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thepocna

1969 ES 355 TDSV Wiring Question

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Thanks again folks for all the discussion. There is a tone and volume difference even when the Varitone is in the bypass position. There is volume drop and tone difference when using the Y cable versus plugging one end of the stereo cable into the rig. Huge volume drop when both pickups are engaged as well. Thanks.

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Perhaps somebody with better sense can derive how the BB King mono plug works...

 

Well I can't convince anyone that I have any sense, but the diagram has a jack with a switch on it. When you plug into the second jack, the tip moves back a little bit when the plug engages it. That's far enough for the main lug on the jack to bend back a little bit, and it falls away from a little contact point. If the plug was not being used, then the signal goes on past that little contact switch and onto the next jack where the two signals are combined from stereo to mono. If the plug is being used, the contact opens and it no longer connects to the second jack and they work independently. Same idea behind disconnecting the battery when you plug in an auxiliary power plug into a stomp box. Sorry I can't remember if that's considered an "open" or a "closed" jack.

 

Now as for the bigger picture, it seems that the Lucille has no problem with the two channels bridged running through one cord to a single amplifier - so perhaps I'd suspect that the subject guitar here has a phase problem. Perish the thought but maybe you need to pull the harness and set it aside for your grandchildren when they have it appraised, and rewire it? or maybe the pickups are out of phase? sorry we're going in circles here.

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..... - so perhaps I'd suspect that the subject guitar here has a phase problem. Perish the thought but maybe you need to pull the harness and set it aside for your grandchildren when they have it appraised' date=' and rewire it? or maybe the pickups are out of phase? sorry we're going in circles here.[/quote']

 

Now that's an interesting thought. Maybe somebody wanted to use the 345 with a BF/SF Fender amp and figured that the way to get around the two channels being 180 degrees out of phase was to make the pickups likewise - thereby cancelling the effect.

 

thepocna, have you tried plugging the guitar into two sides of an amp of this type?

 

Who knows - there may be a Deluxe Reverb/Vibrolux/Twin Reverb/Super Reverb/Pro Reverb (or whatever) in your future? eusa_angel.gif You should know that my ES345 -> my 74 Pro Reverb = instant Wes Montgomery (subject to finger limitations).

 

RN

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Robin, I really don't know what you mean with the two channel being out of phase??

 

With my ES 345 using the "Y" chord, if I plug both output jacks into both inputs on the Vibrato or Normal Channel on my Super, I do get an out of phase sound. When I seperate the the "Y", one out put jack into input 1 of the Normal, and input 1 of the Vibrato, the guitar sounds normal. Using a two channel amp, or two amps works for me. It is the same sound if I pull out the input jack, say half-way, whereas I can make contact with both pick ups, I get the same thing.

 

Getting back to the wiring, I had stated before that I believe each pick up is wired seperately to the Vari-tone and the stereo output jack. As stated before, each pick up works independent of the other, unlike a ES 335, where you need the volume up on one pick for the other to work. Another thing, on my ES 335, if you are using one pick up, you hear alittle bit of hum, when you put the selector switch in the middle, for both picks up to work, they cancel out each other & eliminate the hum. On my ES 345, with each pick up wired seperately, that doens't happen. You pick up some hum from each pick-up.

 

I guess the best way to find out, is to find an old ES 345 wired in stereo that is beyond repair, and take it apart and see what makes it work!

 

So these pick-ups must be wired to each other. I'm no electrical expert, but I would think you would have to re-wire the whole guitar to make it mono like a ES 335.

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Robin' date=' I really don't know what you mean with the two channel being out of phase??

 

With my ES 345 using the "Y" chord, if I plug both output jacks into both inputs on the Vibrato or Normal Channel on my Super, I do get an out of phase sound. When I seperate the the "Y", one out put jack into input 1 of the Normal, and input 1 of the Vibrato, the guitar sounds normal. Using a two channel amp, or two amps works for me. It is the same sound if I pull out the input jack, say half-way, whereas I can make contact with both pick ups, I get the same thing.[/quote']

 

Ken,

 

I think your 345 has been rewired so that the pickups are out of phase with the consequence that when you plug both pups into one channel you get the out-of-phase sound but when you run a pup into each channel, the sound is in-phase.

 

With the two 345s that I have owned, that I know to be stock, I get the out-of-phase sound when I use both channels – whether on my Pro, Vibrolux or Deluxe. I have discussed all this with local guitar and amp techs and also at another reputable forum.

 

The way it's been explained to me is that there is an extra tube in the vibrato channel on these types of amps. The output from a tube is 180 degrees out of phase with the input. In other words, when the input signal has maximum positive amplitude, the output signal has maximum negative amplitude. This means that in theory if you feed an identical signal into each channel of such an amp, the outputs from the pre-amps that are received by the power stage will be 180 degrees out of phase with each other and will cancel. In practice you hear a significant loss of bass and get that thinner sound. It's just like wiring stereo speakers out of phase.

 

As a special favour to this fine website, I did an experiment to confirm this. I ran the mono headphone output from my bedside radio into a mixer with stereo outputs. There was some jazz on. I then ran each side of the mixer output into the two channels of my SFDR. When the pan knob on the mixer channel was to one side or the other, the sound coming out of the amp was fine. When the pan was in the middle so that identical signals were going to each channel of the amp, the sound from the amp was missing the bass. I noted that the effect was not as pronounced with a talk show.

 

Why were the amps designed like this given that the 345 was already around by the early 60s? I guess it was not seen as a selling point to include phase switching.

 

 

RN

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Robin, thanks for the explanation. I purchased my ES 345 brand new in 76, so I know it was stock when I bought it. My Fender Super Reverb was made in 1980, maybe that would help explain something. Also, that was 2nd Super I have owned, and it worked fine using both channels w/the Y chord. I don't think Gibson would have changed the schematic on these guitars over the years.

 

But it seems went thru alot of trouble to try and find the answer!

 

You mentioned when you use both channels seperately, you get the out of phase sound.

 

I did an experiment of my own. I took my mono guitar, plugged it into the Vibrato channel (w/reverb) and took a 2nd guitar chord and connected both channels. I played with the inputs but kept both channels connected to each other. It all worked fine, and I even was able to get reverb in my Normal channel that doesn't have Reverb. I did the same thing w/my ES 345 and Y chord. Both channels were used seperately and connected to each other. I was able to reverb out of the Normal channel, and didn't get the out of phase sound. So it seems one channel will feed the other, I guess that is a good explanation.

 

After all of this discussion, you think Gibson would set the story straight.

 

Just to check, I went and checked out the tube chart on my 1980 Fender Super Reverb, here are the tubes: 2 - 6L6GC, 4 - 12AT7, 2-7026. I also checked my one channel two input Fender Hot Rod Deluxe amp, the tubes are: 2 - 6L6GC, and 3 - 12AT7, if this helps with anything.

 

There isn't much more I can add, except the Y chord works for me using two different channels in my Super, or using two different amps. If I patch both channels together using a mono guitar, or my stereo guitar, it works fine no out of phase sound. Plugging both Y chord extensions into the two inputs of the same channel, I get the out of phase sound.

 

If anybody else has a stereo ES 345 and a Fender Twin or Super, I would curious to see what they come up with.

 

We could go on the Fender website and post on their Amp forum to see if anybody has the out of phase problem using the two seperate channels on their amps.

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Hmmmm..... a 1980 Super Reverb you say, and no rectifier tube in your list - suggesting one of the later models with the solid state rectifier. Maybe Fender had put the channels in phase by this time. My amps are a bit older and have tube rectifiers.

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Robin, you are right about Fender channels being 180 out of phase. Also, as you mentioned, the ES345 PU's could have been installed out of phase when using one Fender amp with two channels.

 

Rayba, when I get a chance to go to my kid's studio, I'll check on the my Twin reverb that I have. All I know is that my 345 sounds rich with two amps, and tinnie with one amp.

 

 

Just for info...here is how you can change the phasing on PU's.

 

http://www.youtube.com/watch?v=BU74r2m8cJk

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One of the recent tips newsletters from Stewart MacDonald's has a simple explanation of how to reverse the phase of a pickup. Assuming that you've got single conductor (plus shield) wire connected to the pickup, you would not want to go in an desolder and resolder the pickup leads, and you don't have to.

 

Are your pickups still covered? if so you'll need to desolder one of the covers. You loosen, but do not remove, the screws holding the bobbins to the baseplate until the magnet slides loose. Slide it out and flip it over and return everything. With the magnet flipped you have reversed the magnetic polarity and therefore the phase of the pickup relative to the other pickup. In this case you'd be restoring the pickup to the same phase as the other pickup. Take a look at the newsletter (just sign up for them, then go in and search backissues) for nice pictures.

 

All you have left is the problem of the varitone sucking from both pickups at once, but that could be corrected by disconnecting both sides of the varitone and then just connecting one side of it to the output (after the volume, tone, and switch). Then bridge the two outputs by replacing the jack with a mono jack.

 

That is, assuming you want to rewire or modify anything. You could just use two channels of an amp that happen to be out of phase. Two wrongs sometimes do make a right.

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A few of the guys wanted to know how had I hooked my ES-355 up to go from Stereo to Mono without modifying the guitar and here is a video explaining how I plug it in.

 

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Maybe somebody wanted to use the 345 with a BF/SF Fender amp and figured that the way to get around the two channels being 180 degrees out of phase was to make the pickups likewise - thereby cancelling the effect. RN

 

That seems to be the theory behind the design of the stereo guitars - I just stumbled across a resurrected thread on the gearpage:

 

http://www.thegearpage.net/board/showthread.php?t=255707

 

There's mention of how the blackface and silverface dual-channel amps of the time happened to be out of phase (perhaps they assumed it wouldn't matter since Fender expected you'd have a guitar and accordion or some such, and not the same guitar running to two channels). Also an interesting link there for a guy who did sound clips with and without the varitone stereo harness.

 

Seems like you may need to flip a magnet on one of your pickups to get them in phase and then use a new mono harness.

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