Tube Amps / Music Electronics
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|4/1/1998 2:24 PM|
|Daniel R. Haney
||Tube Drivers and similar|
Tube Works made Tube Driver variations called
the Real Tube and Blue Tube. All are distortion
units with differing drive and clipping qualities,
but similar with a family resemblance. These rack
mount units have been discontinued. The pedal
versions don't sound as good.
I bought a used Blue Tube, compared it to a
Real Tube schematic & noted that it swapped
values on the MASTER and HIGH pots, 100K & 500K,
respectively. (BTW, Tube Works changed owners
again and no longer supplies schemata.)
If you swap those pots in the Blue Tube, it
sounds exactly like a Real Tube, a distinct
improvement, IMO. Clever. The only other
difference (that I can tell) between the two
units is that one is painted black and the other blue.
Anyone have any experience with these boxes?
Also, after the Fulltone Fracas (tm), I would
not publicly offer to distribute a schematic.
Private consultations are a different matter.
|4/2/1998 8:55 AM|
Are the Tube Works pedals and rackmounts related to the Chandler TDR-101 Tube Driver designed by B.K. Butler? In other words, did Tube Works "fuller-ize" Chandler? Is the Real Tube a "fuller-ization" of the original Tube Driver?
In reading here of Mike Fuller's woes trying to make it as a business owner, perhaps his wish will come true and his name will become well-known throughout the world- like Benedict Arnold or Thomas Crapper.
Getting back to your question (and mine), I had the original foot pedal Chandler Tube Driver but traded it in a year later for the rack mount version, which had more knobs so it had to be better- right? So are these animals related to the Tube Works products?
|4/2/1998 2:24 PM|
|Daniel R. Haney
> Are the Tube Works pedals and rackmounts related to the
> Chandler TDR-101 Tube Driver designed by B.K. Butler? In
> other words, did Tube Works "fuller-ize" Chandler?
Let's not give Mr. F. more importance than he's due.
Both the Real Tube and the Blue Tube rackmount boards
say "TDR-101D" dated 1989 on them. I suspect Chandler
licensed the production of Tube Driver et.al. to Tube Works.
> I had the original foot pedal Chandler Tube Driver but
> traded it in a year later for the rack mount version,
> which had more knobs so it had to be better- right?
Um. The rack mounts ARE better, having CONTOUR and BIAS
controls which give you great flexibility of tone & timbre.
CONTOUR looks like a midrange pre-equalizer and the BIAS
controls the plate bias on the 12AX7 tube.
Afterthoughts: The TDR-101D circuit boards have components
soldered on the trace side with the trace side up. The
opamps (whose pinouts are NOT biaxially symettrical) are
on the PCB bottom. All of these boards had to be stuffed
from the center out, hand-soldering along the way.
Ugh. very labor intensive.
It looks like Chandler had 1000's of boards made upside
down, reversed, wrong, whatever, and the assembly labor was
killing them. Tube Works probably offered to take over
production. The engineer at Tube Works says there are no
more circuit boards to be had. I suspect they were
a little relieved when the rack mount sales began to
decline so that they could ditch that albatross, same as Chandler had years ago.
more murky conjectures from...
|4/17/1998 6:27 PM|
I had a chance to look over the schematic of the rack mount Tube Driver. I found several things unusual about it.
It is basically just an opamp buffer, followed by an opamp booster stage driving the 2 sections of a 12AX7 and then a buffer and output mixer (dual opamp). I was surprized that this unit is not using Butler's patented bias method, but is straight forward triode gain stages powered by +/- 16v or so.
If I am tracing this correctly, the clean signal is inverted when passed to the output and the distorted signal from the tubes ends up non-inverted at the output: in other words, the signal switches polarity when you punch the bypass switch. That could raise a little havoc with a downstream effect (especially phasers/flangers/chorus) or even with careful mike placements for recording.
Also, the second opamp stage has a LOT of gain! So much so that it can probably drive the tube into saturation which causes the infamous flatulent sound. Obviously a fix for that is to keep the gain control down low.
You could fix the phase change & eliminate 2 op-amp stages with some careful re-engineering. Less op-amp stages = less noise.
Maybe I should put a tube overdrive on my list of projects? Any suggestions for desired features?
|4/17/1998 7:37 PM|
|Daniel R. Haney
[re: Real Tube RT902]
> Also, the second opamp stage has a LOT of gain!
> So much so that it can probably drive the tube into
> saturation which causes the infamous flatulent sound.
> Obviously a fix for that is to keep the gain control
> down low.
My opinion is that the Real Tube doesn't begin
to sound interesting until the DRIVE and CONTOUR
controls are up. It sounds farty for chords but is
good for solo work. Some pre-equalization works
well here if you roll off some bass. With the
DRIVE knob at middling levels, it sounds more like
a mild overdrive.
In my Blue Tube variant, the noise is mostly
60+120Hz hum, no surprise since the power supply
is unregulated and the unrectified tube filament
AC is on the same circuit board. One project
in my list is to put DC on those filaments,
or to get aggressive and move the power supply
onto a separate board.
The circuit board design is peculiar: Traces and
components all on the same side (except for opamps).
|4/20/1998 1:02 AM|
Sounds like a good project. I'd certainly be interested in building one if you design it...
I have a tube driver, and my biggest problem with it is that it only has one tone control. I'd like to see something with a _active_ bass, mid, and treble.
I'd also like to have two drive/volume levels. But with a basic circuit I could probably add that myself.
|4/20/1998 2:01 PM|
B.K Butler designed them all. As he was starting up Tube Works, he designed the Tube Driver for Chandler, the Overlord for Dean Markley (same layout and box as the Real Tube, a LOT more gain, and a scooped tone, a Metal Tube if you will), and the Tube King for Ibanez (which I don't think started production until years later).
My Overlord pedal (a dog) actually had a Real Tube branded 12AX7 in it, so the products don't predate TubeWorks. My guess is he licensed out several designs to get Tube Works off the ground.
I personally don't like the tone from any of the Butler designs. I think the even the solid-state Tube Screamer series sounds more authentic than them, and the high plate voltage pedals like the Hot Chili Tubester and V-Twin are in a different league all together.
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