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I just picked up the "re-issued" reverb tank made in 76'. I've tried to find
some
schematics on the web of that year with no luck, but maybe it didn't change
much?
Is that basically the same circuitry as the 60's 6G15 models?
The 76-78 Fender Reverb Tanks were Fenders first "reissues" of the
tank. The reverb driver on the '76 is a 6V6, where as the old ones
had a 6K6GT. I've heard the '76-78s had a slightly different
schematic. I remember hearing that the '76-78s had something that
once you'd unplug the input it would be cut off. So if you were to
kick it while it was just plugged into the amp you'd get no crash.
The original ones would crash if your guitar was plugged into it or
not. Is that true?
Bill
www.reluctantaquanauts.com
--- In , "darklsurf" <dcordes@s...> wrote:
>
> I just picked up the "re-issued" reverb tank made in 76'. I've tried
to find some
> schematics on the web of that year with no luck, but maybe it didn't
change much?
>
> Is that basically the same circuitry as the 60's 6G15 models?
>
both the 6G15 and the silverface schematic are on ampwares.com - they
differ quite a lot, SF has a preamp tube more, to begin with.
the 6V6 and 6K6 thing shouldn't be that important, the new reissues
that ARE very close to 6G15 come with a 6v6 too - just an
availability issue. and I understand that the 6K6 doesn't sound
better for everyone (it does for me tho)
I've heard people put the SF reverb tanks down like crap, and I've
heard people rave about them. never heard or played one myself. Let
us know how you like it!
WR
--- In , "supertwangreverb"
<supertwangreverb@y...> wrote:
>
> The 76-78 Fender Reverb Tanks were Fenders first "reissues" of the
> tank. The reverb driver on the '76 is a 6V6, where as the old ones
> had a 6K6GT. I've heard the '76-78s had a slightly different
> schematic. I remember hearing that the '76-78s had something that
> once you'd unplug the input it would be cut off. So if you were to
> kick it while it was just plugged into the amp you'd get no crash.
> The original ones would crash if your guitar was plugged into it or
> not. Is that true?
>
> Bill
> www.reluctantaquanauts.com
>
> --- In , "darklsurf" <dcordes@s...>
wrote:
> >
> > I just picked up the "re-issued" reverb tank made in 76'. I've
tried
> to find some
> > schematics on the web of that year with no luck, but maybe it
didn't
> change much?
> >
> > Is that basically the same circuitry as the 60's 6G15 models?
> >
>
Darkl,
Yep, it's basically the same. The biggest change is the
driver tube - it's now a 6V6 instead of the original 6K6.
That was done because the 6K6 was no longer being made.
Several other small changes were made to component values,
mainly in the power supply section, but also in the driver
circuit part. Should sound about the same (good!) as an
older unit, as your's is still the handwired variety.
Fortunately, 6K6's are now back in production. If the
reverb sounds distorted when you turn it up (as required
for surf music), it's due to the more powerful 6V6 over-
driving the springs. Change it out for a 6K6, and you'll
get the exact same tone as the original units.
unlunf
--- In , "darklsurf" <dcordes@s...> wrote:
>
> I just picked up the "re-issued" reverb tank made in 76'.
> I've tried to find some schematics on the web of that year
> with no luck, but maybe it didn't change much?
>
> Is that basically the same circuitry as the 60's 6G15 models?
>
--- In , "unlunf" <unlunf@y...> wrote:
>
> If the reverb sounds distorted when you turn it up (as required
> for surf music), it's due to the more powerful 6V6 over-
> driving the springs. Change it out for a 6K6, and you'll
> get the exact same tone as the original units.
I have a silly question... If the 6V6 distorts because it is
overdriving the tank, why can't you just back down the level a little
so it doesn't overdrive the tank? Wouldn't you then still be hitting
it hard enough for surf? Seem to me, you'd be hitting it as hard as you
can without overdriving it.
This is my first tank, so I think it sounds great. I just got it working today
and haven't
played with the band yet. As far as I can tell it sounds like the tones I hear
on record.
Wow! I hear reverb on the lower registers now. Pretty cool. All of you were
right about
the onboard units not being the same. Our bass player (a gear collector) has an
63'
and a later model 65'-66'(?) tank and we'll do a Pepsi challenge to see if
there's a
difference.
One thing I noticed that's a bit strange to me is that the 6V6 tube touches the
tank. Is
that normal? Shouldn't the tank be comepletely free to twang?
Haven't tried the unplugged "crash" test yet Bill, but I'll let you know.
Being a strip board wired amp, it does offer some flexibility to modify it, but
I'd rather
be playing. If I decide to put a 6K6 in there, do I need to modify anthying
else? Or just
plug and play?
Jeff,
> I have a silly question... If the 6V6 distorts because it is
> overdriving the tank, why can't you just back down the level
> a little so it doesn't overdrive the tank? Wouldn't you then
> still be hitting it hard enough for surf? Seems to me, you'd
> be hitting it as hard as you can without overdriving it.
Well, the theory goes like this.....
In essence, the dwell time of a tank's springs is dependent
on the incoming voltage level - reduce one, you also reduce
the other. (As seen in the schematic, the dwell control.)
Where the problem arises is in that the same voltage level
also drives the tube to some particular rated wattage.
For a 6V6, it's about 8 or 8.5 watts, for a 6K6, it's
about half that.
So if you're driving, say 1.0 volts into a tank at 4 watts,
and everything sounds good, what happens when you switch to
the higher wattage tube? The dwell time is the same length,
but the springs are now distorting the signal - they're being
overdriven with more wattage than they were designed to handle.
Reducing the incoming voltage level (turning down the dwell)
to reduce the distortion works, but it also has the undesired
side effect of reducing the dwell time. (Well, duh!)
OK, yeah, I can hear some of you now. "The dwell time is too
longer with 6V6", you say. Ever hear of a distortion box that
also sustains? Same principle here - the lower signal levels
were increased to higher levels (the paramount operation of a
sustainer), so that added a slight bit to the overall dwell
time (more signal of a higher level present before total decay).
But the signal is very distorted, and to my ears, unpleasant.
Jeff, I hope that helped. There's lots more theory behind
this, but I tried to keep it short and sweet. <g>
unlunf
Darkl,
Glad you like the tone of the unit! As it happens,
I just looked at one of these the other day. Fella
brought it in for a blown fuse. Turns out that the
pilot lamp had burned out. He thought "no light,
no power", and just brought 'er in. That's my kind
of customer! <g>
Yes, you can simply pull the 6V6, and plug in the 6K6,
no problem. And the tube definitely should NOT be
hitting or resting on the tank. Bad juju, that.
Make sure the tube isn't partially out of the socket.
If it's seated correctly, then check the tank itself.
Has it been removed and re-installed incorrectly?
Is it just resting back there because it broke loose
from its mounting screws? Fortunately, you've got a
close relative nearby to examine (your buddy's unit).
Use that as a guide to see how the tank should be
mounted.
While you're at it, make sure the travel-lock works
as advertised. If it doesn't, you won't wreck your
unit (all other things being in order), but if you
do travel a lot, then have it fixed. The springs
will thank you for it. <g>
unlunf
--- In , "darklsurf" <dcordes@s...> wrote:
>
> This is my first tank, so I think it sounds great. I just got it
> working today and haven't played with the band yet. As far as I
> can tell it sounds like the tones I hear on record. Wow!
> I hear reverb on the lower registers now. Pretty cool. All of
> you were right about the onboard units not being the same. Our
> bass player (a gear collector) has an 63' and a later model
> 65'-66'(?) tank and we'll do a Pepsi challenge to see if there's
> a difference.
>
> One thing I noticed that's a bit strange to me is that the 6V6
> tube touches the tank. Is that normal? Shouldn't the tank be
> completely free to twang?
>
> Haven't tried the unplugged "crash" test yet Bill, but I'll let
> you know.
>
> Being a strip board wired amp, it does offer some flexibility to
> modify it, but I'd rather be playing. If I decide to put a 6K6 in
> there, do I need to modify anthying else? Or just plug and play?
>
--- In , "darklsurf" <dcordes@s...> wrote:
>
> This is my first tank, so I think it sounds great. ... we'll do a
Pepsi challenge ...
awesome, congrats on the tank - the biggest hard-on I ever got from
gear was when i got my tank. glad you like it. Please, do the pepsi
challenge (a.k.a. 'do the Marty' )- I'd be very inetrsted in what you
find, 'cause opinions seem to differ tremendously.
WR
Thanks for the explanation, but I don't know if I can buy it. First
let me say that I've never fooled around with either unit, and that
I'm not anywhere as sensitive to the differences in sound as most
players. I'm also sure you hear a difference, so please don't take
any offence.
That said, I'm looking at the schematic right now, and as I see it,
the "Dwell" pot is nothing more than the equivalent of a volume pot
on an amp. In and of itself it wouldn't affect the duration of the
sustain of the reverb, except that it's controlling the level of the
signal to the 12AT7 that's driving the 6V6 which drives the reverb
tank. So the harder the reverb tank is hit, the longer the reverb
will sustain or dwell. So what I'm trying to say is that, I would
think that the dwell is totally a function of how much voltage the
driver tube is allowing to flow through the reverb transducer, if
driven just below the point that is too much, the dwell should be the
same whether the driving tube in the circuit is capable of driving it
harder or is at it's limit. BTW, the power rating of a tube is like
it's save upper limit, so replacing a tube that can deliver more
power doesn't mean it necessarily will, it's not like a light bulb.
Maybe the 6K6 itself, having a lower power rating is actually
distorting or compressing causing a different sound.
--- In , "unlunf" <unlunf@y...> wrote:
>
> Jeff,
>
> > I have a silly question... If the 6V6 distorts because it is
> > overdriving the tank, why can't you just back down the level
> > a little so it doesn't overdrive the tank? Wouldn't you then
> > still be hitting it hard enough for surf? Seems to me, you'd
> > be hitting it as hard as you can without overdriving it.
>
> Well, the theory goes like this.....
>
> In essence, the dwell time of a tank's springs is dependent
> on the incoming voltage level - reduce one, you also reduce
> the other. (As seen in the schematic, the dwell control.)
> Where the problem arises is in that the same voltage level
> also drives the tube to some particular rated wattage.
> For a 6V6, it's about 8 or 8.5 watts, for a 6K6, it's
> about half that.
>
> So if you're driving, say 1.0 volts into a tank at 4 watts,
> and everything sounds good, what happens when you switch to
> the higher wattage tube? The dwell time is the same length,
> but the springs are now distorting the signal - they're being
> overdriven with more wattage than they were designed to handle.
> Reducing the incoming voltage level (turning down the dwell)
> to reduce the distortion works, but it also has the undesired
> side effect of reducing the dwell time. (Well, duh!)
>
> OK, yeah, I can hear some of you now. "The dwell time is too
> longer with 6V6", you say. Ever hear of a distortion box that
> also sustains? Same principle here - the lower signal levels
> were increased to higher levels (the paramount operation of a
> sustainer), so that added a slight bit to the overall dwell
> time (more signal of a higher level present before total decay).
> But the signal is very distorted, and to my ears, unpleasant.
>
> Jeff, I hope that helped. There's lots more theory behind
> this, but I tried to keep it short and sweet. <g>
>
>
> unlunf
>
Jeff,
Your reasoning is not bad at all. Not quite founded on the
accepted principles of elementary electronics, but it does
show that you are thinking logically. You just need to have
a few more pieces to put the puzzle together, that's all. <g>
And before I go on, wasn't I the one who was just accused of
not being to hear things that I should be able to? <g>
(See the discussion about Bandmaster versus Bassman amps.)
OK. This can get real long, and it will need to get quite
technical. Sorry, but that's the nature of it. Before I
get all long-winded publicly, let me do this: I propose
to carry on with Jeff in private email, but I don't want
to lose anyone who is interested. I just don't want to
waste everyone's bandwidth each time I post a long message,
that's all.
If anyone else is interested, PM me, and I'll include you as
Jeff and I battle it out. <g> After the whole thing is done,
we'll see if we can't make up and post a summary that feels
good to those involved with the primary discussion.
Does this get everyone's approval? Jeff, let's give it a
day or two for any responses. Thanks for being patient.
unlunf
--- In , "Jeff Leites" <jeff_leites@y...> wrote:
>
> Thanks for the explanation, but I don't know if I can buy it. First
> let me say that I've never fooled around with either unit, and that
> I'm not anywhere as sensitive to the differences in sound as most
> players. I'm also sure you hear a difference, so please don't take
> any offence.
>
> (a bunch more stuff that needs deep explanation)
>
> And before I go on, wasn't I the one who was just accused of
> not being to hear things that I should be able to? <g>
> (See the discussion about Bandmaster versus Bassman amps.)
I don't have time to read every post :-( so I didn't know that. (My
boss just brought me some work now, sheesh, what do the want from me).
I can tell the difference between the sound of BB King, Santanna, and
Paul Johnson, but I'm not aware of more subtle differences ;-)
I look forward to your e-mail!
Has it been removed and re-installed incorrectly?
Is it just resting back there because it broke loose
from its mounting screws? Fortunately, you've got a
close relative nearby to examine (your buddy's unit).
unlunf
...................................
Unlunf,
The chasis is totally different on the 76'. The tubes are angled toward the
tank. I'm
looking at the original 66' model and the tubes are straight down, the 76' is at
about
30º. I'll have to modify it so the tank sits a bit closer to the case, but far
enough to
still be floating. The problem is that it will crash easier.
Who'd of known? I thought they were pretty much the same.
Wow Marty your really Famous now. LOL!!!!
Jeff(bigtikidude)
--- In , "mono_tones_1" <rockverb@h.
. Please, do the pepsi
> challenge (a.k.a. 'do the Marty' )-
> WR
>
> Wow Marty your really Famous now. LOL!!!!
> Jeff(bigtikidude)
The verdict is still out whether the sales guy was pushing the A/B switch or the
LED
for Marty... :)
I can't say the Pepsi Challenge was very scientific or fair or not tainted by
previous
bias, but I'll tell you what I heard. There are so many varibles that really,
it's just these
two and any other tanks would probably sound different as well.
66' vs 76'
I put these at the same settings 666 and then tweaked the 76' to match as close
to
the 66'. Why? Because the 66' sounded GREAT!!! Dang, I have to return it soon.
The 66' (6k6) sounded less harsh, had a rounder musical tone with a real snappy
"twang". With all the varibles, everything is up for grabs. The owner says it's
the same
tubes as when he got it new. They do look pretty old. It's in absolutely
beautiful
shape.
The 76' (6v6) Still sounded great. Had more of a Fender Twin twang if that makes
any
sense. Don't like the design with the angled tubes (putting tubes in is a pain)
and still
have the issue with the tube touching the tank. A bit more echo-ish feedback
than
the 66'.
All in all, at a busy club with drinks flowing and the drummer beating your
brains in,
no one could tell the difference except, well, the players on this list.
Darkl,
Wait, I did know that.... that the chassis is slanted.
What I wanted you to look for was 'only' the placement
of the tank itself. I'm sure (but I don't have it in
front of me anymore) that the tank mounts with 4 screws
onto the back of what is actually the front panel.
Those screws should be through little grommets, sort of
like rubber doughnuts, which in turn are through holes
in the lips of the carrier itself.
It's important to not have the screws tightened all the
way down. Instead, when the travel lock is engaged,
there should be a bare (threadless) shoulder extending
out past the top of the grommet. With the lock diseng-
aged, the tank should come out far enough to clear the
cushion underneath, and everything should sound normal.
Just don't let the screw sit too far out of the hole,
or the tank might not only touch the tube, but might
also come completely loose, and that's not good. <g>
If the screw holes haven't worn out, then the
screws should be pretty tight in the wood, more
than enough to hold the tank in place, yet leave it
room to reverberate without crashing.
And, as you are contemplating doing, there is the
distinct possibility that someone re-positioned the
tank to a different location, for whatever reason
that struck their fancy. After you remove it, check
to see where those holes are, then look for evidence
of a second set of holes. That's a dead giveaway
of prior monkey-wrenching.
If, after all this, the tube is touching the tank
(and in factory stock units, they don't), then there's
still the possibility that the 6V6 is oversized. A
few such have been made in the last decade, supposedly
to better dissipate heat. A normal 6V6 should be
about the same size, or maybe a touch larger than a
6K6. If it's almost the size of 6L6, or even a 5881
(a bit smaller than a 6L6), then try to find another
tube and see what happens.
That's all I can think of, without seeing the unit.
Hope it helped.
unlunf
--- In , "darklsurf" <dcordes@s...> wrote:
>
>> Has it been removed and re-installed incorrectly?
>> Is it just resting back there because it broke loose
>> from its mounting screws? Fortunately, you've got a
>> close relative nearby to examine (your buddy's unit).
>>
>> unlunf
>
> ...................................
>
> Unlunf,
>
> The chasis is totally different on the 76'. The tubes are angled
> toward the tank. I'm looking at the original 66' model and the
> tubes are straight down, the 76' is at about 30º. I'll have to
> modify it so the tank sits a bit closer to the case, but far
> enough to still be floating. The problem is that it will crash
> easier.
>
> Who'd of known? I thought they were pretty much the same.
>
Speaking of A/B testing, I received my copy of the Ace "Quite A Party" CD today
and was struck by the sound quality of some of the older recordings such as
those by the Rebels and Ventures on the CD, both from 1961. I pulled out the
SFM CD version of the Ventures doing Bulldog and queud up for simutaneous
playback with the Ace CD. I then toggled between the two. Well, it's just a good
sounding recording to begin with, this new Ace release may sound a hair better
but it's hard to tell. It's just startling to see how good the old recordings
sound against all of the other great recordings on the disk.
-Marty
----- Original Message -----
From: Jeff
To:
Sent: Thursday, November 03, 2005 5:38 PM
Subject: [SurfGuitar101] Re: 76' Reverb Tank
Wow Marty your really Famous now. LOL!!!!
Jeff(bigtikidude)
--- In , "mono_tones_1" <rockverb@h.
. Please, do the pepsi
> challenge (a.k.a. 'do the Marty' )-
> WR
>
.
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--- In , "unlunf" <unlunf@y...> wrote:
> If anyone else is interested, PM me, and I'll include you as
> Jeff and I battle it out. <g>
Howz about writing the tech stuff down as an essay and putting it in
files folder - either right away or after we have a winner ;-)? -
perhaps Brian can chime in, whether that's an idea and whether there's
storage space? if not count me in.
WR
