Jumping channels on a '65 BandMasrter head? (Stratman)

[greco]

Stratman posted a pic of his Bassman head with the channels jumped in this thread:

https://forum.seymourduncan.com/showthread.php?t=107980

Can the channels be safely jumped on a '65 BandMaster head? Are there any precautions when doing/using this concept?

What is the advantage of jumping the channels?
(I did do a search of Amplifier Central...came up empty)

Thanks

Dave

 

[kmcguitars]

Re: Jumping channels on a '65 BandMasrter head? (Stratman)

All Fender BF/SF reverb models have channels that are out of phase. (I'm not certain if this is true on the Non-verb models?) Before I was aware of this I would jumper my Twin with a A/B box. (I wondered why the amp sounded strange with both channels on?:doh: ) The advantage is you can set one channel for your rhythm work, Than kick the other one on for a lead boost.
Here is a nifty Lil' device that solves the phase issue.
http://www.barberelectronics.com/LaunchPad.htm

 

[jeremy]

Re: Jumping channels on a '65 BandMasrter head? (Stratman)

on non-reverb models you can jump the channels. in the reverb models the vibrato channel has one extra gain stage which puts that channel out of phase with the other. its a non-issue on the non-reverb models

 

[Farkus]

Re: Jumping channels on a '65 BandMasrter head? (Stratman)

So jumping the channels (in phase on non reverb BF's) puts the preamps in parallel. Not to be difficult, but to those who jumper, what is the benefit of that in your tone? I've tried it before, and I think it warms the tone up some...is that why you guys do it?

 

[jeremy]

Re: Jumping channels on a '65 BandMasrter head? (Stratman)

yeah i think it gives a bigger wider tone

 

[Lava Man]

Re: Jumping channels on a '65 BandMasrter head? (Stratman)

I have made Y cables (female jack to two mono 1/4 plugs) for this as well as 4-channel Marshall's and clones...seems to work pretty well and a lot players prefer the sound this way.

 

[krall]

Re: Jumping channels on a '65 BandMasrter head? (Stratman)

I thought you couldn't jump the early Blackface AA864 circuit because they were out of phase? Can anyone confirm that?

 

[CapoFirstFret]

Re: Jumping channels on a '65 BandMasrter head? (Stratman)

I thought you couldn't jump the early Blackface AA854 circuit because they were out of phase? Can anyone confirm that?

We just went over this? If it's a reverb model, you can't do it without an extra box to do so to flip the phase around. On a non-reverb model you can. Simple as that. No blackface this, silverface that...it's a reverb issue.

 

[greco]

Re: Jumping channels on a '65 BandMasrter head? (Stratman)

Many thanks to everyone for the responses so far.

Dave

 

[Stratman]

Re: Jumping channels on a '65 BandMasrter head? (Stratman)

Any non-reverb fender amp is OK to jump; however, reverb based fender amps are out of phase and sound like it.

When jumping channels, you can dial in a bigger tone/sound.

It's an old trick - Jimi and (Early-Bluesbreaker) Clapton used it all the time.

 

[krall]

Re: Jumping channels on a '65 BandMasrter head? (Stratman)

We just went over this? If it's a reverb model, you can't do it without an extra box to do so to flip the phase around. On a non-reverb model you can. Simple as that. No blackface this, silverface that...it's a reverb issue.

I always thought you couldn't jump from the AA 864 (Blackface) circuit..After some research it turns out i'm right! Bassman's with this circuit do not have reverb and the channels are out of phase..You cannot jump! Here's a quote:

"I think all 6G6s are additive.(can be jumped)
AA864 is not additive. (cannot jump)
AA165 is not additive. (cannot jump)
AB165 is additive. (can be jumped)

The two channels on the AA864 and the AA165 are out of phase and so are not additive in volume because of odd and even number of preamp stages on the two channels."