Fender PA100 Amp Service & Restoration - Pt. 1 | Overview, 3 prong power cord

[@jonathanhorne6503]

It’s been well over a decade, nearer to two since I’ve owned and modded one of these. As I remember, I’m 70+ so it’s fading a bit, the tone stacks were HiFi, 12 o’clock was basically neutral. It needs to be changed to more friendly tone controls. Secondly, the kathode resistor for the four channels (V1AB&V2AB)are shared by one 270Ω resistor and cap. I suggest you seperate those with individual RCs to ground. It’s a chance to easily voice each channel differently. I made one channel a fender, one Vox, one Marshall and one Valvo. If you want to give up a channel make one an EF86 pentode channel. That was my next planned mod but I gave the amp away so some Jr High age garage band could use it. It was a massively loud amp and didn’t fit my then current playing style.

[@jamesbracken4618]

Put a 65 Champ tone circuit in channel 1 and a 65 super reverb circuit in channel 2. Slightly different. No need for a middle tone control, they just suck. You could add a bright cap and switch if you want. It dosent need it.. Good job.

[@ARONHALLAM]

I have one of these unmodded it's a bit lower mid-dy as it is for guitar. That sounds like a good idea

[@jamesbracken4618]

I've been doing the same thing as you for the past 15 years, bought a Webster Ekotape reel to reel with a tube amp inside, it had a 6v6, 2 of a 6av6, a 6aq5, and a 5y3 rectifier. The same as a Champ, so i gutted the tape recorder components and built a Champ using the 2 6av6s, 6v6, and 5y3. It sounds as good as my 1976 Vibro Champ without the Vibro. I bought the reel to reel for 45.00 bucks. since then I've bought 10 of them for as low as 15.00. They are cheap if you find the right seller. GOD BLESS YOU AND YOU FAMILY GOD BLESS AMERICA!! GLORY BE TO GOD!!! IN JESUS NAME I PREY!!!!!!!

[@Zelleram55]

You are correct the stiff HiFi sound comes from the 4 tone stacks. I have one of these I picked up for $400. I changed channel 1 to Deluxe Reverb tone stack, channel 1 input jack resistors to standard Fender Values, I separated the pre amp cathode by pass caps to each have their own 25/25 cap, and lastly I added 3 prong cord, eliminating the Death cap, this freed up the ground switch, so I made the ground switch an on/off negative feedback switch. OMG this thing sings now. Big beautifully clean and takes pedals well. I left channel 2,3,4 stock, so if you turn the negative feedback switch to On and plug into channel 2,3, or 4 it is still the original sound of the amp.

[@leiferickson3183]

The chinese 12axt's usually had that sticker on them, at least through the 90's and early 2000's. The PA100 is an amp that whenever I had one I didnt want it and whenever I didnt have one I wanted one - haha. Those transformers are normal sized for a Twin Reverb. The power transformer is likely the same part.

[@geezberry8889]

i'm in the process of converting this into a 4-channel head. i'll be using some relays and will have clean,vox,marshall,slo channels. front panel is perfect for this each channel has pre,master,treble,middle,bass

[@ARONHALLAM]

THe reverb comes from pre amp valve number 5 doesn't it?

[@fiddlix]

Great overview of a very misunderstood amplifier. Looking at the condition of the main filter supply, I would advise to leave them in. Unless he or she is out gigging constantly. Then I would advise to replace them.

[@jamesbracken4618]

Don't sand over you amp. Sand particles will fall in it.