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I hope my Surf guitar 101 brethren can give me some advice. i hope
i can explain this well enough. I bought a '67dual showman amp and
1x15 cabinet that had been covereted to a 2x 15 cabinet. It has JBL
D130 F 8 ohm speakers. One of the speaker says 8-16 ohms (?). I
had the local tube amp wizzard (Bruce at Mission amps) go though it
and fix 'er up. He did the standard cap job, replaced some other
parts, and gave it all new (?) preamp tubes. I had the cabinet
fixed up, because it was pretty rough. i finally got it all
together yesterday, and fired it up, expecting the "big Dual
showman " sound. It didn't happen. It sounds really thin, and
trebley, with hardly any low end, even with the bass knob cranked
all the way up.
I have a Vibrosonic Reverb, and I plugged the cabinet into
that, and it was better, but still not what I was hoping for. I
haven't plugged the showman head into another cabinet.
Do I have the cabinet wired wrong? I checked the polarity of the
speakers, and I think I got it right, even thought the 8-16 ohm
speaker tested backwards, the red lead was -, the black was +,
opposite the other speaker.
any help would be greatly appreciated!
Chris
Those JBLs are wired 'backwards: spkr. + to amp. + sucks the cone in,
instead of pushing it out. Mine are hooked up amp + to speaker - on both
speakers: The important thing is that the speakers are in phase: Both moving
in or out together. If in doubt, use a 9v battery to test your speakers,
then hook 'em up to the amp accordingly, even if it looks 'wrong'.
Check it out:
-Brad
_____
From: kahunatikiman [mailto:]
Sent: Friday, January 28, 2005 9:16 PM
To:
Subject: [SurfGuitar101] fender Showman tech. question, readers beware.
I hope my Surf guitar 101 brethren can give me some advice. i hope
i can explain this well enough. I bought a '67dual showman amp and
1x15 cabinet that had been covereted to a 2x 15 cabinet. It has JBL
D130 F 8 ohm speakers. One of the speaker says 8-16 ohms (?). I
had the local tube amp wizzard (Bruce at Mission amps) go though it
and fix 'er up. He did the standard cap job, replaced some other
parts, and gave it all new (?) preamp tubes. I had the cabinet
fixed up, because it was pretty rough. i finally got it all
together yesterday, and fired it up, expecting the "big Dual
showman " sound. It didn't happen. It sounds really thin, and
trebley, with hardly any low end, even with the bass knob cranked
all the way up.
I have a Vibrosonic Reverb, and I plugged the cabinet into
that, and it was better, but still not what I was hoping for. I
haven't plugged the showman head into another cabinet.
Do I have the cabinet wired wrong? I checked the polarity of the
speakers, and I think I got it right, even thought the 8-16 ohm
speaker tested backwards, the red lead was -, the black was +,
opposite the other speaker.
any help would be greatly appreciated!
Chris
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Remember that the problem can be in the (1)amp, (2)speaker, or (3)
both. This reply is just about the speaker cabinet, because I'm way
out of my league on amps.
This is my first post and I've been out of this for a long time,
BUT, wasn't it true (and maybe the community out there can help me
with this...) the single 15" Showman cabinet was somewhat smaller
than the Dual Showman cabinet? I tried to find some cabinet
dimensions on the web but was unsuccesful.
This is important to your result because any 2 speaker mod to an
even slightly smaller single speaker cabinet will neccessarily
result in same bass as the larger box version.
So...a little help out there on the dimensions of Showmen question?
Dave
--- In , "kahunatikiman" <chris@b...>
wrote:
>
> I hope my Surf guitar 101 brethren can give me some advice. i
hope
> i can explain this well enough. I bought a '67dual showman amp
and
> 1x15 cabinet that had been covereted to a 2x 15 cabinet. It has
JBL
> D130 F 8 ohm speakers. One of the speaker says 8-16 ohms (?). I
> had the local tube amp wizzard (Bruce at Mission amps) go though
it
> and fix 'er up. He did the standard cap job, replaced some other
> parts, and gave it all new (?) preamp tubes. I had the cabinet
> fixed up, because it was pretty rough. i finally got it all
> together yesterday, and fired it up, expecting the "big Dual
> showman " sound. It didn't happen. It sounds really thin, and
> trebley, with hardly any low end, even with the bass knob cranked
> all the way up.
> I have a Vibrosonic Reverb, and I plugged the cabinet into
> that, and it was better, but still not what I was hoping for. I
> haven't plugged the showman head into another cabinet.
>
> Do I have the cabinet wired wrong? I checked the polarity of
the
> speakers, and I think I got it right, even thought the 8-16 ohm
> speaker tested backwards, the red lead was -, the black was +,
> opposite the other speaker.
>
> any help would be greatly appreciated!
>
> Chris
kahunatikiman wrote:
> Do I have the cabinet wired wrong? I checked the polarity of the
>speakers, and I think I got it right, even thought the 8-16 ohm
>speaker tested backwards, the red lead was -, the black was +,
>opposite the other speaker.
>
>any help would be greatly appreciated!
>
>Chris
>
>
Hopefully this is something easy. I also second the motion on checking
the phasing on your speakers. Make sure they are both in phase. I used a
9V battery, but Dave Wronski suggested a 1.5V. I believe my Dual Showman
wants to see a 4 Ohm speaker load (8 * 8) / (8 + 8). If one of your
speakers was a 16 Ohm you'd get (8 * 16) / (8 + 16) = 5.333 Ohm which
doesn't seem like much of a difference.
I guess I'd make sure you've got the speakers wired in parallel and that
they are in phase (move in the same direction when you put a battery
across their leads).
If that's okay maybe suspect the head.
I obviously don't know what I'm talking about, but I wish you good luck!
I'm no expert on amps, but my Dual Showman can kick you right in the
chest with bass if you want it to...hopefully you will find yours.
BN
PS BTW, here are the cabinet dimensions from the Fender Amp Field Guide
Showman 12 (early): , 21" x 32" x 11½ (53.3 x 81.3 x 29.2 cm)
Showman 12 & 15: sealed, 24½" x 36" x 11½" (62.2 x 91.4 x 29.2 cm)
Dual Showman (63-67): sealed, 24½" x 36" x 11½" (62.2 x 91.4 x 29.2 cm)
Dual Showman (67): sealed, 45½" x 30" x 11½" (115.6 x 76.2 x 29.2 cm)
Correction:
I (of course) should have said: This is important to your result
because any 2 speaker mod to an even slightly smaller single speaker
cabinet will neccessarily result in "some bass loss" as the larger
box version.
Should have had my coffee before sending a letter. Dave
--- In , "stratrhythm"
<lawyerschroeder@s...> wrote:
>
>
> Remember that the problem can be in the (1)amp, (2)speaker, or (3)
> both. This reply is just about the speaker cabinet, because I'm
way
> out of my league on amps.
>
> This is my first post and I've been out of this for a long time,
> BUT, wasn't it true (and maybe the community out there can help me
> with this...) the single 15" Showman cabinet was somewhat smaller
> than the Dual Showman cabinet? I tried to find some cabinet
> dimensions on the web but was unsuccesful.
>
> This is important to your result because any 2 speaker mod to an
> even slightly smaller single speaker cabinet will neccessarily
> result in same bass as the larger box version.
>
> So...a little help out there on the dimensions of Showmen question?
>
> Dave
>
>
> --- In , "kahunatikiman" <chris@b...>
> wrote:
> >
> > I hope my Surf guitar 101 brethren can give me some advice. i
> hope
> > i can explain this well enough. I bought a '67dual showman amp
> and
> > 1x15 cabinet that had been covereted to a 2x 15 cabinet. It has
> JBL
> > D130 F 8 ohm speakers. One of the speaker says 8-16 ohms (?).
I
> > had the local tube amp wizzard (Bruce at Mission amps) go though
> it
> > and fix 'er up. He did the standard cap job, replaced some
other
> > parts, and gave it all new (?) preamp tubes. I had the cabinet
> > fixed up, because it was pretty rough. i finally got it all
> > together yesterday, and fired it up, expecting the "big Dual
> > showman " sound. It didn't happen. It sounds really thin, and
> > trebley, with hardly any low end, even with the bass knob
cranked
> > all the way up.
>
>
>
> > I have a Vibrosonic Reverb, and I plugged the cabinet into
> > that, and it was better, but still not what I was hoping for.
I
> > haven't plugged the showman head into another cabinet.
> >
> > Do I have the cabinet wired wrong? I checked the polarity of
> the
> > speakers, and I think I got it right, even thought the 8-16
ohm
> > speaker tested backwards, the red lead was -, the black was
+,
> > opposite the other speaker.
> >
> > any help would be greatly appreciated!
> >
> > Chris
You also said the cabinet was converted from a single speaker model.
What does yours look like inside?
Mine has got insulation around the interior edges and back panel. It has
a divider between the speakers that doesn't quite go all the way to the
top or bottom. I've seen several pictures on Ebay and seen lots of
variation in what these looked like inside.
Can your amp push out the volume? Or is it only bass limited?
BN
I see from Brian Neal's posting of the dimensions that the single
and double 15" cabinet were the same size. So disregard my previous
point.
Wow, I guess I had forgotten there was ever a Showman with a 12"!
I remember the first concert I ever went to was the Beach Boys. They
had all Dual Showmen. White, if I remember correctly. (The Zombies
and the Searchers were the warm up act. And "some guy" who wasn't
Brian was playing Bass)
Anyway, good luck..
Dave
--- In , Brian Neal <brian@s...> wrote:
> kahunatikiman wrote:
>
> > Do I have the cabinet wired wrong? I checked the polarity of
the
> >speakers, and I think I got it right, even thought the 8-16 ohm
> >speaker tested backwards, the red lead was -, the black was +,
> >opposite the other speaker.
> >
> >any help would be greatly appreciated!
> >
> >Chris
> >
> >
> Hopefully this is something easy. I also second the motion on
checking
> the phasing on your speakers. Make sure they are both in phase. I
used a
> 9V battery, but Dave Wronski suggested a 1.5V. I believe my Dual
Showman
> wants to see a 4 Ohm speaker load (8 * 8) / (8 + 8). If one of
your
> speakers was a 16 Ohm you'd get (8 * 16) / (8 + 16) = 5.333 Ohm
which
> doesn't seem like much of a difference.
>
> I guess I'd make sure you've got the speakers wired in parallel
and that
> they are in phase (move in the same direction when you put a
battery
> across their leads).
>
> If that's okay maybe suspect the head.
>
> I obviously don't know what I'm talking about, but I wish you good
luck!
> I'm no expert on amps, but my Dual Showman can kick you right in
the
> chest with bass if you want it to...hopefully you will find yours.
>
> BN
>
> PS BTW, here are the cabinet dimensions from the Fender Amp Field
Guide
>
> Showman 12 (early): , 21" x 32" x 11½ (53.3 x 81.3 x 29.2 cm)
> Showman 12 & 15: sealed, 24½" x 36" x 11½" (62.2 x 91.4 x 29.2 cm)
> Dual Showman (63-67): sealed, 24½" x 36" x 11½" (62.2 x 91.4 x
29.2 cm)
> Dual Showman (67): sealed, 45½" x 30" x 11½" (115.6 x 76.2 x 29.2
cm)
Sorry,
didn't have time to read the full thread, but want to join in
nonetheless. Just got two JBL D140F's in mint condition. Actually
they look brand new. really. anyone know 'till when they were made?
anyay, three points to add to the speaker thread:
- I checked the JBLS for +/- wiring using the 'just listen' method,
cause I paired each one up with another speaker. The difference is
very discernable. i was able to a-b cause I have two of each and they
are at this moment all in separate cabs. maybe if you have 'em in one
cab, the battery method is easier.
- impedance: someone said that 8+16 parralel is almost equal to 8+8
parrallel. that's true, however: the reason for the relATIVLY SMALL
INFLUENCE OF THE 16OHMER ON THE TOTAL IMPEDANCE, IS THAT THE LARGEST
PART (oops, caps on) of the power goes to the 8 ohmer anyway, because
its resistance is lower. that means that you will be hearing the 8
ohm speaker mostly in that config. (which technically is not a
problem, btw)
- it seems Fender never paid too much attention to cab size, given
that they put all sorts of spakers in the same closed cabs and all.
Of course, to get 'the' fender sound he cab should be exactly as the
original whteher the size was matched to the speaker or not, but so
many other things come into play that I wouldn't worry about an inch
more or less.
wr
