First Guitar Amp Help

[Daveis]

Depends on level and settings, but where isnt distortion happening in the Champ?

I was thinking that maybe at least the first half of the 12AX7 was just for gain. I was wondering if the distortion happened in the second half of the 12AX7 or the following stage. Now this may sound wrong, but if the first stage truly is just for gain then could it be replaced with JFET's?

I'm kind of wondering if there's anything you could do in that first stage that would get the voltage level of the guitar up with the least amount of noise pickup.

 

[noisenyc]

the most prominent distortion is the output stage clipping. in these low wattage SE amps, it is considered desirable by guitar players

 

[Daveis]

Is power stage clipping more desireable than 12AX7's clipping?

I seem to remember another amp that had 4 stages of 12AX7. It's distortion was very heavy and buzzy. I actually preferred a tube screamer to it.

 

[dsavitsk]

do yourself a favor and buy carbon comp resistors from mouser, at least for the high voltage plate loads. don't go above 20mf each for the PS caps and use low-end electrolytics.

That is certainly going to make this cheaper. You prefer these to ABs or Rikens?

thoses eminence speakers are quite good and not expensive. i have tried them all and found a few that are great for specific sounds...theere is quite a range of choices. too many actually.

what size speaker are you going with?

I was looking at one of those Jensen "Vintage" 8" speakers -- I found one for $27 or something. For the eminence speakers, they have a chart on their website detailing the character of the various speakers. In your experience, are these pretty accurate? Any specific speakers you like for this style of amp?

I have not played in years, so I am very excited to get back in to this. I have a mid 70's Les Paul Custom that I bought for almost nothing literally a month before Appetite for Destruction came out, so any amp suggestions to pair with that particuar guitar would also be helpful.

-d

 

[Tweeker]

Now this may sound wrong, but if the first stage truly is just for gain then could it be replaced with JFETs?

You might need to redo the tone stack too, and it may sound different. 12ax7s even when not overdriven have some distortion.

The second 12ax7 being overdriven gives a different sound than the power tube distortion and/or both distorting. This is where the settings comment came in. You cant get certain sounds with just preamp distortion, but both may be needed for the particular tone your after.

it worked great. the guitar basically ignored cable issues and sounded the same at all volume settings, rather than rolled-off in the treble at lower settings as you would expect. only problem - too aggressively bright

Sometimes people will bypass the onboard pots with a small silver mica to mitigate the treble loss at lower settings.

do yourself a favor and buy carbon comp resistors from mouser, at least for the high voltage plate loads.

The carbon comps with lots of voltage across them, as in plate loads, add more distortion. Its part of the vintage tone. I wouldnt go high end here if your after distortion. If you dont want this distortion and noise, use NI wirewounds for resistors between ~8k-100k. Allen Bradleys are carbon comp, Rikkens are carbon film, which is not quite the same.

 

[noisenyc]

That is certainly going to make this cheaper. You prefer these to ABs or Rikens?-d

not for everything. but for a guitar amp, the xicons are fine.

the eminence descriptions are kinda hypey. hard to put a finger on...

for 8's the jensens vintage are ok and the jensen alnico p8r's awesome. eminence has nothing too good in this size...