Differences between input 1 and input 2 on tweed twin

[companydamned]

Was using my gibson R4 (p90's) into my Clark low-country 5E8A low power tweed twin replica today and was having trouble getting a tone I was 100% satisfied with. After messing with the EQ a bunch, I decided to try plugging into the #2 input on the normal channel vs. the #1 input of that same normal channel. Seeing as how they are both "normal" inputs, I wasn't expecting much, except maybe less volume. To my surprise, in addition to needing a bump on the volume knob to give the same volume as input 1, I also got a smoother, fatter, cleaner, and more "acoustic like" tone that I really dug. Compared to input 1, it didnt exhibit the farty kind of distortion that I believe is caused by the higher-output p90's overdriving the V1 preamp tube either. I've heard that the #2 inputs can be darker in tone for some reason, but that's not exactly how I would describe the change. There was the same mix of bass, mids and highs as with the #1 input, but it lacked a kind of spiky harshness that I was getting in input #1 but remained just as "bright," with what I thought was actually an increase in clarity (less harsh but more clarity? how does that work!?. Also, when cranking the amp up into distortion, it seemd to be thicker and smoother with less fizz and buzz.... Can you guys explain why it sounded better and had the differences I describe? Is the 2nd input more common to use with p90 guitars??? Thanks alot!

[I-IV-V]

I can't answer your question, and you may already know the info in the following link, but anyway, this thread explains the high and low inputs very well.

http://www.thegearpage.net/board/sho...ighlight=input

I don't think it will answer your question about the difference in tone, though.

[pdf64]

See Fig 14, about 3/4 of the way down here
http://buildyourguitar.com/resources/lemme/
you can see how as the load value decreases, so does the pickups resonant peak; you are comparing the 1M of input 1 to 136k of input 2, with the lower value giving more of a 'hifi' type response.

[tlpruitt]

The inputs work differently on a stock 5E8a compared to most other Fender amps with the two 68k and one 1M resistors. On the 5E8a input 1 has a 1M load to ground and input 2 has a 500k load to ground.

[companydamned]

so does that mean it doesn't end up being as dark or attenuated as the "traditional" input 2 with a 136K input impedence?

[tlpruitt]

Originally Posted by companydamned

so does that mean it doesn't end up being as dark or attenuated as the "traditional" input 2 with a 136K input impedence?

Generally yes.

[jay42]

What are your V1 and V2 tubes? I'm guessing 12ax7....s/b 12ay7 or 5751.

[companydamned]

the V1 and V2 preamp tubes are actually 12AY7's, as per original fender spec. I tried 12ax7's in their place but preferred the sound of the ay's. I'm also curious about the comment that Pdf64 made about the lower input impedence of input 2 giving a more hi-fi response. could someone elaborate on this further? I always thought a higher input impedence would yeild a brighter signal with more hi's and therfore be more 'hi fi', but if the opposite is true then this could explain the increase in clarity I'm hearing while at the same time being less "harsh." Thanks for the info guys, I really enjoy learning about this stuff and please bare with me as I truly am still learning

[Ronsonic]

Impedances aren't so much about "more or less" but about matching. In this instance, with your guitar and cable and guitar volume and tone control settings the #2 input seems to be a better match to your pickups.

With a lot of guitar / amp combinations there is an unpleasant bit of break up when you push that first tube a bit too hard. I hear it a lot myself with Gibson into Fender set ups.