#169042  by Abide
 Thu Dec 24, 2020 6:04 am
Hey guys,

So I got one of the Eastwood Wolfs a while back. Embarrassingly, I've barely messed with it (I tend to play more bass...that along with real life has made playing guitar difficult). However, as we enter the new year I am determined to play more guitar, which brings me to my questions...

So I've read a bunch of posts regarding the OBEL system and I wondering if you guys are aware of a good youtube video showing how to adjust the trimpot, etc?

Also, Eastwood is going to produce a Tiger bass which might make playing guitar even more difficult! :)

Wishing you all a HAPPY HOLIDAY!!
 #169044  by Abide
 Thu Dec 24, 2020 7:33 am
And this is why I need help!! )

That's what I get for trying to adopt vernacular I don't understand! It's the Eastwood Wolf.
 #169045  by strumminsix
 Thu Dec 24, 2020 7:59 am
Hi, last I checked Eastwood was a non-traditional setup but close to the Jerry thing and Alembic thing.

If there's a trim pot it has something like an Alembic Stratoblaster.

A proper Garcia type OBEL has a buffer just above unity which allowed JG to goose it a hair:
https://rukind.com/viewtopic.php?t=16583

Make sure as you review what you received from Eastwood that it's truly OBEL. Their initial offering called it stereo output.
 #169047  by Jon S.
 Thu Dec 24, 2020 9:13 am
Maybe I'm missing something but I thought Garcia's buffer was slightly below unity gain. This old post from the thread strumminsix links to agrees with what my understanding has always been (emphasis added):

Re: Unity Gain vs. Non-Unity Gain
#143085 by Scarlet
Thu Dec 04, 2014 6:53 am
I found the email exchange I had with Waldo from 2010:

You state that "The TPC1 is not a Unity Gain Preamp. A Unity Gain version is optional at time of purchase". Could you explain the difference further please.

Unity gain is essentially the same output level as the pickups with no buffer. what goes in level wise is what comes out. with the stock TPC1 it is slightly less then unity or slightly less output level. what this accomplishes is that you can run your preamp a notch higher in level vs. unity output. in tube preamps this gives a slight increase in voltage to the preamp tubes and for some, and jerry, this was a desired effect. tone wise from the guitar standpoint there is no tone difference unity or slightly less. as i stated, it is just an output level.
 #169049  by TI4-1009
 Thu Dec 24, 2020 10:40 am
Two different animals. The onboard buffer is a preamp in the guitar that boosts the signal. It has a trimpot that lets you adjust how strong you want that boost. Doesn't need an OBEL (and the OBEL doesn't need it). But they play nice together.

The OnBoard Effects Loop allows you the switchable option of sending your signal from the guitar directly to the amp, OR sending the signal out through your effects loop, back into the guitar, then out to the amp. This does a few things. Most importantly it hits the effects with the full signal from the guitar no matter where your guitar volume knob is set. This really helps to "push" effects like the envelope filter and octave divider while at reasonable volumes. It also lets you have your effects preset, then turn them on or off with a flip of the switch on your guitar.

(this all assumes that the OBEL is wired correctly and the junction box and/or "Y" connector that you use is compatible with your wiring. Incorrectly wired OBELs have been an issue with a number of different tribute guitars for many years).
strumminsix liked this
 #169050  by wpmartin1979
 Thu Dec 24, 2020 11:29 am
All you do is pop off the back plate and identify the buffer/preamp. Then you just take a small screw driver and turn the knob. The knob is easy to identify because it is round with a screw driver slot.
Righty is up and lefty is down.
I found the best results with it all the way down (far left as she goes)
 #169051  by wpmartin1979
 Thu Dec 24, 2020 11:31 am
TI4-1009 wrote:
Thu Dec 24, 2020 10:40 am
Two different animals. The onboard buffer is a preamp in the guitar that boosts the signal. It has a trimpot that lets you adjust how strong you want that boost. Doesn't need an OBEL (and the OBEL doesn't need it). But they play nice together.

The OnBoard Effects Loop allows you the switchable option of sending your signal from the guitar directly to the amp, OR sending the signal out through your effects loop, back into the guitar, then out to the amp. This does a few things. Most importantly it hits the effects with the full signal from the guitar no matter where your guitar volume knob is set. This really helps to "push" effects like the envelope filter and octave divider while at reasonable volumes. It also lets you have your effects preset, then turn them on or off with a flip of the switch on your guitar.

(this all assumes that the OBEL is wired correctly and the junction box and/or "Y" connector that you use is compatible with your wiring. Incorrectly wired OBELs have been an issue with a number of different tribute guitars for many years).
Yeah for my Tiger tribute I had to reverse the wired on the TRS jack for it to work correctly with my OBEL junction box.

Or you can switch the tip and ring in the box, but doing in in the guitar is easy if you can solder.
 #169054  by Jon S.
 Thu Dec 24, 2020 11:49 am
I have a couple of guitars with buffers and a couple with preamps. For mine, the preamps have trim pots, the buffers don't.

Looking at Eastwood's writeup on their unit, it's hard for me to tell exactly what it is. Perhaps it's a buffered preamp! But it certainly has a trim pot. Anyone know for sure?

Transwarp™ Pre-amp -

The Eastwood Wolf Guitar features our Transwarp™ Pre-Amp which
acts as a buffer for the circuit. The Transwarp™ is active at all times and cannot be
deactivated.

The unit is powered by the 9V battery. The gain setting on the Transwarp™ (Located on the
side cavity next to the 9V battery compartment) can be adjusted using the small trim pot
located on the unit using a small screwdriver to set your desired gain amount. If you are
experiencing gain clipping we recommend that you reduce the gain by adjusting the trim pot
anti-clockwise.

The instrument cable should be removed from the guitar when not in use to avoid draining the
battery.
 #169066  by Abide
 Sat Dec 26, 2020 7:46 am
Thank all! Hopefully, I'll have the chance to make some adjustments later!
 #169068  by lbpesq
 Sat Dec 26, 2020 11:37 am
Don’t on-board preamps also buffer? I believe the Alembic Blaster also acts as a buffer. Am I misinformed?

Bill, tgo
 #169069  by Jon S.
 Sat Dec 26, 2020 11:47 am
Admittedly, we're splitting hairs now, but I though a buffer is an op-amp low impedance out versus the 'blaster being a JFET boost/high impedance out. But maybe I'm wrong!

This being said, a buffer can certainly be designed to also boost, and I suppose a JFET boost could be designed into a circuit that also buffers.
 #169070  by wpmartin1979
 Sat Dec 26, 2020 11:49 am
lbpesq wrote:
Sat Dec 26, 2020 11:37 am
Don’t on-board preamps also buffer? I believe the Alembic Blaster also acts as a buffer. Am I misinformed?

Bill, tgo
I think you are correct Bill. The Blaster is actually just a buffer in disguise.
 #169072  by Jon S.
 Sat Dec 26, 2020 12:50 pm
wpmartin1979 wrote:
Sat Dec 26, 2020 11:49 am
The Blaster is actually just a buffer in disguise.
Based on tone and not comparing the circuits (I'm a musician, not an engineer!), trusting my ears, I'd respectfully disagree because the tone on my Blaster-equipped guitar is colored by the Blaster (in a mild, good way) in a manner that my buffer-only guitars are not.

As bradpdx put it on the TDPR in 2018 (emphasis added by me),

"I used to do electronics design work with Alembic, back in the late 1980s.

The Stratoblaster is a single FET amplifier, really simple. The whole idea was to eliminate the treble losses from cables when using passive pickups, while providing a boost (there is little pot on the inside to adjust the gain). Hence an FET, for its high input impedance.

These days, it's easier to make such a thing using a simple op-amp, but the Stratoblaster was designed in the early 70s. The FET design allows it to use very little battery power, which was otherwise a real challenge in those days. The unexpected "charm" of the circuit (such as it is) is that it can generate a bit of mild distortion due to the lack of significant feedback (unlike an op-amp version). Another side effect is that the Stratoblaster flips the phase of your guitar signal - a non-issue mostly, but there it is."

The circuit below is accurate except that it's missing Alembic's 1M resistor from the FET gate to ground (necessary to prevent pops).

Image
 #169073  by wpmartin1979
 Sat Dec 26, 2020 1:04 pm
Jon S. wrote:
Sat Dec 26, 2020 12:50 pm
wpmartin1979 wrote:
Sat Dec 26, 2020 11:49 am
The Blaster is actually just a buffer in disguise.
Based on tone and not comparing the circuits (I'm a musician, not an engineer!), trusting my ears, I'd respectfully disagree because the tone on my Blaster-equipped guitar is colored by the Blaster (in a mild, good way) in a manner that my buffer-only guitars are not.


The whole idea was to eliminate the treble losses from cables when using passive pickups, while providing a boost (there is little pot on the inside to adjust the gain). Hence an FET, for its high input impedance.

These days, it's easier to make such a thing using a simple op-amp ...
Great info Jon, you have me convinced that the blaster is indeed unique!
Seems like it was created for basically the same purpose as a buffer (don’t all buffers eliminate signal loss while also boosting signals?) and ended up with unique characteristics of its own.
Perhaps the “Transwarp Preamp” is a Stratoblaster clone with an op-amp instead of FET?