Fender Deluxe Reverb AB763. Help! Schematic doesn't match layout
Bluesbreaker
places. In each version the schematic differs (in several places)
from the layout. I'm performing a blackface to silverface conversion
and I was hoping to nail down the AB763 values, but now I'm confused
about which is correct; the schematic or layout diagram?
Anyway, here are my findings of where the schem and layout differ:
[1] The 3rd 7025 (V4 in the preamp). The 2nd half of the triode (post
reverb recovery). The schem shows a 3.3M || 10pF attached to the
grid. The layout shows 4.7M || 10pF.
[2] Vibrato circuit, 12AX7 cathode. Schem shows 100K || 25uF/25v.
Layout shows 56K || 25uF/25v.
[3] 12AT7 phase inverter, long-tail resistor. Schem shows 22K, layout
shows 27K.
[4] 12AT7 phase inverter, plate load resistors. Schem shows 82K on
plate 1, and 100K on plate 2. Layout shows 100K on both plates.
None of the differences appear huge, but that can also be said of most
changes from blackface to silverface. I'm leaning toward trusting the
schematic more than the layout diagram, but I would love some advice
from those that know for sure!
Stephen Cowell
"Bluesbreaker" <bluesb...@gmail.com> wrote
> I've downloaded the Fender Deluxe Reverb AB763 schematic from several
> places. In each version the schematic differs (in several places)
> from the layout. I'm performing a blackface to silverface conversion
What? Then why 'nail down ab763'?
__
Steve
.
always trust the schematic
over the layout
Bluesbreaker
<stephenleeNOSPAMcow...@gmail.com> wrote:
> "Bluesbreaker" <bluesbrea...@gmail.com> wrote
Whooops! I meant silverface to blackface.
WB
>
>
> always trust the schematic
> over the layout
>
>
Stephen Cowell
"WB" <sp...@there.com> wrote in message
news:4b6b95c2$0$26722$bbae...@news.suddenlink.net...
... meaning, never convert?
Here's what I suggested to a buddy, he got the most
fabulous blackface conversion ever.
Borrow a BF like you want... take pictures inside...
verify the schematic, etc. Copy the thing, down
to the type of wire and wire placement. His Twin
truly rocks now.
__
Steve
.
WB
> I've downloaded the Fender Deluxe Reverb AB763 schematic from several
> places.
>
> reverb recovery). The schem shows a 3.3M || 10pF attached to the
> grid. The layout shows 4.7M || 10pF.
minor .. none critical tone path .. what does your real circuit have ?
>
> [2] Vibrato circuit, 12AX7 cathode. Schem shows 100K || 25uF/25v.
> Layout shows 56K || 25uF/25v.
minor .. ditto
>
> [3] 12AT7 phase inverter, long-tail resistor. Schem shows 22K, layout
> shows 27K.
minor .
>
> [4] 12AT7 phase inverter, plate load resistors. Schem shows 82K on
> plate 1, and 100K on plate 2. Layout shows 100K on both plates.
>
>
minor .. these balance the signal feed to the power tubes. YMMV.
Define "SF" ... What model do you have ?
This converation has been discussed in detail . SF->BF in general
means removing some components that return an amp to a dirtier sound.
Some SF can never be BF due to the OT linear xfr ( you have to replace
the OT ).
WB
>>>
>> Alway trust what is in there over the schematic !
>
> ... meaning, never convert?
no .. what is in * there * is what is interesting .
A schematic is just a reference and each actual production
may be slightly different .. these were hand crafted,
and not stuffed by a massive IC presser. Maybe the builder grabbed
the wrong part as he put together .. no 10pf in the
tray ? ,.. use a 12pf.
Bluesbreaker
I'm working on a '73 SF Deluxe Reverb, if that helps.
RD Jones
Was there ever an Ultralinear Deluxe ?
(with the so-called Williamson screen taps)
I've never heard of one ...
rd
Stephen Cowell
"Bluesbreaker" <bluesb...@gmail.com> wrote
> I've downloaded the Fender Deluxe Reverb AB763 schematic from several
> places. In each version the schematic differs (in several places)
> from the layout. I'm performing a blackface to silverface conversion
> and I was hoping to nail down the AB763 values, but now I'm confused
> about which is correct; the schematic or layout diagram?
As you may have noticed, there's not enough difference
between the two to spit at... I'm looking at the A1172...
this is what you're working with, right? The only circuit
difference is the parasitic suppressor caps off of the
final grids... the rest of the amp is just about exactly
the same...
... except for the plastic wire. And the plastic wire
sucks, bigtime... you can't properly lead-dress a
plastic-wire amp; that's why the suppressor caps are
in there. Remove them... you'll find out why they're
there, in a hurry... or it'll work fine, crap shoot.
A true BF'ing involves taking out all that crap
plastic stranded wire and subbing in solid-core...
might as well use cloth, since it's easier to work
with and looks like old times. Then you can lay
the wires down just like the little old ladies that
worked for Leo when the magic was goin' on...
that is, if you know what you're doing, or have
a pristine BF to copy from.
Good luck.
__
Steve
.
don't forget to twist the grid wires!
jh
> Bluesbreaker wrote:
>> I've downloaded the Fender Deluxe Reverb AB763 schematic from several
>> places.
>> [1] The 3rd 7025 (V4 in the preamp). The 2nd half of the triode (post
>> reverb recovery). The schem shows a 3.3M || 10pF attached to the
>> grid. The layout shows 4.7M || 10pF.
>
> minor .. none critical tone path .. what does your real circuit have ?
dry to reverb balance. I disagree
>>
>> [2] Vibrato circuit, 12AX7 cathode. Schem shows 100K || 25uF/25v.
>> Layout shows 56K || 25uF/25v.
>
> minor .. ditto
yes
>>
>> [3] 12AT7 phase inverter, long-tail resistor. Schem shows 22K, layout
>> shows 27K.
>
> minor .
that's the R which sets the bias of the PI. I'd xpect at last a tonal
change, if not harsher tones when overdriven.
>>
>> [4] 12AT7 phase inverter, plate load resistors. Schem shows 82K on
>> plate 1, and 100K on plate 2. Layout shows 100K on both plates.
>>
>>
> minor .. these balance the signal feed to the power tubes. YMMV.
>
I'd not want to have constantly imbalanced signal to feed the power
tubes, which is with the two 100Ks.
Jochen
jh
..seems like the one who was ordered to draw the AB763 Layout took the
AA763 and just changed the header.
The points you found seem to be a brief description of the
changes/improvements from the AA to the AB763 Deluxe Reverb. Thanks for
that.
Anyone ever got the possibility to compare an AA to an AB in real life?
There should be some differences.
So you've got the choice of converting to an early or a late 63' amp ;-)
rgards
Jochen
WB
>>> [1] The 3rd 7025 (V4 in the preamp). The 2nd half of the triode (post
>>> reverb recovery). The schem shows a 3.3M || 10pF attached to the
>>> grid. The layout shows 4.7M || 10pF.
>>
>> minor .. none critical tone path .. what does your real circuit have ?
> the dry signal has to pass this R; a change severely changs tone and the
> dry to reverb balance. I disagree
>
I disagree on your disagreement ! Such a large R ( 3 or 4m) will
make an insufficient change that can be heard. IMO.
>>> [4] 12AT7 phase inverter, plate load resistors. Schem shows 82K on
>>> plate 1, and 100K on plate 2. Layout shows 100K on both plates.
>>>
>>>
>> minor .. these balance the signal feed to the power tubes. YMMV.
>>
> I'd not want to have constantly imbalanced signal to feed the power
> tubes, which is with the two 100Ks.
Those values have changed over various versions the amp. I've never
experimented with wrangling the right combination.
>
WB
What does the sticker in the cab says the circuit is ?
You may be pretty close already. If you have a UL OT your
screwed. Best thing is move the weird caps in the PI and
power section that were added to remove hi freq oscillations and
make the circuits shine clean.
Lord Valve
You're a fucking retard.
I believe I addressed that before - and you
got pWN3d that time, too. I'll let the other
rocket scientists spank your lame ass
this time around.
Lord Valve
Expert (please obsess)
Bluesbreaker
I'm not sure which type of OT is in this amp.
Here's whats stamped on it:
022640
-606-2-46
Any ideas?
Tony Elka
Lord Valve <detr...@ix.netcom.com> wrote:
> You're a fucking retard.
You can catch more flies with honey than with vinegar.
Tony
Dave Curtis
It's not a UL OPT, and Fender sure didn't make a UL amp in '73 (or at
all, for that matter, that used 6V6s). You have a standard Deluxe
Reverb P/P OPT. It was also used in the Deluxe. They didn't change a
whole lot on these.
WB
>
> I believe I addressed that before
HOLY FUCKING SHIT
FAT ASS JOINS IN ON A AMP TOPIC
Ether
> Bluesbreaker wrote:
> > On Feb 4, 11:09 pm, WB <s...@there.com> wrote:
> >> Stephen Cowell wrote:
>
> >>>> Alway trust what is in there over the schematic !
> >>> ... meaning, never convert?
> >> no .. what is in * there * is what is interesting .
>
> >> A schematic is just a reference and each actual production
> >> may be slightly different .. these were hand crafted,
> >> and not stuffed by a massive IC presser. Maybe the builder grabbed
> >> the wrong part as he put together .. no 10pf in the
> >> tray ? ,.. use a 12pf.
>
> > I'm working on a '73 SF Deluxe Reverb, if that helps.
>
> What does the sticker in the cab says the circuit is ?
>
> You may be pretty close already. If you have a UL OT your
> screwed.
No '73 Fender had a UL OT. Hello?
> Best thing is move the weird caps in the PI and
> power section that were added to remove hi freq oscillations and
> make the circuits shine clean.
What are you smoking?
--E
Ether
Standard Deluxe Reverb OT. Made in '72. Leave it alone.
--E
Ether
The only thing you should change in that amp are--
1) the resistor values in the phase inverter secrion
2) and the bias circuit.
It will sound great. I'd even leave the phase inverter coupling cap
alone.
--E
Bluesbreaker
balance) to blackface (bias adjustment). I also changed the PI
resistors from 330K to 1M (blackface spec).