Fender PA 100: Another Amp Restoration Project (Completed!)

[Don Mogle]

I need some advice from some of you electronics experts.

I have a chance to purchase this Fender PA 100 at a real good price. It's very clean, has a good history of gentle use, new preamp and power tubes, new filter caps replaced in the past few days, etc.

One potential red flag that I see is a possible issue with the power transformer. It has some kind of goo coming out of the top of the transformer. I'd like some opinions from you experts: is this a serious red flag and/or deal breaker? See pics...














Thanks!

Don

[Bob Sigafoos]

A few questions:
Is this "goo" sticky? "goo" could just be the laquer that the transformer innards are dipped in at the factory. Shouldn't be sticky tho.
Are the wires coming out of the two holes charred or just discolered?
Is fuse blown? If so could be blown power transformer. Would cost about $120 to buy a new one. I suggest testing voltages with a multimeter. Schematic should be on a web site somewhere.
If fuse is intact does turning on bypass switch light up the power lamp on front?
Photos dont suggest any fried resistors at power tubes.
Flip chassis over and look at large power caps and resistors under doghouse cover. Be VERY careful doing so. What do they look like?
The problem might not be the transformer but something else that took out the transformer such as a bad resistor or capacitor in the power area.

Just some thoughts, Let some of the amp tech guys on this forum chime in to. I'm just a builder hobbyist.

[Stephen Cowell]

In my experience they all do that... it's nothing to worry about. Make sure that the fuse is not way high, of course. The rest of the amp looks clean, go for it.

[Don Mogle]

Thanks Bob and Stephen!

The light on front works fine. I checked the fuse and it was correct value (3 amps) and looked good too. The seller let me bring it home and gave me a two-day money back guarantee. When I got it home, it made a lot of humming noise. I returned it for a full refund. I suspected the filter caps since they were original to the amp as shown below:





The pictures I posted earlier were sent to me by the seller at my request. I don't know if the substance is actually sticky...it was just my attempt to describe it.

The seller just replaced the filter caps. He said he was going to run it for a few days to insure there are no functional issues. It's now working fine...no obnoxious hum when the amp is turned on. Should be good to go. He found a broken wire on one of the orginal caps and feels it broke after putting the cover on the doghouse upon completing the pictures.



Here's his recent email to me:

Don,

I have finished the repair and everything works as it should. I'm going to run it for a few days this week to ensure that it is reliable and then send you a video. Look for that later in the week.

I used new OEM capacitors and resistors of the correct value, I tested each new component before installing. I double-checked each new solder joint for continuity and mechanical integrity. I added new foam risers to the underside of the doghouse to accommodate the smaller diameter of the new generation of capacitors, to ensure that vibrations would not damage the module over time.

A power-up test was successful, with no ac line noise and the amp is fully functional.

I'll be in touch soon with a full walkthrough of the amp on YouTube.

Thanks for your patience.

SL


Think I'll go green light and move forward on the purchase.

Thanks for responding!

[Bob Sigafoos]

I kind of thought the doghouse parts were suspect. Good for the seller for changing out the old parts. Now get a Iridium or Session 400 Preamp and you will be in business. I thought those PA's by Fender had reverb. Is there a reverb pan in the chassis? How much does this thing weigh? Cant be as much a Super Twin I once owned.

[Don Mogle]

Bob,

Yes, the seller is a stand-up guy who I'd gladly do business with again if the situation arises.

Reverb: Yes, this Fender PA 100 does have reverb! It's basically a Fender Twin Reverb power section with a different tone stack. I plan to rebuild the face of this amp to dress up the area where grille cloth use to be.



Tone Stacks: Tom Brumley cut Together Again with a vintage Fender Bassman amp, Lloyd Green cut the Sweethearts of the Rodeo albumn with a blackface Deluxe Reverb, and Live at Panther Hall with a blackface Twin Reverb with JBLs.

In time, I want to modify the amp something like this (taking inspiration from Ken Fox's previous modifications to another Fender PA 100):

Channel #1: Fender Twin Reverb AB 763 tone stack
Channel #2: Fender Deluxe Reverb AB 763 tone stack
Channel #3: Fender Bassman 100 tone stack (5F6? Silverface?)
Channel #4: Stock tone stack--no changes

Here's a previous post about this amp and some mods for consideration...

viewtopic.php?t=339653&highlight=fender++100

Weight: This amp is a beast, but then again, everything I have is heavy. I'm guessing it weighs in the neighborhood of 35-45 pounds. I might be able to decrease weight by putting a different back on the amp...something like a wire mesh so the tubes can breathe easier. Fortunately, this amp will not be gigged so weight is not an issue. It will reside in my music room or be on stage at church.



TC Furlong Sesh 400: I've been researching the Sesh 400 pedal and it sounds awesome with great reviews. However, would this end up turning a Fender into a Peavey? Or would it some kind of hybrid--a Peavender! The fact that I have other Peavey guitar amps (Special 130, Peavey Deuces, PA 400, Monitor amp) makes this pedal very attractive for getting the pristine sound of a classic steel amp. At a price of around $400 with taxes and shipping, I'm not ready to shell out the cash since there are other priorities. But who knows, maybe I can pick up one used here on the Forum someday.


Don

[Len Amaral]

I have had my PA-100 for quite some time and I enjoy the amp just as it is. I realize the tone stack is different but I get the clean Fender vibe and it takes pedals very well. The reverb is also killer.

[Don Mogle]

Thanks Lenny!

Yes, I know the existing tone stack is acceptable stock. I will probably just use it as-is for awhile. I do have an Analogman-modded Boss GE-7 on my pedalboard for tone sculpting.

However, having four channels make it tempting for experimenting with different tone stacks. I think Ken Fox would say “go for it!” I hope Ken will read this and comment on my plan for channels 1-3.

Lenny, I really like what you did with your PA 100 with matching speaker cabinet. Could you post another picture of it on this thread? I want rebuild the front face area of this amp with either grille cloth or tolex to dress it up…similar to yours. Thanks in advance.

Here's Lenny's previous post:

viewtopic.php?t=273882&highlight=fender++100

Don

[Bob Carlucci]

I had a few over the years.. Basically a Twin/Showman reverb with a different tonestack... It was fine for guitar and steel as is, but modding it to a proper Twin bass/treble/mid setup would be an improvement,,, OR, you could take a much easier course of action, and just use an EQ pedal.... bob

[Don Mogle]

Hey Bob...thanks for the input.

I have a Boss GE-7 on my pedalboard which should be able to do the job nicely. However, there are times when I like to adjust the sliders for a dobro effect. In these situations, it would be good to have the channel(s) modded.

[Don Mogle]

I'm going to be picking up this amp later this week. My plan is to work on the front of the amp and get it all cleaned and polished up as I do with all my amp restoration projects.

I'm kind of undecided how to dress it up. However, I found this previous post and really liked the facelift provided by the Fuch's mod. I think I might take a cue from this and workup my own take on it. Here's the post:

viewtopic.php?t=277632&highlight=fuchs+mod

Since I will be using some reconfigured Peavey cabinets from a Special 130, I might put some side strips on it to match. See pics to follow in next post...

[Don Mogle]

I'm going to be picking up this amp tomorrow. The seller just sent me this video showing its operation after replacing all the filter caps under the doghouse.

https://www.youtube.com/watch?v=WFFdr9dUBYg

I think it sounds great!

Here,s the facing option I'm considering. I've been kicking around a Vox/Dumble-vibe, while keeping the black/silver theme going. The side strips will be stock Peavey aluminum to match the repurposed Peavey amp cabinets. These side strips will also cover the gap left by the wire mesh screen on each side.




Face Restoration: Classic Black/Silver (cabinets loaded w/ 1201-8 Black Widows)






Thanks,

Don

[Len Amaral]

Hi Don:

Yes, I'm sure with the filter caps replaced the amp will respond the way it should. I am using my PA 100 with a Stereo Steel cab and a JBL K-130 4 ohm speaker.
The vibe is very enjoyable. I no longer have the cab I had made to fit the amp as I prefer a closed back cab.

[Don Mogle]

That's cool Lenny. That cab really looked good with it.

I brought this amp home and have been playing it a couple days. Man, this thing sounds awesome! There's just something special about these big-block Fenders. And this has it in spades. It's quiet too.

Since we've had over 100 degree days here for the last month, I don't know when I will get the face rebuilt. Maybe this winter it will cool off, but won't hold my breath.

[Len Amaral]

Don, since you started this topic I started using my PA-100 more often and positioned it to my #1 practice amp. I have amps up the wazoo but the PA-100 that I was using for guitar has that sound for pedal steel. If you are going to mod the amp, I would keep one channel just as it is and you have 3 others modify. Leo Fender is smiling down at us.

[Don Mogle]

Lenny,

Yes, I think the amp sounds great as it is. I discussed this amp with my local amp tech a few days ago. He recommended keeping it stock since it is already designed for ultra-clean, zero-coloration, PA applications. In other words, great for steel! What instrument sounds more human voice-like than a steel guitar?

Right now, the only mod I'm moving forward with is rebuilding the face. Man, I wish I knew where and/or how to source and/or make a blackface faceplate for this amp! (Calling David Biggers!!)

Someone should be able to keep these old Fender tube amps running for a very long time. As another amp tech told me several months ago, "I can always rebuild a tube amp!"

[Don Mogle]

Here is a quick mock-up of option #1. More work to be completed.

[Don Mogle]

Did some more work today. I think it turned out pretty well. This is my poor-man’s Little Walter system.







For the eagle eyed Forumites reading this, you'll notice the cabinets are not exactly the same. The one on the left has a Peavey 1201-8 ohm 12" speaker. The one on the right has an Alter 417 12" Alnico speaker which sounds especially SWEET! I have another Peavey 1201-8 cabinet combination hooked up to the PA 100 right now in my music room.

[Len Amaral]

Very Cool, an impressive-looking setup. Must have a sweet vibe. Congrats

[Larry Dering]

Looks awesome and no bet a sweet sounding rig. Excellent work on the front grill and appearance.

[Don Mogle]

Thanks guys!

[Stephen Cowell]

Now you gonna make me post my similar project... haven't even had the courage to power it up yet. The amp works, the cabinet works... I'll play them together tomorrow.

The cab was designed to go under the PA head, obviously... thanks to Will Dyke at Armadillo Amp Works for the construction. Note the baffle slant! The JBL F model is a recone (thanks Joe Long!).

[Don Mogle]

Looks great Stephen! Anxious to hear the results of its maiden voyage at your gig. Let me know how it all works out for you.

By the way, do you have a back panel for the PA 135?

[Don Mogle]

This morning I finished the back panel keeping the metal mesh theme on the backside.










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Both recent restorations at home in my music/steel room.








Thanks for watching!

[Larry Dering]

Looking good in your music room. I love the skate under the amp. I do the same thing to make moving easier. Great job Don.