Amp Reassignment Surgery - 60s Lafayette PA Thinks it's a Marshall 2204 

Forgot to mention... Marshall and Fender schematics used in this video came from the Tube Amp Book. I have an early edition, but the later editions are nicer. Good book to own for most common schematics: amzn.to/2DYyFv0

It's about time Brad!!!! Re-purposing old PA and Hi-Fi amps for guitar is what originally brought me to your channel. I hope to see more in the future. Great work.

Nice Roadstar II and great video, as always. Those era Ibanez guitars will always be worth every cent anybody paid for them.

Lafayette Electronics - a blast from the past!

Wow Brad that PA turned out great! I usually just gut the entire pre-amp, and then copy an existing design of an amp I know I like. You took what was there and made changes until it sounded like you wanted, a much more daunting challenge. Bravo, well done Take care, Tom

Nothing says "skill" like this video. Truly impressive when you can design a circuit that predicts tones when "improvising" like you were. I only wish I could do some like that. The interaction with the family solidifies my opinion of you as an individual. Keep on doing what so few can do!

To my ears, this amp sounds as good as any i've ever heard (for the type of tone amp i like to play through). Killer tone. Nice noodling to.. good pickin' and good finger tone.

Hey man! Just wanted to congratulate you on your channel! It is truly a very informative and super interesting channel to watch! I'm a guitar player myself and an electronic engineering minor, so I find your videos super cool, and can't stop watching them. I also love the way you go about "troubleshooting" these pieces of equipment, very logical, no non-sense and to the point, with some great electronic tips and tricks to go along with it! Thank you so much and keep doing what you do!

Wow your final result is amazing! It sounded choked at the first stage but you really opened it up to breath. Nice!

Where did you find that banner Brad ? That’s so cool, RCA all the way. If that doesn’t get a thumbs up nothing will. Great video Brad keep them coming.

Awesome video Brad, I always love the long videos. I can sink my teeth into it, and enjoy the process. Cheers.

1 AM? You, Brad, are one hard working dude.

That thing sounds amazing! you did as such a fantastic job it's inspirational thanks for helping us all learn how to do these things

Wow, what a beautiful, spotlessly clean chassis underneath; looks fresh from the factory floor! I love beautiful, clean design, especially on tube equipment!

DAMN, that sounds good!!! I remember ordering Lafayette catalogs when i was a kid, pretty much when this amp was made. Never seen anything in person since then. Freakin' lucky so and so who got this and found you to Fire It Up!!

Yes you nailed it again Brad, just awesome 👍

There were several parts of this one I didn't quite understand Brad but this was really outstanding and I'd love to have one. I just can't believe the sounds you are able to get out of this but like I said, you got into some repair areas I don't remember you talking about before but I've picked up some books and picking up a lot. Really enjoyed this video and the final sounds of the amplifier. Amazing what you can do with a 60's PA head! (That was cute with your daughter at the end of the video)

Awoke this morning to ANOTHER demonetized video. They are doing it to every single one now. And they're throttling them as well. I can see the stats where they only do x suggested videos per hour, and it's capped like a plateau. I hate RU-vid more and more each day. They are about to break me, I hate to say.

The best part for me was seeing your smile when you saw your daughter.

My father just built 3 of these and I'm currently testing an older model 645A and it's the dog's balls. Just a fantastic, organic, warm and round tone. Loves pedals. Running through an older 80's slant front 2x12 Marshall cab (from the Mosfet days) with 35 watt Celestions and I'm LOVING it!! Lightweight and loud. Great gigging amp.

I have redone 4 of these and they do rock the house, they make awesome rocking amps with minimal work , keep building, love been hooked for years

I loved Lafayette stores and the equipment was really good. I grew up in Canada and they did not sell it there.

Super Vid..!! Great modifications to the Lafayette...kind of Sounds like my 1963 Bassman

You always pull off crazy shit... like not using that Bertha iron for the chassis soldering. Just knowing that the shop speaker is laying down on a stool. Terrific playing as always inspired by Hoegaarden 40:53 Greeting from Hoegaarden in Belgium!

That turned out great. What a versatile amp.

Dig the 'Initech' mug...nice work on the amp too!!

Awesome job Brad !!! Sounds Great !!

Your a real badass on that guitar bud! Great video and even better picking!

Nice video. This gives a new meaning to the "la - Mar" conversion, and it's even a little bit Fendericky.

I’d forgotten how far out of the fingerboard the trussrod extended on those Roadstar II’s. Looks like about an ‘85 to me. My first electric was a RS-II ‘84 strat copy bought and paid for with my first cheque from my first job ($280 CAN)... :) 46 Guitars later and I’m still a huge Ibanez guy... :) Great Vid!!

Thanks for keeping me entertained while I deal with the flu!

OMG you got a KORG NUTUBE DIDN'T YOU? excited for the video!

The Treble Bass Middle layout isn't unheard of, it's that way on the best guitar amp ever made! The 1986 actually has half the bias resistor and twice the bias resistor of a 5F6 input stage. Either way it's more gain for certain frequencies. The mishmash Fender/Marshall amps I've built have been the favorite amps of their owners. The 6V6 15 to 20 watt type have been very popular in SoCal. I can't take credit for the 6V6 2204, Doug Hoffman has a great design on his website that kills! There's a few of mine down here you might hear in Hollywood venues ; )

thanks,that is one heck of a do all amp mod,sound great here.!

Superb job on that one....and superb playing too. Jeez!

Cool amp NOW. GREAT JOB like always, Alfred NYC/PR

Another great sounding amp Brad!

LOVE the RCA banner. !

Nice work, and awesome RCA banner.

i donno if i'm drunk or the marshal sound had more depth... but i know what i see. top job fella.

Nice mod. Like them old amps back in the day they sold as kits you could build and learn electronics

I think your wife has a negative feedback issue.

I had a Bogen for an amp as a teenager. The look and name of this amp makes it very cool cosmetically.

I still love you! And learn a lot. Thanks

Sounds awesome Brad!! I like the re-purposing amp videos you do.. I like the idea period of odd ball looking pedals and amps.. Looks like a P.A. roars like a Marshall !! Going to a gig and plugging into something that looks like VCR but sounds beastly the looks you get is PRICELESS!! Lol .. I've used some odd ball looking pedals before at a gig and as soon as i kicked the pedal in afterwards i get asked what was that..??

That packing job was overkill....but much better than receiving broken up stuff.

After seeing what you done to this PA, makes me want to experiment with my Montgomery ward airline tube amp

My 1kW Variac came in a plane white factory box which was padded with styrofoam but was apparently dropped on one corner, and the extra fuse rattling around in the bottom. With the weight of the thing I was lucky that it survived.

I bet ya Korg sent you a bunch of those nuTubes to play with, can’t wait to see what you build with them.

Hello from Hazard Ky, Brad! Really enjoy your content.

That turned out well, it sounds pretty good.

You took it for zero to hero. That's one I'd own.

Well done, nice conversion. Sounds good.

hey man, i reallllly loved that playing you were doing around 41:15 or so. very flamenco sounding. could you say where you got that vibe of playing from? i'd love to hear more of it and to know what other artists to check out like that. cheers and mad love for your channel.

Nice work turned out great !!

The old Weller/Ungar screw-in heater irons work very well for chassis soldering.

We had a Lafayette store in North Olmsted, Ohio, in the '70s-spent a lot of time and money there-lol!

That turned out quite musical. That Ibanez is a sleeper!

I liked the fender sound nice playing btw. my 2nd guitar was Ibanez Roadster it wasn't as nice as yours tho. great job on the amp I don't what you did to the dirty chn but wow you will have a happy customer.

Negative feedback - from the wife! Oh Lord.. I remember those days..

I'm pretty sure that chassis and output tube slanted socket area are aluminum. The leads that were soldered (for the first time) are touching the chassis but solder will not stick to aluminum so may need to tie those to the chassis with a bolt or run a wire...

Oh CRAP that thing sounds good.

Hard to beat. Thanks Sir.

I would clean out the solder splodge / drip you made + clean off the solder flash that is sitting on the wire below your soldering. before switching anything on.

I feel sorry for your daughter when she gets older, all her boyfriends are gonna want to hang out with you making noise.

Love your vids Brad.

As Skynyrd would say, TURN IT UP!

Another great video

”hey im brad and im just a casual shredder“

Wow. It went from shite to spanking right. I think I want one lmao. This thing kicks ass.

That's A Killer Amp Great Mods!!!!

Outstanding

When you say demonetized, I'm unclear. I admit I am not up to speed on you tube, only a user. I'm assuming they decided this vid will not make you any money through advertisers? I'll look up the meaning, I'm sure theres a lot out there about this and what it means but I'm really interested in why its happening. Have they come forward to you to explain exactly why? Then again, I'm also guessing discussing policy on here is against... policy??? Sorry man. I'm a huge fan, as I'm an old guitarist still learning and discovering, now wanting to learn circuit analysis to work on my vintage amps, and really dig your posts, so I can understand the process a bit more....your a big help to people like us.. I also know it takes a freakin huge amount of time to do these vids, and as a working guy, time is never in abundance.. hell in my case, its non-existent. Thanks buddy.

The '70' and '25' lugs on the terminal strip are for 70 and 25 volt, respectively, distributed audio, commonly used in institutional and industrial applications...along with some churches on a budget. The output of the power amp is tied to an autotransformer, then each speaker has a corresponding transformer, with taps labeled 1/2-watt, 1-watt, etc. In theory, therefore, such an amp, if rated, for instance, at 100 watts, could handle 200 transformer-isolated speakers, tapped at 1/2-watt (although, in practice, you never loaded an amp to more than 80% capacity). The jumper tied to the 4-ohm lug was often set up that way to enable the 25-volt output of the autotransformer. Disconnecting it would allow you to connect a 4-ohm load, or use the 70-volt output. The fact that it was connected probably means that the amp was being used either as part of a school intercom system or the page circuit of a fire alarm system, bot of which typically used the 25-volt circuit...that allowed connection of 8 times as many speakers. The entire science is WAY too long to post here!! This is the stuff i worked with (along with 'Pro' audio, and a number of other low-voltage systems, for over 40 years...including stints with NSCA and Lincoln Tech, as an instructor.

Lol, I certainly feel sorry for then next tech that gets ahold of this amp. He's gonna think Gene wilder went nuts. No pun intended ! great damn work dude!

Well I don't think I'm dense but "political content"?... I don't think so... just great instructive videos for those of us who want to LEARN somethin' and really appreciate the way our Brad spells it out. Just because the Guitologist has some style doesn't make him a something wing radical... hello? Thanx for another great vid, Brad and many happy reruns! cheers

Sounds like a great rockin marshall to my ears. The only downfall for me would be no reverb circuit.

Good job sounds great .

Can you do a video comparing a new tube amp to a vintage amp? Pros and Cons of each

ive watched like alot of your vids, i dont know like 50% of whats going on, but fuck is it interesting. makes me want to try it, but i think im too lazy to research what a capacitor and resister do. keep up the great vids dude. =]

Enjoy your videos. How about making a basic knowledge tutorial for those of us who only understand a portion of what you do? Perhaps explain what exactly resistors, caps and transistors do? Sort of a beginners class for your less knowledgeable fans? Thank you

The only thing that'd be better is ha e that thing foot switchable, but that's a lot more work. Another tone stack and all kinds of fun stuff. If it was my amp I'd pay for that to be done for sure.

It's starting to piss her off which means it's badass-bahahahahaha, I about fell over laughing. Geat video!

Fourth guitar from the left. Is that a Secova Bison? That was the model of my first electric guitar my folks bought me for Christmas when I was 14.

That is an awesome amp. If you could replicate that in a simple 20 watt head for a reasonable price, I think you could sell a lot of them.

I keep saying this a golden opportunity moment for someone to start alternates to facebook, google and youtube.

The old center -tap to a common ground point, and those transformer wires look rough?

If that 6AV6 tube was changed to a 12AX7, the amp could be re-wired so that it was a JTM45.

Trying this out at one is a shure way to get single

Have you tried gas operated soldering irons? Works like charm! I'd buy one immediately if I had more soldering work than once a year.

Well for me it was an awesome video bro. All the best and sad ewetoob has gone this way

Lafayette made some great equipment and thier store was great as well. Too bad Radio Shack bought them out.

it reminds me of a Bogen PA amp. only up to 4:48 of this vid.

@ :40 seconds I'm guessing a Korg Noise-gate from the 80's???

Looks like it got warmer all right looks like it was Blazing

Yo Brad, @ 21'30", the soldering of the cathodes, maybe that tab is aluminium? It looked like it took a long time to get a good bond? Nice video thank you.

Add 100K's across the bypass caps and it will eliminate the switch popping

I have a 1973-74 traynor YGM-4 Studio mate that needs looked at. May need rejuvenated. I am the original owner bought in 1974 out of high school. From a high school friend who started a music store.Can you help?

Kind of sounded like "You think you're tough" by Ratt 48:28

Yes indeed that is why you would want to make the effort to repair a Marshall amplifier. Dodgy amps from Britain that make fantastic sounds.