FDP Home Page / FDP Forum / FAQ's

The FDP is made possible by the following companies and individual members like you.
Please use the links below to show them we value their sponsorship.



WD Music

Apex Tube Matching

Guitar Center

Advertise here

Amplified Parts

Musician's Friend

Antique Electronics Supply

Yellowjackets Tube Converters

Jensen Loudspeakers

* God bless America and our men and women in uniform *

* Illegitimi non carborundum! *

If you benefit and learn from the FDP and enjoy our site, please help support us and become a Contributing Member or make a Donation today! The FDP counts on YOU to help keep the site going with an annual contribution. It's quick and easy with PayPal. Please do it TODAY!

Chris Greene, Host & Founder



Find musicians
in your area!
  Search the Forums  

FDP Forum / Amp Mods, Repairs, and Projects / input jumper vs Y cord on SF Bassman100: any difference?



May 14th, 2017 04:41 PM   Edit   Profile  

I hooked up an A/B/Y pedal to my SFBM100 to compare the channels and happy surprise! the amp sounds EVEN MORE AWESOME(and loud AF!) than usual if I simply keep both channels on and use the volume knob for each channel to mix them, both on simultaneously. it occurred to me that I often use "input 2" to connect to another amp, IOW the inputs are parallel in/out, so I should get the same result if I just put a short patch cord between "input 2" of the "bass instrument" channel and "input 1" of the "NORMAL" channel... will this work exactly like running a Y cord or A/B/Y pedal to plug in to both channels at once? this is assuming I want both channels on and not needing to switch between them. hope my question makes sense...



May 15th, 2017 07:22 AM   Edit   Profile  

The channel inputs aren't directly in parallel, rather there are mixing resistors between them, probably to mitigate interaction between the inputs.
Those resistors (68k) will tend to lose a bit of signal, most significantly high frequency roll off will be exacerbated.
So use of a Y splitter should be better in that regard.

Contributing Member

I tried to think

but nothing happened!
May 18th, 2017 08:24 PM   Edit   Profile  

Let me ask this- if using a passive a/b/y switcher to input into both channels, is the signal strength into each input halved?



May 19th, 2017 05:39 AM   Edit   Profile  

In the Y mode, the 2 parallel inputs will load the instrument's PUs a tiny bit more than 1 input, but assuming use of the regular loud #1 input of a regular guitar amp, the effect on signal strength will be minuscule.
If one or both of the inputs is a medium impedance eg line type, then the loading effect will be much greater, and signal strength may well drop 6dB.



May 19th, 2017 12:56 PM   Edit   Profile  

I know this is subject to all sorts of psycho-acoustic cognitive dissonance on my part, but plugging in to this amp this way makes it "sound" twice as loud. when I start turning the volume up on both channels at once it feels like I am actually hearing both channels coming up in volume. in any case, the amp has more volume, headroom, depth of tone, clarity.. just overall sounds better and is really easy to dial in a little more of whatever part of my tone or overdrive I want at any volume. I'm actually using the stereo outputs on my TC Trinity Reverb to split into both channels now. sounds awesome.

FDP Forum / Amp Mods, Repairs, and Projects / input jumper vs Y cord on SF Bassman100: any difference?

Reply to this Topic
Display my email address             Lost your password?
Your Message:
Link Address (URL):
Link Title:

Moderators: Chris Greene  Iron Man  reverendrob  

FDP, LLC Privacy Policy: Your real name, username, and email
are held in confidence and not disclosed to any third parties, sold, or
used for anything other than FDP Forum registration unless you specifically authorize disclosure.

Internet Application Development

Copyright © 1999-2018 Fender Discussion Page, LLC   All Rights Reserved