. A power booster with "CD" inputs might be expensive,
    so I'd opt for a Plain unit and simply wire the L-R-G input connections
    to a subminiature stereo jack. With this setup (and a rockman, etc),
    one could easily be the loudest player on the street!
                        
    	Joe Jas

    Yo, to whomeveer may read this in the future.
    Here I am in the desolate land of "Responding to a note written
    5 months Ago" again. 
    Last summer I bought the ugliest blue portable ever made. It has
    a cord, or you can stick in 12 AA Battaries. It had a 4" speaker;
    replaced with a 3" from radio shack when I fried it with a Marshall.
    ( Worked good until somebody turned the marshall up past 1/2. )
    Cost me 49.95 at Center Music House in framingham, and was made by
    'Memphis'( Really some japanese company starting with prince. )
    It tends to lose the battaries when you drop it. 
    But I think I'll keep it.
    

Hi,

I am trying to convert a small Gorilla GG-20 guitar amp (it says 30 watts but
it's probably a marketing statement, rated at clipping or something like that)
to battery operation.

It currently runs off 120 VAC.  I opened the chassis and observed the
front-end: the AC power cord, fuse, transformer, full-wave rectifier, and 2
large electrolytic filter caps.  This is what I expected.  It appears that the
rectifier/filter's output is +14 Volts DC and -14 Volts DC.  I haven't looked
at the rest of this simple-looking amp, but I don't think I need to.  The amp
itself is a 5-pin semiconductor device bonded to a heat sink.

What I'd like to do is hook up 2 12 volt batteries (12 is close enough to 14
to satisfy me) to run the thing.  Can I do the following to supply the +/- 12:


      +--------------------------> +12 VDC
      |
      |
   +--+--+
   | pos |
   |     |
   | 12V |
   | batt|
   |     |
   | neg |
   +--+--+
      |
      +--------------------------> GND
      |
   +--+--+
   | pos |
   |     |
   | 12V |
   | batt|
   |     |
   | neg |
   +--+--+
      |
      |
      +--------------------------> -12 VDC

I'd like to be able to use this simple solution instead of having to build a
DC-to-DC converter with dual polarity outputs.  Can I get away with this? 
Also, is it advisable/preferable to leave in the large electrolytic filter
caps?  I assume it is not possible to run this thing with a single-ended supply
(the negative 12 volts amplifies the negative peaks, right?)

thanks,

adam

    Adam,...
    
    	Assuming usingh only 12 volts won't hurt the amp (thats not an
    assumption I would make without checking it out somehow) then you can
    do what you drew for a power supply schematic...
    
    	I'm wondering if you wouldn't be better off buying a Rockman
    or whatever... have you checked those things out?
    
    							/Bill
    

re:     <<< Note 812.17 by STAR::SALKEWICZ "It missed... therefore, I am " >>>
>                                  -< ..or... >-
>
>    	Assuming usingh only 12 volts won't hurt the amp (thats not an
>    assumption I would make without checking it out somehow) then you can
>    do what you drew for a power supply schematic...

I don't know how I could damage the amp by running it 2 volts below the normal
power supply rails.  The only side effects I could think of are earlier onset
of clipping, which probably wouldn't be a problem if I don't crank it (and the
distortion might sound cool :-))

Any other potential problems you can think of?

>    	I'm wondering if you wouldn't be better off buying a Rockman
>    or whatever... have you checked those things out?

Well, that's always an alternative.  The fact is, the sound on this little
Gorilla ain't too bad, and it's compact and light.  And I might be able to fit
the latern batteries inside the cabinet.  With a Rockman, you'd need to hook up
an external speaker cabinet anyway, right?  Unless they have some combo amps
I'm not aware of.  Basically, I'm satisfied with this amp for my needs, and I'm
going for a cheap (operative word) solution.

thanks,

adam

    Yeah, and how in the hell are *TWO* 12 volt batteries gonna make it
    "portable". Yeah sure, you wont have to rely on the Electric company,
    but damn, the amp will weigh *more* than a Twin!
    
    "sakman"

re:                     <<< Note 812.19 by MARX::SAKELARIS >>>

>    Yeah, and how in the hell are *TWO* 12 volt batteries gonna make it
>    "portable". Yeah sure, you wont have to rely on the Electric company,
>    but damn, the amp will weigh *more* than a Twin!

After reading this, I realized I was confusing two types of batteries.  There
are those 6 volt "lantern" batteries that are about 3 inches by 3 inches
(cross-section) and about 4 inches high, and weigh about 3/4 pound each.  Two
of those would fit nicely inside the amp cabinet, and don't weigh that much. 
But 2 12 volt batteries - that's a different story.  Are there 12 volters that
are roughly the same size as the aforementioned 6 volt "lantern" batteries?

thanks,

adam

ps. I understand what you're saying about battery size.  I'm *not* looking to
use motorcycle, boat, or car batteries.  That's clearly too big, especially if
I need 2.

    re my last
    
    >>*TWO* 12 volt batteries
    
    Oh! I immediately thought of Car batteries, not lantern batteries.
    Nevermind.
    
    But then again, are there 12 V lantern batteries or are they 6 volt?

    Lantern batteries are 6v. So hook up four of them.
    
    						Reddy Kilowatt

    You can series up 4 6 volters to do something very similar
    to what you intended to do with the two 12 volters,...
    
    As far as "other problems" that might be caused,.. I can't really
    think of anything,.. but that doesn't mean there aint any there
    lurking,.. waiting,.. :-)
    
    I'm not sure if :"Rockman" is the right name for what I'm thinking
    of,.. but you clip 'em on your belt,.. throw in a 9 (?) volt
    battery,.. plug in some earphones,.. and voila,.. porivate practice
    portable DC powered guitar amp... and you can even throw in a tape
    and jam along with Jerry and Bob :-),.. and they even (if I remember
    right) come with distortion/chorus etc. Kevin McDonnough was looking
    to unload one of these recently,.. might want to contact him 
    (DECWIN::KMCDONNOUGH)
    
    If you think the Rockman is no good because it has no speaker,.. then
    you're stuck. I wouldn't think this would be such a problem bnecause
    any jams you wanted to go to you would have to have 110 Ac,.. or else
    all your jammers would have to be battery powered (not likely),..
    For "travelling",.. I think you'd be better off with a nice not  too
    expensive acoustic guitar anyway,.. but I think we've had that
    conversation before (?)
    
    Anyway ,.. good luck
    
    							/Bill
    

	Years ago I converted a Mike Mathews Freedom amplifier from using
	40 D cells to AC powered. 12 volt batteries should work fine as
	long as they can supply the needed current. Car batteries would
	work fine.

							Jens

re:     <<< Note 812.23 by STAR::SALKEWICZ "It missed... therefore, I am " >>>

>    I'm not sure if :"Rockman" is the right name for what I'm thinking
>    of,.. but you clip 'em on your belt,.. throw in a 9 (?) volt
>    battery,.. plug in some earphones,.. and voila,.. porivate practice
>    portable DC powered guitar amp... and you can even throw in a tape

The purpose of this whole charade is to be able to bring my electric guitar on
a camping trip, since I do not own an acoustic and financial realities indicate
I will not get one in the near future, unless someone sells me one (with nice
action) for well under $100.  :-)  That's why I thought a rockman wasn't
appropriate in this case.  My amp has a headphone outlet anyway :-)
    
>    You can series up 4 6 volters to do something very similar
>    to what you intended to do with the two 12 volters,...

Great.  This is the *main* question I was trying to get answered.  Whether I
use 2 6-volters or 1 12 volter for the +12, and the same for the -12, I wanted
to make sure that the circuit topology was correct; that is, I could use 2 12
volt sources, hooked up as I drew, with a ground point in the middle, to give
me a split supply.  I thought there might be some fundamental difference
between a split power supply giving you -12 volts and a battery hooked up
backwards to give you the same -12 volts.

I have yet to work out the current requirements, but I *am* aware that I will
need to get a battery with sufficient amp-hours to allow me to play for more
than 6 minutes at a time. :-)

If anyone knows of a source of 12-volt batteries that are smaller than a
car-type battery, please let me know.

thanks,

adam

    Grab one of those baby Marshall's (about $45) and party on ... save
    yourself some trouble.

Rockman + little speakers + Cigarett lighter adaptor or AA's = portable 
STEREO amp.

Jmystr

    
    
    	Try your local model shop, I used to fly radio controlled
    aeroplanes and you can get 12v rechargable nicad's, normally used
    for powering starters and glow plugs...I imagine that would suit 
    you down to the ground.....
    
    	J
    

>The purpose of this whole charade is to be able to bring my electric guitar on
>a camping trip, 
    
    I'm with Jerry, you can get one of those little Marshall MS-2 amps
    (something like 1 watt into a dinky 2" speaker) for about $35-$40 and
    it runs off a 9v battery.  It's small enough to take pretty much
    anywhere, gets loud enough to scare the wild animals in the woods, and
    the battery will last a long time.
    
    I've had one for a couple of years (a Christmas gift) and it's great
    for travelling.
    
    I know Dean Markley makes something similar, and I've seen other makers
    too.  Check around, I bet you could get one for not much more then the
    price of the batteries you're gonna have to buy...
    
    Greg
                                                              

    Sam Ash was only asking $29.95 for the Marshall MS-2.

    Given that those 6v lantern batteries go for $6-7 each and you'd need
    4, it sounds like a good tradeoff to me.  Don't know how much the 12v
    versions are, but probably a little more.
    
    My wife paid $34.88 for mine from Musician's Friend.
    
    Greg

I second the MS-2 option !!

I use mine ALL the time - It's perfect for playing along with the stereo
and learning toons, and has a pretty happenin' (scaled down) Marshall Tone too!
jc

    I donno man, I think it sounds basically crappy, but it makes a sound
    you can hear.  It's the best thing for travelling that I've found.  I
    hate headphone amps, so even if something doesn't sound as good, if it
    makes an audable sound it's better for me.
    
    Sound bears very little resemblance to a Marshall even if it's got a
    tiny 1/4 inch tall "Marshall" logo on the grillcloth (yeah, it has real
    grillcloth!).
    
    Greg

    Hook up a bigger speaker to one of those little pups and they'll sound
    a LOT better.  You might even be able to use the headphone jack, I
    doubt they bothered to even install a dropping resistor since the amp
    has so little power (maybe 1/4 of a watt).  
    
    						Base Freely

Their like puppies tho - who could get mad at one of the little cuties
when they crap on the carpet ?!?!?

jc (Who thinks his is GREAT !)

    I use the MS-2 in hotel rooms (10000 Motels).
    
    I have also used it with mini-headphones on a half-full wide-bodied jet
    on a long flight, and on an Amtrak coach as well.
    
    When my reserve unit took over a hotel and its pub in Scotland last
    year, it was loud enough for us to use sharing the guitar (a road
    beater) and having drunk sailors and officers sing with it.
    The battery lasts longer than it has any right to.
    
    Buy one. 
    \Gary

 For a tiny critter, it's surprisingly loud when you turn it up. I find 
 that the overdrive channell distorts the sound out of all proportion unless
 you turn the volume on the gee-tah down. Great for those sleepless nights 
 when you don't want to wake the neighbours up ( again :) ) 

 It weighs next to nothing, doesn't cost that much, the battery lasts forever,
 it even has a nifty little red led on the front ;-)  - why would you want to 
 heave all those batteries for a big amp around with you ?

 No frills, but it does what it's meant to, & quite well IMHO.


				Nik. 

	Anybody see/try one of the new Pocket Rockets?  I traded in my
	Bass Rockman for one, and so far I'm pleased with it.  It plugs
	directly into your amplifier socket, and runs exclusively on
	batteries (9-volt), so there are lots fewer wires to deal with.
	The bass version does chorus and distortion - there are two
	different guitar versions.  You can also hook up a tape player/
	CD and push everything through the headphones (like the Rockman).
	Unlike the Rockman, this one specifically states that it can be
	used as a pre-amp as well.

	The size is a real bonus - fits in the palm of my hand.

	I got mine at Ted Herbert's in Manchester - believe the asking
	price was $69.99.

	Sandy

    My only beef with the MS-2 is that it's not heavy enough on the bottom
    to keep itself consistently upright when a guitar cord is plugged into
    it.  It's like the weight of a metal 1/4" plug (like a Switchcraft) and
    the wire is enough to unbalance it so that it wants to fall forward
    onto it's face.  I've thought about gluing a piece of steel to the
    bottom of it to help stabilize it.

    Greg

    The MS-2 has a belt clip in the back so that it can be worn as you walk
    or stand.  Weighting it down as a design criterion would defeat its
    portability.  If you have a long enough cord, it won't keep falling
    over.
    
    This string is starting to sound like the old NASA/DoD aerospace horror
    stories where an engineer starts out to specify something very simple
    and functional, but the Government ends up buying something that has to
    deal with every possible contingency and environment and doesn't do any
    one thing particularly well.
    \Gary

    How would adding a little bit of weight to get it's balance right hurt
    it's portability?  I wasn't talking about adding a 20 lb slab of steel
    to the bottom, just a few oz. of sheet metal so it'll stand up better.
    
    Plus, I could care less about the belt clip, I don't want it on my
    belt.  I've never used it and I doubt I ever will.  
    
    Greg

    Good idea Greg.  If you set it on a flat surface (i.e., table) it
    usually vibrates to the edge.
    
    Mike

    
    	Greg, I have an idea.  Get a large sized book-end with a
    	non-skid bottom and just hook the belt loop of the MS-2 
    	over the top of it!  Might do the trick.  Or fabricate 
    	a stand for the same purpose.

    That's a pretty good idea, thanks Pat!
    
    Greg