Jonny Lang "Experience Hendrix" Deluxe Reverbs

[Brad1]

June 2010 issue of Premier Guitar, page 117, shows two "handwired Deluxe Reverb Reissues" played by Jonny Lang.

Both of them have what appears to be a "Y" cable plugged into both the Normal and Vibrato channels.
(Quote: "He plugged into both the Normal and Vibrato channels simultaneously for extra thickness and texture.")

Questions. What might have been done to allow for that? Internal mod to run inverted stage into Normal channel? What would that be?

I've read some people suggesting "change the polarity of one end of a 1/4" cable, and jumper them". That seems...not advisable. Seems like that would take the tip of each channel, and ground them?!

Actually, in the article, it doesn't show how the split to four inputs is made from a single cable output from his Boss AW-3.

Another thing that came to mind. If the two channels on these kinds of amps are out of polarity, would that mean that if you were to use, say, a pulse generator...would the initial attack of one channel pop the speaker forward, and the other channel pop it backward (kind of like testing the speaker polarity with a 9V battery)? If that is so, which channel is sending the initial attack toward the wall? Or, is there something I'm missing?

If there were a relatively easy way to get both channels working "in phase", I'd like to try it. The EVM12L and tube swaps made a bit of difference, but I'm wondering if there isn't a bit more to be squeezed out of it.

Thanks,

Brad1

[J M Fahey]

Normal and reverb channels normally are out of phase because the second one has an extra (inverting) triode in the signal path.
There's no easy way to solve that without major surgery, which is not worth the3 small, if any, improvement possible.
Inverting wiring in one plugs does not work, obviously it was suggested by some beginner which has a *very* thin knowledge of electronics, yet posts with authority. Oh well.
All it does is short hot to ground the very second those plugs are plugged .
Yes, your pulse generator analogy basically applies.
*If* it's that important to you, you can build a unity gain phase inverting Op Amp: in an "LM741/TL071" pinout, it would go: 1 M resistor from pin6 (P6) to P2; 1M from P2 to input jack, P6 to output jack; P3 ground; P4 to -15V; P7 to +15V.
This is not a "how to" guide, just to show what can be done in the simplest way.
You should run your guitar signal straight to one channel and some of it to the other one, going through the inverter.
Yet I insist, there would be very little "improvement" over going straight into the Reverb channel, because both are voiced practically the same.
It's different on a Plexi or Tweed Bassman because both channels sound very different.

[Brad1]

Thanks, J M,

It's not really THAT important. I just saw the Jonny Lang thing, and wondered about all that, and his reasons. Of course, since his was "handwired", I suppose the two channels could have easily also been voiced differently...so that would explain it. Not gonna do anything, but is your circuit pretty much like in a Barber Launch Pad (with their other boost, etc. of course)...just out of curiousity?

Brad1

[pdf64]

There are a few ways of linking the channels together internally, making the trem/rev effects available to both channels, which would make this feasible, see
http://music-electronics-forum.com/t16234/
because it stops the 'as stock' inversion between the normal and effects channels.
As suggested above, I doubt that the external splitter would then be much of a benefit, though if it works for him then...

[Gibsonman63]

Just because the two channels are voiced the same, doesn't mean that they have to be adjusted to give the same sound. Back before I knew about phase cancellation, I used to jumper the normal and reverb channels together on my Vibrolux reverb, then dial in most of the bottom on the normal channel use the reverb channel for the mids and highs. My idea was to have the reverb just on the top end and to leave the bottom alone so it would always have definition. I can't say that I noticed any phase cancellation, but ignorance can be bliss. I'll have to try again sometime and see if my ears are the same now that you guys have been bringing me enlightenment for a while.

[J M Fahey]

Hi Brad.
I don't even know what a

Barber Launch Pad

is, although I'll google for it now.
What I suggested is just the simplest "working" way to do it, being a Minimalist at heart.
Really you can't strip it to much less than an op amp and 2 resistors.[]
Good luck.
PS: anyway, *try* to jump both channels and experiment a little, as was suggested abobe.
You will burn nothing and you might get something.
I imagine some kind of a very rough comb filter might appear on certain controls positions.
Just wondering with an open mind.

[Dan T.]

If you were to wire a small signal transformer to a plug and jack , and plug it into one of the channel's input jacks and the other half of the 'y' splitter to the other channel , that might work .
Like one of those transformers for using an unbalanced line with a balanced one.
Any one want to expand on this idea(or debunk if needed)?

[J M Fahey]

Hi Dant.
Technically, it would work, yes, if one took care to wire the secondary out of phase, and it's being done everyday on live sound situations if necessary, but most transformers are 600 to 600 ohms or so, low impedance; and high to high ones , as needed here, are more difficult to get.
Hi Brad1.
Now that I've seen it, yes, I think the Barber must include an inverting stage just like this, to drive the "-" signal out.
I like buffers in signal paths, specially if already built in the guitar/bass itself.
Rather than post-facto "cleaning" a signal, it's better to keep it clean right from the beginning.

[Brad1]

I found the link to the actual printed article to the Jonny Lang thing (although it wasn't there a couple days ago). This is what started all this. I knew about the "phase" issue, and just wondered how he did it. It is actually more curiousity, and "this got me to thinkin" type of thing. Figured if there was an easy way to goose just a bit more out of it, may try. No biggie. Curiousity has been satisfied.

Axes Bold as Love: The Gear of Experience Hendrix Tour 2010 - Premier Guitar

Thanks guys,

Brad1

[Bruce / Mission Amps]

Hey Brad where have you been lately?