jumping channels????

toddr513

Joined: Dec 30, 2013
Posts: 245
1 Contributor Pin

Posted on Jan 22 2014 04:48 PM

so i see a lot of people combine channels on bassmans...why is that...and could you do it on a twin?

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Badger

Joined: Nov 16, 2013
Posts: 4537
Wisconsin
United States

Posted on Jan 24 2014 07:26 AM

Not sure; I seem to recall reading something quite awhile back about the number of gain stages in Bassmans allowing that to work well, but not in a TR so much, although don't think it hurts the amp. Try googling "jumpering channels Twin Reverb" or similar. I never did it to mine; I just plugged into the vibrato channel & played it.

—

Wes
SoCal ex-pat with a snow shovel

DISCLAIMER: The above is opinion/suggestion only & should not be used for mission planning/navigation, tweaking of instruments, beverage selection, or wardrobe choices.

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bigtikidude

Joined: Feb 27, 2006
Posts: 25696
Anaheim(So.Cal.)U.S.A.
United States

Posted on Jan 24 2014 08:39 AM

I've heard on a twin that the channels are out of phase with
Each other so it would a actually cause a volume decrease.

—

Jeff(bigtikidude)

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alphaking

Joined: Jan 02, 2013
Posts: 214
United States

Posted on Jan 24 2014 08:58 AM

I do it on my 59 Bassman clone. There is a volume decrease (good in my situation) but it also adds some fuller sound from the Normal channel to the Bright channel. The Bright channel alone is too bright for me, and with the jumper, I can use the volume from the Normal channel to dial in a little more bass/low end into the Bright channels sound. So I may run the Bright volume at 4 and the Normal at 2. My Bassman has 4 inputs; a low and hi for Normal and the same for Bright. So I use a short section of a Lava solderless pedalboard kit to jumper Bright 2(Low) to Normal 1(High), and plug the guitar into Bright 1(High). Works great. I cant help you with the Twin, just no experience with one.
Chris

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ArabSpringReverb

Joined: Jul 13, 2012
Posts: 490
San Diego CA
United States

Posted on Jan 25 2014 12:02 PM

I believe Jeff is correct about the 2 channels being out of phase on a Twin...not much benefit from jumpering...if you want more grind ,plug into the vibrato channel and pull the V1 tube from the normal channel.

Jumping or cascading the inputs on a 4 input amp like a bassman or early marshall gives a little extra gain stage and more oomph to the bright channel

if you need more from a Twin just plug a pedal of your choice into the front

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elwrongo

Joined: Jul 05, 2010
Posts: 60
Perth
Australia

Posted on Jan 29 2014 01:59 AM

I have a 66 Bandmaster and when I jump channels on that it drives the amp harder and gets a pretty great sound. What I do now is jump the channels but have a pedal switch in the jump loop so I can switch the jumped channels on at will. This produces my lead sound and works extremely well for rock boost. No other pedals except for a 63 Reissue Fender Reverb Tank. Just me, the guitar and the amp, ace.

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JObeast

Joined: Jul 24, 2012
Posts: 2762
Finknabad, Squinkistan
Turkmenistan

Posted on Jan 29 2014 05:21 AM

"Jumpering" or "bridging" is feeding the same instrument signal into the preamps of both channels, which then run parallel to the power stage. Bassman amps are typically run in this configuration to take advantage of their thick overdrive. I first saw the cable bridging both channels on a Holland "Gibb Droll" Bassman clone with added reverb-only speaker (like a Guild amp). That was one excellent piece of amplification gear.
I guess Twin's "Normal" and "Tremolo" channels are out of phase because of the reverb effect (someone explain this?). I use a short cable to feed both "Normal" and "Treble" channels on my old Gretsch Electromatic Twin, when I want a fat or distorted tone. For skinny vintage Fender sounds I use just the "Treble" channel.

—

Squink Out!

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mike_fried

Joined: Aug 02, 2012
Posts: 162
Nashville, TN
United States

Posted on Jan 30 2014 11:39 PM

The channels of a Twin (and other two-channel Fender reverb amps) are out-of-phase because the reverb/vibrato channel has one more gain stage than the Normal channel (it's the reverb recovery stage). Each preamp gain stage reverses the signal's phase, so an even number of them will be out-of-phase with an odd number of them.

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JObeast

Joined: Jul 24, 2012
Posts: 2762
Finknabad, Squinkistan
Turkmenistan

Posted on Jan 31 2014 06:12 AM

Aha! That's it! Thanks, I'll remember that – the same reason you can't jumper the channels of a Mesa Boogie Mk II.
I've heard that putting both channels in phase ( and both reverbed) only takes moving one wire.

—

Squink Out!

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FlatRacer

Joined: Apr 07, 2008
Posts: 182

Posted on Feb 05 2014 01:20 PM

elwrongo wrote:

I have a 66 Bandmaster and when I jump channels on that it drives the amp harder and gets a pretty great sound. What I do now is jump the channels but have a pedal switch in the jump loop so I can switch the jumped channels on at will. This produces my lead sound and works extremely well for rock boost. No other pedals except for a 63 Reissue Fender Reverb Tank. Just me, the guitar and the amp, ace.

That's interesting. The channels on my '61 Brownface Band Master are out of phase with each other. I guess that varies from one design generation to the other, so there's no general rule. You just have to try it to find out.

Eric

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toddr513 Joined: Dec 30, 2013 Posts: 245	Posted on Jan 22 2014 04:48 PM so i see a lot of people combine channels on bassmans...why is that...and could you do it on a twin? Top
Badger Joined: Nov 16, 2013 Posts: 4537 Wisconsin	Posted on Jan 24 2014 07:26 AM Not sure; I seem to recall reading something quite awhile back about the number of gain stages in Bassmans allowing that to work well, but not in a TR so much, although don't think it hurts the amp. Try googling "jumpering channels Twin Reverb" or similar. I never did it to mine; I just plugged into the vibrato channel & played it. — Wes SoCal ex-pat with a snow shovel DISCLAIMER: The above is opinion/suggestion only & should not be used for mission planning/navigation, tweaking of instruments, beverage selection, or wardrobe choices. Top
bigtikidude Joined: Feb 27, 2006 Posts: 25696 Anaheim(So.Cal.)U.S.A.	Posted on Jan 24 2014 08:39 AM I've heard on a twin that the channels are out of phase with Each other so it would a actually cause a volume decrease. — Jeff(bigtikidude) Top
alphaking Joined: Jan 02, 2013 Posts: 214	Posted on Jan 24 2014 08:58 AM I do it on my 59 Bassman clone. There is a volume decrease (good in my situation) but it also adds some fuller sound from the Normal channel to the Bright channel. The Bright channel alone is too bright for me, and with the jumper, I can use the volume from the Normal channel to dial in a little more bass/low end into the Bright channels sound. So I may run the Bright volume at 4 and the Normal at 2. My Bassman has 4 inputs; a low and hi for Normal and the same for Bright. So I use a short section of a Lava solderless pedalboard kit to jumper Bright 2(Low) to Normal 1(High), and plug the guitar into Bright 1(High). Works great. I cant help you with the Twin, just no experience with one. Chris Top
ArabSpringReverb Joined: Jul 13, 2012 Posts: 490 San Diego CA	Posted on Jan 25 2014 12:02 PM I believe Jeff is correct about the 2 channels being out of phase on a Twin...not much benefit from jumpering...if you want more grind ,plug into the vibrato channel and pull the V1 tube from the normal channel. Jumping or cascading the inputs on a 4 input amp like a bassman or early marshall gives a little extra gain stage and more oomph to the bright channel if you need more from a Twin just plug a pedal of your choice into the front Top
elwrongo Joined: Jul 05, 2010 Posts: 60 Perth	Posted on Jan 29 2014 01:59 AM I have a 66 Bandmaster and when I jump channels on that it drives the amp harder and gets a pretty great sound. What I do now is jump the channels but have a pedal switch in the jump loop so I can switch the jumped channels on at will. This produces my lead sound and works extremely well for rock boost. No other pedals except for a 63 Reissue Fender Reverb Tank. Just me, the guitar and the amp, ace. Top
JObeast Joined: Jul 24, 2012 Posts: 2762 Finknabad, Squinkistan	Posted on Jan 29 2014 05:21 AM "Jumpering" or "bridging" is feeding the same instrument signal into the preamps of both channels, which then run parallel to the power stage. Bassman amps are typically run in this configuration to take advantage of their thick overdrive. I first saw the cable bridging both channels on a Holland "Gibb Droll" Bassman clone with added reverb-only speaker (like a Guild amp). That was one excellent piece of amplification gear. I guess Twin's "Normal" and "Tremolo" channels are out of phase because of the reverb effect (someone explain this?). I use a short cable to feed both "Normal" and "Treble" channels on my old Gretsch Electromatic Twin, when I want a fat or distorted tone. For skinny vintage Fender sounds I use just the "Treble" channel. — Squink Out! Top
mike_fried Joined: Aug 02, 2012 Posts: 162 Nashville, TN	Posted on Jan 30 2014 11:39 PM The channels of a Twin (and other two-channel Fender reverb amps) are out-of-phase because the reverb/vibrato channel has one more gain stage than the Normal channel (it's the reverb recovery stage). Each preamp gain stage reverses the signal's phase, so an even number of them will be out-of-phase with an odd number of them. Top
JObeast Joined: Jul 24, 2012 Posts: 2762 Finknabad, Squinkistan	Posted on Jan 31 2014 06:12 AM Aha! That's it! Thanks, I'll remember that – the same reason you can't jumper the channels of a Mesa Boogie Mk II. I've heard that putting both channels in phase ( and both reverbed) only takes moving one wire. — Squink Out! Top
FlatRacer Joined: Apr 07, 2008 Posts: 182	Posted on Feb 05 2014 01:20 PM elwrongo wrote: I have a 66 Bandmaster and when I jump channels on that it drives the amp harder and gets a pretty great sound. What I do now is jump the channels but have a pedal switch in the jump loop so I can switch the jumped channels on at will. This produces my lead sound and works extremely well for rock boost. No other pedals except for a 63 Reissue Fender Reverb Tank. Just me, the guitar and the amp, ace. That's interesting. The channels on my '61 Brownface Band Master are out of phase with each other. I guess that varies from one design generation to the other, so there's no general rule. You just have to try it to find out. Eric Top

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jumping channels????