Little tricks for getting what you want from Fender amps

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noisepunk
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Re: Little tricks for getting what you want from Fender amps

Post by noisepunk » Thu Jul 08, 2010 5:06 pm

:derp: :wacko: Yikes, I was hoping it would be more like "Yeah man, plug a 1/4th into X from Y and..." Should've figured I'd have to learn some basic amp knowledge though...

So I need some caps... and some balls... as I'd really like to do this, but if I somehow screw up my amp I'm going to kill myself...

I read through the thread, and your jargon seemed more manageable then their jargon, so I'm thinking I might try your second option (so long as you're relatively sure it won't hurt anything, as you can tell I'm super paranoid about doing anything to my amp), is there anyway I could have you make me up a labeled schematic? From what I know, it's a '77 ultra linear 135 Watt, but just to be safe the serial is A768166. I need to fix the bass knob (doesn't do anything) on the Vib. Side, and the Bright switches on both anyway, so this might be a good excuse to get in there and get my hands a little dirty.
They tried to give me advice, down at the record shop. I said "Sit down boys, this may come as a SHOCK. But alls I listen to, it's all freedom rock."

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Re: Little tricks for getting what you want from Fender amps

Post by øøøøøøø » Thu Jul 08, 2010 9:35 pm

Probably don't have time to make up a labeled schematic, sorry. Things have gotten a little busier for me than they were when I used to do shit like that on this forum a lot. :w00t:

But maybe this will help. A step-by-step.
  • 1) Get a 500pF silver mica cap.
    2) Locate V3. This will be the third tube from the right, looking at the back of the amp. This is your reverb driver tube and should be a 12AT7.
    3) Now locate pin 7 of this 12AT7. Many tube sockets have little numbers, but if not, this will help. There's an 'empty space' in the pins that serves to make sure you put the tube in the right way. Looking at the "solder side" of the tube socket, the pin clockwise of the gap is "pin 1" and the pin counterclockwise of it is "pin 9." Heaters connect to pins 4/5 (tied together) and 9. That should be more than enough info to help you locate pin 7.
    4) Attached to pin 7 is a wire. It goes into and under the eyelet board and eventually (invisibly) terminates at a junction between an existing 500pF capacitor and a 1M resistor. This point is "northeast" of where the wire goes under the board by a little bit, if you're looking into the chassis from the back. Make a note of this point. Call it "point A"
    5) Locate the "normal" channel's output. This will be a .047 cap, probably, very near the "right" (input jack) side of the eyelet board. It will likely be the fourth cap from the right. One side connects to pin 6 V1 and also to a 100k resistor that forms half of a "v-shaped pair" of 100k resistors. You want the other end-- which connects only to a wire that runs under the board. Call this point "point B"
    6) Solder your new 500pF cap between "point A" and "point B."
    7) Tell us how it works out, because I've never tried this exact mod before.
Caveat emptor-- the only Twin schematic I have in front of me is the AA270. I don't have a copy of the late '70s ultralinear model, so if that's what you have, it might be quite different. So if what I wrote above doesn't make any sense, you're either on your own, or link me to a good clean schematic of your amp and I can take another look.

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Re: Little tricks for getting what you want from Fender amps

Post by noisepunk » Fri Jul 09, 2010 8:57 pm

This'll probably be much more helpful once I actually have the parts and open up my amp. Thanks for the help, no worries on the schematic (I'll find one myself for when I need to fix the other real issues I listed and once again call upon the amp ninja for guidance) the things your busy with are probably way more important then me wanting verb on my normal channel.
They tried to give me advice, down at the record shop. I said "Sit down boys, this may come as a SHOCK. But alls I listen to, it's all freedom rock."

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Re: Little tricks for getting what you want from Fender amps

Post by username » Sun Oct 17, 2010 5:23 am

I don't have an Amp to try the mods :(, but thanks for the info!
One day... when I built a Champ I will come back to your mods :-)
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Re: Little tricks for getting what you want from Fender amps

Post by claytonjohn18 » Mon Jan 24, 2011 4:00 pm

This thread is amazing. I'm gonna go pull the V2 of my Bandmaster!

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Re: Little tricks for getting what you want from Fender amps

Post by Johnophean » Tue Feb 15, 2011 12:27 pm

Any way to make a RI Twin Reverb sound like a Deluxe Reverb????
The Twin Reverb makes fuzzes horribly fizzy and the Deluxe Reverb's seem to make em sing and be fat and toneful.
Can a Twin take 6V6's or perhaps even EL84's? Anyone ever do this or something like it to make the amp have less headroom and more Mid-MEAT to make Big Muff's etc sound mean and not fizzy and washy?
I guess the point is "more gain, less output". ;)
I've never been able to get the Twin over 2 or 3 MAX. without breaking windows or clipping mic's. :P
Well it does sound pretty good on 6-10
...well if you wanna go DEAF, get thrown off a stage, make your drummer break 2B sticks and you want to get the cops called on you when your at home. Yeah we don't want to be doing that...I want 2 to be the new 5 so to speak. ;D

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Re: Little tricks for getting what you want from Fender amps

Post by jjones » Thu Feb 17, 2011 4:02 am

Johnophean wrote:Any way to make a RI Twin Reverb sound like a Deluxe Reverb????
The Twin Reverb makes fuzzes horribly fizzy and the Deluxe Reverb's seem to make em sing and be fat and toneful.
Can a Twin take 6V6's or perhaps even EL84's? Anyone ever do this or something like it to make the amp have less headroom and more Mid-MEAT to make Big Muff's etc sound mean and not fizzy and washy?
I guess the point is "more gain, less output". ;)
I've never been able to get the Twin over 2 or 3 MAX. without breaking windows or clipping mic's. :P
Well it does sound pretty good on 6-10
...well if you wanna go DEAF, get thrown off a stage, make your drummer break 2B sticks and you want to get the cops called on you when your at home. Yeah we don't want to be doing that...I want 2 to be the new 5 so to speak. ;D
I would just sell the twin and get a deluxe if that is the sound you're after. No sense in having a super heavy amp when you desire the sound of a much lighter amp.

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Re: Little tricks for getting what you want from Fender amps

Post by Johnophean » Thu Feb 17, 2011 2:15 pm

;D My thoughts exactly since posting this. The Twin is just a sentimental piece of my gear, but not my main amp, so I think I am ready to part with it.
Went out the other day checking out a few low watt amps and actually found that the sound in my head is getting less Fender and more Vox. Tried 3 Deluxe's and an original 65 or 66. and...
The conclusion I came to was - a Vox AC15...weird...unexpected...but different and kind of exciting! :w00t:

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Re: Little tricks for getting what you want from Fender amps

Post by kimjongsick » Fri Feb 18, 2011 9:25 am

Vox has never done anything wrong except for make shitty standby switches.
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Re: Little tricks for getting what you want from Fender amps

Post by Johnophean » Fri Feb 18, 2011 8:49 pm

Only thing I'm weary about is the Top Boost and Normal channel being 2 separate inputs. Kinda weirded out by that.
Well see, I got my Twin Reverb for sale now so as soon as it's sold I'll have to decide if it's "the new amp" for me. =)

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Re: Little tricks for getting what you want from Fender amps

Post by willfulmurder » Sun Mar 06, 2011 10:10 pm

Thanks for a great post. Good information.

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Re: Little tricks for getting what you want from Fender amps

Post by johnnysomersett » Sun Mar 06, 2011 10:32 pm

I have a question/problem:

My '76 Twin Reverb (master volume, non-ultralinear), if you use the reverb, after about 10 minutes it suddenly SCREAMS.. like at TOP VOLUME (despite what the volume is actually set at). It's loud enough and high pitched enough to actually make you wanna run away and makes me shit myself its so loud.

I don't use the reverb much anyway as there's so damn much hiss on it anyway - another issue I need to rectify. Is the tube the culprit? is that 10 minutes enought to get it hot enough to scream? Is that why its so 'hissy' too?

Any ideas??!?

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Re: Little tricks for getting what you want from Fender amps

Post by kimjongsick » Sun Mar 06, 2011 10:58 pm

My uneducated assumption would be a tube that's gone microphonic.
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Re: Little tricks for getting what you want from Fender amps

Post by johnnysomersett » Mon Mar 07, 2011 10:43 am

kimjongsick wrote:My uneducated assumption would be a tube that's gone microphonic.
That was my assumption. I think it's the 3rd one in from the right, a 12at7, but reluctant to swap it for the only other 12at7 as im not sure what that one does LOL

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Re: Little tricks for getting what you want from Fender amps

Post by Johnophean » Tue Mar 08, 2011 8:52 am

I got the Vox AC15C1...like it alot...I'm now selling the Twin Reverb.
It's mint condition and hardly ever gets used anymore. Anyone interested lemme know. :)
http://www.offsetguitars.com/forums/vie ... 14&t=44566" onclick="window.open(this.href);return false;

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