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Hoffman Amps Forum image Author Topic: Hi and Lo sensitivity inputs...does anyone use the Lo input?  (Read 2709 times)

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Offline PharmRock

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Hi and Lo sensitivity inputs...does anyone use the Lo input?
« on: February 19, 2022, 08:47:40 am »
I've been playing guitar for 40 years, and have owned a lot of amps and have built a few the past 10 years.  Regardless of whether I have a strat with vintage single coils, or a guitar with high output HBs, I always plug into the Hi input.
If a HB-equipped guitar is "too much", I just dial back the volume on the guitar. 
Just wondering how many of you 1) build amps with Hi and Lo sensitivity inputs, and 2) actually use the Lo input?
Come to think of it, about the only time I've used a Lo-input is for jumpering the Normal and Hi Treble channels on a Plexi-style amp.  B

Offline HotBluePlates

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Re: Hi and Lo sensitivity inputs...does anyone use the Lo input?
« Reply #1 on: February 19, 2022, 09:03:35 am »
Just wondering how many of you ... 2) actually use the Lo input?

I almost never do.  But I've talked to folks who do use it.

Just wondering how many of you 1) build amps with Hi and Lo sensitivity inputs ...

When I build an amp I have only one input jack.

Offline uki

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Re: Hi and Lo sensitivity inputs...does anyone use the Lo input?
« Reply #2 on: February 19, 2022, 09:55:17 am »
I do use both, but usually the low goes to the high in the other channel as link.
I've experimented with low input, but I preffer to use the high input, It took me too long to know about the channel link,
I like it a lot, by just dialing the volumes is possible to dig some really nice tones !
Theory is when everyone knows everything but nothing works, practice is when stuff works but nobody knows why !!!
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Offline thetragichero

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Re: Hi and Lo sensitivity inputs...does anyone use the Lo input?
« Reply #3 on: February 19, 2022, 10:07:37 pm »
yes i use the low input on my amp for church. 15w can be awful loud for them church folk (personally i feel like the bassist should turn up and drummer should hit harder but i guess that's just my punk rock roots talking) so i get more usable tone in the low input/easier to control volume from clean to overdriven with pedals
now for marshally jmp kind of amps i have normal, bright, and 'both' as input options (and usually use the both option for channel-jumped goodness)

Offline Willabe

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Re: Hi and Lo sensitivity inputs...does anyone use the Lo input?
« Reply #4 on: February 19, 2022, 11:00:01 pm »
Leo also made a lot of steel guitars.

I wonder how hot those PUP's were in some of the steels?

Offline sluckey

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Re: Hi and Lo sensitivity inputs...does anyone use the Lo input?
« Reply #5 on: February 20, 2022, 01:00:06 am »
When Fender first started putting those nice Hi/Lo jacks on amps, it was not unusual to see two guitars plugged into the HI/LO jacks. In that situation, the jacks are no longer Hi/Lo. They mix the two guitars equally.
A schematic, layout, and hi-rez pics are very useful for troubleshooting your amp. Don't wait to be asked. JUST DO IT!

Offline PharmRock

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Re: Hi and Lo sensitivity inputs...does anyone use the Lo input?
« Reply #6 on: February 20, 2022, 08:13:47 am »
My main go-to guitar has always been a strat, although I do have some HB-equipped guitars.  Of the 18-watters, Plexis, and the 5E3 I played through with Hi/Lo, I've always gone through the Hi input and never gave it a second thought.  If I was looking for a cleaner sound, I just rolled back the guitar volume a little bit.
Having said that, using the Lo input for linking two Plexi channels is definitely useful, although I suppose a switch could accomplish that too.

Wasn't sure about keeping the Lo inputs on this rebuild of an existing 18-watter.  I know on a typical 1974 the Lo is one triode and the Hi is parallel, but since I am using an EF86 here I will just go with a single input.  This will free up some front panel real estate for an extra potentiometer.

Thanks for the feedback!
 

 


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